Role of spectral presaturation attenuated inversion-recovery fat-suppressed T2-weighted MR imaging in active inflammatory bowel disease.

PURPOSE: To retrospectively evaluate the efficacy of spectral presaturation attenuated inversion-recovery (SPAIR) fat-suppressed (FS) partial Fourier single shot (SSH) T2-weighted (T2W) and gadolinium-enhanced (Gd) FS 3D-gradient echo (3DGRE) T1-weighted (T1W) delayed phase MRI to differentiate active bowel inflammation from fibrotic disease in patients with Crohn's disease (CD).

MATERIALS AND METHODS: MRI studies of 81 patients (mean age, 43 years; range, 22-77 years; M:F ratio 33:48) had T2W and T1W imaging including SPAIR-SSH and delayed Gd-3DGRE. The ability to assess disease activity in bowel segments affected were retrospectively evaluated by a grading scheme based on subjective analysis of signal intensities. These results were compared against the standard clinical parameters of disease activity.

RESULTS: SPAIR-SSH images correlated better (r=0.74, P<0.0001) with activity than delayed Gd-3DGRE (r=0.39, P=0.0003), with a significant difference between the two techniques (P<0.0001). SPAIR-SSH images showed higher specificity in detection of severely active disease in per patient (98%) and segmental (98%) analysis compared to Gd-3DGRE (57%, 70%). Gd-3DGRE technique showed significantly higher sensitivity (P=0.01) in identifying active disease in per patient (83%) and segmental (85%) analysis compared to SPAIR-SSH (70%, 64%).

CONCLUSION: SPAIR-SSH detects actively diseased CD bowel segments with a high level of specificity. Noninflammatory bowel fibrosis corresponds to abnormal uptake on delayed phase Gd-3DGRE images but without associated elevated abnormal signal on SPAIR-SSH.