Overuse of CT in patients with complicated gallstone disease

When compared with ultrasound, CT scans are more expensive, have substantial radiation exposure and lower sensitivity, specificity, positive, and negative predictive values for patients with gallstone disease.

We reviewed data on patients emergently admitted with complicated gallstone disease between January 2005 and May 2010. Use of CT and ultrasound imaging on admission was described. Multivariate logistic regression was used to evaluate factors predicting receipt of CT.

Five hundred and sixty-two consecutive patients presented emergently with complicated gallstone disease. Mean age was 45 years. Seventy-two percent of patients were female, 46% were white, and 41% were Hispanic. Seventy-two percent of patients had an ultrasound during the initial evaluation and 41% had a CT. Both studies were performed in 25% of patients (n = 141), 16% (n = 93) had CT only, and 47% (n = 259) had ultrasound only. CT was performed first in 67% of those who underwent both studies. Evening imaging (7 PM-7 AM, odds ratio [OR] = 4.44; 95% CI, 2.88-6.85), increased age (OR = 1.14 per 5-year increase; 95% CI, 1.07-1.21), leukocytosis (OR = 1.67; 95% CI, 1.10-2.53), and hyperamylasemia (OR = 2.02; 95% CI, 1.16-3.51) predicted use of CT.

Our study demonstrates the overuse of CT in evaluation of complicated gallstone disease. Evening imaging was the biggest predictor of CT use, suggesting that CT is performed not to clarify the diagnosis, but rather a surrogate for the indicated study. Surgeons and emergency physicians should be trained to perform right upper quadrant ultrasound to avoid unnecessary studies in the appropriate clinical setting.