Use of computed tomography sinography for evaluation of draining tracts in 27 dogs and one cat

To describe the clinical findings, imaging findings and outcome in patients in which CT sinography was performed, and assess to what degree this technique adds information about the extent of a tract or increases the accuracy of diagnosis of foreign bodies on CT.

Retrospective review of medical records of 27 dogs and one cat with draining tracts that had CT sinography. Pre- and post-intravenous (IV) contrast CT series were compared with CT sinography in each patient.

Median duration of clinical signs before referral was 85 days (range 2 to 1478 days). The most common reported clinical signs were swelling (14/28, 50%) and regional pain (5/28, 18%). CT sinography revealed a more extensive tract than post-IV contrast CT in 21% cases. On post-IV contrast CT, 31% of foreign bodies were detected compared to 23% on CT sinography. All four foreign bodies detected by CT were observed in the non-contrast images. Surgery was performed after CT in 22 (79%) cases. Thirteen (46%) draining tracts resolved after surgery, three (11%) resolved without surgery, six (21%) persisted or recurred after surgery, and six (21%) were lost to follow-up.

CT sinography provides limited additional information about the extent of draining tracts compared to pre- and post-IV contrast CT images and did not increase the number of foreign bodies identified.