What type of HIDA (Hepatobiliary Iminodiacetic Acid) scan with gallbladder ejection fraction (GBEF) measurement should be ordered for a patient with suspected gallbladder dysfunction?

HIDA Scan Ordering for Suspected Gallbladder Dysfunction

Order a HIDA scan with cholecystokinin (CCK) stimulation using sincalide 0.02 μg/kg infused over 60 minutes to measure gallbladder ejection fraction (GBEF), with the patient fasting for 4-6 hours beforehand. 1, 2

Specific Order Details

Radiopharmaceutical and Dosing

• Request Technetium-99m (Tc-99m) mebrofenin as the preferred HIDA agent, administered at 5 mCi intravenously 2, 3
• For non-jaundiced patients: 74-185 MBq (2-5 mCi) 3
• For patients with serum bilirubin >1.5 mg/dL: 111-370 MBq (3-10 mCi) 3

CCK Stimulation Protocol

• Sincalide dose: 0.02 μg/kg body weight 1, 2
• Infusion duration: 60 minutes (NOT 3 minutes or 30 minutes) 1
• Administer CCK only after adequate gallbladder filling is documented 1, 2

Patient Preparation Requirements

• Minimum 4-6 hours fasting (preferably 4 hours) to ensure adequate gallbladder filling 2, 3
• Withhold opiates and anticholinergics for at least 48 hours before testing 2
• Perform only on outpatient basis, not during acute illness or hospitalization, as acute illness spuriously decreases GBEF 2

Imaging Protocol Specifications

Timing and Image Acquisition

• Dynamic imaging performed continuously for up to 60 minutes after radiotracer injection to assess gallbladder filling 2
• After gallbladder fills, begin CCK infusion and acquire images in left anterior oblique projection at 1-minute frames for 60 minutes 1
• If gallbladder has not filled by 60 minutes in properly prepared patient, report as abnormal (consistent with acute or chronic cholecystitis depending on clinical presentation) 2

Interpretation Criteria

Normal vs. Abnormal GBEF

• Normal GBEF: ≥38% using the 60-minute sincalide infusion protocol 4, 2
• Abnormal GBEF: <38%, which in appropriate clinical setting is consistent with functional gallbladder disorder 4
• Upper limit of normal approaches 100% with no clinical significance to high normal values 4

GBEF Calculation Method

• GBEF = (peak counts - minimum counts) / peak counts, all corrected for liver background 1
• Region of interest (ROI) drawn around gallbladder and liver, with gallbladder counts corrected for liver background 1

Critical Pitfalls to Avoid

Infusion Duration Matters

• Never order rapid CCK infusion (<30 minutes) as this causes non-physiologic gallbladder neck/cystic duct spasm and non-specific abdominal cramping in 48-53% of patients 1
• Rapid infusions (1-3 minutes) produce very high peak serum CCK levels unlike physiologic gradual rise 1
• With 60-minute infusions, no subjects develop symptoms, making this the only reliable protocol 1

Symptom Provocation Has No Diagnostic Value

• Do NOT use CCK-induced abdominal pain or symptoms as diagnostic criteria for gallbladder dysfunction 1
• CCK stimulates duodenum and colon in addition to gallbladder, causing non-specific symptoms 1
• Report should note that symptom development does not have diagnostic value and does not necessarily reflect gallbladder disease 1

Contraindications to Document

• Pregnancy (sincalide may stimulate preterm labor) 2
• Known allergic reaction to sincalide 2
• Intestinal obstruction 2

Clinical Context for Ordering

Primary Indication

• Suspected functional gallbladder disorder (biliary dyskinesia) in patients with typical biliary pain and normal ultrasound 1
• The only randomized controlled trial showed 10/11 patients (91%) with GBEF <40% became asymptomatic after cholecystectomy versus majority unchanged in no-surgery group 1

When NOT to Order

• Do NOT order for asymptomatic cholelithiasis - no evidence supports using CCK-CS to predict symptom progression 1
• Do NOT order for acute cholecystitis evaluation - standard HIDA without CCK is appropriate for this indication 2
• Atypical symptoms (indigestion, flatulence, heartburn, bloating, belching, nausea) are less likely to resolve after cholecystectomy and may not warrant testing 1

Diagnostic Performance

• HIDA scan has higher sensitivity (97%) and specificity (90%) for biliary tract abnormalities compared to ultrasound 5
• For acute cholecystitis specifically, HIDA has 84.2% sensitivity versus ultrasound 67.3% and CT 59.8% 2

Order Summary Statement

Write the order as: "HIDA scan with CCK stimulation for gallbladder ejection fraction. Use Tc-99m mebrofenin 5 mCi IV. After gallbladder filling, administer sincalide 0.02 μg/kg IV over 60 minutes. Patient to fast 4-6 hours. Outpatient only. Calculate and report GBEF." 1, 2, 3