Serology and ultrasound for diagnosis of choledocholithiasis.
BACKGROUND
Magnetic resonance cholangiopancreatography (MRCP) is not a routine investigation to exclude choledocholithiasis unless there is clinical or biochemical suspicion of common bile duct (CBD) stones. This study attempted to determine which radiological or serological parameters best predicted CBD stones.


METHODS
All patients undergoing MRCP from 2005 to 2011 were selected. Patients with pancreatitis were excluded. Liver function tests (LFTs) at admission and prior to MRCP were recorded, as was abdominal ultrasonography and MRCP results. Parameters measured routinely on LFTs included alkaline phosphatase (ALP), alanine transaminase (ALT) and bilirubin. Receiver operating characteristic curve area analysis (area under the curve [AUC]) and chi-squared analysis were undertaken.


RESULTS
Overall, 195 patients were identified, 71 of whom had CBD stones on MRCP. Raised ALP levels on admission demonstrated a correlation with CBD stones (AUC: 0.619, odds ratio [OR]: 3.16, p=0.06). At ultrasonography, a dilated CBD (OR: 3.76, p<0.001) and intrahepatic duct dilation (OR: 5.56, p<0.001) were highly significant predictors. However, only 37% of patients had a dilated CBD on ultrasonography. Ongoing elevation of LFT parameters, particularly ALP (AUC: 0.707, OR: 4.64, p<0.001) and ALT (AUC: 0.646, OR: 5.40, p<0.001), displayed a significant correlation with CBD stones.


CONCLUSIONS
Ongoing (even if minor) elevations of liver function test parameters should prompt the need to exclude CBD stones even in the presence of a normal CBD diameter on ultrasonography.
University Hospitals of Leicester NHS Trust, UK. john.d.isherwood@uhl-tr.nhs.uk.
J
J
Isherwood
G
G
Garcea
R
R
Williams
M
M
Metcalfe
A R
AR
Dennison
D000410:Alanine Transaminase / Q000378:metabolism; D000469:Alkaline Phosphatase / Q000378:metabolism; D001653:Bile Ducts, Intrahepatic / Q000473:pathology; D001663:Bilirubin / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D049448:Cholangiopancreatography, Magnetic Resonance / Q000592:standards; D042883:Choledocholithiasis / Q000000981:diagnostic imaging* / Q000473:pathology; D003135:Common Bile Duct / Q000473:pathology; D004108:Dilatation, Pathologic; D005260:Female; D006801:Humans; D008111:Liver Function Tests / Q000379:methods; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014463:Ultrasonography
D015415:Biomarkers; D000410:Alanine Transaminase; D000469:Alkaline Phosphatase; D001663:Bilirubin