Thoracic aorta cardiac-cycle related dynamic changes assessed with a 256-slice CT scanner

Area of Science:

• Cardiovascular imaging
• Thoracic aorta dynamics
• Aortic biomechanics

Background:

• Previous studies documented dynamic changes in the ascending and abdominal aorta.
• The dynamic behavior of the thoracic aorta during the cardiac cycle was less understood.

Purpose of the Study:

• To investigate if dynamic changes observed in other aortic segments are also present in the thoracic aorta.
• To quantify conformational changes in the descending thoracic aorta throughout the cardiac cycle.

Main Methods:

• Utilized CT angiography (CTA) with ECG-gating on a 256-MDCT scanner.
• Measured maximal and minimal aortic diameters at three levels (10, 40, 80 mm from left subclavian artery).
• Excluded patients with diffuse aortic atherosclerosis.

Main Results:

• Descending thoracic aorta diameters were significantly larger during systole compared to diastole (P<0.01).
• Maximal diameters were consistently larger than minimal diameters across all measurements (P<0.05).
• These changes were observed irrespective of the distance from the left subclavian artery.

Conclusions:

• The thoracic descending aorta exhibits significant dynamic conformational changes during the cardiac cycle.
• These findings suggest pulsatile behavior similar to other major arteries.
• This pilot study highlights the dynamic nature of the thoracic aorta.