P158. Prospective comparison of magnetic resonance imaging, rectal and perineal ultrasound and the surgical findings of complicated perianal Crohn's disease: a new kid on the block
R. Bor1, A. Bálint1, K. Farkas1, M. Szucs2, Z. Szepes1, T. Wittmann1, F. Nagy1, T. Molnar1, 1University of Szeged, First Department of Medicine, Szeged, Hungary, 2University of Szeged, Department of Medical Physics and Informatics, Szeged, Hungary
Magnetic resonance imaging (MRI) and rectal ultrasound (RUS) are the two accepted imaging modalities for the evaluation of perianal fistulas and abscesses. RUS requires high experience, while MRI is expensive and its urgent access is limited in many places. Although perineal ultrasound (PUS) is easy to learn and can be performed at any time, its diagnostic accuracy in complicated perianal Crohn's disease (CD) had never been evaluated prospectively. The aim of our study was to compare the diagnostic sensitivity of MRI, RUS and PUS with the surgical findings of CD patients with perianal fistulas and abscesses.
Twenty-three patients with active perianal CD (12 women, 11 men, mean age: 36.7 years; current therapy: antibiotics in 69.6%, azathioprine in 56.5%, biologicals in 73.9%; frequency of previous surgery 26.1%; proportion of smokers 39.1%) were included in this prospective study. Fistulas were classified as simple (43.8%) or complex (52.2%). Perianal Disease Activity Index (PDAI) was estimated in every patient. All patients underwent MRI, RUS and PUS within a few days before perianal surgery. The sensitivities of the diagnostic modalities were compared with the surgical findings. Chi-square test was used to assess the value of the different imaging techniques in the evaluation of the type of fistulas.
The mean PDAI was 8.43 (4–15). The sensitivities of MRI, RUS and PUS in the diagnosis of perianal fistulas were 82.6%, 82.6% and 100%, respectively. The sensitivities of MRI, RUS and PUS in the detection of abscesses were 92.3%, 69.2% and 91.3%. PUS was significantly more accurate in the diagnosis of the types of the fistulas than the others (78% vs. 69% and 69%, p = 0.025).
PUS is a very accurate and easy to perform diagnostic method with an outstanding sensitivity compared to MRI and RUS in the evaluation of complicated perianal CD. Due to its simplicity and low cost, PUS is recommended be the first diagnostic modality in case of complicated CD.