Valve tissue characterization by magnetic resonance imaging in calcific XXXX .

@entity1 @entity5953 @entity472 @entity886
BACKGROUND: Calcific @entity886 affects 10%-15% of the elderly population, causing considerable morbidity and mortality. There is no imaging technique that allows for the assessment of tissue composition of the valve in  vivo. We thus investigated whether multiparametric magnetic resonance imaging (MRI) could characterize and quantify lipid, fibrous, and mineralized tissues within aortic valve (AV) cusps. METHODS: AV leaflets were explanted from @entity1 with severe @entity472 at the time of valve replacement surgery. Aortic cusps were imaged ex  vivo using 1.5T MRI using 3 gradient-echo sequences with T1, moderate T2, and proton density weightings (T1w, T2w, and PDw). Histopathologic analysis was performed on coregistered slices to identify and measure mineralized tissue, fibrous tissue, and lipid-rich tissue. Area and mean grey values were measured in @entity5953 weightings by standardized software. RESULTS: Four hundred ninety-two regions of interest from 30 AV leaflets were studied. Total leaflet surface and the areas of mineralized (P < 0.0001), fibrous (P  = 0.002), and lipid-rich (P  = 0.0001) tissues measured by MRI matched closely those measured by histopathologic examination. @entity5953 weightings provided significant discrimination between median grey values for mineralized, fibrous, and lipid-rich tissues (P < 0.0001 for T1w, moderate T2w, and PDw). A best-fit equation integrating the grey value data from @entity5953 weightings allowed multiparametric MRI to identify valve leaflet components with areas under the receiver operating characteristic curve of 0.92, 0.81, and 0.72, respectively. CONCLUSIONS: AV leaflet characteristics, including tissue composition, distribution, and area, may be successfully measured by multiparametric MRI with good to excellent accuracy.
