Common bile duct dilatation on MRI in autosomal dominant polycystic kidney disease.

PURPOSE: Polycystic liver disease is the most prevalent extrarenal manifestation of autosomal dominant polycystic kidney disease (ADPKD). Non-obstructive asymptomatic common bile duct (CBD) dilatation has been observed anecdotally on CT scans, but CT is not optimal for biliary visualization. Here, we measured CBD diameter on T2-weighted MRI in ADPKD subjects to determine if CBD dilatation is associated with ADPKD.

METHODS

CBD diameter was measured retrospectively on ADPKD subjects (n = 254) and on age- and sex-matched controls without ADPKD (n = 254) who underwent abdominal MRI. CBD diameter in these groups was compared and correlated with clinical, laboratory and magnetic resonance imaging (MRI) features, including organ volumes and cyst burden.

RESULTS

CBD median diameter [interquartile range, IQR, 25%, 75%] was 22% larger in ADPKD compared to controls (5.6 [4.7, 6.9] mm vs. 4.6 [3.9, 5.4] mm, p < 0.001). CBD diameter measurements had excellent inter-observer agreement (Intraclass correlation coefficient = 0.92). Thirteen (5.1%) ADPKD subjects had a CBD diameter ≥ 10 mm compared to 1 (0.4%) control subject (p < 0.001). Multivariable analysis found the presence of PKD1 or PKD2 mutation (beta = 1.5, P < 0.001) and age (beta = 0.04, p < 0.001) to be associated with increased CBD diameter and serum albumin associated with decreased CBD diameter (beta=-0.39, p < 0.001).

CONCLUSION

ADPKD subjects had 22% larger CBD diameters than in non-ADPKD controls and were more likely to have CBD dilatation ≥ 10 mm without CBD obstruction. Awareness of this association of non-obstructive CBD dilatation with ADPKD may limit unnecessary diagnostic testing.