Significance of ultrasonography in the diagnosis of appendicitis

AIM: The authors aim to evaluate the sensitivity and specificity of abdominal ultrasonography in 183 in-patients (113 females--70 males), aged between 3 and 78 years old, in the General Surgery department of Pugliese Hospital in Catanzaro, for abdominal pain and possible acute appendicitis, using a retrospective study. All patients underwent ultrasonography at the Division of Radiology in the same hospital. METHODS: The technique used was graded-compression US (useful to eliminate gas artifacts and to reduce the distance from the appendix) using a linear transducer between 3.5 and 7.5 MHz. The method lasted an average of 15 minutes and was performed by specially trained radiologists. The transducer was held between the forefinger and thumb and pushed into the abdomen using both palms, as if palpating the abdomen. When compression is applied slowly and gently, the pain is surprisingly well tolerated by the patient. The radiologist records whether the inflamed appendix is visualised ultrasonographically and with what degree of certainty, and whether perforations or the formation of abscesses and other pathological processes can be seen. In this case, clinical diagnosis was confirmed by radiological imaging and eventually by surgical evidence. RESULTS: Of the 183 patients examined, 135 showed positive US findings, 11 refused surgery and pain was resolved by pharmacological treatment, and 9 presented other pathologies (3 gastric ulcers, 4 acute cholecystitis and 2 extrauterine pregnancies). Therefore, 115 patients were effectively positive. Of the 183 patients, 48 were negative but of these, only 39 were effectively negative because 3 were false negatives and 6 revealed other pathologies when examined using other methods of diagnosis. Even if the diagnosis of appendicitis was confirmed by clinical examination in most cases, US is of value both to confirm the clinical diagnosis and to rule out any complications. In this particular case it was also useful for the surgeon as a means of locating the position of the appendix. Even if this method is partly conditioned by the patient's clinical conditions, the results were excellent. CONCLUSIONS: The authors conclude that US of the appendix is a valuable aid in the diagnosis of appendicitis, especially in the case of acute or subacute forms in which other radiological imaging might worsen the pathology and lead to the onset of further complications. US offers undeniable advantages using a non-invasive, low cost technique with a specificity of around 80% and sensitivity between 85 and 93%. It also provides a means of identifying other sources of low abdominal pain. However, we still regard clinical examination as being essential for diagnosis.