Anovaginal and rectovaginal fistulas: endoluminal sonography versus endoluminal MR imaging.
OBJECTIVE
The exact location of anovaginal and rectovaginal fistulas cannot be determined by physical examination and conventional techniques. The objective of our study was to compare the accuracy of endoluminal sonography and endoluminal MR imaging in revealing the location of anovaginal and rectovaginal fistulas.


METHODS
Nineteen consecutive patients (age range, 28-56 years; median age, 39 years) with clinical indications of an anovaginal or rectovaginal fistula were included in our retrospective study. Endoluminal sonography was performed using a 7.5-MHz transducer. Endoluminal MR imaging was performed at 0.5 T for 10 patients and 1.5 T for nine patients; axial T2-weighted gradient-echo, coronal and sagittal T2-weighted turbo spin-echo (0.5 T), or axial and radial T2-weighted turbo spin-echo and axial T2-weighted fat saturated turbo spin-echo (1.5 T) images were obtained. For a variety of reasons, surgery of the fistula was not attempted in six of these 19 patients. The imaging findings were compared with the findings obtained during surgery in the remaining 13 patients.


RESULTS
In 12 of the 13 patients, the fistula was found during surgery: seven of the fistulas were anovaginal, and five were rectovaginal. Findings of endoluminal sonography were true-positive in 11 patients, true-negative in one, and false-negative in one. Findings of endoluminal MR imaging were true-positive in 11 patients, false-negative in one, and false-positive in one. Positive predictive value for endoluminal sonography and endoluminal MR imaging were 100% and 92%, respectively. Imaging findings for anal sphincter defects were comparable.


CONCLUSIONS
Endoluminal sonography and endoluminal MR imaging have comparable positive predictive values in revealing the location of anovaginal and rectovaginal fistulas.
Stoker
Jaap
J
Department of Radiology, Academic Medical Center, University of Amsterdam, P. O. Box 22700, 1100 DE Amsterdam, The Netherlands.
Rociu
Elena
E
Schouten
W Ruud
WR
Laméris
Johan S
JS
D000328:Adult; D001003:Anal Canal / Q000000981:diagnostic imaging / Q000473:pathology; D003951:Diagnostic Errors; D019160:Endosonography; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D011237:Predictive Value of Tests; D012006:Rectovaginal Fistula / Q000175:diagnosis* / Q000000981:diagnostic imaging; D012007:Rectum / Q000000981:diagnostic imaging / Q000473:pathology; D012189:Retrospective Studies; D014621:Vagina / Q000000981:diagnostic imaging / Q000473:pathology