Role of transperineal ultrasound in infective and inflammatory disorders

To evaluate the role of transperineal ultrasound as screening tool in infective and inflammatory diseases of perianal region.

Initially, clinical examination of the perineal region of patients (pts) for perianal external opening of tracts, swelling and tenderness is done. The perineal USG was performed using 2 -5 MHz sector probe and 7 -13 MHz linear probe on GE logiq P 5 ultrasound machine. Internal opening of any fistulous tract were described with clockwise position and tracts were traced upto their external opening and perifocal area were screened for any ramification. The Park et al. classification was used for classifying the tracts.

Out of 492 pts, 60 pts were normal, 257 pts had fistula, 114 pts had sinuses, 44 pts had only abscess without fistula or sinus and 17 pts had other pathologies with 95% sensitivity (Sn), 100% specificity (Sp) and Positive Predictive Value (PPV) and 95% Negative Predictive Value (NPV) for fistula and 94% Sn, 97% Sp, 89% PPV and 98% NPV for active sinuses and 98% Sp, 96% ppv and 100% NPV and Sn for abscesses.

Transperineal Ultrasound should be performed as first line imaging modality for suspicion of low perianal fistula with high sensitivity, specificity, and negative predictive value at much lower cost and less time as compared to perineal MRI.