Accuracy of noncompressive sonography of children with appendicitis according to the potential positions of the appendix.

OBJECTIVE This study evaluates noncompressive sonography of appendicitis in children according to the potential positions of the appendix. SUBJECTS AND METHODS We evaluated 425 consecutive boys and girls clinically suspected of having appendicitis. Noncompressive sonography used a 5.0-MHz curved-array transducer to assess deep layers. We systematically investigated the possible positions of the appendix by evaluating the right retrocecal region through the flank, the pelvis through the suprapubic region with the urinary bladder full, and the right lower quadrant. Whenever the appendix was not visualized, graded compression examination was performed with 5.0-MHz curved-array and 7.5-MHz linear transducers, and the remainder of the abdomen was thoroughly examined with 5.0- and 3.75-MHz curved-array transducers. Sonographic findings were correlated with pathology findings after surgery in 212 cases and with clinical follow-up in 213. RESULTS Of the 425 patients with abdominal pain, 199 had surgically confirmed appendicitis; noncompressive examination accurately identified 135 (31.7%) of these 425 cases, and the combined noncompressive and compressive examinations diagnosed 196 cases. The combined noncompressive and compressive techniques had a sensitivity of 98.5% (95% confidence interval, 96.8-100), specificity of 98.2% (96.5-99.9), positive and negative predictive values of 98.0% (99.9) and 98.7% (97.2-100), respectively. CONCLUSION The noncompressive technique is a valuable tool in sonographic investigation of appendicitis.