Role of EUS for Evaluating Bile Duct Dilation in Patients with Normal Liver Tests and Normal CT/MRU

Role of EUS for Evaluating Bile Duct Dilation in Patients with Normal Liver Tests and Normal CT/MRU Mark S. Lemert, Robert Lin, Gordon Hunt, Mary Lee Krinsky, Thomas Savides Background: Due to widespread use of noninvasive imaging studies, patients are frequently encountered with findings of common bile duct (CBD) dilation without evidence of pancreatic/ampullary mass or CBD stones on CT/MRI. The aim of this study was to compare the diagnostic yield of EUS for CBD dilation in patients with a history of normal versus elevated liver function tests (LFTs). Methods: Retrospective review of patients who were referred for EUS evaluation of CBD dilation from January 2001 to November 2004. The inclusion criteria were evidence of CBD dilation (O7 mm) without obvious obstructing mass lesion or CBD stone by preliminary imaging [transabdominal U/S, CT scan, and/or MRI/MRCP]. A comparison of EUS findings in patients with normal and elevated LFTs was conducted. Among patients without malignancy or choledocholithiasis, a comparison of CBD diameter, based on a clinical cut score of 7 mm was conducted across four groups with regard to the following risk factors: age O 60 and/or a history of cholecystectomy (CCY). Results: 127 patients met the inclusion criteria. The mean age was 63 (range 22-93), 76% were female, 67% reported symptoms of abdominal pain, and 43% were status-post CCY. 11% had normal bile duct diameters on EUS. Of 74 patients with normal LFTs, 4 cases (5%) of choledocholithiasis were diagnosed. Of 53 patients with a history of elevated liver tests, either stones or cancer was diagnosed in 30 (57%), with choledocholithiasis in 20 (34%), pancreatic cancer in 6 (11%), and ampullary cancer in 5 (9%). This difference in EUS findings between normal versus abnormal LFTs was significant when analyzed using the chisquare statistic (XZ41.29, pZ0.00). Examination of EUS determined CBD diameter in patients without pathology findings on EUS demonstrated that those patients with R1 risk factors for CBD dilation had significantly increased likelihood of CBD diameter exceeding the clinical cut-off of 7 mm (X Z 12.16, pZ.007). Conclusion: Patients who are referred for EUS to evaluate a dilated CBD, but have no lesion on CT/MRI and have normal liver tests are significantly less likely to have any pathology (5% chance of stones), compared to similar patients with elevated liver tests (57% chance of stones or tumors). Implications: Patients who are found by body imaging studies to have a dilated bile duct, but have a normal CT/MRI and normal LFTs may not need further diagnostic testing.