Flow pattern analysis in the abdominal aorta with velocity-encoded cine MR imaging

Area of Science:

• Cardiovascular imaging
• Biomedical engineering
• Fluid dynamics

Background:

• Atherosclerotic plaque often deposits in specific regions of the aortic wall.
• Altered shear stress, influenced by secondary and retrograde blood flow, is implicated in plaque formation.
• Understanding these flow dynamics is crucial for predicting atherosclerosis risk.

Purpose of the Study:

• To detect secondary and retrograde flow patterns in the abdominal aorta using velocity-encoded cine (VEC) magnetic resonance (MR) imaging.
• To investigate the relationship between flow patterns and potential risk factors for atherosclerosis.
• To compare in vivo findings with in vitro flow models.

Main Methods:

• Velocity-encoded cine (VEC) magnetic resonance (MR) imaging was performed on nine healthy volunteers.
• Imaging was conducted at five distinct levels of the abdominal aorta.
• Quantitative analysis of net retrograde flow and its duration over the cardiac cycle was performed.

Main Results:

• Net retrograde flow increased from proximal to distal abdominal aorta levels, peaking near the renal arteries.
• Retrograde flow duration over the cardiac cycle also increased distally.
• Significant interindividual variations in diastolic retrograde flow amount and duration were observed.

Conclusions:

• VEC MR imaging effectively visualizes in vivo abdominal aortic blood flow patterns.
• Observed variations in retrograde flow suggest potential population-level vascular geometric risk factors for atherosclerosis.
• Findings align with previous in vitro flow visualization studies, validating the imaging technique.