Abstract

Objective: Fatty changes at vertebral corners have been reported on MRI in ankylsoing spondylitis but the distribution or specificity of these lesions to axial-SpA has not been determined. This study assessed the diagnostic utility of Fatty Romanus Lesions (FRLs) for axial-SpA in a chronic back pain population.

Methods: Axial-skeleton TI SE and fat-suppressed MRI were performed on 174-patients with back pain and 11-controls. MRI lesions including FRLs were scored blind. An imaging diagnosis was given on MRI findings alone and compared to the gold-standard treating physician diagnosis.

Results: Twenty-nine patients had FRLs. Thirty-one percent(20/64) of SpA, 13%(6/45) of degenerative arthritis, 4%(2/45) of spinal malignancy, 5%(1/20) of "other" diagnoses and 0/11 normals. The majority of FRLs in SpA 59%(135/226) were present in the thoracic-spine. The diagnostic utility of FRLs for SpA(LR=4.7) was significantly(p<0.05) greater than for other diagnoses and increased further(LR=12.6,p<0.05) when >5 FRLs were present. Of note 5/20(25%), of SpA patients with FRLs had no diagnostic bone-oedema lesions on fat-suppressed MRI suggesting that FRLs may be useful diagnostically in axial-SpA.

Conclusion: This study defines the FRL as a diagnostic imaging feature of axial-SpA which may be useful where inflammatory changes are absent on fat-suppression MRI and where radiography is normal.