SONOGRAPHIC VERSUS ENDOSCOPIC RETROGRADE CHOLANGIOGRAPHIC MEASUREMENTS OF THE BILE-DUCT REVISITED - IMPORTANCE OF THE TRANSVERSE DIAMETER

OBJECTIVE. The purpose of this study was to investigate how frequently the cross section of the bile duct is oval versus round on sonography and whether the transverse diameter of the bile duct (D-TRV) on sonog raphy corresponds better than the conventional anteroposterior diamete r (D-AP) to measurements on endoscopic retrograde cholangiography (ERC ). SUBJECTS AND METHODS. In 44 consecutive patients with a D-AP greate r than or equal to 8 mm, D-TRV was measured on short-axis sonograms. D iameter of the bile duct measured on ERC (D-ERC) was compared with D-A P and D-TRV in patients who underwent ERC shortly after sonography. RE SULTS. The cross section of the bile duct was oval in 31 patients (70% ). In 20 patients who underwent ERC after sonography, mean D-ERC was s tatistically indistinguishable from mean D-TRV but statistically diffe rent from mean D-AP Comparing both D-AP and D-TRV with D-ERC in each p atient, we found no statistically significant difference between D-ERC and D-TRV, but we did find a statistically significant difference bet ween D-ERC and D-AP. CONCLUSION. An oval cross section is common in bi le duels with a D-AP greater than or equal to 8 mm. The discrepancy be tween measurements of the bile duct made sonographically and those mad e on ERC is largely attributable to different cross-sectional diameter s. Because D-TRV correlates better than conventional D-AP with D-ERC m easurement of D-TRV can be helpful in confirming or excluding true bil iary dilatation in patients with a D-AP larger than normal.