title: Repeatability of ultrashort echo time-based two-component T2* measurements on cartilages in human knee at 3 T.
abstract: Repeatability of in vivo measurement of multicomponent T2* relaxation in articular cartialges in human knee is important to clinical use. This study evaluated the repeatability of two-component T2* relaxation on seven healthy human subjects. The left knee was scanned once a day in three consecutive days, on a clinical 3T MRI scanner with eight-channel knee coil and ultrashort echo time pulse sequence at 11 echo times=0.6-40 ms. The intrasubject and intersubject repeatability was evaluated via coefficient of variation (CV=standard deviation/mean) in four typical cartilage regions: patellar, anterior articular, femoral, and tibial regions. It was found that the intrasubject repeatability was good, with CV<10% for the short- and long-T2* relaxation time in the layered regions in the four cartilages (with one exception) and CV<13% for the component intensity fraction (with two exceptions). The intersubject repeatability was also good, with CV∼8% (range 1-15%) for the short- and long-T2* relaxation time and CV∼10% (range 2-20%) for the component intensity fraction. The long-T2* component showed significantly better repeatability (CV∼8%) than the short-T2* component (CV∼12%) (P<0.005). These CV values suggest that in vivo measurement of two-component T2* relaxation in the knee cartilages is repeatable on clinical scanner at 3 T, with a signal-to-noise ratio of 90.
authors.affiliation: MR Research Center, Department of Radiology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA; Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA. qiany@upmc.edu
authors.forename: Yongxian
authors.initials: Y
authors.lastname: Qian
authors.forename: Ashley A
authors.initials: AA
authors.lastname: Williams
authors.forename: Constance R
authors.initials: CR
authors.lastname: Chu
authors.forename: Fernando E
authors.initials: FE
authors.lastname: Boada
mesh_terms: D000328:Adult; D000465:Algorithms; D016477:Artifacts; D002358:Cartilage, Articular / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007719:Knee Joint / Q000033:anatomy & histology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity