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Normal subchondral high T2 signal on MRI mimicking sacroiliitis in children: frequency, age distribution, and relationship to skeletal maturity

  • Musculoskeletal
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To determine patterns of variation of subchondral T2 signal changes in pediatric sacroiliac joints (SIJ) by location, age, sex, and sacral apophyseal closure.


MRI of 502 SIJ in 251 children (132 girls), mean age 12.4 years (range 6.1–18.0), was obtained with parental informed consent. One hundred twenty-seven out of 251 had asymptomatic joints and were imaged for non-rheumatologic reasons, and 124 had low back pain but no sign of sacroiliitis on initial clinical MRI review. After calibration, three subspecialist radiologists independently scored subchondral signal changes on fat-suppressed fluid-sensitive sequences from 0 to 3 in 4 locations, and graded the degree of closure of sacral segmental apophyses. Associations between patient age, sex, signal changes, and apophyseal closure were analyzed.


Rim-like subchondral increased T2 signal or “flaring” was much more common at sacral than iliac SIJ margins (72% vs 16%, p < 0.001) and was symmetrical in > 90% of children. Iliac flaring scores were always lower than sacral, except for 1 child. Signal changes decreased as sacral apophyses closed, and were seen in < 20% of subjects with fully closed apophyses. Signal changes were more frequent in boys, and peaked in intensity later than for girls (ages 8–12 vs. 7–10). Subchondral signal in iliac crests was high throughout childhood and did not correlate with other locations.


Subchondral T2 “flaring” is common at SIJ of prepubertal children and is generally sacral-predominant and symmetrical. Flaring that is asymmetrical, greater in ilium than sacrum, or intense in a teenager with closed apophyses, is unusual for normal children and raises concern for pathologic bone marrow edema.

Key Points

• A rim of subchondral high T2 signal is commonly observed on MRI at pediatric sacroiliac joints, primarily on the sacral side before segmental apophyseal closure, and should not be confused with pathology.

• Unlike subchondral signal changes elsewhere, high T2 signal underlying the iliac crest apophyses is a near-universal normal finding in children that usually persists throughout adolescence.

• The following patterns are unusual in normal children and are suspicious for pathology: definite iliac flaring, iliac flaring more intense than sacral flaring, left-right difference in flaring, definite flaring of any pattern in teenagers after sacral apophyseal closure.

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  1. Tse SM, Laxer RM (2012) New advances in juvenile spondyloarthritis. Nat Rev Rheumatol 8:269–279.

    Article  CAS  PubMed  Google Scholar 

  2. Herregods N, Dehoorne J, Joos R et al (2015) Diagnostic value of MRI features of sacroiliitis in juvenile spondyloarthritis. Clin Radiol 70:1428–1438.

    Article  CAS  PubMed  Google Scholar 

  3. Sieper J, Rudwaleit M, Baraliakos X et al (2009) The Assessment of SpondyloArthritis international Society (ASAS) handbook: a guide to assess spondyloarthritis. Ann Rheum Dis 68(Suppl 2):ii1–i44.

    Article  PubMed  Google Scholar 

  4. Jaremko JL, Liu L, Winn NJ, Ellsworth JE, Lambert RG (2014) Diagnostic utility of magnetic resonance imaging and radiography in juvenile spondyloarthritis: evaluation of the sacroiliac joints in controls and affected subjects. J Rheumatol 41:963–970.

    Article  PubMed  Google Scholar 

  5. Lambert RG, Bakker PA, van der Heijde D et al (2016) Defining active sacroiliitis on MRI for classification of axial spondyloarthritis: update by the ASAS MRI working group. Ann Rheum Dis 75:1958–1963.

    Article  PubMed  Google Scholar 

  6. Bollow M, Braun J, Kannenberg J et al (1997) Normal morphology of sacroiliac joints in children: magnetic resonance studies related to age and sex. Skeletal Radiol 26:697–704.

    Article  CAS  PubMed  Google Scholar 

  7. Weiss PF, Xiao R, Biko DM, Chauvin NA (2016) Assessment of sacroiliitis at diagnosis of juvenile spondyloarthritis by radiography, magnetic resonance imaging, and clinical examination. Arthritis Care Res (Hoboken) 68:187–194.

    Article  CAS  Google Scholar 

  8. Weiss PF, Brandon TG, Bohnsack J et al (2020) Variability in magnetic resonance imaging interpretation of the pediatric sacroiliac joint. Arthritis Care Res (Hoboken).

  9. Herregods N, Dehoorne J, Van den Bosch F et al (2017) ASAS definition for sacroiliitis on MRI in SpA: applicable to children? Pediatr Rheumatol Online J 15:24.

    Article  PubMed  PubMed Central  Google Scholar 

  10. Broome DR, Hayman LA, Herrick RC, Braverman RM, Glass RB, Fahr LM (1998) Postnatal maturation of the sacrum and coccyx: MR imaging, helical CT, and conventional radiography. AJR Am J Roentgenol 170:1061–1066.

    Article  CAS  PubMed  Google Scholar 

  11. Bowen V, Cassidy JD (1981) Macroscopic and microscopic anatomy of the sacroiliac joint from embryonic life until the 8th decade. Spine (Phila Pa 1976) 6:620–628.

  12. Chauvin NA, Xiao R, Brandon TG et al (2019) MRI of the sacroiliac joint in healthy children. AJR Am J Roentgenol 212:1303–1309.

    Article  Google Scholar 

  13. Herregods N, Dehoorne J, Pattyn E et al (2015) Diagnositic value of pelvic enthesitis on MRI of the sacroiliac joints in enthesitis related arthritis. Pediatr Rheumatol Online J 13:46.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  14. Herregods N, Jaremko JL, Baraliakos X et al (2015) Limited role of gadolinium to detect active sacroiliitis on MRI in juvenile spondyloarthritis. Skeletal Radiol 44:1637–1646.

    Article  CAS  PubMed  Google Scholar 

  15. Landis JR, Koch GG (1977) The measurement of observer agreement for categorical data. Biometrics 33:159–174.

    Article  CAS  PubMed  Google Scholar 

  16. Cicchetti DV (1994) Guidelines, criteria, and rules of thumb for evaluating normed and standardized assessment instruments in psychology. Psychol Assess 6:284–290.

    Article  Google Scholar 

  17. Zejden A, Jurik AG (2017) Anatomy of the sacroiliac joints in children and adolescents by computed tomography. Pediatr Rheumatol Online J 15:82.

    Article  PubMed  PubMed Central  Google Scholar 

  18. Laor T, Jaramillo D (2009) MR imaging insights into skeletal maturation: what is normal? Radiology 250:28–38.

    Article  PubMed  Google Scholar 

  19. Cobb JG, Kan JH, Gore JC (2013) T1ρ mapping of pediatric epiphyseal and articular cartilage in the knee. J Magn Reson Imaging 38:299–305.

    Article  PubMed  PubMed Central  Google Scholar 

  20. Zbojniewicz AM, Laor T (2011) Focal Periphyseal Edema (FOPE) zone on MRI of the adolescent knee: a potentially painful manifestation of physiologic physeal fusion? AJR Am J Roentgenol 197:998–1004.

    Article  PubMed  Google Scholar 

  21. Muller LS, Avenarius D, Damasio B et al (2011) The paediatric wrist revisited: redefining MR findings in healthy children. Ann Rheum Dis 70:605–610.

    Article  PubMed  Google Scholar 

  22. Jans LB, Jaremko JL, Ditchfield M, Verstraete KL (2011) Evolution of femoral condylar ossification at MR imaging: frequency and patient age distribution. Radiology 258:880–888.

    Article  PubMed  Google Scholar 

  23. Oudjhane K (2015) Normal development. In: Stein-Wexler R, Wootton-Gorges S, Ozonoff M (eds) Pediatric orthopedic imaging, 1st edn. Berlin, Heidelberg, Springer, New York, pp 25–39

    Chapter  Google Scholar 

  24. Soliman A, De Sanctis V, Elalaily R, Bedair S (2014) Advances in pubertal growth and factors influencing it: can we increase pubertal growth? Indian J Endocrinol Metab 18(Suppl 1):S53–S62.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  25. Risser JC (1958) The iliac apophysis: an invaluable sign in the management of scoliosis. Clin Orthop 11:111–119

    CAS  PubMed  Google Scholar 

  26. Otobo TM, Conaghan PG, Maksymowych WP et al (2019) Preliminary definitions for sacroiliac joint pathologies in the OMERACT juvenile idiopathic arthritis magnetic resonance imagings score (OMERACT JAMRIS-SIJ). J Rheumatol 46:1192–1197.

    Article  PubMed  Google Scholar 

  27. Bray TJP, Sakai N, Dudek A et al (2020) Histographic analysis of oedema and fat in inflamed bone marrow based on quantitative MRI. Eur Radiol.

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Correspondence to Nele Herregods.

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The scientific guarantor of this publication is Herregods Nele.

Conflict of interest

The authors of this manuscript declare no relationships with any companies whose products or services may be related to the subject matter of the article.

Statistics and biometry

One of the authors (Stefanie L. De Buyser, Biostatistics Unit, Faculty of Medicine and Health Sciences Ghent University) has significant statistical expertise.

Informed consent

Written informed consent was obtained from all subjects (patients and their parents) in this study.

Ethical approval

Institutional Review Board approval was obtained.

Study subjects or cohorts overlap

Some study subjects or cohorts have been previously reported in some of our previous reports on other topics (77/251 patients). We have published on pediatric patients with low back pain or established spondyloarthritis. This is our first manuscript focused on normal children with no history of back pain. This manuscript focuses on new data on a unique group of 127 “normal” patients, with asymptomatic sacroiliacal joints who were being imaged for non-rheumatologic conditions, of whom we have not published before. We compare findings in this group to a set of 124 “LBP” patients whom we have previously analyzed, who did not show features of sacroiliitis at initial clinical MRI review but who presented with inflammatory back pain symptoms. The high similarity we note in physiologic findings between findings in the normal and “LBP” cohorts is an important observation that can help guide study design for future research in this field.


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Herregods, N., Jans, L.B.O., Chen, M. et al. Normal subchondral high T2 signal on MRI mimicking sacroiliitis in children: frequency, age distribution, and relationship to skeletal maturity. Eur Radiol 31, 3498–3507 (2021).

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