Best Initial Imaging for a New Soft Lump in the Right Upper Quadrant

Primary Recommendation

The American College of Radiology recommends right upper quadrant ultrasound as the first-line imaging modality for patients presenting with a palpable mass or lump in this region, rated 9/9 (usually appropriate) 1, 2

Ultrasound provides a comprehensive evaluation of the liver, gallbladder, biliary tree, and can identify both solid and cystic masses with high accuracy (96% for gallbladder pathology), according to the American College of Radiology 3
The American College of Radiology suggests that ultrasound is noninvasive, portable, does not involve radiation exposure, has lower cost, and provides faster results than CT or MRI 3

If ultrasound is diagnostic and shows gallbladder pathology (stones, wall thickening, pericholecystic fluid), the American College of Radiology recommends proceeding with clinical management or considering cholescintigraphy if acute cholecystitis is suspected but ultrasound is equivocal 1, 3
For suspected biliary obstruction or bile duct pathology, the American College of Radiology recommends MRCP as the next appropriate imaging modality with sensitivity of 85-100% and specificity of 90% for biliary tree evaluation 2
For suspected solid hepatic mass requiring characterization, the American College of Radiology suggests that MRI abdomen with IV contrast is superior to CT for evaluating hepatic and biliary abnormalities 4, 5
For critically ill patients or suspected complications (abscess, perforation, hemorrhage), the American College of Radiology recommends CT abdomen with IV contrast as it can detect complications and alternative diagnoses 3, 5

The American College of Radiology advises against ordering CT as the initial imaging study for a palpable RUQ lump, as CT has lower sensitivity (~75%) for gallstones and exposes patients to unnecessary radiation when ultrasound is more appropriate and diagnostic 2, 3
The American College of Radiology recommends not skipping ultrasound and proceeding directly to advanced imaging (MRI or CT) unless the patient is too unstable for ultrasound or there is a specific contraindication 1, 2, 3
If ultrasound demonstrates a solid mass, the American College of Radiology suggests not assuming it is benign without further characterization, and proceeding to contrast-enhanced MRI or CT to evaluate for malignancy, abscess, or other pathology requiring intervention 4, 5