{"paper_id":"c1a24e74-ddfd-4fab-b8c7-737ac4dbbcf3","body_text":"Submit Manuscript | http://medcraveonline.com\nAbbreviations and Acronyms: SE, Spin Echo; MRI, \nMagnetic Resonance Imaging; USL, Uuterosacral Ligament; HE, \nHematoxylin-Eosin Staining\nIntroduction\nEndometriosis is characterized by endometriotic tissue consisting \nof hormone-dependent glandular formations, stromal cells and smooth \nmuscle in sites located outside of the uterine cavity. 1-6 The estimated \nprevalence of endometriosis is high and makes it to one of the most \ncommon pathologies in women of reproductive age.1,7-9\nMagnetic resonance imaging (MRI) is becoming a mainstay of pre \noperative diagnostics, in particular for diagnosing deep infiltrating \nendometriosis.10-17 MRI sensitivity and specificity depends on the \nlocalization of endometriosis. 17 The most important technique for \nMRI uses T2-weighted and T1-weighted sequences. Hemorrhages \nwithin endometriotic foci are considered one hallmark feature \nof endometriosis distinguishable by MRI. 18-21 According to the \nliterature, the T1-weighted sequence with fat suppression improves \nthe diagnostic value of MRI for endometriosis because it allows \nstructures containing lipid to be differentiated from those containing \nblood.18-22 High-signal-intensity spots on the T1-weighted images \ncount as characteristic features for detecting uterine adenomyosis \nin MRI diagnostics.23,24 In a recently published study on the value of \nMRI in the diagnosis of bladder endometriosis, high-signal-intensity \nspots were observed in 72% of all endometriotic foci. 25 However, \nthere are no data on the frequency of high-signal-intensity spots at \nfat-suppressed T1-weighted imaging in other localizations of pelvic \nendometriosis. In addition, typical findings in adenomyosis are \nhigh signal spots or strips in T2-weighted images. 23,24 In bladder \nendometriosis, high-signal-intensity spots in T2-weighted sequences \nwere detected in 61.1% of histologically verified endometriosis. 25 \nNo data are available on the frequency of T2 spots in other sites of \nlocalized pelvic endometriosis.\nThe objective of this study was to investigate the incidence of \nhigh-signal-intensity lesions at preoperative T1 and T2-weighted \nmagnet resonance imaging (MRI) in patients with endometriosis at \ndefined pelvic locations.\nMaterials and methods\nThe study was approved by the institutional review board and \ncarried out in accordance with The Code of Ethics of the Declaration \nof Helsinki. Prior to inclusion, the patients were presented with \ncomprehensive information about the study. All patients gave their \ninformed written consent to participate.\nPatient population\nDuring the period from 2009 to 2012, 252 women with clinical and \nsonographic findings suspicious of endometriosis underwent an MRI \nexamination followed by laparoscopy involving surgical ablation of \ntheir endometriosis.\nIn all patients, medical history was taken followed by a clinical \nrectovaginal examination, transvaginal sonography and MRI. The \nsurgical biopsies were histopathologically analyzed. All women had \nbeen examined according to our recently published MRI protocol. 17 \nObstet Gynecol Int J. 2017;6(6):162‒165. 162\n©2017 Karsten et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which \npermits unrestrited use, distribution, and build upon your work non-commercially.\nMagnet Resonance Imaging in Preoperative \nEndometriosis: Incidence of High-Signal-Intensity \nSpots on Fat-Suppressed T1-Weighted and T2-\nWeighted Images\nVolume 6 Issue 6 - 2017\nKarsten Krger,  Lana Gilly, Kai Behrendt, \nAndreas D Ebert \nDepartment of Radiology, Vivantes Humboldt Hospital, Germany\nCorrespondence: Karsten Krger, Department of Radiology, \nVivantes Humboldt Hospital, Am Nordgraben 213509 Berlin, \nGermany, T el 49-30-130-12-3701, \nEmail \nReceived: March 20, 2017 | Published: May 03, 2017\nAbstract\nObjectives: To investigate the incidence of high-signal-intensity lesions at preoperative T1 \nand T2-weighted magnet resonance imaging (MRI) in patients with pelvic endometriosis.\nStudy Design: Between 2009 and 2012, 252 women with clinical and sonographic suspicion \nof endometriosis underwent pelvic MRI using T2 and unenhanced T1 sequences with and \nwithout fat saturation. Two radiologists interpreted the following regions retrospectively by \nconsensus according to a standardized protocol: uterus, vagina, pouch of Douglas, rectum, \nuterosacral ligament (USL). High-signal-intensity lesions in the fat-suppressed T1-weighted \nimages were defined as hemorrhagic foci. Their incidence and that of high-signal-intensity \nspots in T2-weighted images were documented in histopathological verified endometriosis.\nResults: In patients with rectal endometriosis (128/252 patients), high-signal-intensity \nspots were detected on 10.2% of T1-weighted fat-suppressed images and on 16.9% of T2-\nweighted images. In uterus adenomyosis (236/252 patients) high-signal-intensity spots on \nT1 and T2 weighted images occurred in 43.2% and 24.2%, respectively (vagina (115/252, \n31.3% and 41.9%; USL 119/252, 7.6% and 13.8%, pouch of Douglas 169/252, 31.4% and \n28.1%, other localizations 7/252, 71.4% and 57.1%)\nConclusion: The incidence of high-signal-intensity spots on T1 and T2-weighted images \ndepends on the localization of endometriosis. T1 und T2 high-signal-intensity spots are less \nrelevant in diagnosing endometriosis of the rectum and uterosacral ligament.\nObstetrics & Gynecology International Journal\nResearch Article\n Open Access\n\n\nMagnet Resonance Imaging in Preoperative Endometriosis: Incidence of High-Signal-Intensity Spots on \nFat-Suppressed T1-Weighted and T2-Weighted Images\n163\nCopyright:\n©2017 Karsten et al.\nCitation: Karsten KG, Lana G, Kai B, et al. Magnet Resonance Imaging in Preoperative Endometriosis: Incidence of High-Signal-Intensity Spots on Fat-\nSuppressed T1-Weighted and T2-Weighted Images. Obstet Gynecol Int J. 2017;6(6):162‒165. DOI: 10.15406/ogij.2017.06.00227\nIn brief, the examinations were performed on a 1.5 Tesla MRI \n(Magnetom, Avanto, Siemens, Erlangen, Germany) using a 6-channel \nbody coil without intravenous contrast medium. Transversal and \nsagittal T2-weighted and T1-weighted spin echo sequences with \nand without fat saturation were performed. Immediately before the \nexamination, 200 ml of water were administered rectally, 10 ml of \nsterile gel (Instillagel, Farco-Pharma, Cologne, Germany) vaginally \nand 20 mg of butylscopolamine (Buscopan, Boehringer Ingelheim, \nGermany) intravenously. An optimal filling status of the bladder was \nachieved as recently described. 25 In all patients, the examinations \nwere performed outside of the menstrual phase. 26 The inclusion and \nexclusion criteria were described recently. 17 Two MRI-experienced \nradiologists evaluated the scans by consensus. The MRI studies were \nevaluated on a work station approved for the review of radiological \nimages (monitor: EIZO, Eizo Nanao Corporation, Hakui, Japan; \nPACS: Impax, AGFA Health Care, Bonn, Germany). In conducting \nthe study, patient data were pseudonymized by replacing the patient’s \nname with a number.\nSurgery\nThe surgical technique was recently described in detail.17 In short, \nall patients underwent a preoperative MRI of the pelvis, a transvaginal \nand transrectal ultrasound and a rectoscopy. Laparoscopies were \nperformed by an experienced gynecological endoscopist. Inspection \ncovered the cecum and appendix region, ascending colon, right medial \nand epigastric peritoneum, right diaphragmatic dome, right liver \nregion and gastric curvature and extended to the left diaphragmatic \ndome, left hepatic region, spleen and the left medial and epigastric \nperitoneum, the intestinal folds and omentum. After placing the patient \nin a maximum head-down Trendelenburg position, the entire pelvic \nperitoneum was scrutinized. Next, the standardized examination \nwas performed of the round ligaments, bladder peritoneum, tubes, \novaries, ovarian fossae, uterosacral ligaments, pouch of Douglas and \nuterus. Finally, the foci were resected one-by-one and subjected to \nhistopathological examination. The staging of endometriosis was \ncharacterized using the Classification of the ASRM and the ENZIAN \nclassification for deep infiltrating endometriosis.27\nPathology\nAs previously described in detail,17 the surgically resected lesions \nwere stained with hematoxylin and eosin (HE) for histopathologic \nstudies. Diagnosis of endometriosis was based on proof of ectopic \nendometrial glands and stroma in the resected lesions. 28 In all cases, \nthe presence of estrogen and progesterone receptors and KI 67 (kiel) \nwas verified. 29 Histopathological verification of endometriosis was \nclassified as a positive finding.\nStatistics\nIf not otherwise stated, the numbers are expressed as means ± \nstandard deviations or percentages. Laparoscopy with histological \nverification of the diagnosis for endometriosis was used as the gold \nstandard. In Adenomyosis, medical history, uterine ultrasound and \nendoscopic criteria such as serositis, ischemic areals, and changes \nin muscular consistence confirmed the surgical diagnosis of \nendometriosis genitalis interna.\nUterus\nA denomyosis was correctly diagnosed by MRI in 236 of 252 \npatients (93.6%). Of the patients with positive finding of adenomyosis \n102 patients (43.2%) had high-signal-intensity spots in T1 weighted \nimages with fat suppression within the lesion. High signal spots or \nstripes in T2 weighted images with in the lesion were detected in \n24.2% of the patients\nVagina\nMRI finding of vaginal endometriosis was correctly diagnosed in \n115 of the 252 patients (46.6%).. In 31.3% of manifestations with a \ncorrect positive diagnosis on the MRI, high signal intensities were \nobserved in the fat-suppressed T1 SE sequence. High-signal-intensity \nspots in T2 weighted imaging were detected in 41.9%.\nRectum\nA MRI positive finding of rectum endometriosis was proved by \nhistopahology in 128 of the 252 patients (50.8%). In 13 patients \n(10.2%) with histopathology proven endometriosis of the rectum high \nsignal intensities were observed in the fat-suppressed T1 SE sequence \nand in 19.6% high signal spots in T2 weighted imaging, (Figures 1-3).\nFigure 1 40-year-old woman with primary dysmenorrhea and dyspareunia in \nendometriosis stage rASRM II°. Rectal endometriosis with high signal intensity \nspots on T2-weighted spin echo images (arrow in a) but without any bright \nspots on T1 weighted images with fat suppression (b).\nFigure 2 Example for rectal endometriosis in a 35-year-old woman. Many high \nsignal intensity spots were detectable on both, T1 weighted images with fat \nsuppression (arrow in b) and on T2 weighted images (arrow in a).\nFigure 3  39-year-old woman with endometriosis stage rASRM II°. MRI \ndemonstrates rectal endometriosis with only a few high signal intensity spots \non T1 weighted images with fat suppression (b). On T2 weighted images (a) the \nendometriotic lesion shows a low signal intensity but without high signal spots.\n\n\nMagnet Resonance Imaging in Preoperative Endometriosis: Incidence of High-Signal-Intensity Spots on \nFat-Suppressed T1-Weighted and T2-Weighted Images\n164\nCopyright:\n©2017 Karsten et al.\nCitation: Karsten KG, Lana G, Kai B, et al. Magnet Resonance Imaging in Preoperative Endometriosis: Incidence of High-Signal-Intensity Spots on Fat-\nSuppressed T1-Weighted and T2-Weighted Images. Obstet Gynecol Int J. 2017;6(6):162‒165. DOI: 10.15406/ogij.2017.06.00227\nUterosacral ligaments\nIn 47.2% (119 of 252) of the patients, endometriotic implants were \nhistopathologically proved in the uterosacral ligaments. In 9 patients \n(7.6%) of manifestations with a correct positive diagnosis on the \nMRI, high signal intensities were observed in the fat-suppressed T1 \nSE sequence. In T2 weighted images high-signal-intensity spots were \nobserved in 13.8%\nPouch of Douglas\nIn 169 patients (67.1%) the MRI finding of endometriotic lesion \nin the pouch of Douglas was proved. Of these patients high-signal-\nintensity spots in T1 weighted fat suppressed sequences were observed \nin 53 endometriotic lesions (31.4%) and T2 weighted spots in 28.1%.\nOther manifestations\nIn 7 of the 252 patients (2.8%), endometriotic implants were found \nat the following locations: abdominal wall in 5 and in the groin in 1 \nand at vaginal introitus one. In 5 of 7 manifestations on the MRI image \n(71.4%), high signal intensities were observed in the fat-suppressed \nT1 SE sequence. High-signal-intensity spots were observed in 57.1% \nin T2 weighted images.\nComment\nMRI ranks as one of the main stays for diagnosing endometriosis. \nThis study tried to further evaluated characteristics of endometriosis \nin MRI. According to the literature, the T1-weighted sequence with \nfat suppression improves the diagnostic value of MRI18-22 because this \nsequence enables a differentiation between structures containing lipid \nand those containing blood. Endometriotic lesions typically appear \nwith low signal intensity on T2 weighted images. They are further \ncharacterized by high-signal-intensity spots in the fat-suppressed \nT1-weighted sequence. In a recently published study on bladder \nendometriosis high-signal-intensity spots were found in 72% of all \nendometriotic lesions. 25 Also for uterine adenomyosis high-signal-\nintensity spots in the T1 -weighted in MRI were found as a typical \nfinding.23,24 These spots are the result of hemorrhages and count as \ncharacteristic features in MRI diagnostics. 18-21 The T1-weighted \nsequence with fat suppression are said to improve the diagnostic value \nof MRI for endometriosis because this sequence allows for structures \ncontaining lipid to be differentiated from those containing blood.18-22\nHowever, so far there are no data about the frequency of high signal \nT1-weighted spots in different localizations of pelvic endometriosis. \nIn our study, we investigated a large patient group of histologically \nproved endometriosis and positive findings in MRI at different \nlocalizations. Interestingly, the frequency of high-signal-intensity \nspots in our patient population was very variable. It was lowest in \nendometriotic lesions of the uterosacral ligaments (8%), followed \nby rectal endometriosis (10%), the endometriosis of the vagina and \nthe pouch of douglas (both with 31%) and the uterus with 43%. The \nfrequency of high-signal-intensity spots was remarkable lower than \nin the recently published data on bladder endometriosis. Obviously, \nbleeding in the endometriotic lesions occurs with different frequency. \nWe only can speculate about the reasons why these differences occur. \nOne possible reason could be the activity and the duration of the \ndisease.\nIn our patient population, endometriosis at other locations was rare. \nHowever hemorrhagic foci were observed at a very high frequency of \n71%. We did not provide data about the frequency of high-signal-\nintensity spots in T1 for ovarian and peritoneal endometriosis because \nfor both this is a very typical or even the only feature in MRI and \nreaches 100%. For ovarian endometriosis one should keep in mind \nthat we have morphological criteria like thickening of an ovarian \ncyst wall, reactions in the surrounding tissue, the so called “dark \nclot sign” 30 and the markedly lower apparent diffusion coefficient \n(ADC) in endometriomas than in functional ovarian cysts which can \nimprove the specificity of MRI. 31 Peritoneal manifestations are only \ndetected by MRI if they contain blood. Therefore, T1 high-signal-\nintensity spots are very important to detect peritoneal endometriosis. \nHowever, by no means do all peritoneal endometriotic implants \nfeature hemorrhagic foci. These are the pigmented and black clusters \ncontaining hemosiderin-laden macrophages. Only these are detectable \nin the fat-suppressed T1 SE sequence. 19 For this reason, MRI has a \nlow sensitivity in the diagnostic of peritoneal endometriosis and plays \nnot an important role in this part of the disease.17\nAnother feature of endometriosis in MRI are high-signal-intensity \nspots in T2 weighted images. These were observed in 61% in bladder \nendometriosis25 and are characteristic features in MRI diagnostics \nfor uterine adenomyosis. 23,24 In our study on other localization we \nfound high-signal-intensity spots in a frequency between 14% for \nendometriosis of the uterosacral ligaments and 42% for endometriosis \nof the vagina. As with high signal T1, the frequency of high-signal-\nintensity T2 lesions is very variable.\nLimitations\nOne limitation of this study was its retrospective design. We \ninterpreted the high-signal-intensity lesions in fat saturated T1 images \nas hemorrhagic foci as in the literature,18-21 but this was not correlated \nwith histopathology.\nConclusion\nThe data of our study show that the relevance of the fat-saturated T1 \nsequence and T2 spots for diagnosing endometriosis varies, depending \non its location. T1 und T2 high-signal-intensity spots are less relevant \nin diagnosing endometriosis of the rectum and uterosacral ligaments.\nAcknowledgments\nNone.\nConflicts of interest\nNone.\nReferences\n1. Bulun SE. Endometriosis. N Engl J Med. 2009;360(3):268–279.\n2. Leyendecker G, Wildt L, Mall G. The pathophysiology of endometriosis \nand adenomyosis: tissue injury and repair. Arch Gynecol Obstet . \n2009;280(4):529–538.\n3. Sylvia Mechsner, Jessica Schwarz, Johanna Thode, et al. 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