Ultrasonography in the acute abdomen

In a prospective study 152 consecutive patients presenting with acute abdominal pain were assessed clinically and an ultrasonographic examination was performed immediately. Of these, 16 (11 per cent) patients would normally have had an immediate ultrasonographic scan requested; routine (within 24 h of admission) ultrasonographic examination would have been requested in a further 66 (43 per cent) patients. In 70 (46 per cent) patients an ultrasonographic examination would not have been requested. Ultrasonography altered the diagnosis in one patient from probable appendicitis to cholecystitis. Ultrasonography missed one abdominal aortic aneurysm and one empyema of the gallbladder. Ultrasonography had a sensitivity of 96 per cent, a specificity of 94 per cent, a positive predictive value of 96 per cent, a negative predictive value of 94 per cent and an accuracy of 95 per cent in diagnosing appendicitis. Exactly the same values were found for the clinical diagnosis of appendicitis. The study shows that routine immediate ultrasonographic examination of the acute abdomen is rarely helpful, with the possible exception of appendicitis. Where an urgent ultrasonographic scan is necessary on clinical grounds the expertise of a radiologist is probably required, whereas in specific areas, for example in the diagnosis of right iliac fossa pain, there may be a place for training the surgical trainee.