Which test shows the ejection fraction of the gallbladder?

Cholecystokinin-Cholescintigraphy (CCK-CS) Is the Test That Shows Gallbladder Ejection Fraction

Cholecystokinin-cholescintigraphy (CCK-CS) is the specific test used to measure gallbladder ejection fraction (GBEF), providing a physiologic, noninvasive, and quantitative assessment of gallbladder contraction. 1

How CCK-CS Works to Measure Gallbladder Ejection Fraction

The procedure involves several key steps:

1. A Tc-99m-labeled HIDA (hepatobiliary iminodiacetic acid) radiopharmaceutical is injected intravenously
2. The radiotracer is taken up by the liver and excreted into the biliary system
3. The radiotracer accumulates in the gallbladder
4. Cholecystokinin (CCK) is administered to stimulate gallbladder contraction
5. Dynamic imaging captures the gallbladder emptying process
6. GBEF is calculated as the percentage of bile ejected from the gallbladder

Standardized Protocol for Optimal Results

The consensus protocol recommended by experts includes:

• Infusion of 0.02 μg/kg of sincalide (synthetic CCK) over 60 minutes
• Dynamic imaging (1 image per minute) during the infusion
• GBEF calculation at 60 minutes
• Normal GBEF defined as ≥38% 1

Clinical Applications

CCK-CS with GBEF measurement is primarily used for:

• Evaluating patients with suspected functional gallbladder disorder
• Assessing patients with upper abdominal pain thought to be biliary in origin who have normal ultrasound findings
• Predicting severity of cholecystitis (GBEF <30% may indicate higher complication rates during laparoscopic cholecystectomy) 1

Important Considerations and Limitations

• Patient preparation is crucial - patients should fast for 4-6 hours before the test
• Certain medications can affect gallbladder contraction and should be avoided 24 hours prior (including nifedipine, indomethacin, octreotide, theophylline, benzodiazepines) 1
• Nicotine and alcohol should also be avoided before testing
• Recreation of symptoms during CCK administration may be more predictive of underlying gallbladder pathology than the GBEF value alone 2
• GBEF tends to decline with age, which should be considered when interpreting results 3

Comparison to Other Imaging Modalities

While CCK-CS is the gold standard for measuring GBEF, other imaging modalities have different roles in gallbladder assessment:

• Ultrasound remains the initial test of choice for evaluating right upper quadrant pain due to its speed, ability to detect stones, and evaluation of bile ducts 1
• CT and MRI can provide anatomical information but cannot assess gallbladder function or calculate ejection fraction 1

Emerging Concepts

Recent research suggests that:

• Patients with biliary hyperkinesia (GBEF >80%) may also benefit from cholecystectomy if they have typical biliary symptoms 4
• Symptom reproduction during CCK administration may be more important than the actual GBEF value in predicting surgical outcomes 2, 5

CCK-CS remains the only validated method for quantitatively measuring gallbladder contractility and calculating ejection fraction, making it an essential tool in the evaluation of functional gallbladder disorders.