title: Direct imaging and quantification of carotid plaque calcification.
abstract: Carotid plaque calcification normally appears as a signal void with clinical MR sequences. Here, we describe the use of an adiabatic inversion recovery prepared two-dimensional ultrashort echo time sequence to image and characterize carotid plaque calcification using a clinical 3-T scanner. T(1), T 2*, and free water content were measured for seven carotid samples, and the results were compared with micro-CT imaging. Conventional gradient echo and fast spin echo images were also acquired for comparison. Correlations between T(1), T 2*, free water concentration, and mineral density were performed. There was a close correspondence between inversion recovery prepared two-dimensional ultrashort echo time morphologic and micro-CT appearances. Carotid plaque calcification varied significantly from sample to sample, with T(1) s ranging from 94 ± 19 to 328 ± 21 msec, T 2*s ranging from 0.31 ± 0.12 to 2.15 ± 0.25 msec, and free water concentration ranging from 5.7 ± 2.3% to 16.8 ± 3.4%. There was a significant positive correlation between T(1)(R = 0.709; P < 0.074), T 2* (R = 0.816; P < 0.025), and free water concentration, a negative correlation between T(1) (R = 0.773; P < 0.042), T 2* (R = 0.948; P < 0.001) and CT measured mineral density, and a negative correlation between free water concentration (R = 0.936; P < 0.002) and mineral density.
authors.affiliation: Department of Radiology, University of California, San Diego, California 92103-8226, USA. jiangdu@ucsd.edu
authors.forename: Jiang
authors.initials: J
authors.lastname: Du
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Corbeil
authors.forename: Richard
authors.initials: R
authors.lastname: Znamirowski
authors.forename: Niren
authors.initials: N
authors.lastname: Angle
authors.forename: Michael
authors.initials: M
authors.lastname: Peterson
authors.forename: Graeme M
authors.initials: GM
authors.lastname: Bydder
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Kahn
mesh_terms: D000465:Algorithms; D002114:Calcinosis / Q000150:complications / Q000473:pathology*; D002339:Carotid Arteries / Q000473:pathology*; D016893:Carotid Stenosis / Q000209:etiology / Q000473:pathology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity