Contraindications to HIDA Scan
HIDA scans have no absolute contraindications, but pregnancy represents a relative contraindication where ultrasound and MRI/MRCP without gadolinium should be exhausted first due to fetal radiation exposure. 1, 2
Relative Contraindications and Special Circumstances
Pregnancy
- Abdominal ultrasound is the mandatory first-line imaging throughout pregnancy for suspected biliary disease, avoiding all radiation exposure. 1, 2
- MRI/MRCP without gadolinium is the preferred second-line modality over any nuclear medicine study. 1, 2
- HIDA should only be considered if both ultrasound and MRI/MRCP are equivocal or unavailable, clinical suspicion remains very high, and the diagnosis would significantly alter management affecting maternal or fetal outcomes. 2
- The cumulative ionizing radiation exposure throughout pregnancy should remain below 50 mGy. 1
- Avoid MRI in the first trimester when possible, though no documented harm exists. 2
Recent Medication Use (Causes False-Positive Results)
- Opiates must be withheld for at least 48 hours before scanning because they cause sphincter of Oddi spasm, preventing radiotracer excretion into the duodenum and falsely suggesting cystic duct obstruction. 3, 4
- Anticholinergic drugs must be withheld for at least 48 hours as they directly impair gallbladder contraction and spuriously decrease gallbladder ejection fraction. 5, 3, 4
- Other medications to avoid within 24 hours include nifedipine, indomethacin, octreotide, theophylline, benzodiazepines, phentolamine, isoproterenol, progesterone, nicotine, and alcohol. 3
Inadequate Fasting Status
- Patients must fast for 4-6 hours (optimally overnight) to ensure the gallbladder is adequately filled with bile. 5, 3
- Non-fasting states cause gallbladder emptying, preventing radiotracer accumulation and yielding non-diagnostic studies. 4
Clinical Pitfalls and Limitations
False-Positive Results
- Non-excretion on HIDA can occur in severe hepatocellular dysfunction, total parenteral nutrition, prolonged fasting (>24 hours), and critical illness—all causing false-positive results for acute cholecystitis. 6, 4
- The specificity of HIDA for cholecystitis is only 36% in some studies, meaning many positive scans do not represent true disease. 7
False-Negative Results
- Biliary excretion noted on HIDA does not exclude biliary atresia in infants—misinterpreted scans have led to delayed diagnosis and surgical intervention. 8
- In pediatric biliary dyskinesia, HIDA results are poor prognostic indicators and should not solely guide surgical decisions. 9
Resource and Timing Constraints
- HIDA utilization is limited in clinical practice due to required resources, time (90-minute study duration), and availability, positioning it as third-line imaging after ultrasound and CT. 1, 5
- The study should be performed on an outpatient basis when possible, not during acute illness, to optimize diagnostic accuracy. 3
Appropriate Clinical Positioning
HIDA should be reserved for specific scenarios where ultrasound and CT are equivocal but clinical suspicion for acute cholecystitis persists, given its superior sensitivity (84.2-89.3%) compared to ultrasound (67.3%) and CT (59.8%). 1, 5
For functional gallbladder disorder (biliary dyskinesia), CCK-augmented HIDA with standardized protocol (0.02 μg/kg sincalide over 60 minutes) measures gallbladder ejection fraction, with abnormal defined as <38%. 5, 3