title: T1rho mapping of entire femoral cartilage using depth- and angle-dependent analysis.
abstract: OBJECTIVE
  To create and evaluate normalized T1rho profiles of the entire femoral cartilage in healthy subjects with three-dimensional (3D) angle- and depth-dependent analysis.
  
  
  METHODS
  T1rho images of the knee from 20 healthy volunteers were acquired on a 3.0-T unit. Cartilage segmentation of the entire femur was performed slice-by-slice by a board-certified radiologist. The T1rho depth/angle-dependent profile was investigated by partitioning cartilage into superficial and deep layers, and angular segmentation in increments of 4° over the length of segmented cartilage. Average T1rho values were calculated with normalized T1rho profiles. Surface maps and 3D graphs were created.
  
  
  RESULTS
  T1rho profiles have regional and depth variations, with no significant magic angle effect. Average T1rho values in the superficial layer of the femoral cartilage were higher than those in the deep layer in most locations (p < 0.05). T1rho values in the deep layer of the weight-bearing portions of the medial and lateral condyles were lower than those of the corresponding non-weight-bearing portions (p < 0.05). Surface maps and 3D graphs demonstrated that cartilage T1rho values were not homogeneous over the entire femur.
  
  
  CONCLUSIONS
  Normalized T1rho profiles from the entire femoral cartilage will be useful for diagnosing local or early T1rho abnormalities and osteoarthritis in clinical applications.
  
  
  CONCLUSIONS
  • T1rho profiles are not homogeneous over the entire femur. • There is angle- and depth-dependent variation in T1rho profiles. • There is no influence of magic angle effect on T1rho profiles. • Maps/graphs might be useful if several difficulties are solved.
authors.affiliation: Department of Radiological Sciences, University of California Irvine, 101 The City Drive South, Rt. 140, Bldg. 56, Orange, CA, 92868, USA.
authors.forename: Taiki
authors.initials: T
authors.lastname: Nozaki
authors.affiliation: Department of Radiological Sciences, University of California Irvine, 101 The City Drive South, Rt. 140, Bldg. 56, Orange, CA, 92868, USA.
authors.forename: Yasuhito
authors.initials: Y
authors.lastname: Kaneko
authors.affiliation: Department of Radiological Sciences, University of California Irvine, 101 The City Drive South, Rt. 140, Bldg. 56, Orange, CA, 92868, USA.
authors.forename: Hon J
authors.initials: HJ
authors.lastname: Yu
authors.affiliation: School of Medicine, University of California Irvine, Irvine, CA, USA.
authors.forename: Kayleigh
authors.initials: K
authors.lastname: Kaneshiro
authors.affiliation: Department of Orthopedic Surgery, University of California Irvine, Irvine, CA, USA.
authors.forename: Ran
authors.initials: R
authors.lastname: Schwarzkopf
authors.affiliation: Department of Intelligent Image Information, Division of Regeneration and Advanced Medical Sciences, Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Hara
authors.affiliation: Department of Radiological Sciences, University of California Irvine, 101 The City Drive South, Rt. 140, Bldg. 56, Orange, CA, 92868, USA. hiroshi@uci.edu.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yoshioka
mesh_terms: D000293:Adolescent; D000328:Adult; D002358:Cartilage, Articular / Q000000981:diagnostic imaging*; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging*; D064368:Healthy Volunteers; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D020370:Osteoarthritis, Knee / Q000175:diagnosis* / Q000503:physiopathology; D016474:Weight-Bearing / Q000502:physiology*; D055815:Young Adult
keywords: 3D graph; Angle and depth analysis; Entire femoral cartilage; Surface map; T1rho