Presence of biliary stent may alter biliary dynamics, which may change the results of cholescintigraphy. We assessed the frequency of gallbladder (GB) nonvisualization and its specificity for acute cholecystitis (AC) in patients with stent.
Patients and Methods
Of 44 with stent who had cholescintigraphy, 22 were excluded because of prior cholecystectomy or little to no radiotracer excretion from the liver precluding assessment of GB filling. Cholescintigraphy performed on the remaining 22 with stent and their medical records were reviewed. We also assessed the frequency of GB nonvisualization in the comparison group of 1044 without stent who had cholescintigraphy for evaluation of AC.
Gallbladder was not visualized in 21 (96%) of 22 with stent, 10 of whom did not have high clinical suspicion of AC. Gallbladder was visualized in only 1 patient on delayed imaging at 4 hours. Four had cholecystectomy, 3 had chronic cholecystitis and 1 AC superimposed on chronic cholecystitis. The highest possible specificity derived from our data assuming an extreme hypothetical scenario was only 25% with the true specificity likely being 7% or lower. In contrast to patients with stents, only 188 (18%) of the 1044 without stent had GB nonvisualization (P < 0.0001).
In patients with stents, cholescintigraphy using morphine augmentation or 4-hour delayed imaging is futile to evaluate for AC because the frequency of GB nonvisualization is high and the specificity of GB visualization is low. It is unknown whether further delayed imaging at 24 hours would improve the study efficacy in this population.