Department of Radiology and Nuclear Medicine, Ghent University Hospital, C. Heymanslaan 10, 9000, Gent, Belgium.
CARE ARTHRITIS LTD., Unit 210, 316 Windermere Rd NW, Edmonton, Alberta, T6W 2Z8, Canada.
Eur Radiol. 2021 May;31(5):3498-3507. doi: 10.1007/s00330-020-07328-0. Epub 2020 Oct 29.
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.
• 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.
通过位置、年龄、性别和骶骨骨骺闭合来确定儿童骶髂关节（SIJ）软骨下 T2 信号变化的变化模式。
在父母知情同意的情况下，对 251 名儿童（132 名女孩）的 502 个 SIJ 进行 MRI 检查，平均年龄为 12.4 岁（范围为 6.1-18.0）。251 名儿童中有 127 名无症状关节，因非风湿病原因进行影像学检查，124 名患有腰痛，但初次临床 MRI 检查未见骶髂关节炎迹象。在经过校准后，三位专业放射科医生独立地对脂肪抑制液体敏感序列上的软骨下信号变化进行了 0 到 3 的评分，并对骶骨节段骨骺的闭合程度进行了分级。分析了患者年龄、性别、信号变化和骨骺闭合之间的关系。
在骶骨 SIJ 边缘，边缘状软骨下 T2 信号增高或“扇形扩张”比在髂骨 SIJ 边缘更为常见（72% vs 16%，p < 0.001），并且在> 90%的儿童中是对称的。除了 1 名儿童外，髂骨扇形扩张评分总是低于骶骨。随着骶骨骨骺闭合，信号变化减少，在完全闭合的骨骺中，< 20%的受试者可见信号变化。男孩中的信号变化更频繁，并且比女孩的强度高峰晚（8-12 岁 vs. 7-10 岁）。在整个儿童期，骺软骨下的信号都很高，与其他部位没有相关性。
在青春期前儿童的骶髂关节中，软骨下 T2“扇形扩张”很常见，通常以骶骨为主导，且呈对称性。不对称、髂骨比骶骨更严重或在骨骺闭合的青少年中强烈的扇形扩张，对于正常儿童来说是不寻常的，提示存在病理性骨髓水肿。
在儿童骶髂关节的 MRI 上，通常在骺软骨下可见 T2 高信号的边缘，主要位于骶骨侧，在节段性骨骺闭合之前，不应将其与病理学混淆。
与其他部位的软骨下信号变化不同，骺软骨下髂骨嵴的 T2 高信号是儿童中普遍存在的正常发现，通常在整个青春期都存在。
在正常儿童中，以下模式是不寻常的，提示存在病理学：明确的骺骨扇形扩张、骺骨扇形扩张比骶骨扇形扩张更严重、扇形扩张左右不对称、任何模式的扇形扩张在骶骨骨骺闭合后出现在青少年中。
