{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,30]],"date-time":"2026-03-30T11:02:27Z","timestamp":1774868547186,"version":"3.50.1"},"reference-count":17,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2026,3,28]],"date-time":"2026-03-28T00:00:00Z","timestamp":1774656000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Diagnostics"],"abstract":"<jats:p>Background\/Objectives: This study aimed to examine the prevalence of anatomical variations in the sacroiliac joints (SIJs) as observed through Magnetic Resonance Imaging (MRI), to characterize their manifestations, and to identify MRI features that may resemble inflammatory alterations. Methods: A retrospective review was conducted on consecutive MRI scans of the SIJ performed from January 2009 to January 2022. Eight anatomical variations, along with associated edematous and structural changes, were assessed. Results: The study encompassed 840 patients, with anatomical variations identified in 39.7% of the cohort, occurring more frequently among female participants. The most prevalent variations were accessory SIJ (36.2%) and the iliosacral complex (32.2%). Notably, isolated synostosis and persistent ossification center variations were absent. The increased frequency of variations in women, as well as their correlation with advancing age, was statistically significant (p = 0.034). Accessory SIJ and dysmorphic alterations were linked to bone marrow edema and structural modifications. In the iliosacral complex and semicircular defect variations, prominent vascular structures were observed extending along the bone surfaces. The number and depth of edema slices in sacroiliitis exceeded those observed in the variation (p &lt; 0.001). Conclusions: Anatomical variations of the SIJ are prevalent among women and tend to increase with advancing age. Given that these variations, particularly accessory SIJ and dysmorphic alterations, may present with edematous and structural signal intensity changes that resemble sacroiliitis, it is crucial to recognize these variations. It is recommended to assess axial and coronal images concurrently and to exercise caution in the interpretation of SIJ MR images.<\/jats:p>","DOI":"10.3390\/diagnostics16071020","type":"journal-article","created":{"date-parts":[[2026,3,30]],"date-time":"2026-03-30T09:57:24Z","timestamp":1774864644000},"page":"1020","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Assessment of Anatomical Variations in the Sacroiliac Joint Using Magnetic Resonance Imaging: A Retrospective Study of 840 Patients"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-1549-1677","authenticated-orcid":false,"given":"Selen","family":"Beyaz\u0131t","sequence":"first","affiliation":[{"name":"Department of Radiology, Arsuz State Hospital, 31285 Hatay, Turkey"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Gezmi\u015f","family":"Kimyon","sequence":"additional","affiliation":[{"name":"Department of Rheumatology, Mustafa Kemal University, 31040 Hatay, Turkey"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Sinem","family":"Karazincir","sequence":"additional","affiliation":[{"name":"Department of Radiology, Mustafa Kemal University, 31040 Hatay, Turkey"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,3,28]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1958","DOI":"10.1136\/annrheumdis-2015-208642","article-title":"Defining active sacroiliitis on MRI for classification of axial spondyloarthritis: Update by the ASAS MRI working group","volume":"75","author":"Lambert","year":"2016","journal-title":"Ann. Rheum. Dis."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"323","DOI":"10.1097\/00004728-199903000-00029","article-title":"Sacroiliac joints: Anatomical variants on CT","volume":"23","author":"Prassopoulos","year":"1999","journal-title":"J. Comput. Assist. Tomogr."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"87","DOI":"10.5603\/FM.a2020.0032","article-title":"The variations and degenerative changes of sacroiliac joints in asymptomatic adults","volume":"80","author":"Cihan","year":"2021","journal-title":"Folia Morphol."},{"key":"ref_4","first-page":"209","article-title":"Anatomical variations with joint space measurements on CT","volume":"53","author":"Demir","year":"2007","journal-title":"Kobe J. Med. Sci."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"819","DOI":"10.1007\/s00276-021-02714-9","article-title":"Anatomical variations of the sacro-iliac joint: A computed tomography study","volume":"43","year":"2021","journal-title":"Surg. Radiol. Anat."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"5328","DOI":"10.1007\/s00330-018-5540-x","article-title":"Sacroiliac joints: Anatomical variations on MR images","volume":"28","author":"Badr","year":"2018","journal-title":"Eur. Radiol."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"595","DOI":"10.1007\/s00256-021-03843-3","article-title":"Anatomical variation at the sacroiliac joints in young adults: Estimated prevalence by CT and concomitant diagnostics by MRI","volume":"51","author":"Kiil","year":"2022","journal-title":"Skeletal Radiol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"122","DOI":"10.1007\/s00330-015-3790-4","article-title":"Optimizing the MRI protocol of the sacroiliac joints in Spondyloarthritis: Which para-axial sequence should be used?","volume":"26","author":"Giraudo","year":"2016","journal-title":"Eur. Radiol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"839","DOI":"10.1002\/ca.23539","article-title":"Frequency of anatomical variation of the sacroiliac joint in asymptomatic young adults and its relationship with sacroiliac joint degeneration","volume":"33","author":"Korkmaz","year":"2020","journal-title":"Clin. Anat."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"66","DOI":"10.1007\/s11926-021-01030-w","article-title":"Imaging in Axial Spondyloarthritis: What is Relevant for Diagnosis in Daily Practice?","volume":"23","author":"Weber","year":"2021","journal-title":"Curr. Rheumatol. Rep."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"736","DOI":"10.1002\/art.40429","article-title":"Frequency and Anatomic Distribution of Magnetic Resonance Imaging Features in the Sacroiliac Joints of Young Athletes: Exploring \u201cBackground Noise\u201d Toward a Data-Driven Definition of Sacroiliitis in Early Spondyloarthritis","volume":"70","author":"Weber","year":"2018","journal-title":"Arthritis Rheumatol."},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Badr, S., Jacques, T., Lefebvre, G., Boulil, Y., Abou Diwan, R., and Cotten, A. (2021). Main Diagnostic Pitfalls in Reading the Sacroiliac Joints on MRI. Diagnostics, 11.","DOI":"10.3390\/diagnostics11112001"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1042","DOI":"10.1002\/art.40475","article-title":"Magnetic Resonance Imaging of the Sacroiliac Joints Indicating Sacroiliitis According to the Assessment of SpondyloArthritis international Society Definition in Healthy Individuals, Runners, and Women With Postpartum Back Pain","volume":"70","author":"Berg","year":"2018","journal-title":"Arthritis Rheumatol."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Caetano, A.P., Mascarenhas, V.V., and Machado, P.M. (2021). Axial Spondyloarthritis: Mimics and Pitfalls of Imaging Assessment. Front. Med., 8.","DOI":"10.3389\/fmed.2021.658538"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"15","DOI":"10.1007\/s00256-003-0691-4","article-title":"MR imaging of the normal sacroiliac joint with correlation to histology","volume":"33","author":"Puhakka","year":"2004","journal-title":"Skeletal Radiol."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"60","DOI":"10.1007\/s11926-021-01033-7","article-title":"Anatomical Joint Form Variation in Sacroiliac Joint Disease: Current Concepts and New Perspectives","volume":"23","author":"Ziegeler","year":"2021","journal-title":"Curr. Rheumatol. Rep."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"579","DOI":"10.1007\/s00256-020-03608-4","article-title":"The pediatric accessory sacroiliac joint: Does it exist?","volume":"50","author":"Rixey","year":"2021","journal-title":"Skeletal Radiol."}],"container-title":["Diagnostics"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2075-4418\/16\/7\/1020\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,3,30]],"date-time":"2026-03-30T10:11:50Z","timestamp":1774865510000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2075-4418\/16\/7\/1020"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,3,28]]},"references-count":17,"journal-issue":{"issue":"7","published-online":{"date-parts":[[2026,4]]}},"alternative-id":["diagnostics16071020"],"URL":"https:\/\/doi.org\/10.3390\/diagnostics16071020","relation":{},"ISSN":["2075-4418"],"issn-type":[{"value":"2075-4418","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,3,28]]}}}