The use of pre-operative computed tomography in the assessment of the acute abdomen

INTRODUCTION While there are a lot of data on the accuracy of computed tomography (CT) in diagnosing specific causes of an acute abdomen, there is very little information on the accuracy of CT in the acute general surgical admissions workload. We look at the diagnostic accuracy of CT in patients presenting with an acute abdomen who ultimately required a laparotomy.

METHODS Patients who underwent an emergency laparotomy between 2008 and 2010 at Eastbourne District General Hospital with pre-operative CT on the same admission were included in the study. The CT report was compared with the laparotomy and histology findings and, where a discrepancy existed, the original imaging was reviewed by a senior consultant blinded to the original report and laparotomy findings.

RESULTS A total of 196 emergency laparotomies were performed over the 2-year period, with 112 patients undergoing pre-operative CT. Fifteen patients were excluded from the study due to missing notes. In the remaining 97 patients, 80 CT reports correlated with the final operative diagnosis, giving a diagnostic accuracy of 82%. Of these, the on-call registrar was the initial reporter in 37 scans, with a diagnostic accuracy of 78%. On review of the CT by a second consultant, this increased to 90 correlations, yielding an accuracy of 93%. Delay between CT and the operation did not significantly alter diagnostic accuracy, nor was there any statistically significant reduction in accuracy in reports issued by on-call registrars.

CONCLUSIONS On first reporting, CT misses 18% of diagnoses that ultimately require operative intervention. Reducing the threshold for obtaining a second consultant radiologist review significantly improves the diagnostic accuracy to 93%.