Measurement of Ultrasound Coronal Angle as a Non-Radiological Alternative to Cobb Angle in School-Based Screening for Adolescent Scoliosis: Assessment of Accuracy, Validity, and Feasibility

Measurement of Ultrasound Coronal Angle as a Non-Radiological Alternative to Cobb Angle in School-Based Screening for Adolescent Scoliosis: Assessment of Accuracy, Validity, and Feasibility | 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 Measurement of Ultrasound Coronal Angle as a Non-Radiological Alternative to Cobb Angle in School-Based Screening for Adolescent Scoliosis: Assessment of Accuracy, Validity, and Feasibility Shaobo Yang, Chen Zhang, Peiji Miao, Xiaoyun Yuan, Han Leng, Jing Zhang, and 7 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8690892/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 11 You are reading this latest preprint version Abstract Objective To evaluate the accuracy, validity, and feasibility of the ultrasound coronal angle (UCA) measured by a portable three-dimensional ultrasound imaging device as a non-radiological alternative to the Cobb angle in school-based screening for adolescent scoliosis. Methods A cross-sectional study was conducted in multiple regions of Gansu Province, China, from December 2024 to June 2025, involving 168 suspected adolescent scoliosis patients. A portable 3D ultrasound system (Scolioscan® Air) was used to obtain coronal plane images of the spine and measure the UCA. Concurrently, full-spine X-ray radiographs were taken to measure the Cobb angle. Measurement reliability was analyzed using intra-class correlation coefficient (ICC), mean absolute difference (MAD), and standard error of measurement (SEM). The correlation and agreement between UCA and Cobb angle were examined using Pearson correlation analysis, linear regression, and Bland-Altman analysis. Practical feasibility was assessed by comparing the measurement times of both methods. Results UCA showed a high correlation with the Cobb angle (r = 0.949, P < 0.001), with a mean absolute difference of 2.1° and an SEM of 1.9°. UCA measurement demonstrated excellent intra-rater reliability (ICC = 0.899) and inter-operator consistency. The acquisition time for UCA was significantly shorter than for X-ray examination (7.2 ± 2.6 min vs. 37.5 ± 4.7 min, P < 0.001), representing an efficiency improvement of approximately 79.2%. Conclusion The ultrasound coronal angle exhibits good reliability, validity, and time efficiency in school-based screening for adolescent scoliosis, and can serve as a radiation-free preliminary screening tool suitable for large-scale population screening. Adolescent scoliosis Cobb angle Ultrasound coronal angle Three-dimensional ultrasound imaging School-based screening Radiation-free assessment Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 1. Introduction Adolescent scoliosis (AS) is a three-dimensional spinal deformity characterized by a lateral curvature in one or more segments of the spine, combined with vertebral rotation, leading to core deviation and sagittal progression. Severe scoliosis can lead to serious complications such as cardiovascular issues, decreased pulmonary function, chronic pain, and psychological distress [1] . According to global studies, the prevalence of scoliosis ranges from approximately 1% to 3%[ 2 ], typically emerging around the age of 10 in adolescents[ 3 ]. Epidemiological data may vary slightly across different countries and regions, but the widespread nature of this condition has garnered significant attention. The overall prevalence of scoliosis among Chinese adolescents aged 10–18 is 1.2%[ 4 ], with over 5 million primary and secondary school students affected, and this number is increasing by about 300,000 annually. Since many cases of scoliosis present no significant symptoms during childhood and adolescence, especially in patients with mild curvature, the condition is often discovered incidentally during assessments for height or other health concerns. School-based screening can effectively identify these latent cases, preventing progression, as treatment plans for scoliosis are typically based on several predefined thresholds[ 5 ]. This also makes early screening a key component of disease management[ 6 ]. Regular screening within schools enables early detection of scoliosis, allowing for interventions such as physical therapy, bracing, or surgery, thereby effectively preventing disease progression and improving patients' quality of life. Measuring the coronal Cobb angle on upright full-spine radiographs is the standard procedure in clinical practice for diagnosing, monitoring curve progression, and assigning treatment for scoliosis patients, and is considered the gold standard for diagnosis[ 5 , 7 , 8 ]. The Cobb angle measurement is widely used in clinical and research settings and is highly standardized. However, Cobb angle measurement has significant limitations, primarily radiation exposure. Examining the spine for scoliosis requires full-spine X-rays. Simony et al.[ 9 ] found that the ionizing radiation dose for a full-spine X-ray is 0.8–1.4 mSv per session. Patients are frequently exposed to radiation during scoliosis evaluations, and due to the need for multiple examinations during longitudinal follow-up, this radiation exposure is cumulative[ 10 ]. Additionally, X-ray imaging is expensive and the equipment is difficult to transport[ 11 ], making it unsuitable for large-scale scoliosis screening. Therefore, there is an urgent need for a device that can replace the Cobb angle, is radiation-free, portable, and suitable for large-scale scoliosis screening. The advent of ultrasound imaging devices addresses these shortcomings of traditional X-rays well. Ultrasound imaging is an inexpensive, radiation-free method that allows spinal monitoring in locations without traditional medical imaging equipment. Compared to X-rays, ultrasound imaging systems are more accessible and affordable for patients[ 12 ]. In recent years, with the exploration of ultrasound for spinal imaging, there has been considerable research on the quantitative relationship between the ultrasound coronal angle (UCA) and the Cobb angle, but there is less research on the application of UCA as a replacement for the Cobb angle. Therefore, to validate the measurement accuracy, substitutive validity, and clinical feasibility of UCA measured by a 3D ultrasound imaging device for assessing the Cobb angle in school-based screening for adolescent scoliosis, our research team incorporated the portable 3D ultrasound imaging system Scolioscan® Air (SCN201) into the screening protocol during scoliosis screening for primary and secondary school students across the entire Gannan Tibetan Autonomous Prefecture, Yongjing County in Linxia Hui Autonomous Prefecture, Anding District and Longxi County in Dingxi City, China. On-site, this device was used to perform ultrasound spinal imaging on suspected positive patients who simultaneously tested positive on the Adams Forward Bend Test and had an Angle of Trunk Rotation (ATR) ≥ 5° measured by an electronic scoliometer. UCA was measured by two personnel. After a week of screening, free clinics were held at local hospitals where patients who came for consultation underwent full-spine X-ray imaging, and the Cobb angle was measured on-site. Subsequently, the UCA measurements obtained during school screening were compared with the Cobb angle measurements from the clinics to validate the substitutive effectiveness of UCA for the Cobb angle. The time required for UCA measurement was recorded during the screening process to verify its clinical feasibility, ultimately aiming to optimize the school-based adolescent scoliosis screening process. 2. Materials and Methods 2.1 Study Subjects This study included 168 suspected AS-positive patients aged 10–18 years, with no metal implants or history of spinal surgery, who simultaneously tested positive on the Adams Forward Bend Test and had an ATR ≥ 5°. All subjects were drawn from suspected AS-positive patients screened by our research team from December 2024 to June 2025 in Gannan Tibetan Autonomous Prefecture, Yongjing County in Linxia Hui Autonomous Prefecture, Anding District, and Longxi County in Dingxi City, Gansu Province, China (Fig. 1 ), totaling 168 cases (Table 1 ). The interval between full-spine X-ray Cobb angle measurement and 3D ultrasound UCA measurement did not exceed 7 days for any patient. All 3D ultrasound device operations during the study were performed by a skilled technician who had undergone rigorous training and had performed measurements on over 100 individuals. All UCA measurements were independently performed by two personnel using a blinded method, and the average was taken. All Cobb angle measurements based on full-spine X-rays were performed on-site by an expert with over 25 years of specialization in scoliosis research. The screening team and local hospital medical staff involved in the screening received comprehensive training on the screening process and methods. Students were informed about scoliosis and agreed to participate in the study. This study was approved by the Ethics Committee of Gansu Provincial Hospital of Traditional Chinese Medicine (Ethics Approval No.: 2023-048-02).Clinical trial number: not applicable. Table 1 Baseline characteristics of the participants Characteristic n Proportion (100%) Average Gender Male 77 45.8 Female 91 54.2 Age (Years) 10 0 0 14.6 ± 1.5 11 3 1.79 12 11 6.55 13 20 11.90 14 43 25.60 15 63 37.5 16 8 4.76 17 9 5.36 18 9 5.36 19 2 1.18 Cobb Angle Cobb angle<10° 33.33 13.58 ± 7.08 10°≤Cobb angle<25° 58.33 25°≤Cobb angle<45° 8.34 Cobb angle ≥ 45° 0 Measurement time (min) UCA (min) 7.2 ± 2.6 X-ray (min) 37.5 ± 4.7 2.2 3D Ultrasound Imaging Device and Coronal Image Generation This study employed the novel portable ultrasound scoliosis assessment system Scolioscan® Air (SCN201). The system uses ultrasound imaging technology combined with spatial positioning technology to achieve three-dimensional imaging analysis of scoliosis. It can provide B-mode ultrasound imaging and 3D ultrasound imaging of the spinal coronal plane, enabling quantitative measurement of lateral spinal curvature morphology and degree. The product features a portable design, primarily consisting of a handheld probe and a laptop connected via USB cable. Accessories include a trolley case, laptop bag, cart, pull-up banner, height-adjustable support stand, and gel warmer, making it easy to carry and use with low requirements for the usage environment. During operation, the operator first applies ultrasound coupling gel to the subject's back and sets the scanning range according to the subject's height. Additionally, to prevent patient movement due to probe slippage during scanning, the system includes supporting thoracic and pelvic plates to maximally adjust shoulder and hip support, stabilizing the patient without altering their natural standing posture. The handheld probe is then smoothly scanned from bottom to top, covering from the lumbar vertebra (L5) to the thoracic vertebra (T1). Real-time images of the spinal coronal plane are displayed during scanning, and upon completion, the 3D ultrasound image volume data of the spine is obtained, as shown in Fig. 2 . 2.3 Angle Measurement Researchers first need to manually identify vertebral levels, transverse processes, and lamina-facet shadows on the coronal ultrasound images to obtain the UCA. Prior to UCA measurement, evaluators must locate suitable points for placing lines on the ultrasound image. The selection of vertebral structures for line drawing is similar to that for measuring the Cobb angle on X-rays, both depending on the location of the most tilted vertebrae at the upper and lower ends of the curve. As this study involved field screening, for efficiency, if a subject had two or three curves, the curve with the largest angle was selected, as shown in Fig. 3 . Cobb angle measurement on full-spine X-rays was performed by one expert with over 20 years of experience in scoliosis research. UCA measurement and 3D ultrasound scanning were performed by two female personnel who had received strict training in 3D ultrasound device use and measurement and had each operated and measured over 200 scoliosis cases. One female researcher operated the 3D ultrasound device and measured UCA on-site. Another female researcher remeasured UCA based on the day's 3D ultrasound images after the screening work concluded. The final UCA data was the average of the two researchers' measurements. If the measurement difference between the two researchers exceeded 5°, a third operator performed the measurement, and the average of the two closest values was taken. The three researchers performed measurements independently without discussing the selection of end vertebrae or corresponding planes. They were blinded to each other's results. 2.4 Study Design This study was divided into three phases: accuracy, validity, and feasibility. In the accuracy phase, to eliminate inter-operator internal effects, all 37 suspected scoliosis-positive patients screened in the first month underwent operator intra-rater testing via ultrasound scanning with the 3D ultrasound device. Specifically, two operators separately operated the device and measured UCA values for these 37 patients. In the validity phase, the correlation between UCA and corresponding Cobb angle measurements obtained from the 37 suspected positive patients from the reliability phase and an additional 131 suspected positive patients was compared. In the feasibility phase, the time difference between obtaining 3D ultrasound images/UCA and obtaining X-ray/Cobb angle was compared. 2.5 Statistical Analysis Statistical analysis was performed using R software version 4.5.2. In the reliability assessment phase, analysis of UCA measurement results obtained multiple times from a pre-selected sample was conducted to evaluate the consistency of measurements under the same or different conditions by measurers/operators. Intra-rater and intra-operator reliability were assessed using the intra-class correlation coefficient (ICC) ICC(3,1) (two-way mixed-effects model, absolute agreement type) and its 95% confidence interval. Inter-rater and inter-operator reliability were assessed using ICC(2,1) (two-way random-effects model, absolute agreement type) and its 95% confidence interval. To further describe measurement error, the mean absolute difference (MAD) and standard error of measurement (SEM) between repeated measurements were calculated. The interpretation criteria for ICC in this study were as follows: ICC ≥ 0.80 indicated excellent reliability, 0.60–0.79 indicated moderate reliability, and ≤ 0.60 indicated questionable or poor reliability. In the validity assessment phase, the relationship between ultrasound UCA and X-ray Cobb angle for major thoracic and thoracolumbar/lumbar curves was explored using Pearson correlation analysis and simple linear regression. A correlation coefficient < 0.25 was considered very low, 0.25–0.50 low, 0.50–0.75 moderate to good, and ≥ 0.75 high to very high. Methodological agreement between UCA and Cobb angle was further quantified using ICC(2,1) (two-way random-effects model, absolute agreement type) and its 95% confidence interval, along with MAD and SEM. Bland-Altman plots were also drawn to observe potential systematic bias and limits of agreement between the two measurement methods. In the feasibility analysis, the Wilcoxon rank-sum test was used to compare the time required to obtain UCA versus X-ray Cobb angle in the full sample. All statistical tests were two-sided, with the significance level set at P < 0.05. 3. Results This study included a total of 168 suspected AS patients, with a mean age of 14.6 ± 1.5 years and a mean Cobb angle of 13.58 ± 7.08° (Table 1 ). Among them, 37 subjects screened in the first month (13 males, 24 females; mean age 14.5 ± 1.5 years; major curve Cobb angle 11.7 ± 6.3°) were used for intra-rater and inter-operator accuracy testing of UCA measurements. The remaining 131 subjects (48 males, 83 females; mean age 14.6 ± 1.6 years; major curve Cobb angle 14.1 ± 7.2°) participated in the subsequent validity testing. All 168 subjects were included in the feasibility assessment phase. 3.1 Accuracy Test A total of 37 suspected scoliosis subjects were included. The intra-rater accuracy ICC(2,1) for UCA measurement was 0.899 (95% CI: 0.814–0.947), with limits of agreement from − 5.69° to 4.46°. Furthermore, the mean difference in UCA measurement angles between the two operators was − 0.616°, indicating good measurement consistency between different operators (Fig. 4 ). 3.2 Validity Test In the validity phase, the major curve (i.e., the curve with the largest angle) of all 168 subjects was assessed for correlation. The results showed a high linear correlation between UCA and Cobb angle (Pearson r = 0.949, P < 0.001), and the methodological agreement ICC reached 0.901, which is considered excellent. Regarding measurement error, the mean absolute difference (MAD) for the major curve was 2.1°, and the standard error of measurement (SEM) was 1.9°, both within clinically acceptable ranges, indicating that UCA has reliable stability and low error in practical measurements (Fig. 5 ). These results suggest that UCA can adequately reflect curvature changes of the radiological Cobb angle and has potential feasibility as an alternative measurement method. 3.3 Feasibility Test All subjects participated in the feasibility assessment. Compared to X-ray examination, UCA measurement showed a significant advantage in time efficiency: measurement time was reduced by an average of 79.2%, and the difference in measurement time between the two methods was statistically significant (P < 0.001) (Fig. 6 ). The results indicate that UCA demonstrates significant time advantages in mass screening settings, enhancing speed and operational feasibility in large-scale screening scenarios. 4. Discussion This study systematically evaluated the accuracy, validity, and feasibility of UCA measured by a portable 3D ultrasound system as a radiation-free alternative to the radiological Cobb angle, and explored its application value in large-scale screening for adolescent scoliosis. The involvement of strictly trained ultrasound operators and a scoliosis expert with over 25 years of experience provided a solid foundation for the reliability of UCA. The results show that in school-based screening for adolescent scoliosis, UCA has good measurement consistency, a close linear relationship with the Cobb angle, and significant advantages in screening efficiency, demonstrating its clinical advantages as a radiation-free screening tool. Regarding accuracy, UCA exhibited high intra-operator consistency, with an intra-class correlation coefficient (ICC) approaching the reliability range reported for classical X-ray Cobb angle measurements[ 13 ], and in some cases even quite close. This high consistency is crucial for patient follow-up, especially in adolescent female populations requiring long-term longitudinal monitoring[ 14 ]. Bland-Altman analysis further showed narrow limits of agreement for measurement differences between different operators, indicating stable reproducibility of the angles obtained by 3D ultrasound across different measurers. The high ICC values and narrow limits of agreement indicate that UCA can maintain reliable measurement stability even in real screening scenarios with large body type variations and complex field conditions. This is consistent with previous research conclusions on the repeatability of imaging Cobb angle and ultrasound measurements in AS patients[ 11 , 15 – 17 ]. Through standardized training procedures and measurement methods, this study effectively reduced inter-operator bias. Similar operations have also been confirmed to have high reliability in the SonixTABLET system[ 18 ]. Notably, if the difference between two measurers exceeded 5°, agreement could be reached after review by a third experienced operator. This indicates that the method is easy to establish for quality control mechanisms in field screening, thereby improving overall measurement stability. Regarding validity, this study demonstrated a high linear correlation between UCA and Cobb angle (r = 0.949), with a mean absolute difference of only 2.1°, below the clinically accepted threshold of 5° for minimal clinically important difference. Its determination results were consistent with clinical X-ray examination data, ensuring direct comparability[ 19 ]. This indicates that ultrasound measurement can meet the sensitivity requirements for angle measurement in screening and follow-up of mild to moderate scoliosis. Previous studies have confirmed that coronal plane ultrasound measurements based on transverse processes and superior articular processes have reliability and validity[ 20 , 21 ]. Research using SPA and COL methods also reported good correlation between ultrasound and Cobb angle[ 22 , 23 ]. This result is consistent with large-sample studies by Meng et al.[ 24 ] (R² = 0.984, n = 302) and Jiang et al.[ 25 ] ( r = 0.95, n = 42), and aligns with the high consistency reported in existing literature[ 15 , 22 , 26 ], further confirming the validity of UCA in coronal plane assessment of mild to moderate AS. It is important to emphasize that, unlike previous studies conducted under ideal conditions in laboratories or imaging departments, this study was carried out in a real school-based screening environment, facing practical challenges such as crowded conditions, diverse body types, limited operating space, and privacy protection. The fact that UCA maintained high angle consistency in such a complex environment fully demonstrates the robustness of this ultrasound system and its potential for large-scale application in resource-limited areas. This aligns with the conclusions of Zhu et al.[ 27 ] in the Linxia region of Gansu. Despite limitations of time, venue, and population diversity, UCA demonstrated good diagnostic stability, indicating its suitability for large-scale screening scenarios. This also validates the propositions of Lee and Yang et al.[ 28 , 29 ] that ultrasound devices can be used for large-scale adolescent scoliosis screening. In the feasibility phase, UCA acquisition time was significantly shorter than X-ray examination, averaging about 7.2 minutes per subject. Although this time is longer than the 37.3 ± 6.8 seconds reported by Yang et al.[ 29 ] and the average of less than 30 seconds reported by Lee et al.[ 16 ], the primary reasons are related to the field screening setting: some students, despite signing informed consent, were shy and reluctant to expose their backs; overweight individuals required probe changes; female subjects required covering garments; and wiping coupling gel from the subject's skin surface after scanning. These steps increased the per-examination time. However, with process optimization, improved site arrangement, and accumulated operational experience, these issues can be effectively addressed. In contrast, the average time to obtain full-spine X-rays was 37.5 minutes. UCA still saved over 79.2% of the time, which is significant for public health scenarios requiring screening of large numbers of students daily. The longer duration of X-ray examination primarily stemmed from the following factors: in the consultation process, patients needed to obtain examination requests first, and unfamiliarity with the hospital environment and waiting in queues consumed considerable time. Furthermore, this study was organized at the county/district level, with free clinics concentrated on weekends, leading to a high patient volume. Additionally, X-ray equipment and the skill levels of radiology staff varied across some regions, resulting in slow stitching speeds for full-spine images and even equipment failures due to prolonged high-load operation, further extending examination time. Moreover, ultrasound screening does not require X-ray equipment, radiation protection facilities, or specialized imaging department environments[ 30 ]. It can be conducted directly in schools, reducing transportation and time costs for students traveling to medical institutions, offering clear convenience and cost-effectiveness. In summary, this study demonstrates that in adolescent scoliosis screening, the non-radiological indicator UCA has high reliability and shows good agreement with the gold standard Cobb angle in coronal plane assessment. Simultaneously, due to its rapid operation and lack of environmental constraints, it is suitable for large-scale screening, especially in areas with relatively scarce medical resources. This aids in achieving early detection and intervention, reducing delays caused by uneven distribution of medical resources. However, posteroanterior X-rays remain the gold standard for quantifying Cobb angle in AS diagnosis and progression monitoring[ 31 ]. Ultrasound has inherent limitations in anatomical structure visualization and methodology; therefore, it is more suitable as a radiation-free screening and auxiliary monitoring tool rather than a complete replacement for X-ray examination, especially during initial diagnosis or when comprehensive assessment of three-dimensional deformity characteristics is required[ 32 ]. Based on the results of this study, we propose a dynamic monitoring strategy of "Ultrasound Screening - X-ray Confirmation - Ultrasound Follow-up." This involves using 3D ultrasound for initial screening in schools, referring suspected positive cases to hospitals for full-spine X-ray examination and Cobb angle measurement for definitive diagnosis, and subsequently using radiation-free UCA for monitoring during routine follow-ups, with X-ray re-examination every 1–2 years to confirm long-term changes. This strategy can significantly reduce cumulative radiation exposure in adolescents during long-term follow-up, lowering potential cancer risks[ 33 – 35 ], without compromising diagnostic accuracy. It is particularly suitable for adolescent populations during growth spurts. 5. Limitations The subjects in this study primarily had mild to moderate Cobb angles. Future studies need to include more patients with severe curvature to validate the applicability of UCA in high-degree curves. Secondly, due to speed requirements in practical screening, this study focused mainly on the coronal plane and the curve with the largest Cobb angle in suspected positive patients, not involving three-dimensional spinal rotation, sagittal parameters, or curve type classification. Future research urgently needs to explore methods for rapid three-dimensional ultrasound assessment of the spine. Finally, the number of subjects included in this study was limited, and data collection used only a single ultrasound device. Subsequent multi-device, large-scale, multi-center clinical trials and long-term follow-up are needed to validate the universality and stability of this technique. 6. Conclusion Based on this study, in school-based screening for adolescent scoliosis, the ultrasound coronal angle (UCA) detected and measured by radiation-free ultrasound devices is an effective alternative indicator to the Cobb angle measured on radiological full-spine X-ray films. Abbreviations AS adolescent scoliosis UCA ultrasound coronal angle ATR angle of trunk rotation ICC intra-class correlation coefficient MAD mean absolute difference SEM standard error of measurement CI confidence interval 3D three-dimensional. Declarations Ethics approval and consent to participate : This study was approved by the Ethics Committee of Gansu Provincial Hospital of Traditional Chinese Medicine (Approval No. 2023-048-02) and was conducted in accordance with the Declaration of Helsinki. Written informed consent was obtained from all participants and their legal guardians prior to participation. Consent for publication : Not applicable. No identifiable personal data are presented in this manuscript. Availability of data and materials : The datasets used and/or analyzed during the current study are not publicly available due to ethical and privacy restrictions (involving minors), but are available from the corresponding author on reasonable request and with approval from the Ethics Committee of Gansu Provincial Hospital of Traditional Chinese Medicine. Competing Interests : The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Funding : This work was funded by the Major Project of the Gansu Provincial Joint Research Fund (Grant No. 23JRRA1529), Recipient: Jiantao Wen; the Key Project of the Gansu Provincial Joint Research Fund (Grant No. 25JRRA1220), Recipient: Jiantao Wen; the General Project of the Gansu Provincial Joint Research Fund (Grant No. 25JRRA1224), Recipient: Jin Huang; the Gansu Provincial Disease Prevention and Control Research Project (Grant No. GSJKKY2025-08), Recipient: Chen Zhang; and the Gansu Provincial Disease Prevention and Control Research Project (Grant No. GSJKKY2025-46), Recipient: Jiantao Wen. Authors' contributions : SY conceived and designed the study and drafted the manuscript. CZ and PM participated in data acquisition and data curation. XY, HL, JZ, YZ, and DH contributed to clinical/ultrasound assessments and quality control. CD contributed to the methodology and statistical analysis. KY critically revised the manuscript for important intellectual content. JW, JH, and JWen supervised the study and coordinated the project. All authors read and approved the final manuscript. Acknowledgements : We sincerely thank all participating students and their legal guardians. We also thank the staff involved in the school-based screening program and data collection, as well as the collaborating schools and local health authorities for their support. References Li M, Nie Q, Liu J, Jiang Z. Prevalence of scoliosis in children and adolescents: a systematic review and meta-analysis. Front Pediatr. 2024;12:1399049. 10.3389/fped.2024.1399049 . Published 2024 Jul 23. Bunnell WP. The natural history of idiopathic scoliosis. Clin Orthop Relat Res. 1988;(229):20–5. Addai D, Zarkos J, Bowey AJ. Current concepts in the diagnosis and management of adolescent idiopathic scoliosis. Childs Nerv Syst. 2020;36(6):1111–9. 10.1007/s00381-020-04608-4 . Fu X, Meng S, Huang X, Li W, Ye B, Chen S. 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Ultrasonics. 2022;126:106819. 10.1016/j.ultras.2022.106819 . de Reuver S, Brink RC, Lee TTY, Zheng YP, Beek FJA, Castelein RM. Cross-validation of ultrasound imaging in adolescent idiopathic scoliosis. Eur Spine J. 2021;30(3):628–33. 10.1007/s00586-020-06652-9 . Zhu S, Zhao C, Li Y, et al. Scoliosis Screening for Students From Primary and Junior Schools Using Electronic Devices: An Exploratory Study. Spine (Phila Pa 1976). 2025;50(24):1788–97. 10.1097/BRS.0000000000005377 . Lee TT, Lai KK, Cheng JC, Castelein RM, Lam TP, Zheng YP. 3D ultrasound imaging provides reliable angle measurement with validity comparable to X-ray in patients with adolescent idiopathic scoliosis. J Orthop Translat. 2021;29:51–9. 10.1016/j.jot.2021.04.007 . Published 2021 May 19. Yang X, Di D, Lv Y, et al. Three-dimensional ultrasonography: Advancing the clinical evaluation of adolescent idiopathic scoliosis. Ultrason Sonochem. 2025;119:107391. 10.1016/j.ultsonch.2025.107391 . Oquendo Y, Hollyer I, Maschhoff C, et al. Mobile device-based 3D scanning is superior to scoliometer in assessment of adolescent idiopathic scoliosis. Spine Deform. 2025;13(2):529–37. 10.1007/s43390-024-01007-6 . Jada A, Mackel CE, Hwang SW, et al. Evaluation and management of adolescent idiopathic scoliosis: a review. Neurosurg Focus. 2017;43(4):E2. 10.3171/2017.7.FOCUS17297 . Lai KK, Lee TT, Lau HH, et al. Monitoring of Curve Progression in Patients with Adolescent Idiopathic Scoliosis Using 3-D Ultrasound. Ultrasound Med Biol. 2024;50(3):384–93. 10.1016/j.ultrasmedbio.2023.11.011 . Levy AR, Goldberg MS, Hanley JA, Mayo NE, Poitras B. Projecting the lifetime risk of cancer from exposure to diagnostic ionizing radiation for adolescent idiopathic scoliosis. Health Phys. 1994;66(6):621–33. 10.1097/00004032-199406000-00002 . Lansford TJ, Burton DC, Asher MA, Lai SM. Radiographic and patient-based outcome analysis of different bone-grafting techniques in the surgical treatment of idiopathic scoliosis with a minimum 4-year follow-up: allograft versus autograft/allograft combination. Spine J. 2013;13(5):523–9. 10.1016/j.spinee.2013.01.025 . Ronckers CM, Land CE, Miller JS, Stovall M, Lonstein JE, Doody MM. Cancer mortality among women frequently exposed to radiographic examinations for spinal disorders. Radiat Res. 2010;174(1):83–90. 10.1667/RR2022.1 . Additional Declarations No competing interests reported. Supplementary Files Supplementarymaterial.docx Cite Share Download PDF Status: Under Review Version 1 posted Reviews received at journal 29 Apr, 2026 Reviews received at journal 22 Apr, 2026 Reviewers agreed at journal 14 Apr, 2026 Reviews received at journal 10 Apr, 2026 Reviewers agreed at journal 09 Apr, 2026 Reviewers agreed at journal 09 Apr, 2026 Reviewers invited by journal 02 Apr, 2026 Editor invited by journal 04 Mar, 2026 Editor assigned by journal 06 Feb, 2026 Submission checks completed at journal 05 Feb, 2026 First submitted to journal 05 Feb, 2026 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-8690892","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":616300239,"identity":"0f4eeb9c-65bb-4294-8684-f8df732c561b","order_by":0,"name":"Shaobo Yang","email":"","orcid":"","institution":"Gansu University of Traditional Chinese Medicine","correspondingAuthor":false,"prefix":"","firstName":"Shaobo","middleName":"","lastName":"Yang","suffix":""},{"id":616300240,"identity":"5f5360c5-497e-48e8-9a70-42db9a07b92e","order_by":1,"name":"Chen Zhang","email":"","orcid":"","institution":"Gansu Provincial Hospital of Traditional Chinese Medicine","correspondingAuthor":false,"prefix":"","firstName":"Chen","middleName":"","lastName":"Zhang","suffix":""},{"id":616300242,"identity":"95ef0549-e35b-4be1-856c-15b982e7e035","order_by":2,"name":"Peiji Miao","email":"","orcid":"","institution":"Gansu University of Traditional Chinese Medicine","correspondingAuthor":false,"prefix":"","firstName":"Peiji","middleName":"","lastName":"Miao","suffix":""},{"id":616300243,"identity":"e4f7eafb-37f9-4a95-ac22-1d04b90eb10b","order_by":3,"name":"Xiaoyun Yuan","email":"","orcid":"","institution":"Gansu Provincial Hospital of Traditional Chinese Medicine","correspondingAuthor":false,"prefix":"","firstName":"Xiaoyun","middleName":"","lastName":"Yuan","suffix":""},{"id":616300245,"identity":"fdf2fd1c-92e0-403d-8022-d4b868ee4e3d","order_by":4,"name":"Han Leng","email":"","orcid":"","institution":"Gansu Provincial Hospital of Traditional Chinese Medicine","correspondingAuthor":false,"prefix":"","firstName":"Han","middleName":"","lastName":"Leng","suffix":""},{"id":616300246,"identity":"e0321e7c-02bf-42cb-8145-539187a00455","order_by":5,"name":"Jing Zhang","email":"","orcid":"","institution":"Gansu University of Traditional Chinese Medicine","correspondingAuthor":false,"prefix":"","firstName":"Jing","middleName":"","lastName":"Zhang","suffix":""},{"id":616300247,"identity":"fae5e592-9e1e-47f4-a8df-8e322a1d9f3e","order_by":6,"name":"Yanxiang Zhang","email":"","orcid":"","institution":"Gansu University of Traditional Chinese Medicine","correspondingAuthor":false,"prefix":"","firstName":"Yanxiang","middleName":"","lastName":"Zhang","suffix":""},{"id":616300249,"identity":"bec3b987-05ce-4816-a936-0d3e5e33d715","order_by":7,"name":"Dong Hou","email":"","orcid":"","institution":"Gansu University of Traditional Chinese Medicine","correspondingAuthor":false,"prefix":"","firstName":"Dong","middleName":"","lastName":"Hou","suffix":""},{"id":616300250,"identity":"0229f7a5-6613-4087-abd1-e9a8764757f7","order_by":8,"name":"Changquan Dai","email":"","orcid":"","institution":"Gansu Provincial Hospital of Traditional Chinese Medicine","correspondingAuthor":false,"prefix":"","firstName":"Changquan","middleName":"","lastName":"Dai","suffix":""},{"id":616300251,"identity":"fbcfbd11-4802-4f6e-8d4f-13667418f0b3","order_by":9,"name":"Kang Yang","email":"","orcid":"","institution":"Gansu University of Traditional Chinese Medicine","correspondingAuthor":false,"prefix":"","firstName":"Kang","middleName":"","lastName":"Yang","suffix":""},{"id":616300253,"identity":"9604e755-3ed1-41eb-9363-b7c9ce4ff7f2","order_by":10,"name":"Juan Wang","email":"","orcid":"","institution":"Gansu Provincial Hospital of Traditional Chinese Medicine","correspondingAuthor":false,"prefix":"","firstName":"Juan","middleName":"","lastName":"Wang","suffix":""},{"id":616300255,"identity":"db43e43f-e02b-4bcd-a185-2ce3cc17da22","order_by":11,"name":"Jin Huang","email":"","orcid":"","institution":"Gansu Provincial Hospital of Traditional Chinese Medicine","correspondingAuthor":false,"prefix":"","firstName":"Jin","middleName":"","lastName":"Huang","suffix":""},{"id":616300256,"identity":"69167b9d-1faf-4483-80c4-bf1a6d003be7","order_by":12,"name":"Jiantao Wen","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABAUlEQVRIiWNgGAWjYDCCA2CSjQfCq5CDCD4gTgszkD5jDBFMIKwFBIBaGNsgWhjwaeG7fYBN4uMOPhn+2f0HP3ycZyBncO3wQ6AtdnK6Ddi1SJ5LYJOceYaNR+LOYWbJmdsMjCVnpxkAtSQbmx3ArsXgDAPbbd42oF9uJDNI8277k9gvnQDSciBxGz4tf4Fa5G8kM//mnWOQ2Cad/oGwFkagFoMbyWzSvA0GQFty8NsieYax/WcvUIvhjWQzyxnHQH7JKTiQYIDbL3xnmA8b/Gw7Zi93I/HxjQ81wBC7nb75w4cKOzlcWoBx0QAkjmE4GJdyOKghqGIUjIJRMApGMAAAGXRdlP9lkCcAAAAASUVORK5CYII=","orcid":"","institution":"Gansu Provincial Hospital of Traditional Chinese Medicine","correspondingAuthor":true,"prefix":"","firstName":"Jiantao","middleName":"","lastName":"Wen","suffix":""}],"badges":[],"createdAt":"2026-01-25 07:38:33","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8690892/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8690892/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":106348220,"identity":"dabd631f-4277-4db8-b26f-2f8983785196","added_by":"auto","created_at":"2026-04-07 16:44:47","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":10748869,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eGeographical map of the screening areas\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe map illustrates the locations within Gansu Province, China, where the school-based screening was conducted, including Gannan Tibetan Autonomous Prefecture, Yongjing County in Linxia Hui Autonomous Prefecture, Anding District, and Longxi County in Dingxi City.\u003c/p\u003e","description":"","filename":"Fig1.png","url":"https://assets-eu.researchsquare.com/files/rs-8690892/v1/de47db030ef37dea1bdcb963.png"},{"id":106403619,"identity":"134438a2-ad18-4d66-abad-58f5b9dc1ab5","added_by":"auto","created_at":"2026-04-08 09:14:37","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":20998612,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eScolioscan® Air (SCN201) device components and operation\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e(A) The portable 3D ultrasound system setup, consisting of a handheld probe, laptop, and support accessories. (B) Schematic demonstrating the operational procedure, where the probe is swept from the lumbar (L5) to thoracic (T1) region over the subject’s back to acquire coronal spinal images.\u003c/p\u003e","description":"","filename":"Fig2.png","url":"https://assets-eu.researchsquare.com/files/rs-8690892/v1/cd4e379ae88f68c9aa866a20.png"},{"id":106348221,"identity":"7f72b625-fa40-44c1-8cab-f3e96265e1f2","added_by":"auto","created_at":"2026-04-07 16:44:47","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":12188900,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eUltrasound image and angle measurement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA representative coronal ultrasound image of the spine obtained by the Scolioscan® Air system. The ultrasound coronal angle (UCA) is measured by manually identifying vertebral landmarks (e.g., transverse processes) and drawing lines along the endplates of the most tilted vertebrae at the cranial and caudal ends of the major curve, analogous to the Cobb angle method.\u003c/p\u003e","description":"","filename":"Fig3.png","url":"https://assets-eu.researchsquare.com/files/rs-8690892/v1/9624b309af8a492e65858592.png"},{"id":106404520,"identity":"82ef21b8-a0a6-45aa-a66e-575279647b42","added_by":"auto","created_at":"2026-04-08 09:16:09","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":1407650,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eBland-Altman plot showing differences between different operators\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe plot assesses the inter-operator agreement for UCA measurements. The solid horizontal line represents the mean difference between two operators, and the dashed lines indicate the 95% limits of agreement. The close clustering of data points around the mean difference demonstrates good measurement consistency between operators.\u003c/p\u003e","description":"","filename":"Fig4.png","url":"https://assets-eu.researchsquare.com/files/rs-8690892/v1/fe0b4bcb7d54edc66d8f776f.png"},{"id":106404414,"identity":"33f1503a-a723-42ac-80dc-7e3086db9776","added_by":"auto","created_at":"2026-04-08 09:15:58","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":1400914,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eCorrelation and regression equation between Cobb angle and UCA for the major curve\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe scatter plot shows the strong linear relationship between the radiographic Cobb angle (x-axis) and the ultrasound coronal angle (UCA, y-axis) for the major curve in all 168 subjects. The solid line represents the linear regression fit, and the shaded area indicates the 95% confidence interval. The high Pearson correlation coefficient (r = 0.949) is displayed.\u003c/p\u003e","description":"","filename":"Fig5.png","url":"https://assets-eu.researchsquare.com/files/rs-8690892/v1/6873cd2cf05572e52d487359.png"},{"id":106348223,"identity":"7f8e2f6c-b24e-4926-828a-cba972f9db78","added_by":"auto","created_at":"2026-04-07 16:44:47","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":1004666,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eComparison of time required for Cobb angle vs. UCA measurement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e(A) Box-and-whisker plot comparing the distribution of time required for UCA acquisition and full-spine X-ray examination. The central box represents the interquartile range (25th to 75th percentile), the horizontal line within the box indicates the median, and the whiskers extend to the minimum and maximum values. UCA measurement (blue) was significantly faster than X-ray (red). (B) Scatter plot with paired connecting lines, illustrating the time difference for each individual subject (n=168). Each gray line connects the UCA time (blue point) and the X-ray time (red point) for the same participant, visually demonstrating the consistent and substantial reduction in procedure time achieved with the ultrasound method.\u003c/p\u003e","description":"","filename":"Fig6.png","url":"https://assets-eu.researchsquare.com/files/rs-8690892/v1/eb9b5a0ae8c171f9794ff5d5.png"},{"id":106414999,"identity":"db50c754-475f-4265-8b49-0278aa0d334a","added_by":"auto","created_at":"2026-04-08 10:31:46","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":37553827,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8690892/v1/701d5311-5159-499d-9ad8-840a43ffc428.pdf"},{"id":106404100,"identity":"c422ab16-b91c-491e-a2ec-a8ae9e1d9aab","added_by":"auto","created_at":"2026-04-08 09:15:30","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":58421,"visible":true,"origin":"","legend":"","description":"","filename":"Supplementarymaterial.docx","url":"https://assets-eu.researchsquare.com/files/rs-8690892/v1/dc8e9a44048aa293af4d4613.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Measurement of Ultrasound Coronal Angle as a Non-Radiological Alternative to Cobb Angle in School-Based Screening for Adolescent Scoliosis: Assessment of Accuracy, Validity, and Feasibility","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eAdolescent scoliosis (AS) is a three-dimensional spinal deformity characterized by a lateral curvature in one or more segments of the spine, combined with vertebral rotation, leading to core deviation and sagittal progression. Severe scoliosis can lead to serious complications such as cardiovascular issues, decreased pulmonary function, chronic pain, and psychological distress\u003csup\u003e[1]\u003c/sup\u003e. According to global studies, the prevalence of scoliosis ranges from approximately 1% to 3%[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e], typically emerging around the age of 10 in adolescents[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Epidemiological data may vary slightly across different countries and regions, but the widespread nature of this condition has garnered significant attention. The overall prevalence of scoliosis among Chinese adolescents aged 10\u0026ndash;18 is 1.2%[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], with over 5\u0026nbsp;million primary and secondary school students affected, and this number is increasing by about 300,000 annually.\u003c/p\u003e \u003cp\u003eSince many cases of scoliosis present no significant symptoms during childhood and adolescence, especially in patients with mild curvature, the condition is often discovered incidentally during assessments for height or other health concerns. School-based screening can effectively identify these latent cases, preventing progression, as treatment plans for scoliosis are typically based on several predefined thresholds[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. This also makes early screening a key component of disease management[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Regular screening within schools enables early detection of scoliosis, allowing for interventions such as physical therapy, bracing, or surgery, thereby effectively preventing disease progression and improving patients' quality of life.\u003c/p\u003e \u003cp\u003eMeasuring the coronal Cobb angle on upright full-spine radiographs is the standard procedure in clinical practice for diagnosing, monitoring curve progression, and assigning treatment for scoliosis patients, and is considered the gold standard for diagnosis[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. The Cobb angle measurement is widely used in clinical and research settings and is highly standardized. However, Cobb angle measurement has significant limitations, primarily radiation exposure. Examining the spine for scoliosis requires full-spine X-rays. Simony et al.[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e] found that the ionizing radiation dose for a full-spine X-ray is 0.8\u0026ndash;1.4 mSv per session. Patients are frequently exposed to radiation during scoliosis evaluations, and due to the need for multiple examinations during longitudinal follow-up, this radiation exposure is cumulative[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Additionally, X-ray imaging is expensive and the equipment is difficult to transport[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e], making it unsuitable for large-scale scoliosis screening. Therefore, there is an urgent need for a device that can replace the Cobb angle, is radiation-free, portable, and suitable for large-scale scoliosis screening.\u003c/p\u003e \u003cp\u003eThe advent of ultrasound imaging devices addresses these shortcomings of traditional X-rays well. Ultrasound imaging is an inexpensive, radiation-free method that allows spinal monitoring in locations without traditional medical imaging equipment. Compared to X-rays, ultrasound imaging systems are more accessible and affordable for patients[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. In recent years, with the exploration of ultrasound for spinal imaging, there has been considerable research on the quantitative relationship between the ultrasound coronal angle (UCA) and the Cobb angle, but there is less research on the application of UCA as a replacement for the Cobb angle. Therefore, to validate the measurement accuracy, substitutive validity, and clinical feasibility of UCA measured by a 3D ultrasound imaging device for assessing the Cobb angle in school-based screening for adolescent scoliosis, our research team incorporated the portable 3D ultrasound imaging system Scolioscan\u0026reg; Air (SCN201) into the screening protocol during scoliosis screening for primary and secondary school students across the entire Gannan Tibetan Autonomous Prefecture, Yongjing County in Linxia Hui Autonomous Prefecture, Anding District and Longxi County in Dingxi City, China. On-site, this device was used to perform ultrasound spinal imaging on suspected positive patients who simultaneously tested positive on the Adams Forward Bend Test and had an Angle of Trunk Rotation (ATR)\u0026thinsp;\u0026ge;\u0026thinsp;5\u0026deg; measured by an electronic scoliometer. UCA was measured by two personnel. After a week of screening, free clinics were held at local hospitals where patients who came for consultation underwent full-spine X-ray imaging, and the Cobb angle was measured on-site. Subsequently, the UCA measurements obtained during school screening were compared with the Cobb angle measurements from the clinics to validate the substitutive effectiveness of UCA for the Cobb angle. The time required for UCA measurement was recorded during the screening process to verify its clinical feasibility, ultimately aiming to optimize the school-based adolescent scoliosis screening process.\u003c/p\u003e"},{"header":"2. Materials and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Study Subjects\u003c/h2\u003e \u003cp\u003eThis study included 168 suspected AS-positive patients aged 10\u0026ndash;18 years, with no metal implants or history of spinal surgery, who simultaneously tested positive on the Adams Forward Bend Test and had an ATR\u0026thinsp;\u0026ge;\u0026thinsp;5\u0026deg;. All subjects were drawn from suspected AS-positive patients screened by our research team from December 2024 to June 2025 in Gannan Tibetan Autonomous Prefecture, Yongjing County in Linxia Hui Autonomous Prefecture, Anding District, and Longxi County in Dingxi City, Gansu Province, China (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e), totaling 168 cases (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The interval between full-spine X-ray Cobb angle measurement and 3D ultrasound UCA measurement did not exceed 7 days for any patient. All 3D ultrasound device operations during the study were performed by a skilled technician who had undergone rigorous training and had performed measurements on over 100 individuals. All UCA measurements were independently performed by two personnel using a blinded method, and the average was taken. All Cobb angle measurements based on full-spine X-rays were performed on-site by an expert with over 25 years of specialization in scoliosis research. The screening team and local hospital medical staff involved in the screening received comprehensive training on the screening process and methods. Students were informed about scoliosis and agreed to participate in the study. This study was approved by the Ethics Committee of Gansu Provincial Hospital of Traditional Chinese Medicine (Ethics Approval No.: 2023-048-02).Clinical trial number: not applicable.\u003c/p\u003e \u003cp\u003e \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\u003eBaseline characteristics of the participants\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=\"char\" char=\".\" 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=\"char\" char=\"\u0026plusmn;\" 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\u003eCharacteristic\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\u003eProportion (100%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eAverage\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eGender\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e77\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e45.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFemale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e91\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e54.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge (Years)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\" morerows=\"9\" rowspan=\"10\"\u003e \u003cp\u003e14.6\u0026thinsp;\u0026plusmn;\u0026thinsp;1.5\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\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.79\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\u003e12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6.55\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\u003e13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e11.90\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\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e43\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e25.60\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\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e63\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e37.5\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\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4.76\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\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5.36\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\u003e18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5.36\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\u003e19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.18\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003eCobb Angle\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCobb angle\u0026lt;10\u0026deg;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e33.33\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e13.58\u0026thinsp;\u0026plusmn;\u0026thinsp;7.08\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e10\u0026deg;\u0026le;Cobb angle\u0026lt;25\u0026deg;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e58.33\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e25\u0026deg;\u0026le;Cobb angle\u0026lt;45\u0026deg;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e8.34\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCobb angle\u0026thinsp;\u0026ge;\u0026thinsp;45\u0026deg;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eMeasurement time (min)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eUCA (min)\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=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e7.2\u0026thinsp;\u0026plusmn;\u0026thinsp;2.6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eX-ray (min)\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=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e37.5\u0026thinsp;\u0026plusmn;\u0026thinsp;4.7\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 3D Ultrasound Imaging Device and Coronal Image Generation\u003c/h2\u003e \u003cp\u003eThis study employed the novel portable ultrasound scoliosis assessment system Scolioscan\u0026reg; Air (SCN201). The system uses ultrasound imaging technology combined with spatial positioning technology to achieve three-dimensional imaging analysis of scoliosis. It can provide B-mode ultrasound imaging and 3D ultrasound imaging of the spinal coronal plane, enabling quantitative measurement of lateral spinal curvature morphology and degree. The product features a portable design, primarily consisting of a handheld probe and a laptop connected via USB cable. Accessories include a trolley case, laptop bag, cart, pull-up banner, height-adjustable support stand, and gel warmer, making it easy to carry and use with low requirements for the usage environment. During operation, the operator first applies ultrasound coupling gel to the subject's back and sets the scanning range according to the subject's height. Additionally, to prevent patient movement due to probe slippage during scanning, the system includes supporting thoracic and pelvic plates to maximally adjust shoulder and hip support, stabilizing the patient without altering their natural standing posture. The handheld probe is then smoothly scanned from bottom to top, covering from the lumbar vertebra (L5) to the thoracic vertebra (T1). Real-time images of the spinal coronal plane are displayed during scanning, and upon completion, the 3D ultrasound image volume data of the spine is obtained, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3 Angle Measurement\u003c/h2\u003e \u003cp\u003eResearchers first need to manually identify vertebral levels, transverse processes, and lamina-facet shadows on the coronal ultrasound images to obtain the UCA. Prior to UCA measurement, evaluators must locate suitable points for placing lines on the ultrasound image. The selection of vertebral structures for line drawing is similar to that for measuring the Cobb angle on X-rays, both depending on the location of the most tilted vertebrae at the upper and lower ends of the curve. As this study involved field screening, for efficiency, if a subject had two or three curves, the curve with the largest angle was selected, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. Cobb angle measurement on full-spine X-rays was performed by one expert with over 20 years of experience in scoliosis research. UCA measurement and 3D ultrasound scanning were performed by two female personnel who had received strict training in 3D ultrasound device use and measurement and had each operated and measured over 200 scoliosis cases. One female researcher operated the 3D ultrasound device and measured UCA on-site. Another female researcher remeasured UCA based on the day's 3D ultrasound images after the screening work concluded. The final UCA data was the average of the two researchers' measurements. If the measurement difference between the two researchers exceeded 5\u0026deg;, a third operator performed the measurement, and the average of the two closest values was taken. The three researchers performed measurements independently without discussing the selection of end vertebrae or corresponding planes. They were blinded to each other's results.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e2.4 Study Design\u003c/h2\u003e \u003cp\u003eThis study was divided into three phases: accuracy, validity, and feasibility. In the accuracy phase, to eliminate inter-operator internal effects, all 37 suspected scoliosis-positive patients screened in the first month underwent operator intra-rater testing via ultrasound scanning with the 3D ultrasound device. Specifically, two operators separately operated the device and measured UCA values for these 37 patients. In the validity phase, the correlation between UCA and corresponding Cobb angle measurements obtained from the 37 suspected positive patients from the reliability phase and an additional 131 suspected positive patients was compared. In the feasibility phase, the time difference between obtaining 3D ultrasound images/UCA and obtaining X-ray/Cobb angle was compared.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e2.5 Statistical Analysis\u003c/h2\u003e \u003cp\u003eStatistical analysis was performed using R software version 4.5.2. In the reliability assessment phase, analysis of UCA measurement results obtained multiple times from a pre-selected sample was conducted to evaluate the consistency of measurements under the same or different conditions by measurers/operators. Intra-rater and intra-operator reliability were assessed using the intra-class correlation coefficient (ICC) ICC(3,1) (two-way mixed-effects model, absolute agreement type) and its 95% confidence interval. Inter-rater and inter-operator reliability were assessed using ICC(2,1) (two-way random-effects model, absolute agreement type) and its 95% confidence interval. To further describe measurement error, the mean absolute difference (MAD) and standard error of measurement (SEM) between repeated measurements were calculated. The interpretation criteria for ICC in this study were as follows: ICC\u0026thinsp;\u0026ge;\u0026thinsp;0.80 indicated excellent reliability, 0.60\u0026ndash;0.79 indicated moderate reliability, and \u0026le;\u0026thinsp;0.60 indicated questionable or poor reliability.\u003c/p\u003e \u003cp\u003eIn the validity assessment phase, the relationship between ultrasound UCA and X-ray Cobb angle for major thoracic and thoracolumbar/lumbar curves was explored using Pearson correlation analysis and simple linear regression. A correlation coefficient\u0026thinsp;\u0026lt;\u0026thinsp;0.25 was considered very low, 0.25\u0026ndash;0.50 low, 0.50\u0026ndash;0.75 moderate to good, and \u0026ge;\u0026thinsp;0.75 high to very high. Methodological agreement between UCA and Cobb angle was further quantified using ICC(2,1) (two-way random-effects model, absolute agreement type) and its 95% confidence interval, along with MAD and SEM. Bland-Altman plots were also drawn to observe potential systematic bias and limits of agreement between the two measurement methods.\u003c/p\u003e \u003cp\u003eIn the feasibility analysis, the Wilcoxon rank-sum test was used to compare the time required to obtain UCA versus X-ray Cobb angle in the full sample. All statistical tests were two-sided, with the significance level set at \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/p\u003e \u003c/div\u003e"},{"header":"3. Results","content":"\u003cp\u003eThis study included a total of 168 suspected AS patients, with a mean age of 14.6\u0026thinsp;\u0026plusmn;\u0026thinsp;1.5 years and a mean Cobb angle of 13.58\u0026thinsp;\u0026plusmn;\u0026thinsp;7.08\u0026deg; (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Among them, 37 subjects screened in the first month (13 males, 24 females; mean age 14.5\u0026thinsp;\u0026plusmn;\u0026thinsp;1.5 years; major curve Cobb angle 11.7\u0026thinsp;\u0026plusmn;\u0026thinsp;6.3\u0026deg;) were used for intra-rater and inter-operator accuracy testing of UCA measurements. The remaining 131 subjects (48 males, 83 females; mean age 14.6\u0026thinsp;\u0026plusmn;\u0026thinsp;1.6 years; major curve Cobb angle 14.1\u0026thinsp;\u0026plusmn;\u0026thinsp;7.2\u0026deg;) participated in the subsequent validity testing. All 168 subjects were included in the feasibility assessment phase.\u003c/p\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003e3.1 Accuracy Test\u003c/h2\u003e \u003cp\u003eA total of 37 suspected scoliosis subjects were included. The intra-rater accuracy ICC(2,1) for UCA measurement was 0.899 (95% CI: 0.814\u0026ndash;0.947), with limits of agreement from \u0026minus;\u0026thinsp;5.69\u0026deg; to 4.46\u0026deg;. Furthermore, the mean difference in UCA measurement angles between the two operators was \u0026minus;\u0026thinsp;0.616\u0026deg;, indicating good measurement consistency between different operators (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003e3.2 Validity Test\u003c/h2\u003e \u003cp\u003eIn the validity phase, the major curve (i.e., the curve with the largest angle) of all 168 subjects was assessed for correlation. The results showed a high linear correlation between UCA and Cobb angle (Pearson r\u0026thinsp;=\u0026thinsp;0.949, P\u0026thinsp;\u0026lt;\u0026thinsp;0.001), and the methodological agreement ICC reached 0.901, which is considered excellent. Regarding measurement error, the mean absolute difference (MAD) for the major curve was 2.1\u0026deg;, and the standard error of measurement (SEM) was 1.9\u0026deg;, both within clinically acceptable ranges, indicating that UCA has reliable stability and low error in practical measurements (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e). These results suggest that UCA can adequately reflect curvature changes of the radiological Cobb angle and has potential feasibility as an alternative measurement method.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003e3.3 Feasibility Test\u003c/h2\u003e \u003cp\u003eAll subjects participated in the feasibility assessment. Compared to X-ray examination, UCA measurement showed a significant advantage in time efficiency: measurement time was reduced by an average of 79.2%, and the difference in measurement time between the two methods was statistically significant (P\u0026thinsp;\u0026lt;\u0026thinsp;0.001) (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e). The results indicate that UCA demonstrates significant time advantages in mass screening settings, enhancing speed and operational feasibility in large-scale screening scenarios.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"4. Discussion","content":"\u003cp\u003eThis study systematically evaluated the accuracy, validity, and feasibility of UCA measured by a portable 3D ultrasound system as a radiation-free alternative to the radiological Cobb angle, and explored its application value in large-scale screening for adolescent scoliosis. The involvement of strictly trained ultrasound operators and a scoliosis expert with over 25 years of experience provided a solid foundation for the reliability of UCA. The results show that in school-based screening for adolescent scoliosis, UCA has good measurement consistency, a close linear relationship with the Cobb angle, and significant advantages in screening efficiency, demonstrating its clinical advantages as a radiation-free screening tool.\u003c/p\u003e \u003cp\u003eRegarding accuracy, UCA exhibited high intra-operator consistency, with an intra-class correlation coefficient (ICC) approaching the reliability range reported for classical X-ray Cobb angle measurements[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e], and in some cases even quite close. This high consistency is crucial for patient follow-up, especially in adolescent female populations requiring long-term longitudinal monitoring[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Bland-Altman analysis further showed narrow limits of agreement for measurement differences between different operators, indicating stable reproducibility of the angles obtained by 3D ultrasound across different measurers. The high ICC values and narrow limits of agreement indicate that UCA can maintain reliable measurement stability even in real screening scenarios with large body type variations and complex field conditions. This is consistent with previous research conclusions on the repeatability of imaging Cobb angle and ultrasound measurements in AS patients[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan additionalcitationids=\"CR16\" citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Through standardized training procedures and measurement methods, this study effectively reduced inter-operator bias. Similar operations have also been confirmed to have high reliability in the SonixTABLET system[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Notably, if the difference between two measurers exceeded 5\u0026deg;, agreement could be reached after review by a third experienced operator. This indicates that the method is easy to establish for quality control mechanisms in field screening, thereby improving overall measurement stability.\u003c/p\u003e \u003cp\u003eRegarding validity, this study demonstrated a high linear correlation between UCA and Cobb angle (r\u0026thinsp;=\u0026thinsp;0.949), with a mean absolute difference of only 2.1\u0026deg;, below the clinically accepted threshold of 5\u0026deg; for minimal clinically important difference. Its determination results were consistent with clinical X-ray examination data, ensuring direct comparability[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. This indicates that ultrasound measurement can meet the sensitivity requirements for angle measurement in screening and follow-up of mild to moderate scoliosis. Previous studies have confirmed that coronal plane ultrasound measurements based on transverse processes and superior articular processes have reliability and validity[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. Research using SPA and COL methods also reported good correlation between ultrasound and Cobb angle[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. This result is consistent with large-sample studies by Meng et al.[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e] (R\u0026sup2; = 0.984, n\u0026thinsp;=\u0026thinsp;302) and Jiang et al.[\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e] (\u003cem\u003er\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.95, n\u0026thinsp;=\u0026thinsp;42), and aligns with the high consistency reported in existing literature[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e], further confirming the validity of UCA in coronal plane assessment of mild to moderate AS. It is important to emphasize that, unlike previous studies conducted under ideal conditions in laboratories or imaging departments, this study was carried out in a real school-based screening environment, facing practical challenges such as crowded conditions, diverse body types, limited operating space, and privacy protection. The fact that UCA maintained high angle consistency in such a complex environment fully demonstrates the robustness of this ultrasound system and its potential for large-scale application in resource-limited areas. This aligns with the conclusions of Zhu et al.[\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e] in the Linxia region of Gansu. Despite limitations of time, venue, and population diversity, UCA demonstrated good diagnostic stability, indicating its suitability for large-scale screening scenarios. This also validates the propositions of Lee and Yang et al.[\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e] that ultrasound devices can be used for large-scale adolescent scoliosis screening.\u003c/p\u003e \u003cp\u003eIn the feasibility phase, UCA acquisition time was significantly shorter than X-ray examination, averaging about 7.2 minutes per subject. Although this time is longer than the 37.3\u0026thinsp;\u0026plusmn;\u0026thinsp;6.8 seconds reported by Yang et al.[\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e] and the average of less than 30 seconds reported by Lee et al.[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e], the primary reasons are related to the field screening setting: some students, despite signing informed consent, were shy and reluctant to expose their backs; overweight individuals required probe changes; female subjects required covering garments; and wiping coupling gel from the subject's skin surface after scanning. These steps increased the per-examination time. However, with process optimization, improved site arrangement, and accumulated operational experience, these issues can be effectively addressed. In contrast, the average time to obtain full-spine X-rays was 37.5 minutes. UCA still saved over 79.2% of the time, which is significant for public health scenarios requiring screening of large numbers of students daily. The longer duration of X-ray examination primarily stemmed from the following factors: in the consultation process, patients needed to obtain examination requests first, and unfamiliarity with the hospital environment and waiting in queues consumed considerable time. Furthermore, this study was organized at the county/district level, with free clinics concentrated on weekends, leading to a high patient volume. Additionally, X-ray equipment and the skill levels of radiology staff varied across some regions, resulting in slow stitching speeds for full-spine images and even equipment failures due to prolonged high-load operation, further extending examination time. Moreover, ultrasound screening does not require X-ray equipment, radiation protection facilities, or specialized imaging department environments[\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. It can be conducted directly in schools, reducing transportation and time costs for students traveling to medical institutions, offering clear convenience and cost-effectiveness.\u003c/p\u003e \u003cp\u003eIn summary, this study demonstrates that in adolescent scoliosis screening, the non-radiological indicator UCA has high reliability and shows good agreement with the gold standard Cobb angle in coronal plane assessment. Simultaneously, due to its rapid operation and lack of environmental constraints, it is suitable for large-scale screening, especially in areas with relatively scarce medical resources. This aids in achieving early detection and intervention, reducing delays caused by uneven distribution of medical resources. However, posteroanterior X-rays remain the gold standard for quantifying Cobb angle in AS diagnosis and progression monitoring[\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. Ultrasound has inherent limitations in anatomical structure visualization and methodology; therefore, it is more suitable as a radiation-free screening and auxiliary monitoring tool rather than a complete replacement for X-ray examination, especially during initial diagnosis or when comprehensive assessment of three-dimensional deformity characteristics is required[\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eBased on the results of this study, we propose a dynamic monitoring strategy of \"Ultrasound Screening - X-ray Confirmation - Ultrasound Follow-up.\" This involves using 3D ultrasound for initial screening in schools, referring suspected positive cases to hospitals for full-spine X-ray examination and Cobb angle measurement for definitive diagnosis, and subsequently using radiation-free UCA for monitoring during routine follow-ups, with X-ray re-examination every 1\u0026ndash;2 years to confirm long-term changes. This strategy can significantly reduce cumulative radiation exposure in adolescents during long-term follow-up, lowering potential cancer risks[\u003cspan additionalcitationids=\"CR34\" citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e], without compromising diagnostic accuracy. It is particularly suitable for adolescent populations during growth spurts.\u003c/p\u003e"},{"header":"5. Limitations","content":"\u003cp\u003eThe subjects in this study primarily had mild to moderate Cobb angles. Future studies need to include more patients with severe curvature to validate the applicability of UCA in high-degree curves. Secondly, due to speed requirements in practical screening, this study focused mainly on the coronal plane and the curve with the largest Cobb angle in suspected positive patients, not involving three-dimensional spinal rotation, sagittal parameters, or curve type classification. Future research urgently needs to explore methods for rapid three-dimensional ultrasound assessment of the spine. Finally, the number of subjects included in this study was limited, and data collection used only a single ultrasound device. Subsequent multi-device, large-scale, multi-center clinical trials and long-term follow-up are needed to validate the universality and stability of this technique.\u003c/p\u003e"},{"header":"6. Conclusion","content":"\u003cp\u003eBased on this study, in school-based screening for adolescent scoliosis, the ultrasound coronal angle (UCA) detected and measured by radiation-free ultrasound devices is an effective alternative indicator to the Cobb angle measured on radiological full-spine X-ray films.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eAS\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eadolescent scoliosis\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eUCA\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eultrasound coronal angle\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eATR\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eangle of trunk rotation\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eICC\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eintra-class correlation coefficient\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eMAD\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003emean absolute difference\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eSEM\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003estandard error of measurement\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eCI\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003econfidence interval\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e3D\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003ethree-dimensional.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003cstrong\u003e:\u003c/strong\u003eThis study was approved by the Ethics Committee of Gansu Provincial Hospital of Traditional Chinese Medicine (Approval No. 2023-048-02) and was conducted in accordance with the Declaration of Helsinki. Written informed consent was obtained from all participants and their legal guardians prior to participation.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003cstrong\u003e:\u003c/strong\u003eNot applicable. No identifiable personal data are presented in this manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003cstrong\u003e:\u003c/strong\u003eThe datasets used and/or analyzed during the current study are not publicly available due to ethical and privacy restrictions (involving minors), but are available from the corresponding author on reasonable request and with approval from the Ethics Committee of Gansu Provincial Hospital of Traditional Chinese Medicine.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting Interests\u003c/strong\u003e\u003cstrong\u003e:\u003c/strong\u003eThe authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003cstrong\u003e:\u003c/strong\u003eThis work was funded by the Major Project of the Gansu Provincial Joint Research Fund (Grant No. 23JRRA1529), Recipient: Jiantao Wen; the Key Project of the Gansu Provincial Joint Research Fund (Grant No. 25JRRA1220), Recipient: Jiantao Wen; the General Project of the Gansu Provincial Joint Research Fund (Grant No. 25JRRA1224), Recipient: Jin Huang; the Gansu Provincial Disease Prevention and Control Research Project (Grant No. GSJKKY2025-08), Recipient: Chen Zhang; and the Gansu Provincial Disease Prevention and Control Research Project (Grant No. GSJKKY2025-46), Recipient: Jiantao Wen.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026apos;\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003econtributions\u003c/strong\u003e\u003cstrong\u003e:\u003c/strong\u003eSY conceived and designed the study and drafted the manuscript. CZ and PM participated in data acquisition and data curation. XY, HL, JZ, YZ, and DH contributed to clinical/ultrasound assessments and quality control. CD contributed to the methodology and statistical analysis. KY critically revised the manuscript for important intellectual content. JW, JH, and JWen supervised the study and coordinated the project. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003cstrong\u003e:\u003c/strong\u003eWe sincerely thank all participating students and their legal guardians. We also thank the staff involved in the school-based screening program and data collection, as well as the collaborating schools and local health authorities for their support.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eLi M, Nie Q, Liu J, Jiang Z. Prevalence of scoliosis in children and adolescents: a systematic review and meta-analysis. 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Radiat Res. 2010;174(1):83\u0026ndash;90. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1667/RR2022.1\u003c/span\u003e\u003cspan address=\"10.1667/RR2022.1\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\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":"bmc-musculoskeletal-disorders","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bmsd","sideBox":"Learn more about [BMC Musculoskeletal Disorders](http://bmcmusculoskeletdisord.biomedcentral.com/)","snPcode":"","submissionUrl":"https://author-welcome.nature.com/12891","title":"BMC Musculoskeletal Disorders","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Adolescent scoliosis, Cobb angle, Ultrasound coronal angle, Three-dimensional ultrasound imaging, School-based screening, Radiation-free assessment","lastPublishedDoi":"10.21203/rs.3.rs-8690892/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8690892/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eObjective\u003c/h2\u003e \u003cp\u003eTo evaluate the accuracy, validity, and feasibility of the ultrasound coronal angle (UCA) measured by a portable three-dimensional ultrasound imaging device as a non-radiological alternative to the Cobb angle in school-based screening for adolescent scoliosis.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eA cross-sectional study was conducted in multiple regions of Gansu Province, China, from December 2024 to June 2025, involving 168 suspected adolescent scoliosis patients. A portable 3D ultrasound system (Scolioscan\u0026reg; Air) was used to obtain coronal plane images of the spine and measure the UCA. Concurrently, full-spine X-ray radiographs were taken to measure the Cobb angle. Measurement reliability was analyzed using intra-class correlation coefficient (ICC), mean absolute difference (MAD), and standard error of measurement (SEM). The correlation and agreement between UCA and Cobb angle were examined using Pearson correlation analysis, linear regression, and Bland-Altman analysis. Practical feasibility was assessed by comparing the measurement times of both methods.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eUCA showed a high correlation with the Cobb angle (r\u0026thinsp;=\u0026thinsp;0.949, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001), with a mean absolute difference of 2.1\u0026deg; and an SEM of 1.9\u0026deg;. UCA measurement demonstrated excellent intra-rater reliability (ICC\u0026thinsp;=\u0026thinsp;0.899) and inter-operator consistency. The acquisition time for UCA was significantly shorter than for X-ray examination (7.2\u0026thinsp;\u0026plusmn;\u0026thinsp;2.6 min vs. 37.5\u0026thinsp;\u0026plusmn;\u0026thinsp;4.7 min, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001), representing an efficiency improvement of approximately 79.2%.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eThe ultrasound coronal angle exhibits good reliability, validity, and time efficiency in school-based screening for adolescent scoliosis, and can serve as a radiation-free preliminary screening tool suitable for large-scale population screening.\u003c/p\u003e","manuscriptTitle":"Measurement of Ultrasound Coronal Angle as a Non-Radiological Alternative to Cobb Angle in School-Based Screening for Adolescent Scoliosis: Assessment of Accuracy, Validity, and Feasibility","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-04-07 16:44:42","doi":"10.21203/rs.3.rs-8690892/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"editorInvitedReview","content":"","date":"2026-04-29T19:20:03+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-04-22T15:02:03+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"336992133381175973300356212191027409957","date":"2026-04-14T12:58:24+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-04-10T10:33:11+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"172143965499004461152447132689239214049","date":"2026-04-09T15:27:45+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"258181016306560265527424608121685688791","date":"2026-04-09T06:09:02+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-04-02T04:23:52+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2026-03-04T06:44:55+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-02-06T05:08:56+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-02-05T17:48:32+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Musculoskeletal Disorders","date":"2026-02-05T16:30:18+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-musculoskeletal-disorders","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bmsd","sideBox":"Learn more about [BMC Musculoskeletal Disorders](http://bmcmusculoskeletdisord.biomedcentral.com/)","snPcode":"","submissionUrl":"https://author-welcome.nature.com/12891","title":"BMC Musculoskeletal Disorders","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"b26fa02b-c6d8-4264-bc0f-105618a93694","owner":[],"postedDate":"April 7th, 2026","published":true,"recentEditorialEvents":[{"type":"editorInvitedReview","content":"","date":"2026-04-29T19:20:03+00:00","index":75,"fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-04-07T16:44:42+00:00","versionOfRecord":[],"versionCreatedAt":"2026-04-07 16:44:42","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8690892","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8690892","identity":"rs-8690892","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}