From the Guidelines
The best initial radiology study for evaluating elevated liver function tests (LFTs) and jaundice is an abdominal ultrasound, as recommended by the most recent and highest quality study 1. This non-invasive imaging modality provides excellent visualization of the liver, gallbladder, bile ducts, and pancreas without radiation exposure. When performing an ultrasound for this indication, the radiologist will assess for biliary dilation, gallstones, liver parenchymal abnormalities, and masses that might explain the laboratory findings. The American College of Radiology recommends ultrasound as the initial imaging modality for patients with abnormal liver function tests with hepatocellular predominance with mild aminotransferase increase, as well as for those with cholestatic predominance and elevated ALP with or without elevated gamma-glutamyl transpeptidase 1. If the ultrasound shows biliary obstruction but doesn't clearly identify the cause, magnetic resonance cholangiopancreatography (MRCP) would be the appropriate next step, as it provides detailed imaging of the biliary tree and can detect small stones, strictures, or tumors 1. In cases where ultrasound findings are normal but clinical suspicion for pathology remains high, contrast-enhanced CT or MRI of the abdomen may be warranted to evaluate for subtle liver lesions, infiltrative diseases, or vascular abnormalities 1. Key benefits of ultrasound include:
- Readily available
- Cost-effective
- Provides sufficient information to guide next steps in management
- Avoids unnecessary radiation exposure Overall, ultrasound is a valuable initial imaging modality for evaluating elevated LFTs and jaundice, and its use is supported by recent and high-quality evidence 1.
From the Research
Diagnostic Approaches for Elevated LFTs and Jaundice
- The evaluation of patients with jaundice and elevated liver function tests (LFTs) typically involves a combination of laboratory tests, imaging studies, and sometimes invasive procedures like liver biopsy 2.
- Initial laboratory evaluation should include assays for bilirubin, liver enzymes, and other parameters to differentiate between conjugated and unconjugated hyperbilirubinemia 2.
- Imaging studies such as ultrasonography of the abdomen, computed tomography (CT) with intravenous contrast media, and magnetic resonance cholangiopancreatography (MRCP) are first-line options for patients presenting with jaundice, depending on the suspected underlying etiology 2, 3.
Role of Specific Imaging Modalities
- Ultrasonography is useful for assessing liver pathology, including fatty liver and bile duct dilatation, with satisfactory levels of sensitivity and specificity 3.
- Contrast-enhanced sonography can help differentiate between benign and malignant focal lesions in the liver 3.
- Endoscopic ultrasound (EUS) plays a substantial role in evaluating bile duct dilation of unclear etiology, especially in patients with jaundice, with a diagnostic yield of 69.4% 4.
- ERCP is an important diagnostic modality for evaluating obstructive jaundice and has the additional advantage of being therapeutic as well 5.
Diagnostic Yield and Patient Outcomes
- Patients with jaundice are significantly more likely to receive a diagnosis by EUS than those without (78.8% vs 55.3%, P < 0.01) 4.
- The use of EUS for bile duct dilation of unclear etiology remains warranted, even in asymptomatic patients without jaundice or abnormal LFTs, as 8.1% of such patients may have a malignancy diagnosed on EUS 4.
- Obstructive jaundice is common amongst females, and the cause is mostly malignant, with carcinoma of the head of the pancreas being the commonest malignancy 5.