Disease Activity in Patients With Takayasu's Arteritis: Evaluation of 18f-fdg Pet/ct and Angiotomography Performances

Disease Activity in Patients With Takayasu's Arteritis: Evaluation of 18f-fdg Pet/ct and Angiotomography Performances | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Disease Activity in Patients With Takayasu's Arteritis: Evaluation of 18f-fdg Pet/ct and Angiotomography Performances Fabrícia Fonseca Simil, Marcelo Mamede, Raul Silva Filho, Gustavo Gomes Resende, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7715443/v1 This work is licensed under a CC BY 4.0 License Status: Under Revision Version 1 posted 9 You are reading this latest preprint version Abstract Objective To evaluate the performance of 18F-FDG PET/CT in assessing disease activity in patients with Takayasu arteritis (TA), by comparing 18F-FDG PET/CT findings with clinical and laboratory parameters, as well as vascular alterations observed on angiotomography (CTA). Methods In this cross-sectional study, 19 patients with TA were evaluated for clinical, laboratory and imaging activity (CTA and 18F-FDG PET/CT). Vascular activity on CTA was defined by the presence of vessel wall thickening and/or double-ring signs. PET vascular activity score (PETVAS) and maximum standardized uptake value (SUVmax) were used to assess ¹⁸F-FDG PET/CT activity. Results Patients with clinical activity demonstrated greater aortic wall thickening compared to those in remission [median (range): 2.9 mm (0–6) vs. 0 mm (0–5.5); p = 0.02]. In contrast, no significant difference was observed in vessel wall thickening of the aortic branches. Aortic wall thickening greater than or equal to 3.3 mm showed a sensitivity of 45% and specificity of 86% to predict disease activity. No significant differences in SUVmax values and PETVAS scores were observed between patients with active disease and those in remission. Vessel wall thickening values on CTA [median, min. and max. 1.8 (0–6) mm vs. 0 (0-5.3) mm, p = 0.013] were significantly higher in patients with an 18F-FDG PET/CT uptake score ≥ 2. Conclusion The 18F-FDG PET/CT did not demonstrate good performance in assessing disease activity based on clinical criteria, but showed association with vessel wall thickening on CTA, which appears to be a useful marker for disease activity in the aorta. Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 INTRODUCTION Takayasu arteritis (TA) is a rare, chronic granulomatous vasculitis primarily affecting the aorta and its major branches. The clinical course in most patients is characterized by periods of relapse and remission, leading to the cumulative development of permanent and severe vascular damage ( 1 – 3 ). Identifying and monitoring disease activity in patients with TA poses a significant challenge, as inflammatory changes in the vessels correlate with clinical and laboratory criteria in only approximately 50% of cases ( 3 ). Currently, there is no specific biomarker available for the diagnosis and monitoring of disease activity in patients with TA. Some studies [GF1] have indicated an association between edema of the vascular wall and contrast enhancement observed on Gadolinium-enhanced Magnetic Resonance Imaging (MRI) with disease activity ( 4 – 6 ). Conversely, other studies have failed to identify significant differences in MRI findings between active and remissive phases of the disease ( 5 , 6 ). Research has shown that arterial wall thickening, as detected by MRI, may also be present during the vascular remodeling phase ( 7 , 8 ). Computed tomography angiography (CTA), in addition to assessing arterial lesions such as stenosis and aneurysm, also allows for the evaluation of vessel wall thickness and the double halo sign, which are suggestive of inflammatory activity. However, limited research has investigated the utility of this modality in patients with TA ( 9 – 11 ). Despite its low sensitivity, the double halo sign has demonstrated high specificity for identifying active disease ( 12 , 13 ). Positron emission tomography using 18F-Fluorodeoxyglucose in conjunction with computed tomography (18F-FDG PET/CT) can provide whole-body imaging, including the assessment of radiotracer uptake in large vessels. Several studies have proposed that this method may play a crucial role in the management of patients with large vessel vasculitis, particularly for the evaluation of inflammatory activity ( 11 – 14 ). However, the activity assessment criteria frequently used as a reference for comparison with 18F-FDG PET/CT are those established by the National Institutes of Health (NIH) ( 2 , 15 – 19 ), which have demonstrated low sensitivity. The PET Vascular Activity Score (PETVAS) was recently developed to standardize the assessment of 18F-FDG PET/CT activity. This scoring system compares the intensity of radiotracer uptake in the vascular wall of nine distinct arterial territories with that of the liver ( 12 – 14 ). Given the discrepancies in the imaging assessment of large vessel vasculitis, a notable gap exists in the evidence regarding the optimal imaging modality for monitoring disease activity. The primary objective of this study was to analyze the performance of 18F-FDG PET/CT in assessing disease activity in patients with TA, by comparing PET/CT findings with clinical and laboratory variables, as well as vascular alterations observed on CTA. PATIENTS AND METHODS Study Population Between January 2015 and January 2018, patients older than 18 years of age who met the classification criteria for TA established by the American College of Rheumatology (ACR) ( 15 ) were invited to participate in the study. All patients were under regular follow-up at the Outpatient Rheumatology Clinic of Hospital das Clínicas, Universidade Federal de Minas Gerais (UFMG). Prior to inclusion, all participants provided written informed consent. The study received approval from the Research Ethics Committee of UFMG (32148014.0.0000.5149), and was concduted in adherence to the Declaration of Helsinki. Patients who were pregnant, had decompensated diabetes mellitus, contraindications for iodinated contrast administration, a history of neoplasia within the preceding five years, acute infection within the last month, or chronic infection within the last year were excluded from the study . Clinical and Laboratory Data Demographic, clinical, and treatment data were collected during routine consultations by an experienced physician specializing in the management of TA patients, and through a review of medical records. All patients underwent evaluation for the extent of their disease and the presence of complications such as aneurysms, dilations, narrowing, and vascular occlusion, utilizing clinical examination, angiographic classification, and previously performed imaging modalities such as arterial duplex ultrasound, CTA, and MRI. Physician-determined disease activity status was based on clinical history, physical examination, and laboratory assessments. 1) Clinical activity was defined by the appearance or exacerbation of one or more of the following criteria, after excluding other potential causes of the symptoms such as infections and allergies: A) Objective systemic manifestations: fever, dyspnea, chest pain. Fatigue alone was not considered a criterion for clinical activity. B) Manifestations of vascular ischemia or inflammation. 2) Laboratory activity was defined by an increase in the values of acute phase reactants (erythrocyte sedimentation rate (ESR) ≥ 20 mm/h and/or C-reactive protein (CRP) ≥ 10 mg/L) without the presence of systemic manifestations or vascular ischemia. Other potential causes of elevated acute phase reactants, such as infections and allergies, were excluded. The reference ranges defined for ESR were 0 to 20 mm/hour, and for CRP were 0 to 10 mg/liter. Patients were classified into the following categories: 1) Clinical activity: presence of one or more clinical criteria with or without elevated acute phase reactants; 2) Laboratory activity: presence of only laboratory criteria; 3) Remission: absence of any clinical symptoms attributable to vasculitis and acute phase reactants within the reference ranges. The extent of vascular involvement was assessed according to the classification criteria proposed by Hata et al. ( 16 ). The Takayasu Arteritis Damage Score (TADS) index was utilized to quantify the cumulative damage resulting from TA and treatment-related complications ( 17 ). Image Acquisition and Analysis of 18F-FDG PET/CT and CTA Radiologic inflammatory activity in patients was assessed using 18F-FDG PET/CT. Following a fasting period of at least 6 hours, patients received an intravenous administration of 18F-FDG (3.7 MBq/kg). One hour post-administration, a whole-body PET/CT scan was performed using a Discovery PET/CT 600 system (GE Healthcare, Milwaukee, USA). A low-dose computed tomography scan was initially acquired without contrast enhancement and was used for attenuation correction and anatomical image fusion. PET images were reconstructed in a 192 x 192 matrix using an algorithm similar to the ordered subset expectation maximization (OSEM), with 2 iterations and 24 subsets. The 18F-FDG uptake was measured semi-quantitatively as the maximum standardized uptake value (SUVmax), corrected for lean body mass (LBM), using a dedicated PET/CT workstation (AW 4, GE Healthcare). Concurrently, patients underwent CTA of the thoracic and abdominal aorta, including their branches. The CTA analysis encompassed 16 regions: aortic arch, ascending aorta, right and left common carotid arteries, right and left subclavian arteries, brachiocephalic trunk, descending thoracic aorta, celiac trunk, superior and inferior mesenteric arteries, right and left renal arteries, and right and left iliac arteries. Two independent physicians, one specializing in nuclear medicine and the other in radiology, analyzed the images in a blinded manner with respect to the patients' clinical and laboratory parameters. One of the evaluators possessed expertise in vascular imaging. In cases of disagreement, a final interpretation was reached by consensus between the two physicians (kappa value of 1.0 was obtained). Visual analysis of 18F-FDG PET/CT images was performed in 9 regions, according to the PETVAS protocol: ascending aorta, aortic arch, descending thoracic aorta, abdominal aorta, right carotid artery, left carotid artery, innominate artery, right subclavian artery, left subclavian artery ( 12 ). Two parameters were used to evaluate the 18F-FDG PET/CT images: a visual uptake intensity scale and the SUVmax. The visual uptake intensity scale was defined as follows: Grade 0 – no uptake or vascular uptake less than the liver; Grade 1 – vascular uptake less than the liver; Grade 2 – vascular uptake equal to the liver; Grade 3 – vascular uptake greater than the liver. Patients with an uptake grade of 2 or higher were classified as having vascular activity on the 18F-FDG PET/CT ( 12 – 14 , 20 ). The SUV intensity analysis, calculated as the ratio of the SUVmax of a vascular region of interest (ROI) to the SUVmax of the liver, was performed to minimize the influence of the time interval between radioisotope injection and image acquisition, and to reduce the confounding effects of serum glucose levels. In the CTA evaluation, alterations indicative of vascular activity, such as thickening of the arterial wall and the double halo sign, have been described. The double halo sign represents a delayed pattern of vascular contrast uptake, demonstrating contrast enhancement in both the adventitial and intimal layers of the vessels ( 9 – 11 ). Vascular activity on CTA was considered positive for images showing thickening greater than or equal to 2 mm in large vessels (i.e., abdominal and thoracic aorta) and/or greater than or equal to 1 mm in their branches ( 9 – 10 ). Disease activity was assessed on the same day as the 18F-FDG PET/CT and CTA examinations. Statistical Analysis The Minitab (version 17) and IBM SPSS Statistics (Statistical Package for Social Sciences, Version for Windows SPSS Inc., Chicago, IL, USA), version 22.0, software programs were used for data analysis. The Shapiro-Wilk test was used to assess the normality of continuous variables. Categorical data are presented as total numbers and percentages, while numerical data are presented as means or medians. Correlation analyses of numerical variables were performed using the Spearman test. Comparisons of numerical variables between groups were made using the Mann-Whitney U test or the Student's t-test for multiple groups. The presence of active disease in TA, as determined by a defined SUVmax cut-off point, was compared with disease activity as determined by clinical-laboratory evaluation using Fisher's exact test. The following accuracy measures, along with their respective 95% confidence intervals, were calculated for vessel wall thickening values: sensitivity, specificity, positive predictive value, and negative predictive value. RESULTS Patient Characteristics Nineteen patients with TA were selected for the study. Demographic, clinical, laboratory, and treatment data are detailed in Table 1. Table 1 Demographic, clinical, and treatment characteristics of the Takayasu's arteritis patients. Variables n (%) Mean (SD) Median (95%CI) Demographic Age (years) 38 (8.3) Age at diagnosis of TA (years) 27 (8.7) Female sex 18 (95.0) White 12 (63.2) Non-white 7 (36.8) Clinical Mean (SD) Disease duration (years) 11.5 (6.1) Clinical /laboratory disease activity 11 (57,9) Disease in remission 8 (42.1) Laboratory Median (min-max) ESR (mm/hora) 12.0 (2–56) CRP (mg/L) 9.0 (2–86) TADS damage score # 4.0 ( 1 – 4 ) Prednisone 13 (68.4) Daily dose of prednisone (mg) 10.0 (0–80) Synthetic immunosuppressant Methotrexate 9 (47.4) Leflunomide 1 (5.3) Azathioprine 2 (10.5) Infliximab 1 (5.3) Tocilizumab 2 (10.5) ASA 19 (100.0) Note: TA: Takayasu arteritis; CRP: C-reactive protein; ESR: erythrocyte sedimentation rate; AAS: acetyl salicylic acid; #: Takayasu Arteritis Damage Score; n: sample size; SD: Standard Deviation; 95% CI: 95% confidence interval. At the time of data collection, 5 (26.3%) patients were classified as having clinical activity, 7 (36.8%) were in remission, and 7 (36.8%) presented with only laboratory abnormalities. Regarding the extent of disease, the majority of patients exhibited vascular involvement type V (8; 42.1%), followed by type IIa (6; 31.6%) and type IIb (3; 15.8%). During the period between the diagnosis of Takayasu arteritis and the date of inclusion in the study, 10 (52.6%) patients experienced disease relapses. CRP values [median, min. and max. 12.2 (5–86) mg/L vs. 5 ( 2 – 9 ) mg/L, p = 0.04] were significantly higher in patients with clinical activity compared to patients in remission, after excluding patients with exclusively laboratory abnormalities. No significant difference was observed in ESR values [median, min. and max. 20 (3–52) mm/h vs. 10 ( 2 – 12 ) mm/h, p = 0.06] between patients with clinical activity and those in remission. Data pertaining to disease activity, laboratory values, and imaging tests of the study population are presented suplementary material.(Supplement 1) Angiotomography Eighteen patients (94.7%) exhibited alterations indicative of vascular activity on CTA, characterized by thickening of the vessel wall and/or the double halo sign, primarily affecting the ascending aorta, aortic arch, and descending aorta. CTA examinations revealed vessel wall thickening in five (100%) patients with clinical activity. Of the total of 7 patients in remission, all demonstrated vessel wall thickening on CTA. Patients with clinical activity showed greater aortic wall thickening (ascending, aortic arch, descending, and abdominal) compared to patients in remission [median, min. and max. 2.9 (0–6) mm vs. 0 (0-5.5) mm, p = 0.02]. In the analysis of aortic branches, no significant difference was found in vessel wall thickening between patients with clinical activity and those in remission [median, min. and max. 0 (0–3) mm vs. 0 (0–5) mm, p = 0.98] (Fig. 1 A and B). The double ring sign was identified in one (20%) of the 5 patients with clinical activity and was not observed in 5 (71.4%) of the 7 patients in remission. Patients exhibiting the double ring sign on CTA had a shorter disease duration compared to those without this vascular alteration [median, 7.5 (range, 2–22) years vs. 13.4 (range, 5–19) years, p = 0.04]. 18F-FDG PET/CT Based on the visual scale, two (10.5%) patients were classified as grade one, 11 (57.9%) as grade two, and six (31.6%) as grade three. The median of the highest SUVmax value in the studied population was 5.6, with a range of 4.5 to 8.3. 18F-FDG PET/CT demonstrated significant uptake in 1 (20%) of the 5 patients with clinical activity and was negative in 5 (71.4%) of the 7 patients in remission. There was no statistically significant difference in SUVmax values [median, 3.8 (range, 1.2–7.3) vs. 3.7 (range, 1.9–8.3), p = 0.45] and PETVAS score [median, 0 (range, 0–3) vs. 1 (range, 0–3), p = 0.67] between patients with clinical activity and those in remission (Fig. 2 A and B) Comparative analysis of CTA and 18F-FDG PET/CT images Based on the visual scale, 18F-FDG PET/CT identified 17 (94.4%) of the 18 patients with thickening on the CTA and did not show uptake in the one patient (100%) without this vascular alteration. 18F-FDG PET/CT presented significant uptake in 5 (83.3%) of the 6 patients who had a double ring sign on the CTA. There was a weak correlation between the medians of the vessel wall thickening values on the CTA and SUVmax in 18F-FDG PET/CT (Fig. 3) There was no difference in the SUVmax values [median, 5.9 (range, 4.74–7.74) vs. 5.2 (range, 4.56–8.3), p = 0.63] among patients with and without the double ring sign on the CTA. Vessel wall thickening values on CTA [median, min. and max. 1.8 (0–6) mm vs. 0 (0-5.3) mm, p = 0.013] were significantly higher in patients with an 18F-FDG PET/CT uptake score ≥ 2 compared to those with an uptake score < 2 (Fig. 4). Aortic wall thickening greater than or equal to 3.3 mm showed a sensitivity of 45% and specificity of 86% (the area under the ROC curve was 0.67, with 95% CI 0,51 − 0,82, p = 0.04) to predict disease activity considering the clinical criteria as a reference (Fig. 5). There was no association between image exams (CTA and 18 FDGPET/CT) and the various treatments of the studied population ( data not shown). In the present study, which primarily included patients with extensive vascular involvement and long-standing disease, 26.3% were classified as having clinically active disease and 36.8% had only laboratory abnormalities. Vascular alterations, such as vessel wall thickening observed on CTA, were effective in identifying disease activity in the aorta but proved inadequate for assessing its branches. An aortic wall thickness ≥ 3.3 mm demonstrated low sensitivity (45%) but good specificity (86%) for predicting clinical activity. No significant differences were observed in SUVmax values or PETVAS scores between patients with clinically active disease and those in remission. Vessel wall thickening on CTA showed only a weak correlation with vascular activity as assessed by 18F-FDG PET/CT. To date, no clinical criterion has been described in the literature to evaluate disease activity in TA in a standardized manner and with adequate accuracy. Several studies have classified disease activity in TA based on NIH classification criteria ( 4 , 5 , 10 ). More recent studies ( 6 , 7 , 9 , 11 ) defined diseaseactivity without considering image evaluation and with variation in the inclusion of subjective systemic symptoms. Nakaoka et al. ( 20 ) included assessing subjective systemic symptoms, while Grayson et al. ( 12 ) considered only objective systemic symptoms. Due to the lack of definition of a method for assessing TA activity and the heterogeneity of the studies, we chose to define patients as having disease activity with clinical symptoms associated with vasculitis, without considering chronic fatigue. In the study of Arnaud et al. ( 13 ) who evaluated clinical and laboratory criteria separately, 32% of patients presented clinical activity and 34% laboratory activity. In the study of Lee et al. ( 21 , 22 ), 63% of patients had disease activity based on the NIH classification criteria, with 29% due to symptoms of ischemia or inflammation. We found similar results in our study (26.3% active, 36.8% laboratory abnormalities and 36.8% inactive). Early detection of inflammation in the vessel wall in TA is essential before irreversible structural alterations occur ( 2 , 3 ). To date, no single imaging technique is sufficiently accurate to determine activity in the vessel wall. Some vascular alterations identified as disease activity may represent fibrotic remodeling ( 5 , 6 ). A recent recommendation from the European League Against Rheumatism (EULAR) ( 23 ) for the use of images in vasculitis of large vessels indicated MRI as the first choice for investigating mural inflammation and/or luminal alterations in patients with suspected TA, considering the high experience and availability of the technique. 18F-FDG PET/CT, CTA, and ultrasound were indicated as alternative imaging modalities. Regarding MRI, some studies have shown an association between edema of the vascular wall and enhancement by contrast with disease activity in TA ( 7 , 8 ). In contrast, other studies did not identify differences in MRI alterations in the activity and remission phases of the disease ( 4 , 5 ). The MRI with gadolinium also showed low agreement with the development of new lesions in a longitudinal study since edema in the vessel wall, which can indicate activity, may also be present in the remodeling phase of the vascular wall ( 4 – 6 ). CTA, in addition to assessing arterial lesions such as stenosis and aneurysm, also assesses the thickening of the vessel wall, a sign of activity. However, few studies have investigated this method in TA, and all of them included a small sample ( 9 , 10 , 11 , 21 ). In the study by Chen et al. ( 10 ), all patients with TA exhibited vessel wall thickening on CTA; however, the degree of thickening was greater in patients with active disease compared to those with inactive disease. Similarly, in the present study, patients with clinical activity demonstrated increased aortic wall thickening compared to those in remission. In contrast, no significant difference in vessel wall thickening was observed in the aortic branches between patients with and without clinical activity. These findings suggest that CTA is more effective in detecting disease activity in the aortic wall than in its branches. Previous studies have shown that vessel wall thickening ≥ 2 mm in large vessels and/or ≥ 1 mm in their branches on CTA is associated with vascular activity ( 9 – 11 ). In a Chinese study, consistent with our findings, a maximal wall thickness ≥ 3.3 mm demonstrated a sensitivity of 83.1% and a specificity of 89.7% for identifying disease activity in patients with TA. These results suggest that a cutoff value of ≥ 3.3 mm for wall thickness on CTA may serve as a more reliable predictor of vascular activity in patients with TA ( 10 ). The majority of patients with the double halo sign in the study had less than five years of illness, possibly indicating this find as an early change. It is essential to carry out studies with larger samples, which allow separate analysis and comparison of CTA performance between patients with recent-onset TA and those with established disease. In the present study, 89.5% of patients presented vascular uptake on the 18F-FDG PET/CT, classified as vasculitis activity, including 2 of the 7 patients considered to be in remission. High SUVmax values could be a warning for persistent activity and greater difficulty in controlling the disease. This is consistent with recent studies demonstrating that 18F-FDG PET/CT can predict future clinical relapses and is associated with a significantly higher risk of developing new angiographic changes compared to individuals without 18F-FDG PET/CT activity ( 24 – 28 ). No significant differences in SUVmax values and PETVAS scores were observed between patients with active disease and those in remission. In the study of Arnaud et al. ( 13 ), there was also no association between 18F-FDG PET/CT uptake and clinical activity. A similar result was described by Grayson et al. ( 12 ), in which 41 of 71 patients with large vessel vasculitis in remission also presented uptake interpreted as active vasculitis. A recent metanalysis, with great heterogeneity between the studies, described sensitivity of 87% and specificity of 73% of 18F-FDG PET/CT to predict disease activity in TA, considering the NIH activity criteria as a reference. A considerable number of patients in remission presented moderate uptake on the 18F-FDG PET/CT ( 29 – 30 ). Is the low performance of the 18F-FDG PET/CT to evaluate activity in vasculitis of large vessels related to the low sensitivity of the disease activity reference criteria used to date? Does the 18F-FDG PET/CT identify subclinical vascular activity or also present uptake of areas of remodeling in vascular segments without inflammation? The 18F-FDG also accumulates in atherosclerotic vascular lesions, a condition that should be considered mainly in patients with long-term disease, as in the present study ( 21 , 22 , 31 ). Another problem related to 18F-FDG PET/CT is the lack of adequate standardization of the criteria for defining vascular activity. The majority of the studies used the visual uptake intensity scale to evaluate activity ( 9 , 11 , 14 , 18 ). Other studies used the SUVmax and uptake intensity (vascular SUVmax/hepatic SUVmean ratio) or vascular SUVmax/inferior vena cava SUVmean. Recently, the PETVAS score has been used more frequently, making studies more homogeneous in image analyses. Comparing 18F-FDG PET/CT with CTA in this study, 94.4% of patients with thickening and 83.3% of patients with double halo presented abnormal uptake by the 18F-FDG PET/CT visual scale. Vessel wall thickening values on CTA were higher in patients with 18F-FDG PET/CT uptake. Still, there was a weak correlation between the values of the vessel wall thickening and SUVmax of the vessels studied. According to Kobayashi et al. ( 32 ), the accumulation of 18F-FDG does not always coincide with the thickening of the vascular wall because it may represent areas of inflammation that have not yet progressed to the development of vascular thickening. The uptake on the 18F-FDG PET/CT can be an earlier process than the vascular alterations on the CTA. Recently, a study showed the possibility of 18F-FDG PET/CT identifying vasculature lesions early, before clinical, laboratory presentation or image changes on CTA or MRI ( 31 ). There are still not enough prospective studies to confirm whether early 18F-FDG PET/CT uptake could suggest activity and whether it would progress to some vascular damage (30–35). The small sample size, cross-sectional design, and lack of a sensitive and standardized disease activity criterion to assess TA were the main limitations of this study. The majority of studies that evaluate 18F-FDG PET/CT are retrospective analyses of medical records ( 32 , 33 , 34 ). In the current study, all patients underwent imaging tests, with clinical, laboratorial evaluation and imaging tests at the same moment. Conclusion In the present study, a high proportion of patients exhibited inflammatory abnormalities in the vessel walls, despite long-standing disease and often irrespective of clinical activity status. Vessel wall thickening on CTA appears to be a useful marker for detecting disease activity in the aorta; however, its utility is limited in the assessment of aortic branch involvement. A wall thickness cutoff value of ≥ 3.3 mm on CTA may represent a more reliable indicator of vascular activity in patients with TA. Although vessel wall thickening on CTA showed only a weak correlation with SUVmax values, it was consistently greater in patients with 18F-FDG PET/CT uptake, suggesting a potential association with underlying vascular inflammation. There are many uncertainties related to the assessment of disease activity in large vessel vasculitis. 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Association of 18 F- Fluorodeoxyglucose –Positron Emission Tomography Activity With Angiographic Progression of Disease in Large Vessel Vasculitis. Arthritis Rheumatol. 2023;75(1):98–107. Cheng Y, Lv N, Wang Z, Chen B, Dang A. 18-FDG-PET in assessing disease activity in Takayasu arteritis: a meta-analysis. Clin Exp Rheumatol. 2013;31(1 Suppl 75):S22–7. Ma LY, Wu B, Jin XJ et al. A Novel Model to Assess Disease Activity in Takayasu Arteritis Based on 18f-FDG-Pet/Ct: A Chinese Cohort Study. Rheumatology (Oxford, England). 2022;61(SI):SI14–22. Quinn KA, Ahlman MA, Alessi HD, LaValley MP, Neogi T, Marko J, et al. Association of 18 F- Fluorodeoxyglucose –Positron Emission Tomography Activity With Angiographic Progression of Disease in Large Vessel Vasculitis. Arthritis Rheumatol. 2023;75(1):98–107. Quinn KA, Ahlman MA, Alessi HD, Arthritis, Rheumatology et al. (Hoboken, N.J.). 2023;75(1):98–107. Rudd JHF, Warburton EA, Fryer TD, Jones HA, Clark JC, Antoun N, et al. Imaging Atherosclerotic Plaque Inflammation With [ 18 F]-Fluorodeoxyglucose Positron Emission Tomography. Circulation. 2002;105(23):2708–11. Quinn KA, Ahlman MA, Alessi HD, LaValley MP, Neogi T, Marko J, et al. Association of 18 F- Fluorodeoxyglucose –Positron Emission Tomography Activity With Angiographic Progression of Disease in Large Vessel Vasculitis. Arthritis Rheumatol. 2023;75(1):98–107. Kobayashi Y, Ishii K, Oda K, Nariai T, Tanaka Y, Ishiwata K, et al. Aortic wall inflammation due to Takayasu arteritis imaged with 18F-FDG PET coregistered with enhanced CT. J Nucl Med. 2005;46(6):917–22. Chung JW, Kim HC, Choi YH, Kim SJ, Lee W, Park JH. Patterns of aortic involvement in Takayasu arteritis and its clinical implications: Evaluation with spiral computed tomography angiography. J Vasc Surg. 2007;45(5):906–14. Yamada I, Nakagawa T, Himeno Y, Kobayashi Y, Numano F, Shibuya H. Takayasu arteritis: diagnosis with breath-hold contrast-enhanced three-dimensional MR angiography. J Magn Reson Imaging. 2000;11(5):481–7. Additional Declarations No competing interests reported. Supplementary Files Suplemental.docx Cite Share Download PDF Status: Under Revision Version 1 posted Editorial decision: Revision requested 14 May, 2026 Reviews received at journal 03 Apr, 2026 Reviewers agreed at journal 22 Mar, 2026 Reviews received at journal 21 Nov, 2025 Reviewers agreed at journal 16 Oct, 2025 Reviewers invited by journal 09 Oct, 2025 Editor assigned by journal 03 Oct, 2025 Submission checks completed at journal 03 Oct, 2025 First submitted to journal 25 Sep, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7715443","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":531938468,"identity":"10883a75-0616-4809-85c8-6b167347f785","order_by":0,"name":"Fabrícia Fonseca 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15:48:20","extension":"xml","order_by":14,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":98133,"visible":true,"origin":"","legend":"","description":"","filename":"2d5aba4044514248b6260c8e745035bf1structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-7715443/v1/f5be1c8086eabb8ca338f93f.xml"},{"id":94211837,"identity":"d085cec0-fd73-4ef0-9d03-a6654eba6e08","added_by":"auto","created_at":"2025-10-23 15:48:20","extension":"html","order_by":15,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":107293,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-7715443/v1/83e7a73356e6b093364ffce6.html"},{"id":94211822,"identity":"0dbe857d-8363-44ff-bdde-21243ae4d41b","added_by":"auto","created_at":"2025-10-23 15:48:20","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":206804,"visible":true,"origin":"","legend":"\u003cp\u003eAnalysis of aortic wall and branch thickening on CTA according to disease activity. \u003cstrong\u003eA:\u003c/strong\u003e Aortic wall thickening was greater across all four aortic segments (ascending, aortic arch, descending, and abdominal) in patients with active disease compared to those in remission. \u003cstrong\u003eB:\u003c/strong\u003e No significant differences were observed in the thickness of the 12 evaluated aortic branch segments between patients with active disease and those in remission.\u003c/p\u003e","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7715443/v1/e9f4bbd616cd35f98f1f6c00.jpeg"},{"id":94211828,"identity":"e52e5cb7-d933-4505-ba82-286ad71b8463","added_by":"auto","created_at":"2025-10-23 15:48:20","extension":"jpeg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":195526,"visible":true,"origin":"","legend":"\u003cp\u003eAnalysis of SUVmax values and PETVAS scores according to disease activity. \u003cstrong\u003eA:\u003c/strong\u003e PETVAS scores did not differ between the two groups No significant differences in SUVmax values were observed between patients with active disease and those in remission. \u003cstrong\u003eB:\u003c/strong\u003e No significant differences in SUVmax values were observed between patients with active disease and those in remission.\u003c/p\u003e","description":"","filename":"floatimage2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7715443/v1/d5ed944f683502c8cf775207.jpeg"},{"id":94211830,"identity":"b991f003-fa75-4103-bcac-1d2f58e4d391","added_by":"auto","created_at":"2025-10-23 15:48:20","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":41129,"visible":true,"origin":"","legend":"\u003cp\u003eLinear regression analysis of the relationship between parietal thickening (mm) and SUVmax (normalized uptake value). The scatter plot shows observed data points, with the solid black line representing the best-fit regression model (Y = 3.61 + 0.18X). The dotted lines indicate the 95% confidence interval for the regression fit. The Pearson r (0.2) and the coefficient of determination (R² = 0.034) suggest a weak correlation, although the association was statistically significant (p = 0.016).\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-7715443/v1/a3e02925d266b45fdc482ae7.png"},{"id":94211824,"identity":"54f4b0ef-0605-418c-b40a-48cd2dd6dabf","added_by":"auto","created_at":"2025-10-23 15:48:20","extension":"jpeg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":61450,"visible":true,"origin":"","legend":"\u003cp\u003eVessel wall thickening on CTA was significantly greater in patients with an 18F-FDG PET/CT uptake score ≥2 compared to those with a score \u0026lt;2.\u003c/p\u003e","description":"","filename":"floatimage4.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7715443/v1/d86fc9ec6d9d192c3cd88355.jpeg"},{"id":94213436,"identity":"411e5c01-48d3-45f3-abea-d221f9363445","added_by":"auto","created_at":"2025-10-23 16:04:20","extension":"jpeg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":48886,"visible":true,"origin":"","legend":"\u003cp\u003eReceiver Operating Characteristic (ROC) curve demonstrating the diagnostic performance of aortic parietal thickening in predicting disease activity in patients with Takayasu arteritis. The area under the curve (AUC) is 0.67, with a p-value of 0.04. The optimal cutoff point for parietal thickening is ≥3.3 mm, corresponding to a positive likelihood ratio (LR⁺) of 3.15, with 45% sensitivity and 86% specificity. AUC CI (0,51-0,82)\u003c/p\u003e","description":"","filename":"floatimage5.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7715443/v1/1da775ee9c0053b7ce8c504d.jpeg"},{"id":94214562,"identity":"8be0bff3-10e7-47d2-a6e7-a57bb945b512","added_by":"auto","created_at":"2025-10-23 16:12:20","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1191902,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7715443/v1/9a2fef35-5357-4b78-8711-3a660fe32e42.pdf"},{"id":94211825,"identity":"be08d9a3-0d98-44a1-8f17-2b127f897192","added_by":"auto","created_at":"2025-10-23 15:48:20","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":19294,"visible":true,"origin":"","legend":"","description":"","filename":"Suplemental.docx","url":"https://assets-eu.researchsquare.com/files/rs-7715443/v1/ac9704336712801edce39f59.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eDisease Activity in Patients With Takayasu's Arteritis: Evaluation of 18f-fdg Pet/ct and Angiotomography Performances\u003c/p\u003e","fulltext":[{"header":"INTRODUCTION","content":"\u003cp\u003eTakayasu arteritis (TA) is a rare, chronic granulomatous vasculitis primarily affecting the aorta and its major branches. The clinical course in most patients is characterized by periods of relapse and remission, leading to the cumulative development of permanent and severe vascular damage (\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e). Identifying and monitoring disease activity in patients with TA poses a significant challenge, as inflammatory changes in the vessels correlate with clinical and laboratory criteria in only approximately 50% of cases (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e). Currently, there is no specific biomarker available for the diagnosis and monitoring of disease activity in patients with TA.\u003c/p\u003e\u003cp\u003eSome studies [GF1] have indicated an association between edema of the vascular wall and contrast enhancement observed on Gadolinium-enhanced Magnetic Resonance Imaging (MRI) with disease activity (\u003cspan additionalcitationids=\"CR5\" citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e). Conversely, other studies have failed to identify significant differences in MRI findings between active and remissive phases of the disease (\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e). Research has shown that arterial wall thickening, as detected by MRI, may also be present during the vascular remodeling phase (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eComputed tomography angiography (CTA), in addition to assessing arterial lesions such as stenosis and aneurysm, also allows for the evaluation of vessel wall thickness and the double halo sign, which are suggestive of inflammatory activity. However, limited research has investigated the utility of this modality in patients with TA (\u003cspan additionalcitationids=\"CR10\" citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e). Despite its low sensitivity, the double halo sign has demonstrated high specificity for identifying active disease (\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e).\u003c/p\u003e\u003cp\u003ePositron emission tomography using 18F-Fluorodeoxyglucose in conjunction with computed tomography (18F-FDG PET/CT) can provide whole-body imaging, including the assessment of radiotracer uptake in large vessels. Several studies have proposed that this method may play a crucial role in the management of patients with large vessel vasculitis, particularly for the evaluation of inflammatory activity (\u003cspan additionalcitationids=\"CR12 CR13\" citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e). However, the activity assessment criteria frequently used as a reference for comparison with 18F-FDG PET/CT are those established by the National Institutes of Health (NIH) (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan additionalcitationids=\"CR16 CR17 CR18\" citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e), which have demonstrated low sensitivity. The PET Vascular Activity Score (PETVAS) was recently developed to standardize the assessment of 18F-FDG PET/CT activity. This scoring system compares the intensity of radiotracer uptake in the vascular wall of nine distinct arterial territories with that of the liver (\u003cspan additionalcitationids=\"CR13\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eGiven the discrepancies in the imaging assessment of large vessel vasculitis, a notable gap exists in the evidence regarding the optimal imaging modality for monitoring disease activity. The primary objective of this study was to analyze the performance of 18F-FDG PET/CT in assessing disease activity in patients with TA, by comparing PET/CT findings with clinical and laboratory variables, as well as vascular alterations observed on CTA.\u003c/p\u003e"},{"header":"PATIENTS AND METHODS","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003eStudy Population\u003c/h2\u003e\u003cp\u003eBetween January 2015 and January 2018, patients older than 18 years of age who met the classification criteria for TA established by the American College of Rheumatology (ACR) (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e) were invited to participate in the study. All patients were under regular follow-up at the Outpatient Rheumatology Clinic of Hospital das Cl\u0026iacute;nicas, Universidade Federal de Minas Gerais (UFMG). Prior to inclusion, all participants provided written informed consent. The study received approval from the Research Ethics Committee of UFMG (32148014.0.0000.5149), and was concduted in adherence to the Declaration of Helsinki. Patients who were pregnant, had decompensated diabetes mellitus, contraindications for iodinated contrast administration, a history of neoplasia within the preceding five years, acute infection within the last month, or chronic infection within the last year were excluded from the study .\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eClinical and Laboratory Data\u003c/h3\u003e\n\u003cp\u003eDemographic, clinical, and treatment data were collected during routine consultations by an experienced physician specializing in the management of TA patients, and through a review of medical records. All patients underwent evaluation for the extent of their disease and the presence of complications such as aneurysms, dilations, narrowing, and vascular occlusion, utilizing clinical examination, angiographic classification, and previously performed imaging modalities such as arterial duplex ultrasound, CTA, and MRI. Physician-determined disease activity status was based on clinical history, physical examination, and laboratory assessments. 1) Clinical activity was defined by the appearance or exacerbation of one or more of the following criteria, after excluding other potential causes of the symptoms such as infections and allergies: A) Objective systemic manifestations: fever, dyspnea, chest pain. Fatigue alone was not considered a criterion for clinical activity. B) Manifestations of vascular ischemia or inflammation. 2) Laboratory activity was defined by an increase in the values of acute phase reactants (erythrocyte sedimentation rate (ESR)\u0026thinsp;\u0026ge;\u0026thinsp;20 mm/h and/or C-reactive protein (CRP)\u0026thinsp;\u0026ge;\u0026thinsp;10 mg/L) without the presence of systemic manifestations or vascular ischemia. Other potential causes of elevated acute phase reactants, such as infections and allergies, were excluded. The reference ranges defined for ESR were 0 to 20 mm/hour, and for CRP were 0 to 10 mg/liter. Patients were classified into the following categories: 1) Clinical activity: presence of one or more clinical criteria with or without elevated acute phase reactants; 2) Laboratory activity: presence of only laboratory criteria; 3) Remission: absence of any clinical symptoms attributable to vasculitis and acute phase reactants within the reference ranges. The extent of vascular involvement was assessed according to the classification criteria proposed by Hata et al. (\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eThe Takayasu Arteritis Damage Score (TADS) index was utilized to quantify the cumulative damage resulting from TA and treatment-related complications (\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e).\u003c/p\u003e\n\u003ch3\u003eImage Acquisition and Analysis of 18F-FDG PET/CT and CTA\u003c/h3\u003e\n\u003cp\u003eRadiologic inflammatory activity in patients was assessed using 18F-FDG PET/CT. Following a fasting period of at least 6 hours, patients received an intravenous administration of 18F-FDG (3.7 MBq/kg). One hour post-administration, a whole-body PET/CT scan was performed using a Discovery PET/CT 600 system (GE Healthcare, Milwaukee, USA). A low-dose computed tomography scan was initially acquired without contrast enhancement and was used for attenuation correction and anatomical image fusion. PET images were reconstructed in a 192 x 192 matrix using an algorithm similar to the ordered subset expectation maximization (OSEM), with 2 iterations and 24 subsets. The 18F-FDG uptake was measured semi-quantitatively as the maximum standardized uptake value (SUVmax), corrected for lean body mass (LBM), using a dedicated PET/CT workstation (AW 4, GE Healthcare).\u003c/p\u003e\u003cp\u003eConcurrently, patients underwent CTA of the thoracic and abdominal aorta, including their branches. The CTA analysis encompassed 16 regions: aortic arch, ascending aorta, right and left common carotid arteries, right and left subclavian arteries, brachiocephalic trunk, descending thoracic aorta, celiac trunk, superior and inferior mesenteric arteries, right and left renal arteries, and right and left iliac arteries. Two independent physicians, one specializing in nuclear medicine and the other in radiology, analyzed the images in a blinded manner with respect to the patients' clinical and laboratory parameters. One of the evaluators possessed expertise in vascular imaging. In cases of disagreement, a final interpretation was reached by consensus between the two physicians (kappa value of 1.0 was obtained).\u003c/p\u003e\u003cp\u003eVisual analysis of 18F-FDG PET/CT images was performed in 9 regions, according to the PETVAS protocol: ascending aorta, aortic arch, descending thoracic aorta, abdominal aorta, right carotid artery, left carotid artery, innominate artery, right subclavian artery, left subclavian artery (\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e). Two parameters were used to evaluate the 18F-FDG PET/CT images: a visual uptake intensity scale and the SUVmax. The visual uptake intensity scale was defined as follows: Grade 0 \u0026ndash; no uptake or vascular uptake less than the liver; Grade 1 \u0026ndash; vascular uptake less than the liver; Grade 2 \u0026ndash; vascular uptake equal to the liver; Grade 3 \u0026ndash; vascular uptake greater than the liver. Patients with an uptake grade of 2 or higher were classified as having vascular activity on the 18F-FDG PET/CT (\u003cspan additionalcitationids=\"CR13\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e). The SUV intensity analysis, calculated as the ratio of the SUVmax of a vascular region of interest (ROI) to the SUVmax of the liver, was performed to minimize the influence of the time interval between radioisotope injection and image acquisition, and to reduce the confounding effects of serum glucose levels.\u003c/p\u003e\u003cp\u003eIn the CTA evaluation, alterations indicative of vascular activity, such as thickening of the arterial wall and the double halo sign, have been described. The double halo sign represents a delayed pattern of vascular contrast uptake, demonstrating contrast enhancement in both the adventitial and intimal layers of the vessels (\u003cspan additionalcitationids=\"CR10\" citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e). Vascular activity on CTA was considered positive for images showing thickening greater than or equal to 2 mm in large vessels (i.e., abdominal and thoracic aorta) and/or greater than or equal to 1 mm in their branches (\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e). Disease activity was assessed on the same day as the 18F-FDG PET/CT and CTA examinations.\u003c/p\u003e\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\u003ch2\u003eStatistical Analysis\u003c/h2\u003e\u003cp\u003eThe Minitab (version 17) and IBM SPSS Statistics (Statistical Package for Social Sciences, Version for Windows SPSS Inc., Chicago, IL, USA), version 22.0, software programs were used for data analysis. The Shapiro-Wilk test was used to assess the normality of continuous variables. Categorical data are presented as total numbers and percentages, while numerical data are presented as means or medians. Correlation analyses of numerical variables were performed using the Spearman test. Comparisons of numerical variables between groups were made using the Mann-Whitney U test or the Student's t-test for multiple groups. The presence of active disease in TA, as determined by a defined SUVmax cut-off point, was compared with disease activity as determined by clinical-laboratory evaluation using Fisher's exact test. The following accuracy measures, along with their respective 95% confidence intervals, were calculated for vessel wall thickening values: sensitivity, specificity, positive predictive value, and negative predictive value.\u003c/p\u003e\u003c/div\u003e"},{"header":"RESULTS","content":"\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003ePatient Characteristics\u003c/h2\u003e\u003cp\u003eNineteen patients with TA were selected for the study. Demographic, clinical, laboratory, and treatment data are detailed in Table\u0026nbsp;1.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eDemographic, clinical, and treatment characteristics of the Takayasu's arteritis patients.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eVariables\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003en (%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eMean (SD)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eMedian (95%CI)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eDemographic\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAge (years)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e38 (8.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAge at diagnosis of TA (years)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e27 (8.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eFemale sex\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e18 (95.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eWhite\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e12 (63.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eNon-white\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e7 (36.8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eClinical\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eMean (SD)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eDisease duration (years)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e11.5 (6.1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eClinical /laboratory disease activity\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e11 (57,9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eDisease in remission\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e8 (42.1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eLaboratory\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eMedian (min-max)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eESR (mm/hora)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e12.0 (2\u0026ndash;56)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eCRP (mg/L)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e9.0 (2\u0026ndash;86)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eTADS damage score\u003csup\u003e#\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e4.0 (\u003cspan additionalcitationids=\"CR2 CR3\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePrednisone\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e13 (68.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eDaily dose of prednisone (mg)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e10.0 (0\u0026ndash;80)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eSynthetic immunosuppressant\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMethotrexate\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e9 (47.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eLeflunomide\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1 (5.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAzathioprine\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e2 (10.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eInfliximab\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1 (5.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eTocilizumab\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e2 (10.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eASA\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e19 (100.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"5\"\u003eNote: TA: Takayasu arteritis; CRP: C-reactive protein; ESR: erythrocyte sedimentation rate; AAS: acetyl salicylic acid; #: Takayasu Arteritis Damage Score; n: sample size; SD: Standard Deviation; 95% CI: 95% confidence interval.\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eAt the time of data collection, 5 (26.3%) patients were classified as having clinical activity, 7 (36.8%) were in remission, and 7 (36.8%) presented with only laboratory abnormalities. Regarding the extent of disease, the majority of patients exhibited vascular involvement type V (8; 42.1%), followed by type IIa (6; 31.6%) and type IIb (3; 15.8%). During the period between the diagnosis of Takayasu arteritis and the date of inclusion in the study, 10 (52.6%) patients experienced disease relapses.\u003c/p\u003e\u003cp\u003eCRP values [median, min. and max. 12.2 (5\u0026ndash;86) mg/L vs. 5 (\u003cspan additionalcitationids=\"CR3 CR4 CR5 CR6 CR7 CR8\" citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e) mg/L, p\u0026thinsp;=\u0026thinsp;0.04] were significantly higher in patients with clinical activity compared to patients in remission, after excluding patients with exclusively laboratory abnormalities. No significant difference was observed in ESR values [median, min. and max. 20 (3\u0026ndash;52) mm/h vs. 10 (\u003cspan additionalcitationids=\"CR3 CR4 CR5 CR6 CR7 CR8 CR9 CR10 CR11\" citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e) mm/h, p\u0026thinsp;=\u0026thinsp;0.06] between patients with clinical activity and those in remission.\u003c/p\u003e\u003cp\u003eData pertaining to disease activity, laboratory values, and imaging tests of the study population are presented suplementary material.(Supplement 1)\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eAngiotomography\u003c/h3\u003e\n\u003cp\u003eEighteen patients (94.7%) exhibited alterations indicative of vascular activity on CTA, characterized by thickening of the vessel wall and/or the double halo sign, primarily affecting the ascending aorta, aortic arch, and descending aorta.\u003c/p\u003e\u003cp\u003eCTA examinations revealed vessel wall thickening in five (100%) patients with clinical activity. Of the total of 7 patients in remission, all demonstrated vessel wall thickening on CTA.\u003c/p\u003e\u003cp\u003ePatients with clinical activity showed greater aortic wall thickening (ascending, aortic arch, descending, and abdominal) compared to patients in remission [median, min. and max. 2.9 (0\u0026ndash;6) mm vs. 0 (0-5.5) mm, p\u0026thinsp;=\u0026thinsp;0.02]. In the analysis of aortic branches, no significant difference was found in vessel wall thickening between patients with clinical activity and those in remission [median, min. and max. 0 (0\u0026ndash;3) mm vs. 0 (0\u0026ndash;5) mm, p\u0026thinsp;=\u0026thinsp;0.98] (Fig.\u0026nbsp;1 A and B).\u003c/p\u003e\u003cp\u003eThe double ring sign was identified in one (20%) of the 5 patients with clinical activity and was not observed in 5 (71.4%) of the 7 patients in remission. Patients exhibiting the double ring sign on CTA had a shorter disease duration compared to those without this vascular alteration [median, 7.5 (range, 2\u0026ndash;22) years vs. 13.4 (range, 5\u0026ndash;19) years, p\u0026thinsp;=\u0026thinsp;0.04].\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003e18F-FDG PET/CT\u003c/b\u003e\u003c/p\u003e\u003cp\u003eBased on the visual scale, two (10.5%) patients were classified as grade one, 11 (57.9%) as grade two, and six (31.6%) as grade three. The median of the highest SUVmax value in the studied population was 5.6, with a range of 4.5 to 8.3. 18F-FDG PET/CT demonstrated significant uptake in 1 (20%) of the 5 patients with clinical activity and was negative in 5 (71.4%) of the 7 patients in remission. There was no statistically significant difference in SUVmax values [median, 3.8 (range, 1.2\u0026ndash;7.3) vs. 3.7 (range, 1.9\u0026ndash;8.3), p\u0026thinsp;=\u0026thinsp;0.45] and PETVAS score [median, 0 (range, 0\u0026ndash;3) vs. 1 (range, 0\u0026ndash;3), p\u0026thinsp;=\u0026thinsp;0.67] between patients with clinical activity and those in remission (Fig.\u0026nbsp;2 A and B)\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\n\u003ch3\u003eComparative analysis of CTA and 18F-FDG PET/CT images\u003c/h3\u003e\n\u003cp\u003eBased on the visual scale, 18F-FDG PET/CT identified 17 (94.4%) of the 18 patients with thickening on the CTA and did not show uptake in the one patient (100%) without this vascular alteration. 18F-FDG PET/CT presented significant uptake in 5 (83.3%) of the 6 patients who had a double ring sign on the CTA. There was a weak correlation between the medians of the vessel wall thickening values on the CTA and SUVmax in 18F-FDG PET/CT (Fig.\u0026nbsp;3)\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThere was no difference in the SUVmax values [median, 5.9 (range, 4.74\u0026ndash;7.74) vs. 5.2 (range, 4.56\u0026ndash;8.3), p\u0026thinsp;=\u0026thinsp;0.63] among patients with and without the double ring sign on the CTA.\u003c/p\u003e\u003cp\u003eVessel wall thickening values on CTA [median, min. and max. 1.8 (0\u0026ndash;6) mm vs. 0 (0-5.3) mm, p\u0026thinsp;=\u0026thinsp;0.013] were significantly higher in patients with an 18F-FDG PET/CT uptake score\u0026thinsp;\u0026ge;\u0026thinsp;2 compared to those with an uptake score\u0026thinsp;\u0026lt;\u0026thinsp;2 (Fig.\u0026nbsp;4).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eAortic wall thickening greater than or equal to 3.3 mm showed a sensitivity of 45% and specificity of 86% (the area under the ROC curve was 0.67, with 95% CI 0,51\u0026thinsp;\u0026minus;\u0026thinsp;0,82, p\u0026thinsp;=\u0026thinsp;0.04) to predict disease activity considering the clinical criteria as a reference (Fig.\u0026nbsp;5).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThere was no association between image exams (CTA and 18 FDGPET/CT) and the various treatments of the studied population ( data not shown).\u003c/p\u003e\u003cp\u003eIn the present study, which primarily included patients with extensive vascular involvement and long-standing disease, 26.3% were classified as having clinically active disease and 36.8% had only laboratory abnormalities. Vascular alterations, such as vessel wall thickening observed on CTA, were effective in identifying disease activity in the aorta but proved inadequate for assessing its branches. An aortic wall thickness\u0026thinsp;\u0026ge;\u0026thinsp;3.3 mm demonstrated low sensitivity (45%) but good specificity (86%) for predicting clinical activity. No significant differences were observed in SUVmax values or PETVAS scores between patients with clinically active disease and those in remission. Vessel wall thickening on CTA showed only a weak correlation with vascular activity as assessed by 18F-FDG PET/CT.\u003c/p\u003e\u003cp\u003eTo date, no clinical criterion has been described in the literature to evaluate disease activity in TA in a standardized manner and with adequate accuracy. Several studies have classified disease activity in TA based on NIH classification criteria (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e). More recent studies (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e) defined diseaseactivity without considering image evaluation and with variation in the inclusion of subjective systemic symptoms. Nakaoka et al. (\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e) included assessing subjective systemic symptoms, while Grayson et al. (\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e) considered only objective systemic symptoms. Due to the lack of definition of a method for assessing TA activity and the heterogeneity of the studies, we chose to define patients as having disease activity with clinical symptoms associated with vasculitis, without considering chronic fatigue. In the study of Arnaud et al. (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e) who evaluated clinical and laboratory criteria separately, 32% of patients presented clinical activity and 34% laboratory activity. In the study of Lee et al. (\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e), 63% of patients had disease activity based on the NIH classification criteria, with 29% due to symptoms of ischemia or inflammation. We found similar results in our study (26.3% active, 36.8% laboratory abnormalities and 36.8% inactive).\u003c/p\u003e\u003cp\u003eEarly detection of inflammation in the vessel wall in TA is essential before irreversible structural alterations occur (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e). To date, no single imaging technique is sufficiently accurate to determine activity in the vessel wall. Some vascular alterations identified as disease activity may represent fibrotic remodeling (\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e). A recent recommendation from the European League Against Rheumatism (EULAR) (\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e) for the use of images in vasculitis of large vessels indicated MRI as the first choice for investigating mural inflammation and/or luminal alterations in patients with suspected TA, considering the high experience and availability of the technique. 18F-FDG PET/CT, CTA, and ultrasound were indicated as alternative imaging modalities. Regarding MRI, some studies have shown an association between edema of the vascular wall and enhancement by contrast with disease activity in TA (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e). In contrast, other studies did not identify differences in MRI alterations in the activity and remission phases of the disease (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e). The MRI with gadolinium also showed low agreement with the development of new lesions in a longitudinal study since edema in the vessel wall, which can indicate activity, may also be present in the remodeling phase of the vascular wall (\u003cspan additionalcitationids=\"CR5\" citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e). CTA, in addition to assessing arterial lesions such as stenosis and aneurysm, also assesses the thickening of the vessel wall, a sign of activity. However, few studies have investigated this method in TA, and all of them included a small sample (\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e). In the study by Chen et al. (\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e), all patients with TA exhibited vessel wall thickening on CTA; however, the degree of thickening was greater in patients with active disease compared to those with inactive disease. Similarly, in the present study, patients with clinical activity demonstrated increased aortic wall thickening compared to those in remission. In contrast, no significant difference in vessel wall thickening was observed in the aortic branches between patients with and without clinical activity. These findings suggest that CTA is more effective in detecting disease activity in the aortic wall than in its branches.\u003c/p\u003e\u003cp\u003ePrevious studies have shown that vessel wall thickening\u0026thinsp;\u0026ge;\u0026thinsp;2 mm in large vessels and/or \u0026ge;\u0026thinsp;1 mm in their branches on CTA is associated with vascular activity (\u003cspan additionalcitationids=\"CR10\" citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e). In a Chinese study, consistent with our findings, a maximal wall thickness\u0026thinsp;\u0026ge;\u0026thinsp;3.3 mm demonstrated a sensitivity of 83.1% and a specificity of 89.7% for identifying disease activity in patients with TA. These results suggest that a cutoff value of \u0026ge;\u0026thinsp;3.3 mm for wall thickness on CTA may serve as a more reliable predictor of vascular activity in patients with TA (\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eThe majority of patients with the double halo sign in the study had less than five years of illness, possibly indicating this find as an early change. It is essential to carry out studies with larger samples, which allow separate analysis and comparison of CTA performance between patients with recent-onset TA and those with established disease.\u003c/p\u003e\u003cp\u003eIn the present study, 89.5% of patients presented vascular uptake on the 18F-FDG PET/CT, classified as vasculitis activity, including 2 of the 7 patients considered to be in remission. High SUVmax values could be a warning for persistent activity and greater difficulty in controlling the disease. This is consistent with recent studies demonstrating that 18F-FDG PET/CT can predict future clinical relapses and is associated with a significantly higher risk of developing new angiographic changes compared to individuals without 18F-FDG PET/CT activity (\u003cspan additionalcitationids=\"CR25 CR26 CR27\" citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eNo significant differences in SUVmax values and PETVAS scores were observed between patients with active disease and those in remission. In the study of Arnaud et al. (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e), there was also no association between 18F-FDG PET/CT uptake and clinical activity. A similar result was described by Grayson et al. (\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e), in which 41 of 71 patients with large vessel vasculitis in remission also presented uptake interpreted as active vasculitis. A recent metanalysis, with great heterogeneity between the studies, described sensitivity of 87% and specificity of 73% of 18F-FDG PET/CT to predict disease activity in TA, considering the NIH activity criteria as a reference. A considerable number of patients in remission presented moderate uptake on the 18F-FDG PET/CT (\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e). Is the low performance of the 18F-FDG PET/CT to evaluate activity in vasculitis of large vessels related to the low sensitivity of the disease activity reference criteria used to date? Does the 18F-FDG PET/CT identify subclinical vascular activity or also present uptake of areas of remodeling in vascular segments without inflammation? The 18F-FDG also accumulates in atherosclerotic vascular lesions, a condition that should be considered mainly in patients with long-term disease, as in the present study (\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e). Another problem related to 18F-FDG PET/CT is the lack of adequate standardization of the criteria for defining vascular activity. The majority of the studies used the visual uptake intensity scale to evaluate activity (\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e). Other studies used the SUVmax and uptake intensity (vascular SUVmax/hepatic SUVmean ratio) or vascular SUVmax/inferior vena cava SUVmean. Recently, the PETVAS score has been used more frequently, making studies more homogeneous in image analyses.\u003c/p\u003e\u003cp\u003eComparing 18F-FDG PET/CT with CTA in this study, 94.4% of patients with thickening and 83.3% of patients with double halo presented abnormal uptake by the 18F-FDG PET/CT visual scale. Vessel wall thickening values on CTA were higher in patients with 18F-FDG PET/CT uptake. Still, there was a weak correlation between the values of the vessel wall thickening and SUVmax of the vessels studied. According to Kobayashi et al. (\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e), the accumulation of 18F-FDG does not always coincide with the thickening of the vascular wall because it may represent areas of inflammation that have not yet progressed to the development of vascular thickening. The uptake on the 18F-FDG PET/CT can be an earlier process than the vascular alterations on the CTA. Recently, a study showed the possibility of 18F-FDG PET/CT identifying vasculature lesions early, before clinical, laboratory presentation or image changes on CTA or MRI (\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e). There are still not enough prospective studies to confirm whether early 18F-FDG PET/CT uptake could suggest activity and whether it would progress to some vascular damage (30\u0026ndash;35).\u003c/p\u003e\u003cp\u003eThe small sample size, cross-sectional design, and lack of a sensitive and standardized disease activity criterion to assess TA were the main limitations of this study. The majority of studies that evaluate 18F-FDG PET/CT are retrospective analyses of medical records (\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e, \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e, \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e). In the current study, all patients underwent imaging tests, with clinical, laboratorial evaluation and imaging tests at the same moment.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eIn the present study, a high proportion of patients exhibited inflammatory abnormalities in the vessel walls, despite long-standing disease and often irrespective of clinical activity status. Vessel wall thickening on CTA appears to be a useful marker for detecting disease activity in the aorta; however, its utility is limited in the assessment of aortic branch involvement. A wall thickness cutoff value of \u0026ge;\u0026thinsp;3.3 mm on CTA may represent a more reliable indicator of vascular activity in patients with TA. Although vessel wall thickening on CTA showed only a weak correlation with SUVmax values, it was consistently greater in patients with 18F-FDG PET/CT uptake, suggesting a potential association with underlying vascular inflammation. There are many uncertainties related to the assessment of disease activity in large vessel vasculitis. It is essential to develop multicenter, prospective studies that can address these questions.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eFS, GA and GG wrote the main manuscript text and were the principal investigators. RS and MM performed the analyses of the computed tomography angiography (CTA) and PET-CT images.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003ePeter J, David S, Danda D, Peter JV, Horo S, Joseph G. OCULAR MANIFESTATIONS OF TAKAYASU ARTERITIS. Retina. 2011;31(6):1170\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eHoffman GS. Takayasu arteritis: lessons from the American National Institutes of Health experience. Int J Cardiol. 1996;54:S99\u0026ndash;102.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLAGNEAU P, MICHEL JB. Surgical Treatment of Takayasuʼs Disease. Ann Surg. 1987;205(2):157\u0026ndash;66.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSun Y, Ma L, Ji Z, Zhang Z, Chen H, Liu H, et al. Value of whole-body contrastenhanced magnetic resonance angiography with vessel wall imaging in quantitative assessment of disease activity and follow-up examination in Takayasu\u0026rsquo;s arteritis. Clin Rheumatol. 2016;35(3):685\u0026ndash;93.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eEshet Y, Pauzner R, Goitein O, Langevitz P, Eshed I, Hoffmann C, et al. The limited role of MRI in long-term follow-up of patients with Takayasu\u0026rsquo;s arteritis. Autoimmun Rev. 2011;11(2):132\u0026ndash;6.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eTso E, Flamm SD, White RD, Schvartzman PR, Mascha E, Hoffman GS. 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Eur J Radiol. 2011;77(2):369\u0026ndash;74.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eChen B et al. Int J Cardiol. 2019 Assessment of disease activity in Takayasu arteritis: A quantitative study with computed tomography angiography.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSarma K, Handique A, Phukan P, Daniala C, Chutia H, Barman B. Magnetic Resonance Angiography and Multidetector CT Angiography in the Diagnosis of Takayasu\u0026rsquo;s. 2022;18(1):51\u0026ndash;60.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eGrayson PC, Alehashemi S, Bagheri AA, Civelek AC, Cupps TR, Kaplan MJ, et al. 18 F-Fluorodeoxyglucose-Positron Emission Tomography As an Imaging Biomarker in a Prospective, Longitudinal Cohort of Patients With Large Vessel Vasculitis. Arthritis Rheumatol. 2018;70(3):439\u0026ndash;49.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eArnaud L, Haroche J, Malek Z, Archambaud F, Gambotti L, Grimon G, et al. Is 18 Ffluorodeoxyglucose positron emission tomography scanning a reliable way to assess disease activity in takayasu arteritis? Arthritis Rheum. 2009;60(4):1193\u0026ndash;200.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWebb M, Chambers A, AL-Nahhas A, Mason JC, Maudlin L, Rahman L, et al. The role of 18 F-FDG PET in characterising disease activity in Takayasu arteritis. Eur J Nucl Med Mol Imaging. 2004;31(5):627\u0026ndash;34.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003ePeter GRAYSON. C. 2022 American College of Rheumatology/EULAR classification criteria for Takayasu arteritis. Ann Rheum Dis, v. 81, n. 12, pp. 1654\u0026ndash;60.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eHata A, Noda M, Moriwaki R, Numano F. Angiographic findings of Takayasu arteritis: New classification. Int J Cardiol. 1996;54:S155\u0026ndash;63.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKaymaz-Tahra S, Alibaz-Oner F, Direskeneli H. Assessment of damage in Takayasu's arteritis. Semin Arthritis Rheum. 2020;50(4):586\u0026ndash;91.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eNakagomi D, Jayne D. Outcome assessment in Takayasu arteritis. Rheumatology. 2016;55(7):1159\u0026ndash;71.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKerr GS. Takayasu\u0026rsquo;s arteritis. Rheum Dis Clin North Am. 1995;21(4):1041\u0026ndash;58.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eNakaoka Y, Isobe M, Takei S, Tanaka Y, Ishii T, Yokota S, et al. Efficacy and safety of tocilizumab in patients with refractory Takayasu arteritis: results from a randomised, double-blind, placebo-controlled, phase 3 trial in Japan (the TAKT study). Ann Rheum Dis. 2018;77(3):348\u0026ndash;54.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLee KH, Cho A, Choi YJ, Lee SW, Ha YJ, Jung SJ, et al. The role of 18 Fluorodeoxyglucose-positron emission tomography in the assessment of disease activity in patients with Takayasu arteritis. Arthritis Rheum. 2012;64(3):866\u0026ndash;75.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLee SG, Ryu JS, Kim HO, Oh JS, Kim YG, Lee CK, et al. Evaluation of Disease Activity Using F-18 FDG PET-CT in Patients With Takayasu Arteritis. Clin Nucl Med. 2009;34(11):749\u0026ndash;52.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eDejaco C, Ramiro S, Duftner C, Besson FL, Bley TA, Blockmans D, et al. EULAR recommendations for the use of imaging in large vessel vasculitis in clinical practice. Ann Rheum Dis. 2018;77(5):636\u0026ndash;43.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWesterterp M, Pruim J, Oyen W, Hoekstra O, Paans A, Visser E, et al. Quantification of FDG PET studies using standardised uptake values in multi-centre trials: effects of image reconstruction, resolution and ROI definition parameters. Eur J Nucl Med Mol Imaging. 2007;34(3):392\u0026ndash;404.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eQuinn KA, Ahlman MA, Alessi HD, LaValley MP, Neogi T, Marko J, et al. Association of 18 F- Fluorodeoxyglucose \u0026ndash;Positron Emission Tomography Activity With Angiographic Progression of Disease in Large Vessel Vasculitis. Arthritis Rheumatol. 2023;75(1):98\u0026ndash;107.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eCheng Y, Lv N, Wang Z, Chen B, Dang A. 18-FDG-PET in assessing disease activity in Takayasu arteritis: a meta-analysis. Clin Exp Rheumatol. 2013;31(1 Suppl 75):S22\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMa LY, Wu B, Jin XJ et al. A Novel Model to Assess Disease Activity in Takayasu Arteritis Based on 18f-FDG-Pet/Ct: A Chinese Cohort Study. Rheumatology (Oxford, England). 2022;61(SI):SI14\u0026ndash;22.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eQuinn KA, Ahlman MA, Alessi HD, LaValley MP, Neogi T, Marko J, et al. Association of 18 F- Fluorodeoxyglucose \u0026ndash;Positron Emission Tomography Activity With Angiographic Progression of Disease in Large Vessel Vasculitis. Arthritis Rheumatol. 2023;75(1):98\u0026ndash;107.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eQuinn KA, Ahlman MA, Alessi HD, Arthritis, Rheumatology et al. (Hoboken, N.J.). 2023;75(1):98\u0026ndash;107.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eRudd JHF, Warburton EA, Fryer TD, Jones HA, Clark JC, Antoun N, et al. Imaging Atherosclerotic Plaque Inflammation With [ 18 F]-Fluorodeoxyglucose Positron Emission Tomography. Circulation. 2002;105(23):2708\u0026ndash;11.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eQuinn KA, Ahlman MA, Alessi HD, LaValley MP, Neogi T, Marko J, et al. Association of 18 F- Fluorodeoxyglucose \u0026ndash;Positron Emission Tomography Activity With Angiographic Progression of Disease in Large Vessel Vasculitis. Arthritis Rheumatol. 2023;75(1):98\u0026ndash;107.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKobayashi Y, Ishii K, Oda K, Nariai T, Tanaka Y, Ishiwata K, et al. Aortic wall inflammation due to Takayasu arteritis imaged with 18F-FDG PET coregistered with enhanced CT. J Nucl Med. 2005;46(6):917\u0026ndash;22.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eChung JW, Kim HC, Choi YH, Kim SJ, Lee W, Park JH. Patterns of aortic involvement in Takayasu arteritis and its clinical implications: Evaluation with spiral computed tomography angiography. J Vasc Surg. 2007;45(5):906\u0026ndash;14.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eYamada I, Nakagawa T, Himeno Y, Kobayashi Y, Numano F, Shibuya H. Takayasu arteritis: diagnosis with breath-hold contrast-enhanced three-dimensional MR angiography. J Magn Reson Imaging. 2000;11(5):481\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"advances-in-rheumatology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"adrh","sideBox":"Learn more about [Advances in Rheumatology](https://advancesinrheumatology.biomedcentral.com/)","snPcode":"42358","submissionUrl":"https://submission.springernature.com/new-submission/42358/3","title":"Advances in Rheumatology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-7715443/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7715443/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eObjective\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTo evaluate the performance of 18F-FDG PET/CT in assessing disease activity in patients with Takayasu arteritis (TA), by comparing 18F-FDG PET/CT findings with clinical and laboratory parameters, as well as vascular alterations observed on angiotomography (CTA).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn this cross-sectional study, 19 patients with TA were evaluated for clinical, laboratory and imaging activity (CTA and 18F-FDG PET/CT). Vascular activity on CTA was defined by the presence of vessel wall thickening and/or double-ring signs. PET vascular activity score (PETVAS) and maximum standardized uptake value (SUVmax) were used to assess ¹⁸F-FDG PET/CT activity.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ePatients with clinical activity demonstrated greater aortic wall thickening compared to those in remission [median (range): 2.9 mm (0–6) vs. 0 mm (0–5.5); \u003cem\u003ep\u003c/em\u003e = 0.02]. In contrast, no significant difference was observed in vessel wall thickening of the aortic branches. Aortic wall thickening greater than or equal to 3.3 mm showed a sensitivity of 45% and specificity of 86% to predict disease activity. No significant differences in SUVmax values and PETVAS scores were observed between patients with active disease and those in remission. Vessel wall thickening values on CTA [median, min. and max. 1.8 (0–6) mm vs. 0 (0-5.3) mm, p = 0.013] were significantly higher in patients with an 18F-FDG PET/CT uptake score ≥ 2.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe 18F-FDG PET/CT did not demonstrate good performance in assessing disease activity based on clinical criteria, but showed association with vessel wall thickening on CTA, which appears to be a useful marker for disease activity in the aorta.\u003c/p\u003e","manuscriptTitle":"Disease Activity in Patients With Takayasu's Arteritis: Evaluation of 18f-fdg Pet/ct and Angiotomography Performances","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-10-23 15:48:15","doi":"10.21203/rs.3.rs-7715443/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-05-15T01:46:00+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-04-03T11:59:12+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"50200647380945537262808078571025230262","date":"2026-03-22T14:37:53+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-11-21T13:11:02+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"278850589958203831368308950731592234454","date":"2025-10-16T12:16:36+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-10-09T18:09:24+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-10-03T12:03:54+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-10-03T12:02:49+00:00","index":"","fulltext":""},{"type":"submitted","content":"Advances in Rheumatology","date":"2025-09-25T17:58:56+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"advances-in-rheumatology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"adrh","sideBox":"Learn more about [Advances in Rheumatology](https://advancesinrheumatology.biomedcentral.com/)","snPcode":"42358","submissionUrl":"https://submission.springernature.com/new-submission/42358/3","title":"Advances in Rheumatology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"189cca75-f0e4-4532-a9c2-b1429bdfedee","owner":[],"postedDate":"October 23rd, 2025","published":true,"recentEditorialEvents":[{"type":"decision","content":"Revision requested","date":"2026-05-15T01:46:00+00:00","index":"","fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"in-revision","subjectAreas":[],"tags":[],"updatedAt":"2026-05-15T01:54:31+00:00","versionOfRecord":[],"versionCreatedAt":"2025-10-23 15:48:15","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7715443","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7715443","identity":"rs-7715443","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}