Determining normal values for lower trachea and bronchi size in children by computed tomography (CT).

BACKGROUND: Normative data for central airway dimensions are a prerequisite to objectively assess large airway pathologies. Studies with computed tomography (CT) measurements of normal trachea and bronchi size in children are scarce. OBJECTIVE: The purpose of this study is to establish normal values of central airway dimensions in children by CT. METHODS: The study included chest CT studies from children aged 0-18 years. Any condition that predisposed the patient to have an abnormal tracheal or bronchial size was excluded. Airway diameters and cross-sectional area (CSA) were measured using double oblique reconstructions at five levels: proximal trachea, mid-trachea, distal trachea, right main bronchus, and left main bronchus. RESULTS: The inclusion criteria were met by 110 subjects (mean age, 10.8 years; SD, 5.2 years). Various regression models that considered the relationship between patient demographics and anteroposterior (AP) diameter, transverse diameter, and CSA at each of the five levels were assessed. R2 was utilized to select the best model. Multiple formulae (using patient age) were developed to calculate expected normal dimensions for five levels in the central airways on the natural log scale. Finally, z-scores were obtained for central airway dimensions at these five levels. CONCLUSION: Normative data in pediatric central airways are crucial to identify large airway pathologies. We propose using the formulae devised in our study to calculate the predicted dimensions of central airways and their z-scores in pediatric patients. Normative data from our study will aid in objective quantification of central airways, increase clinician confidence, and provide appropriate patient care.

Normal pulmonary artery and branch pulmonary artery sizes in children.

To establish standards for pulmonary artery and branch pulmonary artery (PA and BPA) effective diameter (ED) and cross-sectional area (CSA) by using computed tomography (CT) data in children of a wide range of sizes and investigate the roundness of arteries. The ED (average of short and long axes) and CSA for the PA and BPA were measured using 1-mm collimation double-oblique reconstructions. Ordinary least squares regression was used to investigate models with various functional forms that related ED and CSA to patient size. Aspect ratio (AR), the short axis divided by long axis, was measured to evaluate roundness. The ideal diameter derived from CSA measurements was compared to ED, short axis, and long axis measurements. 108 CT examinations were analyzed in children without reason for abnormal PA size who ranged in age from 0 to 18 years (mean, 10.9 years; SD, 5.9 years). Interrater reliability was excellent. Data were modeled using a natural log-transformed response variable and a linear term for height as the independent variable. AR for the PA, right pulmonary artery, and left pulmonary artery measured < 0.9 for 38, 55, and 37%, respectively, indicating that many arteries are not round. Ideal diameter was not significantly different than ED but was for short- and long-axis diameter measurements. Normal ED and CSA for PA and BPA were determined for children of different sizes. Measurements outside of the normal range are consistent with dilatation or stenosis. Single diameter techniques are likely to introduce error.

Assessment of Primary Site Response in Children With High-Risk Neuroblastoma: An International Multicenter Study.

PURPOSE: The International Neuroblastoma Response Criteria (INRC) require serial measurements of primary tumors in three dimensions, whereas the Response Evaluation Criteria in Solid Tumors (RECIST) require measurement in one dimension. This study was conducted to identify the preferred method of primary tumor response assessment for use in revised INRC. PATIENTS AND METHODS: Patients younger than 20 years with high-risk neuroblastoma were eligible if they were diagnosed between 2000 and 2012 and if three primary tumor measurements (antero-posterior, width, cranio-caudal) were recorded at least twice before resection. Responses were defined as ≥ 30% reduction in longest dimension as per RECIST, ≥ 50% reduction in volume as per INRC, or ≥ 65% reduction in volume. RESULTS: Three-year event-free survival for all patients (N = 229) was 44% and overall survival was 58%. The sensitivity of both volume response measures (ability to detect responses in patients who survived) exceeded the sensitivity of the single dimension measure, but the specificity of all response measures (ability to identify lack of response in patients who later died) was low. In multivariable analyses, none of the response measures studied was predictive of outcome, and none was predictive of the extent of resection. CONCLUSION: None of the methods of primary tumor response assessment was predictive of outcome. Measurement of three dimensions followed by calculation of resultant volume is more complex than measurement of a single dimension. Primary tumor response in children with high-risk neuroblastoma should therefore be evaluated in accordance with RECIST criteria, using the single longest dimension.