From the Guidelines
Ultrasound of the abdomen is the first-line diagnostic test for gallbladder stones, with a reported accuracy of 96% for detection of gallstones 1. When investigating gallbladder stones, the following key investigations should be considered:
- Ultrasound of the abdomen as the initial diagnostic test to detect gallstones and identify complications like biliary dilatation or cholecystitis
- Laboratory tests, including:
- Liver function tests (ALT, AST, ALP, GGT, bilirubin) to assess for biliary obstruction
- Complete blood count to detect infection or inflammation
- Pancreatic enzymes (amylase, lipase) if pancreatitis is suspected In cases where ultrasound results are inconclusive, additional imaging may be necessary, such as:
- CT scan for complicated cases
- MRCP (Magnetic Resonance Cholangiopancreatography) for detailed biliary tract visualization, with an accuracy of detecting CBD stones surpassing 90% 1
- ERCP (Endoscopic Retrograde Cholangiopancreatography) which serves as both a diagnostic and therapeutic tool for removing common bile duct stones
- HIDA scan (hepatobiliary iminodiacetic acid scan) may be used to evaluate gallbladder function and detect cystic duct obstruction, particularly in cases of suspected biliary dyskinesia These investigations help confirm the diagnosis, assess the severity and complications of gallstone disease, and guide appropriate management decisions between conservative treatment, medical dissolution therapy, or surgical intervention. It is essential to note that while other imaging modalities like EUS (Endoscopic Ultrasound) and MRCP have high diagnostic accuracy, ultrasound remains the first choice due to its wide availability, high sensitivity for gallstone detection, and ability to identify complications 1.
From the Research
Key Investigations in Gallbladder Stones
- The initial imaging choice for detecting gallstones and acute cholecystitis is ultrasonography 2
- A hepatobiliary iminodiacetic acid (HIDA) scan can be used to evaluate for cholecystitis in patients with negative or equivocal ultrasound findings 2
- Magnetic resonance cholangiopancreatography (MRCP) is an accurate, noninvasive diagnostic test to identify choledocholithiasis, certain malignancies, and biliary obstruction 2
- Ultrasound has a summary sensitivity of 0.73 (95% CI 0.44 to 0.90) and a specificity of 0.91 (95% CI 0.84 to 0.95) for diagnosing common bile duct stones 3
- Liver function tests, such as serum bilirubin and serum alkaline phosphatase, can also be used as screening tests for common bile duct stones, but their accuracy varies depending on the cut-off values used 3
- Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) can be used to evaluate the gallbladder, especially in cases where ultrasound is inconclusive or additional information is needed 4
Diagnostic Challenges
- The diagnostic accuracy of ultrasound and liver function tests can be limited by factors such as poor methodological quality of studies and variability in test results 3
- False-positive and false-negative results can occur with any diagnostic test, and further testing may be needed to confirm the diagnosis 3
- Accurate imaging assessment of the gallbladder can be challenging due to the variety of presentations and potential pitfalls, and a problem-solving approach may be necessary in some cases 4