Can abbreviated MRİ protocol be used as an alternative in the radiological diagnosis of perianal fistula?

Purpose: We aimed to investigate whether a shorter magnetic resonance imaging protocol can be alternative when assesing perianal fistula and its secondary complications. Materials and methods: MRI images of patients who applied to Adıyaman University Training and Research Hospital Radiology Clinic between January 2019 and January 2022 with a preliminary diagnosis of perianal fistula were evaluated retrospectively. Diffusion weighted B400 and B800, T1-weighted fat saturated contrast enhanced(CE) axial and coronal, T2-weighted propeller images are evaluated separately compared to main protocol for their individual eficency on detecting type of fistula, secondary tracts and abscess, and their grades according to St. James University Hospital classification. Results: 110 patients were included in this study. Perianal fistula types that found were , Intersphinctric type in 71 (64.5%) cases, transsphincteric type in 33 (30%) cases, surface in 4 (3.6%) cases, and supralevator type anal fistula in only 2 (1.8%) cases. There was abscess in 41 (37.3%) cases and second tract in 46 (41.8) cases. In the evaluation of the fistula tract, abscess, secondary tracts and classification T1 CE axial images had excellent (Cohen kappa=0.982) correlation with main protocol. The T2A Propeller sequence (Cohen kappa = 0.817) showed near-perfect performance individually. Conclusion: In our study, when axial T1W fat saturated contrast enhanced and T2 propeller images were evaluated individually for assesment of perianal fistula's radiological diagnosis, detecting additional findings like secondary tracts and abscess, classification we obtained same results in comparison with the main protocol. We think a shorter protocol that includes combination of these two sequences can be used as an alternative for the patients who cannot tolerate MRI for any reason.