In a 32-year-old male with suspected acute cholecystitis, should both a right‑upper‑quadrant abdominal ultrasound and a computed tomography (CT) scan be ordered?

Should Both Ultrasound and CT Be Ordered for Suspected Cholecystitis in a 32-Year-Old Male?

No—order right upper quadrant ultrasound first, and reserve CT with IV contrast only for specific indications such as equivocal ultrasound findings with high clinical suspicion, suspected complications, or critically ill patients with peritoneal signs. 1, 2

Initial Imaging Strategy

Ultrasound is the mandatory first-line imaging test for any patient with suspected acute cholecystitis, including your 32-year-old male patient. 1, 2, 3

• Ultrasound achieves 96% accuracy for detecting gallstones, which are present in the vast majority of acute cholecystitis cases 1, 2
• Ultrasound has 75.7-88% sensitivity and 80-86% specificity for diagnosing acute cholecystitis itself 2
• The combination of gallstones plus sonographic Murphy sign (focal tenderness when pressing the gallbladder with the probe) yields 92.2% positive predictive value for acute cholecystitis 4
• Ultrasound provides rapid results, costs less, avoids radiation exposure, and can identify alternative diagnoses 1, 3

When CT Should NOT Be Ordered

Do not order CT as your initial imaging test—this violates American College of Radiology guidelines and exposes the patient to unnecessary radiation and cost. 1, 2, 5

• CT has only approximately 75% sensitivity for detecting gallstones because up to 80% of stones are non-calcified and appear isodense to bile 5
• CT without IV contrast misses critical early findings of acute cholecystitis, including gallbladder wall enhancement and adjacent liver hyperemia 5
• Ordering both ultrasound and CT simultaneously is redundant and wasteful when ultrasound alone will provide the diagnosis in most cases 1, 2

When CT With IV Contrast IS Indicated

If ultrasound findings are equivocal but clinical suspicion remains high, or if complications are suspected, then order CT abdomen/pelvis with IV contrast. 2, 5, 4

Specific indications for adding CT with IV contrast include:

• Suspected complications: emphysematous cholecystitis, gangrenous cholecystitis, gallbladder perforation, hemorrhage, or abscess formation 2, 5, 4
• Critically ill patients with peritoneal signs or atypical presentations requiring broader abdominal evaluation 2, 5
• Equivocal ultrasound in a patient with high clinical suspicion and ongoing symptoms 2, 5
• Preoperative planning when surgical anatomy needs clarification 5

Alternative Advanced Imaging Options

If ultrasound is negative or equivocal and you need further evaluation:

• HIDA scan (cholescintigraphy) has 96-97% sensitivity and 90% specificity for acute cholecystitis—higher than ultrasound—and is the preferred next step when ultrasound is inconclusive and acute cholecystitis remains the primary concern 1, 2
• MRCP is superior to CT for evaluating the biliary tree if choledocholithiasis or biliary obstruction is suspected (sensitivity 85-100%, specificity 90%) 2, 6

Clinical Algorithm for Your 32-Year-Old Male Patient

1. Order right upper quadrant ultrasound immediately 1, 2, 3
2. If ultrasound shows gallstones + wall thickening + pericholecystic fluid + positive sonographic Murphy sign: diagnose acute cholecystitis and proceed to surgical consultation 2, 4, 7
3. If ultrasound is negative but clinical suspicion remains high: order HIDA scan 1, 2
4. If ultrasound suggests complications (wall irregularity, intramural gas, complex pericholecystic fluid): order CT abdomen/pelvis with IV contrast 2, 5, 4
5. If patient is critically ill with peritoneal signs or shock: consider CT with IV contrast to evaluate for perforation, abscess, or alternative diagnoses 2, 5

Important Caveats

• The sonographic Murphy sign has relatively low specificity and becomes unreliable after pain medication administration 1, 2
• In critically ill patients, gallbladder wall abnormalities are common even without true acute cholecystitis, reducing diagnostic specificity 2
• Never order non-contrast CT for gallbladder evaluation—it misses critical diagnostic features that only IV contrast can demonstrate 5
• A single post-contrast phase CT is sufficient; adding a non-contrast phase provides minimal additional information 5