What is the most appropriate initial diagnostic imaging for a patient with intermittent right upper quadrant pain, nausea, jaundice, and elevated bilirubin and liver function tests?

Initial Diagnostic Imaging for RUQ Pain with Jaundice and Elevated Bilirubin/LFTs

Ultrasound of the abdomen (Answer A) is the most appropriate initial diagnostic imaging for this patient presenting with intermittent right upper quadrant pain, jaundice, and elevated bilirubin and liver function tests.

Rationale for Ultrasound as First-Line Imaging

The clinical presentation of RUQ pain with jaundice and elevated bilirubin/LFTs suggests biliary obstruction or cholestatic pathology, making ultrasound the clear initial choice:

• The American College of Radiology (ACR) Appropriateness Criteria (2023) explicitly recommends ultrasound abdomen as usually appropriate initial imaging for patients with abnormal liver function tests showing hyperbilirubinemia or acute/subacute cholestasis 1

• For right upper quadrant pain specifically, the ACR guidelines and American Family Physician (2015) both designate ultrasonography as the initial imaging test of choice 1

• The Infectious Diseases Society of America (2024) suggests abdominal ultrasound as the initial diagnostic imaging modality for suspected acute cholecystitis or acute cholangitis in nonpregnant adults 1

Why Ultrasound Excels in This Clinical Scenario

Ultrasound provides critical diagnostic information for this presentation:

• Ultrasound effectively detects biliary dilatation, gallstones, and evidence of biliary obstruction—the most likely etiologies given this patient's intermittent RUQ pain and jaundice 1

• For gallbladder and biliary disease specifically, ultrasound correctly diagnosed the disease process in 100% of patients in comparative studies 2

• Ultrasound can confirm or exclude mechanical obstruction with specificities ranging from 71% to 97% 1

• It is readily available, non-invasive, avoids ionizing radiation, and can identify multiple potential causes of RUQ pain simultaneously 1, 3

When to Proceed to Advanced Imaging

While ultrasound is the appropriate initial test, advanced imaging may be needed subsequently:

• If ultrasound is equivocal or non-diagnostic, the ACR recommends either MRCP or CT abdomen with IV contrast as equivalent alternatives for further evaluation 1

• MRCP is superior to CT for evaluating the biliary system and determining the etiology of biliary obstruction, with MRI showing 90.7% accuracy versus CT's 85.1% for detecting biliary obstruction 1

• CT abdomen with contrast can identify the site of obstruction and potential etiologies with high sensitivity (95%) and specificity (93.35%) for malignant biliary strictures 1

Common Pitfalls to Avoid

• Do not skip ultrasound and proceed directly to CT or MRCP as initial imaging—this exposes the patient to unnecessary radiation (CT) or cost/time (MRCP) when ultrasound will likely provide the diagnosis 1

• Patient body habitus may limit ultrasound visualization—if ultrasound is technically inadequate, proceed directly to MRCP or CT rather than repeating ultrasound 1, 3

• Do not order MRCP as initial imaging unless ultrasound has already been performed and is inconclusive—the ACR guidelines clearly position ultrasound first in the diagnostic algorithm 1

Clinical Algorithm

1. Order ultrasound abdomen as initial imaging 1
2. If ultrasound identifies gallstones, biliary dilatation, or cholecystitis: proceed with appropriate management 1
3. If ultrasound is equivocal or shows biliary dilatation without clear etiology: order MRCP to evaluate for biliary obstruction etiology 1
4. If ultrasound is technically limited or non-diagnostic: consider CT abdomen with IV contrast or MRCP based on clinical suspicion for malignancy versus benign obstruction 1, 3