What is the ejection fraction of the gallbladder?

From the Guidelines

A normal gallbladder ejection fraction is defined as ≥38%. Ejection fraction for the gallbladder typically refers to the percentage of bile that the gallbladder expels during contraction after a fatty meal or cholecystagogue stimulation. This measurement is commonly obtained through a hepatobiliary iminodiacetic acid (HIDA) scan with cholecystokinin (CCK) stimulation, as recommended by an interdisciplinary panel 1.

The test protocol involves infusion of 0.02 g/kg of sincalide over 60 minutes, with the calculated gallbladder ejection fraction (GBEF) being used to diagnose functional gallbladder disease 1. An ejection fraction below 38% may suggest gallbladder dysfunction or chronic cholecystitis, potentially explaining symptoms like right upper quadrant pain, bloating, or nausea after meals. However, clinical correlation is essential as some patients with low ejection fractions may be asymptomatic, while others with normal values may still have biliary symptoms.

Key considerations for the test include:

• Fasting for 4-6 hours before the test
• Avoiding opioid medications for 24 hours before the test, as these can affect gallbladder contractility
• Using a standardized CCK-CS protocol, as recommended by the interdisciplinary panel 1
• Interpreting the results in the context of the patient's symptoms and clinical presentation.

From the Research

Ejection Fraction for Gallbladder

• The ejection fraction (EF) of the gallbladder is a measure used to evaluate its function, particularly in cases of suspected biliary dyskinesia or acalculous biliary colic 2, 3, 4, 5, 6.
• A low gallbladder EF (<35%) is often considered an indication for cholecystectomy, as it may suggest impaired gallbladder function 2, 6.
• However, the accuracy of EF in predicting gallbladder pathology is limited, and its utility in clinical decision-making is still debated 3, 4, 5.
• Studies have shown that EF declines with age, and its value may not correlate with the presence of gallbladder pathology in certain populations, such as children and adolescents 3, 4.
• The use of a HIDA scan with EF has been found to be overutilized in the management of biliary dyskinesia, and its results should be interpreted with caution 5.
• A gallbladder EF of less than 35% is generally considered abnormal, but the threshold for considering cholecystectomy may vary depending on the patient's symptoms and clinical presentation 6.

Threshold Values for Ejection Fraction

• A gallbladder EF of <35% is often used as a threshold for considering cholecystectomy 2, 6.
• However, some studies suggest that a higher threshold (e.g., <60%) may be more appropriate in certain cases, particularly if the patient's symptoms are classical for biliary disease 6.
• The optimal threshold value for EF remains unclear and may depend on various factors, including the patient's age, symptoms, and clinical presentation 3, 4, 5.

Clinical Applications of Ejection Fraction

• The measurement of gallbladder EF using a HIDA scan can be a useful diagnostic tool in evaluating patients with suspected biliary dyskinesia or acalculous biliary colic 2, 3, 4, 5, 6.
• However, the results of the HIDA scan should be interpreted in the context of the patient's clinical presentation and other diagnostic findings 5.
• Cholecystectomy may be considered in patients with a low gallbladder EF, particularly if they have symptoms consistent with biliary disease and have not responded to other treatments 2, 6.