Heartbeat-related distension and displacement of the thoracic aorta in healthy volunteers

Purpose: To test our hypothesis that distension and displacement in various segments of the healthy thoracic aorta are significant and can be predicted based on clinical characteristics. Materials and methods: Sixty-one Caucasian volunteers without cardiovascular disease (49 +/- 16 years, range 19-82; 28 men, 33 women) divided into two age groups (A: < 50, B: >= 50 years) underwent 1.5-T MRI. ECG-gated dynamic data sets were acquired at five locations perpendicular to the thoracic aorta. Aortic distension and Centre of Mass (CoM) displacement were determined as percentages of diastolic aortic diameter. A multiple linear regression model including age group, gender, location, mean arterial blood pressure, heart rate and body mass index was tested. Results: Mean aortic distension averaged over all locations was 11.2 +/- 4.1% (age group A) and 6.7 +/- 3.3% (age group B), mean displacement 15.1 +/- 8.3% (A) and 11.0 +/- 6.2% (B). Systolic and diastolic aortic diameter and CoM position significantly differed at all locations (p < 0.001). Distension and displacement could be predicted based on the regression model (p < 0.001). Age group A and women exhibited significantly greater distension and displacement compared to age group B (p < 0.001) and men (p < 0.01), respectively. Distension increased, displacement decreased from proximal to distal. Conclusion: Distension and translational displacement are significant at all levels of the thoracic aorta and can be predicted based on clinical characteristics. (C) 2010 Elsevier Ireland Ltd. All rights reserved.