Liver Acquisition with Volume Acceleration versus T2 fat suppressed MRI sequences in the evaluation of perianal fistula

Abstract

Back groundPerianal fistula is an abnormal communication between the anal canal and the outer perineal skin. It is a disease of young adults, being more common in males.MRI is a noninvasive, well-tolerated imaging modality with high resolution of the soft tissues. It is considered the imaging modality of choice for the initial evaluation and follow-up of perianal fistulas as it is more tolerated and less embarrassing for the patient than other imaging techniques.ObjectivesTo compare MR sequences fat-suppressed (FS) T2-weighted imaging and Liver Acquisition with Volume Acceleration (LAVA) for better visualization and assessment of the perianal fistulas and sphincters.Patients and methodsThis was a retrospective study done in the period between January 2018 and January 2020 on 100 patients. The patients' age ranged from 15 to 67 years, with a mean age of 35.45 ± 12.35 years. All patients had previously undergone MRI pelvis with intravenous contrast. We considered the operative results as the reference standard.ResultsThis study included 36 (36.0%) females and 64 (64.0%) males. LAVA sequence was better than T2 FS MRI sequence for the detection of the internal opening of the fistulous tract as well as secondary fistulous tracts with perfect interobserver agreement (P < 0.001). Both LAVA and T2 FS MRI sequences have the same significance for the detection of the abscesses, horseshoe, and supralevator extension of the fistula, with perfect interobserver agreement between both observers and between them and surgery.ConclusionAdding LAVA sequence to the protocol of MRI in the evaluation of perianal fistula helps to give better details as compared with T2 FS sequence as regarding the internal opening and the secondary tracts of the fistulous tract, but they have the same results regarding the sensitivity to detect abscesses, horseshoe, and supralevator extension of the perianal fistula.