Published online Apr 16, 2023. doi: 10.12998/wjcc.v11.i11.2423
Peer-review started: December 21, 2022
First decision: January 11, 2023
Revised: January 25, 2023
Accepted: March 17, 2023
Article in press: March 17, 2023
Published online: April 16, 2023
Hepatobiliary scintigraphy (HBS) is a useful diagnostic imaging technique that uses radioactive tracers to evaluate the function of the gallbladder (GB) and biliary tract. In segmented GB, some HBS images show inconsistent GB boundaries as compared to anatomical imaging, limiting the evaluation of GB contractility through HBS.
Cholecystectomy is sometimes necessary in patients with gallstones or chronic cholecystitis. In addition, in the case of anatomically segmented GB, cholecystectomy is recommended due to the higher risk of future GB disease. Because there are patients who are reluctant to undergo cholecystectomy, cholecystectomy is recommended again if cholecystectomy decreases after evaluating the GB contractability using HBS. In previous studies, the GB ejection fraction (GBEF) was reduced in the case of segmental GB, but GBEF was often normal when measured in our study.
We evaluated the characteristics of HBS in segmented GB and investigated the effect of segmented GB on the measurement of GBEF using HBS.
From a larger group of patients with chronic cholecystitis, gallstones, or biliary colic, those who underwent HBS were identified. Patients with segmented GB features with segmental lumen stricture were identified using computed tomography (CT) or magnetic resonance (MR) imaging. Patients were asked whether CT or MR was performed either 1 mo before or after HBS. Segmented GB was classified into 3 types based on the filling and emptying patterns of the proximal and distal segments according to the characteristics of HBS images, and GBEF was measured. Type 1 was defined as a normal filling and emptying pattern, Type 2 was defined as an emptying defect on the distal segment, and Type 3 was defined as a filling defect in the distal segment.
Segmented GB accounted for 63 cases (23.5%), including 36 patients (57.1%) with Type 1, 18 patients (28.6%) with Type 2, and 9 patients (14.3%) with Type 3. Thus, approximately 43% of segmented GB cases demonstrated discordance between HBS and anatomical imaging. Although there were no significant differences in clinical symptoms, rate of cholecystectomy, or pathological findings based on the type, most gallstones occurred in the distal segment. Reported GBEF was 62.50% ± 24.79% for Type 1, 75.89% ± 17.21% for Type 2, and 88.56% ± 7.20% for Type 3. Type 1 showed no difference in reported GBEF as compared to the non-segmented GB group (62.50% ± 24.79% vs 67.40 ± 21.78%). In contrast, the reported GBEF was higher in Types 2 and 3 with defective emptying and filling than in Type 1 (80.11% ± 15.70% vs 62.57% ± 24.79%; P = 0.001).
In segmented GB, discordance between HBS and anatomical imaging (CT or MR) could lead to inaccurate estimation of GBEF. Therefore, clinicians should use caution when interpreting GB contractility through HBS in patients with segmented GB.
Since the presence or absence of gallstones may affect HBS, additional studies may be conducted to examine the difference in GBEF according to the presence or absence of gallstones in patients with segmented GB. Further studies using single-photon emission CT to evaluate discrepancies between HBS and anatomical imaging are expected to help determine the need for cholecystectomy.