Mediastinal lymph nodes and pulmonary nodules in children: MDCT findings in a cohort of healthy subjects.

OBJECTIVE: Existing data are very limited on incidentally detected pulmonary nodules or mediastinal lymph nodes in healthy children who undergo chest MDCT. We aimed to evaluate the prevalence, distribution, and average dimensions of these occasional findings in a cohort of otherwise healthy patients. MATERIALS AND METHODS: Two radiologists reviewed in consensus the scans of patients referred for chest MDCT during the preoperative workup for pectus carinatum or pectus excavatum treatments. Exclusion criteria included the presence of any documented malignancy (by date of MDCT or during the 2 years after the examination), history of recent infections, or trauma. Patients' records were assessed after 2 years for the development of any malignancy. RESULTS: A total of 99 individuals (63 boys, 36 girls; mean age, 13.5 years; range, 4-18 years) who fulfilled the study criteria were evaluated. The presence of at least one pulmonary nodule was observed in 75% of the patients, with a mean diameter of 2.8 mm. Of a total number of 225 pulmonary nodules, only 24 (10.7%) were calcified. Mediastinal lymph nodes were also identified in 81% of the cases, with a maximum diameter of 7 mm (smallest axis). CONCLUSION: The presence of pulmonary nodules or mediastinal lymph nodes on the basis of preoperative chest MDCT scans in healthy children is frequent. Given that 95% of the nodules and 100% of the lymph nodes measured less than 6 mm and 7 mm, respectively, we conclude that incidental findings under these limits are very unlikely to be pathologic.

MR imaging evaluation of the normal appendix in children and adolescents.

PURPOSE: To evaluate asymptomatic children and adolescents to determine the rate of detection of the normal appendix at unenhanced magnetic resonance (MR) imaging. MATERIALS AND METHODS: This study was approved by the medical ethics committees of the authors' institutions, and informed consent was obtained from participants' parents or guardians. Forty asymptomatic volunteers underwent MR imaging to detect the appendix. Mean age (+/- standard deviation) for the 18 boys was 12.8 years +/- 2.4 (range, 9-17 years) and for the 22 girls was 12.7 years +/- 2.7 (range, 8-17 years). The MR imaging protocol consisted of axial T1-weighted fast spin-echo (SE), axial and coronal T2-weighted fast SE, and axial T2-weighted fat-saturated fast SE sequences. Two observers interpreted results independently, and kappa coefficients were calculated to evaluate agreement. The rate of detection was defined as the percentage of times that the appendix was visualized with at least one sequence. Body mass index was recorded for all participants. RESULTS: The normal appendix was detected by one observer in 19 cases (48%) and by the other in 20 cases (50%). The rate of appendix detection after observers reached a consensus was 48% (95% confidence interval: 32%, 64%). Interobserver agreement for appendix detection was good for most sequences analyzed. The greatest rate of normal appendix detection was found with the axial T2-weighted fast SE sequence (48%). CONCLUSION: The rate of normal appendix detection in children and adolescents at unenhanced MR imaging was 48%, which is similar to computed tomographic but lower than ultrasonographic detection rates.