Retrospective comparison of STIR and postcontrast MRI signs in the diagnosis of active sacroiliitis

ABSTRACT RETROSPECTIVE COMPARISON OF STIR AND POSTCONTRAST MRI SIGNS IN THE DIAGNOSIS OF ACTIVE SACROILIITIS Purpose: The purpose of the study was to determine the diagnostic value of STIR (short tau inversion recovery ) sequence and to compare with gold standard fat saturated contrast enhanced T1 –weighted spin –echo sequences in the detection of active sacroiliitis. Materials and methods: The study included 202 patients with active sacroiliitis. The presence of bone marrow edema, capsulitis, synovitis and enthesitis were analyzed separately before contrast enhancement with STIR and after contrast enhancement T1 fat saturated MRI sequence. Results: STIR and T1/gadolinium sequences had 100% agreement for depiction of bone marrow edema. In 7(3.4%) patients additional bone marrow edema was depicted on T1 gadolinium sequence. Synovitis was seen in 20/202 (9.9%) patients, in 1 (0.5%) patient was depicted on STIR sequence. Capsulitis was seen in 14/202(6.9%) patients, in 11(5.4%) patients depicted on STIR sequence. Enthesitis was seen in 1/202 (0.5%) patient and depicted only on T1 contrast fat saturated MRI sequence. There were statistically significant for depicting bone marrow edema and capsulitis(p<0.05), but not for synovitis and enthesitis. Conclusion: STIR sequence alone is sufficient to identify bone marrow edema which is the pozitive MRI sign of active sacroiliitis and there was 100% agreement between STIR and gold standart contrast enhancement T1 MRI sequence. There is not diagnostic confidence of capsulitis, synovitis and enthesitis alone without bone marrow edema. Keywords: Sacroiliitis; mri; STIR; contrast enhanced mrı.