The Influence of Region-of-interest Selection on Ejection Fraction Calculation in a Septate Gallbladder

Area of Science:

• Gastroenterology
• Diagnostic Imaging
• Nuclear Medicine

Background:

• Hepatobiliary scintigraphy is used to assess gallbladder function.
• Gallbladder ejection fraction (GBEF) is a key metric derived from this imaging.
• Accurate GBEF calculation is crucial for diagnosing gallbladder motility disorders.

Purpose of the Study:

• To highlight the impact of region of interest (ROI) selection on GBEF calculation.
• To emphasize the importance of considering anatomical variations in scintigraphy analysis.
• To illustrate how incorrect ROI selection can lead to misdiagnosis.

Main Methods:

• Hepatobiliary scintigraphy was performed on a patient with chronic nausea and epigastric pain.
• Initial GBEF calculation used a limited ROI (gallbladder fundus only).
• A revised, comprehensive ROI encompassing all gallbladder compartments was used for recalculation.

Main Results:

• The initial GBEF calculation suggested normal gallbladder function.
• Identification of a septate gallbladder prompted ROI re-evaluation.
• Recalculation with a comprehensive ROI resulted in a lower GBEF, indicative of biliary dyskinesia or chronic cholecystitis.

Conclusions:

• Proper ROI selection is critical for accurate GBEF assessment, especially with anatomical variations like septate gallbladder.
• Correlating functional imaging with anatomical findings is essential for reliable diagnosis.
• This case underscores the need for meticulous review of scintigraphy data.