The gallbladder is a small organ beneath the liver that stores and concentrates bile, a digestive fluid produced by the liver. When a person eats, especially a meal containing fat, the gallbladder contracts and releases this stored bile into the small intestine to aid in digestion. The Gallbladder Ejection Fraction (GBEF) is a quantitative measurement used to assess how efficiently the gallbladder performs this contraction and emptying action. This percentage helps clinicians determine if a patient’s digestive symptoms are related to gallbladder movement.
Measuring Gallbladder Function
The GBEF is measured using a specialized nuclear medicine test called a Hepatobiliary Iminodiacetic Acid (HIDA) scan (cholescintigraphy). The procedure begins with the injection of a radioactive tracer, which travels to the liver, is secreted into the bile ducts, and concentrates in the gallbladder. Once the gallbladder is filled, a powerful stimulant, usually the hormone cholecystokinin (CCK) or a fatty meal, is administered to trigger the organ’s contraction.
A specialized camera tracks the reduction in the tracer within the gallbladder over a set period, typically 30 to 60 minutes, as it empties. The GBEF is calculated by comparing the amount of tracer before and after stimulation, yielding a percentage that reflects the degree of emptying. A GBEF greater than 35% to 38% is generally accepted as the normal functional range for an adult.
When Ejection Fraction Results Are Low
The HIDA scan is most frequently ordered when a patient presents with biliary colic symptoms, such as upper right abdominal pain, but an ultrasound reveals no gallstones. In this scenario, a low GBEF (typically defined as less than 35%) is diagnostic of Biliary Dyskinesia. This indicates the gallbladder is sluggish or hypo-functioning and is not contracting effectively.
The resulting slow or incomplete emptying leads to symptoms that intensify after consuming fatty foods, which demand strong gallbladder contraction. These symptoms include intermittent abdominal pain, nausea, vomiting, and bloating, mimicking the pain caused by gallstones. Biliary Dyskinesia (chronic acalculous cholecystitis) was historically the primary reason for evaluating gallbladder function with a GBEF measurement.
Understanding Gallbladder Hyperkinesis
A GBEF can be too high, particularly when a high result correlates with a patient’s symptoms. The condition where the gallbladder contracts excessively is termed Gallbladder Hyperkinesis (hyperkinetic biliary dyskinesia). While a GBEF in the high normal range (e.g., 60-75%) is usually asymptomatic, a result of 80% or higher is often used to define hyperkinesis.
A hyper-contracting gallbladder is thought to cause pain because it empties too forcefully or rapidly, leading to pressure changes within the biliary system. The symptoms of hyperkinesis are similar to those of Biliary Dyskinesia, including classic biliary colic pain in the upper right abdomen, frequently triggered by eating. This makes diagnosis challenging, as the clinical presentation is indistinguishable from other gallbladder problems.
The underlying mechanism is not fully understood, but one theory suggests the gallbladder muscle is hypersensitive to the stimulating hormone CCK, causing an exaggerated contraction response. The high ejection fraction only becomes a medical concern when it is directly linked to a patient’s chronic biliary pain.
Managing High Ejection Fraction
For a patient diagnosed with symptomatic Gallbladder Hyperkinesis, the primary course of action is often surgical. The standard treatment is a laparoscopic cholecystectomy, the minimally invasive removal of the gallbladder. This intervention is considered when conservative measures, such as dietary modifications, have failed to alleviate the patient’s discomfort.
While initial symptom resolution rates can exceed 90%, surgery is not universally successful for every patient. The decision to proceed is made carefully, confirming that the patient’s pain is reproducible and correlates with the timing of the gallbladder contraction during the HIDA scan. Removing the hyperactive organ is recognized as a viable and effective treatment to resolve the functional pain in these specific cases.