Advanced MRI Sequences for Structural Lesion Assessment in Sacroiliitis

Area of Science:

• Radiology
• Pediatric Imaging
• Musculoskeletal MRI

Background:

• Pediatric sacroiliitis diagnosis is challenging, requiring radiation-free imaging alternatives to CT.
• Assessing structural damage necessitates advanced imaging techniques.

Purpose of the Study:

• Evaluate advanced MRI sequences (3D-MENSA, 3D-MERGE, ZTE) against conventional MRI for detecting structural sacroiliitis lesions.
• Compare MRI performance to low-dose CT (LDCT) as the reference standard.
• Qualitatively assess visibility of active inflammation and fat metaplasia.

Main Methods:

• Cross-sectional study of 23 pediatric patients with enthesitis-related arthritis (ERA).
• Utilized pre-existing LDCT datasets as the reference standard.
• Two blinded radiologists scored structural lesions; interobserver agreement assessed via ICC.

Main Results:

• Advanced MRI sequences (ZTE, 3D-MENSA, 3D-MERGE) showed high agreement with LDCT for erosion detection (ICC 0.924-0.998), outperforming conventional T1-weighted MRI (ICC 0.707).
• 3D-MENSA effectively differentiated sacroiliac joint components and visualized bone marrow edema/fat metaplasia.
• 3D-MENSA identified active and chronic lesions in a single acquisition.

Conclusions:

• 3D-MENSA and 3D-MERGE provide comprehensive, radiation-free evaluation of pediatric sacroiliitis structural lesions with accuracy comparable to LDCT.
• 3D-MENSA shows potential for detecting both active and chronic lesions, suitable for routine pediatric imaging.