A comparative ultrasound and plain abdominal x-ray: Evaluation of non-classical clinical cases of appendicitis

A prospective study of 109 patients with non-classical symptoms of appendicitis using the standard ultrasound (US) machine and plain abdominal x-rays demonstrated that US was superior to plain x-ray with a sensitivitiy, specificity and overall accuracy of 89%, 96% and 91%, respectively as compared with plain x-ray with 48%, 93% and 67% respectively. The negative appendectomy rate was 7%. In the alternative diagnosis, plain x-ray was superior to US due to the prevalence of intestinal diseases, ureteric calculi and basal pneumonia which were best shown in plain x-rays. US was, however, most useful in detecting female pelvic pathology. It is hoped that with improved imaging expertise and the appication of high resolution US machine a higher sensitivity and accuracy can be achieved. US is therefore recommended as the first line in the imaging of non-classical cases of appendicitis. However, in areas where enteric diseases and urinary calculus are endemic, it is prudent to perform both ultrasound and plain abdominal x-rays while the patient is in the radiodiagnostic department.