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MRI of rabbit atherosclerosis in response to dietary cholesterol lowering
M V McConnell1, M Aikawa, S E Maier
1Noninvasive Laboratory, Vascular Medicine, Atherosclerosis Unit, Brigham and Women's Hospital, Boston, MA 02115, USA. mcconnell@stanford.edu
Abstract:
Direct imaging of the atherosclerotic plaque, rather than the angiographic lumen, may provide greater insight into the response of atherosclerosis to cholesterol-lowering therapy. Aortic plaque was studied in vivo by MRI in rabbits undergoing dietary cholesterol intervention. Thirty-one rabbits underwent aortic balloon injury and high-cholesterol diet for 4 months and then were assigned to low-cholesterol versus continued high-cholesterol diet for up to an additional 16 months. High-resolution (310 micrometer) fast spin-echo MRI of the abdominal aorta was performed at 4, 12, and 20 months and compared with histology. MRI demonstrated a significant reduction in % area stenosis in rabbits placed on low-cholesterol diet (44.6+/-2. 1% at 20 months versus 55.8+/-1.5% at 4 months, P=0.0002). In contrast, % area stenosis increased in rabbits maintained on high-cholesterol diet (69.8+/-3.8% at 20 months versus 55.8+/-1.5% at 4 months, P=0.001). Similarly, plaque thickness decreased significantly in the low-cholesterol group (0.60+/-0.05 mm at 20 months versus 0.85+/-0.06 mm at 4 months, P=0.006), with a trend toward increase in the high-cholesterol group (1.02+/-0.08 mm at 20 months versus 0.85+/-0.06 mm at 4 months, P=0.1). Thus, in rabbits undergoing dietary cholesterol lowering, MRI detected regression of aortic atherosclerotic plaque in vivo. Plaque progression was seen with maintenance of high-cholesterol diet. MRI is a promising noninvasive technology for directly imaging atherosclerosis and its response to therapeutic interventions.
Insights
Magnetic Resonance Imaging (MRI) effectively visualized atherosclerotic plaque regression in rabbits on a low-cholesterol diet. This noninvasive imaging method shows promise for monitoring atherosclerosis treatment responses.
Area of Science:
- Cardiovascular Research
- Medical Imaging Technology
- Atherosclerosis Research
Background:
- Assessing atherosclerosis response to therapy often relies on lumen imaging, which may not fully capture plaque changes.
- Direct imaging of atherosclerotic plaque offers deeper insights into therapeutic efficacy.
Purpose of the Study:
- To evaluate the in vivo efficacy of Magnetic Resonance Imaging (MRI) in directly visualizing and quantifying aortic atherosclerotic plaque regression in rabbits undergoing cholesterol-lowering interventions.
Main Methods:
- Thirty-one rabbits with induced aortic plaque underwent high-cholesterol diets, followed by assignment to either low-cholesterol or continued high-cholesterol diets for up to 16 months.
- High-resolution fast spin-echo MRI of the abdominal aorta was performed at multiple time points (4, 12, and 20 months) and compared with histological data.
Main Results:
- MRI demonstrated a significant reduction in % area stenosis in rabbits on a low-cholesterol diet (P=0.0002) and decreased plaque thickness (P=0.006).
- Rabbits maintained on a high-cholesterol diet showed increased % area stenosis (P=0.001) and a trend toward increased plaque thickness (P=0.1).
Conclusions:
- In vivo MRI can accurately detect regression of aortic atherosclerotic plaque in response to dietary cholesterol lowering in rabbits.
- MRI is a promising noninvasive technology for directly imaging atherosclerosis and monitoring its response to therapeutic interventions.