From the Guidelines
A HIDA scan should be ordered in non-pregnant adults with suspected acute cholecystitis when both ultrasound (US) and computed tomography (CT) are equivocal or nondiagnostic and clinical suspicion persists. This recommendation is based on the most recent guidelines from the Infectious Diseases Society of America, published in 2024 1. The HIDA scan is a valuable diagnostic tool for evaluating gallbladder dysfunction and biliary tract disorders, particularly in cases where other imaging modalities are inconclusive.
Key Indications for HIDA Scan
- Suspected acute cholecystitis with equivocal or nondiagnostic US and CT findings
- Evaluation of bile leaks after surgery
- Assessment of biliary obstruction
- Determination of gallbladder ejection fraction in patients with suspected chronic gallbladder disease
- Right upper quadrant pain with inconclusive ultrasound findings
- Persistent symptoms after gallbladder removal
- Evaluation of complications following biliary surgery
Procedure and Preparation
The HIDA scan involves injecting a radioactive tracer that is taken up by liver cells and excreted into bile, allowing visualization of the biliary system. Patients should fast for 4-6 hours before the test, and certain medications like opioids may need to be temporarily discontinued as they can affect gallbladder contraction. The scan typically takes 1-4 hours to complete, with minimal radiation exposure and rare side effects.
Comparison with Other Imaging Modalities
While CT and US are commonly used for initial evaluation, they may not provide functional information about the biliary system. MRI/MRCP can provide a clearer picture of surrounding structures and faster time to result, but is more costly than HIDA scan. The HIDA scan is considered the gold standard for diagnosing acute cholecystitis and is a reasonable option when CT is also equivocal 1.
From the Research
Indications for a HIDA Scan
A HIDA scan should be ordered in the following situations:
- When ultrasound results are inconclusive, but there is a high clinical suspicion for cholecystitis 2
- As the first diagnostic modality in patients with suspected acute cholecystitis, especially when ultrasound is not sensitive enough 3
- In patients with suspected biliary dyskinesia, characterized by altered gallbladder motility, to demonstrate abnormal gallbladder emptying 4
- To assess cystic duct patency or occlusion in patients with suspected acute cholecystitis 5
- In patients with chronic cholecystitis, to evaluate gallbladder function and guide further management 5
Contraindications for a HIDA Scan
A HIDA scan may not be necessary in the following situations:
- When clinical criteria for cholecystitis are already met, as indicated by the Tokyo guidelines 2
- In patients with complicated gallbladder disease, where a HIDA scan may be deemed unnecessary 2
- When ultrasound findings are sufficient to confirm the diagnosis of acute cholecystitis 6
Diagnostic Accuracy of HIDA Scan
The diagnostic accuracy of a HIDA scan is as follows: