Sensitivity of Diffusion-Weighted Image Combined with T2 Turbo Inversion Recovery Magnitude Sequence and as an Alternative to Contrast-Enhanced MRI in the Detection of Perianal Fistula

Abstract

Introduction . Perianal fistula rapidly develops an abscess, requiring surgical decompression. However, simple cases must be managed. However, for patients with renal insufficiency, MRI with contrast is contraindicated. It is proposed to use diffusion-weighted images that can diagnose anal fistulae, showing areas of high signal intensity (inflammatory tissues). The aim is to determine sensitivity of diffusion-weighted image combined with T2 turbo inversion recovery magnitude and as an alternative technique to contrast-enhanced MRI using clinical examination as a reference. Materials and Methods . Study included fifty patients with a clinical diagnosis of perianal fistula. MRI sequences were T2 turbo inversion recovery magnitude in oblique coronal and axial planes, diffusion-weighted image, and T1 weighted image turbo spin echo (fat suppression) pre- and post-administration of contrast agents in oblique axial planes. Three radiologists evaluated the MR imaging data using a questionnaire of parameters that necessitated a binary response, “yes” or “no” answer. Results. Diffusion-weighted image combined with axial T2 turbo inversion recovery magnitude sequence had 96.7 %. All raters agreed that it is sensitive enough to correctly identify perianal fistula with a moderate Kappa agreement (k = 0.586) and p-value<0.001. The mean value of rater's responses was 76.7 % represents sensitivity of diffusion-weighted images + T2 turbo inversion recovery magnitude as an alternative technique to T1-enhanced contrast with moderate (k = 0.553) agreement between raters and P-value<0.001. Discussion and Conclusion . Diffusion-weighted images and T2 turbo inversion recovery magnitude sequences exhibit comparable efficacy to T1-enhanced contrast sequences in detecting perianal fistula. This may be an option for patients with renal impairment who cannot receive an MRI contrast.