The value of ultrasonography in the x-ray negative non-traumatic acute abdomen

Over a period of three years, 122 patients who presented with acute abdomen, and had normal abdominal x-rays on admission were examined with Ultrasonography (U/S) in order to evaluate the use of Abdominal Ultrasonography in patients with negative x-ray findings. Sonographic evaluation was undertaken with Siemen's equipment (Sonoline S1-2) with a 3.5 MHz sector transducer for the abdominal organs and 5 or 7.5 MHz sector transducer for the abdominal organs and 5 or 7.5 MHz linear array for the intestines and right iliac fossa. Analysis included features or organ inflammation, bowel wall changes, and motility and collections. Ultrasound guided aspiration and drainage were done when necessary. Surgical confirmation was obtained in 86 out of the 122 cases. The commonest finding were appendicitis, intestinal obstruction and gynaecological pathologies. Ultrasound correctly identified 76 out of the 86 positive cases (88%). The sensitivity, specificity, positive predictive valve and negative predictive valves were 88%, 78%, 96% and 83% respectively. There were seven (7) false negative findings, and three (3) false positive cases. Pancreatitis was the commonest cause of false negative findings. The study clearly shows that ultrasound imaging can identify the underlying pathology in 88% of patients with acute abdomen with negative, plain abdominal x-ray findings. Ultrasound guided interventional procedures can also be done without delay.