Diffusion-weighted MRI for evaluating perianal fistula activity: Feasibility study

• DOI: 10.1016/j.ejrad.2011.06.052
• Publication Date: 2011-07-24T21:14:52Z
• Authors: Takeshi Yoshizako; Akihiko Wada; Taro Takahara; Thomas C. Kwee; Megumi Nakamura; Koji Uchida; Shinji Hara; Peter R. Luijten; Hajime Kitagaki
• Keywords: Adult; Male; Anal Canal; Reproducibility of Results; Middle Aged; Sensitivity and Specificity; 3. Good health; 03 medical and health sciences; Diffusion Magnetic Resonance Imaging; 0302 clinical medicine; Intestinal Fistula; Feasibility Studies; Humans; Female; Aged

To assess the feasibility of using diffusion-weighted magnetic resonance (MR) imaging (DWI) for evaluating perianal fistula activity.This study retrospectively assessed 24 patients with clinically suspected perianal fistula who underwent a total of 28 MR examinations after conservative treatment with antibiotics. DWI was performed at 1.5 T, using b-values of 0 and 1000 s/mm(2). Apparent diffusion coefficient (ADC) maps were created and ADCs of the lesions were measured. Lesions were classified into two groups based on the need for surgery and surgical findings: positive inflammation activity (PIA) and negative inflammation activity (NIA). ADCs of both groups were compared using an unpaired t-test, and Receiver Operating Characteristic (ROC) analysis was performed.The ADC (in 10(-3) mm(2)/s) of the PIA group (0.908±0.171) was significantly lower (P=0.0019) than that of the NIA group (1.124±0.244). The area under the ROC curve was 0.749. An optimal cut-off ADC of 1.109 yielded a sensitivity of 95.7%, a specificity of 50%, a positive predictive value of 71%, and a negative predictive value of 90%.DWI is a feasible method for evaluating perianal fistula activity. The diagnostic performance of this technique should be established in future, larger prospective studies.