Evaluation of Extremely Contracted Gallbladder After Normal CT and Fasting Ultrasound
The next step is to obtain a cholecystokinin-stimulated cholescintigraphy (CCK-HIDA scan) to assess gallbladder ejection fraction and evaluate for functional gallbladder disorder. 1
Understanding Your Current Findings
An extremely contracted gallbladder on fasting ultrasound is an unusual finding that suggests either:
- The gallbladder has already emptied (which shouldn't occur during fasting)
- Functional gallbladder abnormality
- Chronic inflammation causing fibrosis and contraction
This finding, combined with your symptoms (implied by the workup), warrants functional assessment rather than additional anatomic imaging. 1
Why CCK-HIDA Scan is the Appropriate Next Step
CCK-cholescintigraphy is the gold standard for evaluating gallbladder function and has the highest sensitivity (97%) and specificity (90%) for diagnosing functional gallbladder disorders when anatomic imaging is unrevealing. 1
Technical Specifications for the Test:
- You must fast for at least 4 hours (preferably overnight) before the study 2
- The test uses Tc-99m HIDA radiotracer to visualize gallbladder filling 1
- Sincalide (CCK) is infused at 0.02 μg/kg over 60 minutes to stimulate gallbladder contraction 1, 3
- Gallbladder ejection fraction (GBEF) is calculated from peak counts to minimum counts 1
Interpretation of Results:
Low ejection fraction (GBEF <35%):
- Indicates biliary dyskinesia or functional gallbladder disorder 1, 4
- Predicts 94.5% improvement or cure rate with cholecystectomy 5
- This is a recognized indication for laparoscopic cholecystectomy 6, 4
High ejection fraction (GBEF >80%):
- May indicate gallbladder hyperkinesia 6
- Recent evidence shows 61% complete resolution and 76% overall improvement rate with cholecystectomy in this population 6
- This represents an emerging indication for surgery, though less established than low GBEF 6
Normal ejection fraction (35-80%) with symptom reproduction during CCK infusion:
- Still may benefit from cholecystectomy with 83.4% improvement rate 5
- Symptom reproduction during CCK administration is clinically significant 7, 5
Why Not Other Imaging Modalities?
MRI/MRCP is not indicated because:
- You already have normal contrast CT, which has ruled out structural abnormalities 1
- MRI/MRCP evaluates anatomy, not function 1
- Your contracted gallbladder suggests a functional rather than structural problem 1
Repeat ultrasound or CT is not helpful because:
- Anatomic imaging has already been completed and is normal 8
- The issue is functional assessment, not additional anatomic detail 1
- Adding noncontrast phases provides little additional information 8
Clinical Pathway Based on CCK-HIDA Results
If GBEF <35%:
- Proceed with laparoscopic cholecystectomy 1, 4, 5
- Expected pathology: chronic cholecystitis (69.5%), cholesterolosis (22%) 6
- Expected outcome: >90% symptom improvement or cure 5
If GBEF >80%:
- Consider laparoscopic cholecystectomy if symptoms are clearly biliary in nature 6
- This is a newer indication with 76% overall improvement rate 6
- Discuss risk-benefit ratio given less established evidence base 6
If GBEF 35-80% but symptoms reproduced with CCK:
- Consider cholecystectomy with expected 83% improvement rate 5
- Symptom reproduction is clinically meaningful even with normal GBEF 7, 5
Important Caveats
Avoid pre-emptying with CCK before the HIDA scan, as this reduces test specificity and you should wait at least 4 hours after any CCK administration before beginning the study. 2
Obtain careful medication history, particularly regarding opiates, as morphine and other opiates can falsely lower gallbladder ejection fraction by affecting the sphincter of Oddi. 2
The extremely contracted gallbladder on fasting ultrasound is itself abnormal and may indicate chronic pathology even before functional testing, making the CCK-HIDA scan particularly important for surgical decision-making. 1, 6