No delayed imaging or CCK administration is needed in most cases when bowel excretion does not occur but gallbladder fills promptly.

Abstract

On hepatobiliary scintigraphy, "preferential gallbladder (GB) filling without tracer excretion into the small bowel (SB) [p-GB-no-SB]" is occasionally seen on images obtained up to an hour. In such cases, many practitioners administer cholecystokinin (CCK) (even when the measurement of GB ejection fraction is not indicated) or obtain delayed images (DI) to exclude common bile duct (CBD) obstruction. We aimed (1) to assess the prevalence of clinically relevant CBD obstruction found by CCK administration or DI in this circumstance and (2) to find imaging findings and/or parameters that can be used to triage patients who do or do not need such maneuvers. Of 1244 scans reviewed, 1089 were excluded because of one or more of the following reasons: SB visualized within 60min, GB not visualized within 60min, severely decreased hepatic function, and less than 1month of clinical follow-up after scanning. The remaining 155 showed p-GB-no-SB with clinical follow-up available for ≥ 1month. For the 155 scans, clearance of liver parenchymal activity was assessed. Of the 155 scans, 142 showed visually prompt clearance of liver parenchymal activity (group A), while 13 scans showed mild to moderately delayed clearance of liver parenchymal activity with or without initial decreased hepatic uptake (group B). 134 of 142 in group A had additional imaging (99 CCK or 35 DI); all 134 showed SB visualization. Eight remaining scans were terminated without additional imaging. None of the 142 had any event attributable to CBD obstruction on follow-up. All 13 in group B had additional imaging (9 CCK, 4 DI); SB visualized in 11, but not in two; clinical follow-up revealed no CBD obstruction in 11. ERCP revealed CBD obstruction in the latter two. When a HIDA scan shows p-GB-no-SB, the probability of identifying clinically relevant CBD obstruction by additional imaging with CCK or DI is virtually zero in an acute clinical setting if clearance of liver parenchymal activity is prompt. Additional imaging with CCK or DI can be reserved for only those showing abnormal clearance of liver parenchymal activity.