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Helical CT without contrast in choledocholithiasis diagnosis
I Jiménez Cuenca1, L del Olmo Martínez, M Pérez Homs
1Radiodiagnostic Service, Hospital Universitario, Valladolid, Spain.
Insights
Helical CT without contrast shows good diagnostic value for diagnosing choledocholithiasis (bile duct stones). This imaging technique is accurate enough for initial screening, helping to identify patients needing further examination.
Area of Science:
- Medical Imaging
- Gastroenterology
- Diagnostic Radiology
Background:
- Choledocholithiasis, or bile duct stones, requires accurate and timely diagnosis.
- Endoscopic retrograde cholangiopancreatography (ERCP) is a common diagnostic and therapeutic tool.
- Non-invasive imaging modalities are sought to improve the diagnostic pathway.
Purpose of the Study:
- To evaluate the diagnostic performance of contrast-free helical computed tomography (CT) for suspected choledocholithiasis.
- To compare the accuracy of helical CT with ERCP in detecting bile duct stones.
Main Methods:
- Prospective study of 40 patients with suspected choledocholithiasis.
- Helical CT performed immediately prior to ERCP.
- Analysis focused on stone detection in the bile duct and ampulla of Vater, and evaluation of biliary dilation.
Main Results:
- Helical CT demonstrated 80% sensitivity and 100% specificity for choledocholithiasis.
- The overall accuracy of helical CT was 90%.
- No false positives were observed with helical CT.
Conclusions:
- Contrast-free helical CT is a valuable screening tool for suspected choledocholithiasis.
- Its high specificity and good sensitivity support its use in the initial diagnostic workup.
- Helical CT can effectively identify patients requiring further evaluation for bile duct stones.
Abstract:
The goal of this study was to determine the diagnostic value of the helical CT without contrast in suspected cases of choledocholithiasis, comparing this test with endoscopic retrograde cholangiopancreatography (ERCP). Forty patients with possible choledocholithiasis were studied prospectively. There were 23 women and 17 men, ranging in age from 24 to 91 years. Helical CT was performed immediately before ERCP (time interval between the two procedures was less than 1 h). A biliary area previously selected was studied with a technique of pitch 1 and slice thickness of 3.2 mm. Average time was 30 s. Reconstruction with different increments and windows were made. Stone presence was evaluated in bile duct and Vater's ampulla. Biliary dilation was evaluated too. Endoscopic retrograde cholangiopancreatography found stones in 19 patients and absence of stones in 20. One case was failed, but stones in bile duct were demonstrated during intraoperative cholangiography. Helical CT demonstrated stones in 15 of the 19 patients with positive ERCP. There were no false positives with CT. Patients without stones in ERCP were also negative in CT. The patient having the failed ERCP was considered positive in CT. The CT sensitivity was 80% and specificity was 100%, with an accuracy of 90%. Helical CT without contrast has sensitivity and specificity good enough to be used as a screening technique in patients with suspected choledocholithiasis.