Multi-contrast MRI in Characterizing Atherosclerotic Plaque Constituents
Multi-contrast MRI provides a possible means to non-invasively characterize atherosclerotic plaque constituents and evaluate plaque vulnerability based on the morphological information. It may also help understand how hemodynamic factors impact plaque genesis and progression. My research involves both ex vivo coronary plaque and in vivo carotid plaque imaging using multi-contrast MRI. Ex vivo and in vivo scans are conducted on a 4.7T Varian INOVA MR scanner and a 3T Philips ACHIEVA scanner, respectively. Besides traditional proton density, T1 and T2 weighted SE MRI, my research also includes quantitative measurement of T1, T2 and apparent diffusion coefficient (ADC) values of plaque constituents. These values are important in MR pulse sequence optimization and assessing the ability of different contrast mechanisms in characterizing atherosclerotic plaque. The multi-contrast MR images are classified based on a penalized fuzzy k-means algorithm, validated by histology and reconstructed into three-dimensional models for hemodynamic studies. Some classification examples are show in the following pictures.