Radiologists' confidence in interpretation of sonography and CT in suspected pediatric appendicitis

OBJECTIVE. We sought to determine radiologists' confidence in interpretation of sonography and CT performed using rectal contrast material for diagnosing pediatric appendicitis. SUBJECTS AND METHODS. We prospectively examined 139 children and young adults with equivocal clinical findings for appendicitis who were seen in the emergency department of an urban pediatric teaching hospital between July and December, 1998, Patients were initially examined with pelvic sonography. If the sonographic results were equivocal or if the appendix was not visualized, CT was performed. Radiologists recorded their level of confidence in interpretation of the sonograms and CT examinations. RESULTS. Sonography was interpreted with very low, low, or medium confidence in 59 (42.4%) of 139 patients and width high or very high confidence in 80 (57.6%) of 139, CT was interpreted with very low, low, or medium confidence in nine (8.3%) of 108 and with high or very high confidence in 99 (91.7%) of 108 children. Radiologists were more confident in their interpretation of CT than sonography (p < 0.001), If the sonography was a true-positive examination, radiologists were more confident in its interpretation than if it was a false-positive study (P = 0,003). Radiologists were more confident in sonographic interpretation of a true-negative examination than of a false-negative study (p = 0,03). Patient age and sex and the radiologists' level of experience did not make a significant difference in the confidence of interpretation of sonography or CT. CONCLUSION.. In the evaluation of childhood appendicitis, radiologists' confidence in interpretation is influenced by the choice of imaging technique as well as by the results of the study.