Association of the apparent diffusion coefficient with maturity in adolescent sacroiliac joints

Abstract

PurposeTo determine the extent to which apparent diffusion coefficient (ADC) values vary with skeletal maturity in adolescent joints.Materials and MethodsA retrospective study was performed with Institutional Review Board (IRB) approval. We used a picture archiving and communication system (PACS) search to identify and recruit all adolescents who had undergone 1.5T magnetic resonance imaging (MRI) of the sacroiliac joints (SIJs) between January 2010 and June 2015, and had no evidence of sacroiliitis and normal inflammatory markers. In all, 55 individuals were assessed. For each patient, coronal and sagittal images of the sacrum were visually analyzed to determine sacral maturity. Patients were divided into three groups depending on the degree of fusion of the sacral segmental apophyses: “Fused,” “Partial,” and “Unfused.” For each group, SIJ ADC was measured using a linear region‐of‐interest technique.ResultsMean ADC values were 690 × 10−6 mm2/s in the fused group, 720 × 10−6 mm2/s in the partial group, and 842 × 10−6 mm2/s in the unfused group. ADC values were significantly higher in the unfused group than in the fused group (P = 0.046). ADC values were also higher in unfused subjects than partially fused subjects (P = 0.074).ConclusionJoint ADC values are higher in skeletally immature (unfused) patients than in skeletally more mature (fused) patients. ADC values measured in the unfused group overlap with those previously reported in sacroiliitis. These results suggest that ADC measurements in adolescent joints must be interpreted in light of joint maturity. Joint immaturity may lead to misdiagnosis of sacroiliitis, since immature juxta‐articular bone may appear similar to inflammation. J. Magn. Reson. Imaging 2016. J. Magn. Reson. Imaging 2016;44:556–564.

Simultaneous Quantification of Bone Edema/Adiposity and Structure in Inflamed Bone Using Chemical Shift‐Encoded MRI in Spondyloarthritis

“…Although imaging may be particularly valuable in this early‐onset group , changes in skeletal maturity may influence PDFF and R2* measurements and therefore make quantification of inflammation more difficult. Younger patients may have more cellular (i.e., less fatty) marrow and unossified juxta‐articular bone, which may mimic bone marrow edema . Maturity‐related changes in marrow composition potentially could be adjusted for using background marrow as a reference.…”

ASDAS is associated with both the extent and intensity of DW-MRI spinal inflammation in active axial spondyloarthritis

“…However, this method has not been validated. Factors such as age, osteoporosis35 and skeletal maturity36 may affect the ADC values, and axial SpA patients are more prone to osteoporosis 37. On normalisation, nADC values showed decreased interobserver reliability, and the associations with ASDAS were lost.…”

The usefulness of diffusion-weighted imaging (DWI) and dynamic contrast-enhanced (DCE) sequences visual assessment in the early diagnosis of axial spondyloarthritis

“…Moreover, as the values of ADC significantly differ according to age and sex, it is advisable to use a rather relative ADC value [16]. We should also be especially careful with ADC value measurement in younger cohorts, as ADC value in skeletally immature patients could overlap with the values reported for the active sacroiliitis [26]. Another important issue, that has not been covered yet, is the ADC value cutoff points for discrimination between healthy individuals and patients with active axSpA.…”