Revisiting hepatobiliary imaging: experience at a teaching institution

Introduction: Hepatobiliary scintigraphy (HIDA) has been utilized for decades to evaluate various hepatobiliary diseases. Evaluation for acute cholecystitis remains the commonest indication. We recently reviewed HIDA cases at our institution to reassess the utility of this technique for diagnosing acute cholecystitis and its influence on subsequent treatment strategy.

Methods: There were a total of 166 consecutive patients with a mean age of 56.3 ± 20 years who had been hospitalized at our institution between January to December 2017 and had been evaluated for acute cholecystitis using HIDA scan. The HIDA scan was considered positive when the gallbladder was not visualized within the first hour of obtaining dynamic images after the radiotracer administration. The continuous variables were expressed as means with standard deviation, and the categorical variables were expressed as percentages. The Receiver Operating Characteristic (ROC) curve analyses were used to evaluate our HIDA scan as a tool in diagnosing acute cholecystitis.

Results: Of the 166 patients, 53 patients (32%) had no gall bladder visualization on scintigraphy and their findings were considered compatible with acute cholecystitis in appropriate clinical setting. Of these patients, 25 patients (47%) required inpatient interventions with surgical cholecystectomy (18 patients) or percutaneous cholecystostomy tube (7 patients) while ten (19%) underwent an outpatient cholecystectomy procedure. The sensitivity of the HIDA scan was 78.1% and the specificity was 79.1%. The positive predictive value of this tool was 47.2% and the negative predictive value was 93.8%. The ROC curve analyses showed acceptable discriminatory effect with AUC (area under ROC curve) value of 0.79 (95% CI: 0.72 to 0.85; p< 0.0001; Fig).

Conclusions: The utilization of the HIDA scan as a diagnostic tool for acute cholecystitis remains essential with acceptable sensitivity and predictability in the appropriate clinical setting.

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