Impact of indwelling biliary stent or sphincterotomy on gallbladder visualization on cholescintigraphy

1675 Objectives Biliary dynamics may be altered in patients with biliary stent placement (STENT) or sphincterotomy (SPHIX). We assessed the frequency and positive-predictive value (PPV) of gallbladder (GB) nonvisualization on cholescintigraphy for acute cholecystitis in such patients. Methods Of 1,650 cholescintigraphy performed over the past 10 years, a medical record search revealed 48 scans performed in post STENT patients and 11 scans in post SPHINX patients. From the STENT group, 22 cases were excluded; 17 were excluded because of history of cholecystectomy and 5 were excluded because the scan showed no or minimal radiopharmaceutical excretion from liver parenchyma, leaving 26 cases for analysis. From the SPHINX group, 4 cases were excluded because of history of cholecystectomy, leaving 7 for analysis. Results Of the 26 post STENT cases, GB was visualized after 60 minutes in only 1 case and not visualized in the remaining 25. Of the 25 without GB visualization, 5 GBs were surgically removed; 4 of these demonstrated chronic cholecystitis and 1, acute cholecystitis on histopathology. Of the 7 post SPHINX cases, GB was visualized in 5 (3 within 1 hour and 2 after morphine administration) and not visualized in the remaining 2; GB was removed from one of the 2 and demonstrated acute cholecystitis. Conclusions In patients with indwelling biliary stents, cholescintigraphy is futile in the evaluation of acute cholecystitis as the frequency of GB non-visualization is extremely high (25/26 in this study) and the PPV of this finding is very low. On the other hand, cholescintigraphy appears useful in excluding acute cholecystitis in patients with sphincterotomy as the frequency of GB visualization is fairly high, while the PPV of GB nonvisualization in this population is uncertain.