Main Pulmonary Artery-to-Ascending Aorta Diameter Ratio in Healthy Children on MDCT.

OBJECTIVE: This study was performed to ascertain whether the adult ratio of 1:1 of the diameter of the main pulmonary artery (MPA) to the diameter of the ascending aorta (AA) (referred to hereafter as the MPA-to-AA ratio) on MDCT is applicable to children. MATERIALS AND METHODS: Our hypothesis, which is based on experiential observation, is that the MPA-to-AA ratio would be higher than 1 in healthy children. A retrospective analysis of vessel calibers in a population of children without pulmonary hypertension who had undergone MDCT was performed. RESULTS: The MPA-to-AA ratio was statistically significantly higher in children of all ages than in adults. We would, therefore, submit that the normal MPA-to-AA ratio in children on MDCT is greater than 1 and closer to 1.09. CONCLUSION: The demonstration of an MPA segment that is slightly larger than the AA in children undergoing MDCT should not suggest a diagnosis of pulmonary arterial hypertension.

Perianal disease in pediatric Crohn disease: a review of MRI findings.

Perianal complications of Crohn disease are a common occurrence in children and can result in significant morbidity when not accurately characterized prior to surgical intervention. MRI is an excellent imaging modality for the evaluation of perianal inflammatory bowel disease - allowing characterization and detailed description of perianal fistulas. MRI has many advantages over other imaging modalities for the pediatric patient. Radiologists will benefit from a sophisticated understanding of perianal anatomy, the classification of perianal fistulas, the advantages MRI offers in characterization of perianal fistulas as well as the common and incidental findings that are important in the MRI evaluation of perianal inflammatory bowel disease in children. Perianal fistulas are found at a high rate in pediatric referrals and are more commonly found in male patients.