Diagnostic utility of cholescintigraphy in emergency department patients with suspected acute cholecystitis: comparison with bedside RUQ ultrasonography.

Tc-99m-HIDA cholescintigraphy studies of gallbladder (GB) emptying are considered to be the most accurate method to diagnose acute cholecystitis (AC). With increasing use of bedside ultrasound (US) by emergency physicians for the evaluation of GB pathology, it is important to determine the role of cholescintigraphy as an adjunct to emergency ultrasound of the gallbladder. The objective of this study was to determine the utility of cholescintigraphy as an adjunct to bedside ultrasound in the evaluation of Emergency Department (ED) patients with suspected acute cholecystitis. We retrospectively reviewed US studies of 102 patients being evaluated for AC at a large community ED with a residency program. All patients over 18 years of age presenting to the ED over a 1-year period who received an ED US of the GB followed by a cholescintigraphy were enrolled. Bedside ultrasonography was performed after an initial physical examination by a hospital-credentialed emergency sonologist. Criteria used to diagnose AC include the finding of gallstones with a sonographic Murphy sign, significant wall thickening over 5 mm, pericholecystic fluid, impacted stone, or a combination of these. US reports were compared to cholescintigraphy results, final diagnosis, disposition, and pathology results when applicable. Statistical analysis included descriptive statistics calculated using StatsDirect software. A total of 102 patients fit criteria for this study over a 1-year period. Three patients were dropped from data analysis due to incomplete data. ED US and cholescintigraphy examinations agreed for presence or absence of AC in 76 of 99 patients (77%; 95% confidence interval [CI] 68-84%) resulting in a correlation value of rs = 0.74. A total of 38 of 99 (38%; 95% CI 30-49%) patients were diagnosed with AC on cholescintigraphy and ED US agreed in 20 patients. ED US diagnosed 25 (25%; 95% CI 18-34%) patients with AC and cholescintigraphy agreed in 20 patients. Of 99 patients enrolled, 63 were admitted to the hospital (63%; 95% CI 53-72%). Of the admitted patients, 36 (36%; 95% CI 27-46%) went to the operating room (OR) for presumed AC. Of the 31 (79%; 95% CI 64-89%) with AC on cholescintigraphy who went to the OR, only 13 (42%; 95% CI 26-59%) had pathology-based diagnosis of AC; 15 (48%; 95% CI 32-65%) had chronic inflammation only and 3 (10%; 95% CI 4-25%) had a diagnosis of cholelithiasis only. In 12 of 15 OR cases (80%; 95% CI 62-98%), where cholescintigraphy diagnosed AC but ED US did not, operative diagnosis agreed with US. Five patients with normal cholescintigraphy but ED US diagnosis of AC were taken to OR; pathology agreed with ultrasonography in all. Three other patients diagnosed with AC on cholescintigraphy, but not on ED US, never required operative intervention based on consulting surgeon evaluation. Our study demonstrates that the utility of cholescintigraphy in the evaluation of ED patients with suspected acute cholecysitis after a negative ultrasound examination is very limited.