CT evaluation of pararectal varices.
This study was undertaken to determine the prevalence of pararectal varices on CT scan in patients with portal hypertension and to see if dilatation of the inferior mesenteric vein (IMV) or the presence of pararectal varices on CT correlates with rectal varices noted on colonoscopy. We reviewed 83 consecutive CT scans of the abdomen and pelvis performed in patients with portal hypertension. The size and prevalence of pararectal varices were determined. Correlation with colonoscopic and endoscopic reports was performed. The diameter of the IMV was compared in those patients with pararectal varices with that in those patients without, as was the presence of esophageal varices. Twenty patients (24%) had CT evidence of pararectal varices, ranging from 5 to 11 mm in diameter (mean 7.8 mm). Colonoscopic correlation was available in 30 patients. Of these, 6 of 30 (20%) had pararectal varices on CT and no rectal varices on colonoscopy, 3 of 30 (10%) had pararectal varices on CT and rectal varices on colonoscopy, and 3 of 30 (10%) had no pararectal varices on CT but did have rectal varices on colonoscopy. Endoscopic correlation (available in 48 patients) demonstrated esophageal varices in 88% of patients with rectal or pararectal varices and in 66% of patients without rectal or pararectal varices (p = 0.170). The IMV was significantly larger in patients with pararectal varices (mean diameter 7.5 mm, SD 2.3) as compared with those without (mean diameter 5.8 mm, SD 2.0) (p = 0.014). However, in patients with colonoscopically proven rectal varices, only two of six (33%) had an IMV diameter of > or = 7 mm. Inclusion of the pelvis on CT scans of patients with portal hypertension can yield further information about the presence and extent of pararectal venous collaterals, which may be of particular importance in those patients requiring pelvic surgery. The presence of pararectal varices on CT and the diameter of the IMV do not correlate with the presence of rectal varices on colonoscopy. Decompression of portal hypertension by rectal and pararectal varices does not result in a decreased incidence of esophageal varices.