Main Pulmonary Artery-to-Ascending Aorta Diameter Ratio in Healthy Children on MDCT
Gregory L Compton1,2, Joshua Florence1, Cathy MacDonald1
11 Department of Diagnostic Imaging, The Hospital for Sick Children, University of Toronto, ON, Canada.
Insights
The main pulmonary artery (MPA)-to-ascending aorta (AA) ratio is typically 1:1 in adults. In children, this ratio is higher, with a normal MPA-to-AA ratio on MDCT closer to 1.09.
Area of Science:
- Pediatric Radiology
- Cardiovascular Imaging
- Thoracic Imaging
Background:
- The main pulmonary artery (MPA)-to-ascending aorta (AA) ratio is a standard metric in adult cardiovascular imaging.
- The 1:1 ratio is commonly used as a reference in adults, but its applicability in pediatric populations is not well-established.
Purpose of the Study:
- To determine if the adult 1:1 MPA-to-AA ratio is applicable to children.
- To establish a normal MPA-to-AA ratio for healthy children using MDCT.
Main Methods:
- Retrospective analysis of vessel calibers in children without pulmonary hypertension who underwent MDCT.
- Calculation of the MPA-to-AA ratio for different pediatric age groups.
Main Results:
- The MPA-to-AA ratio was statistically significantly higher in children of all ages compared to adults.
- The normal MPA-to-AA ratio in children on MDCT is greater than 1, approximating 1.09.
Conclusions:
- A slightly larger MPA than AA in children on MDCT does not indicate pulmonary arterial hypertension.
- The findings suggest a revised reference range for the MPA-to-AA ratio in pediatric populations.
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.
