MRI in pediatric sacroiliitis, what radiologists should know

Current Role of Conventional Radiography of Sacroiliac Joints in Adults and Juveniles with Suspected Axial Spondyloarthritis: Opinion from the ESSR Arthritis and Pediatric Subcommittees

“…MRI has even more value if an image with a larger field of view to depict the entire pelvis, either axial or coronal, has been added to the protocol including the hips, because the hip joint is commonly affected in children with JIA. 40 Therefore, in JSpA, CR should only be used when MRI is unavailable or contraindicated. The main MRI sequences used for imaging pediatric SIJs are similar to those in adults.…”

“…Semi-coronal T1-weighted images and STIR sequences, and an axial STIR sequence are key sequences for evaluation. 40 Additional sequences such as diffusion-weighted images or 3D sequences (e.g., VIBE), which have shown to have additional value for detecting erosions in adults, are still being studied in children.…”

Evaluation of sacral hiatus changes in children using ultrasound

“…Consequently, we can infer that the distribution of intercornual distance in children older than one year was close to that in adults. However, it is challenging to compare adults with children due to the normal developmental changes that the immature skeleton undergoes [ [20] , [21] , [22] ], as children are not merely small adults.…”

Challenges in treating juvenile idiopathic arthritis

“…One common pitfall is to overcall normal subchondral T2 signal or ‘flaring’ of the sacrum in prepubertal children as representing bone marrow edema (inflammation). This flaring is typically symmetric and disappears in postpubertal children and adults [31 ▪▪ ]. Another potential pitfall would be to overcall a thin line of increased T2 signal in the joint space (in the absence of other signs of inflammation) as representing arthritis, when it is likely a physiologic phenomenon.…”

“…Another potential pitfall would be to overcall a thin line of increased T2 signal in the joint space (in the absence of other signs of inflammation) as representing arthritis, when it is likely a physiologic phenomenon. A third potential pitfall to avoid is misinterpreting the normal vascular channels abutting the superior edge of the joint as representing capsulitis [31 ▪▪ ].…”