title: [Relevance of susceptibility-induced geometrical distortion for validity of MRI-based cartilage volume and density measurements of the knee joint].
abstract: The aim of the present study was to analyze the relevance of susceptibility-induced geometrical distortion to the accuracy of MR-based cartilage volume and thickness measurement in the human knee joint. Nine cadaveric knee joints were imaged in the sagittal plane with MRI at a resolution of 2 x 0.31 x 0.31 mm3, using a fat-suppressed gradient echo sequence, with a normal gradient orientation and also with the frequency- and phase-encoding directions changed. CT arthrographic data sets were then obtained. On the basis of 3-D constructions, we determined the cartilage volume and, with a 3-D minimal distance algorithm, the thickness distribution, of the patella, femur and tibia. Irrespective of the gradient orientation, good agreement was observed between MRI and CT arthrography in terms of cartilage volumes and maximum cartilage thickness. With a normal gradient orientation the volume was overestimated by 2.5% in MRI, and 2.3% when the gradients were changed. The maximum cartilage thickness was underestimated by 0.24 intervals (interval = 0.5 mm) with a normal gradient orientation, and by 0.22 intervals when the gradient orientation was changed. In none of the joint surfaces was a relevant difference between the two methods observed. It can be shown that, using high-resolution, fat-suppressed gradient-echo sequences--susceptibility-induced geometrical distortion has no significant effect on the accuracy of MR-based cartilage volume and thickness measurements. MRI would therefore appear suitable for the design of patient-specific finite element models with the aim of analysing load transmission in diarthrodial joints and planning surgical interventions.
authors.affiliation: Ludwig-Maximilians Universität München.
authors.forename: M
authors.initials: M
authors.lastname: Schnier
authors.forename: J
authors.initials: J
authors.lastname: Priebsch
authors.forename: S
authors.initials: S
authors.lastname: Faber
authors.forename: M
authors.initials: M
authors.lastname: Haubner
authors.forename: C
authors.initials: C
authors.lastname: Glaser
authors.forename: K H
authors.initials: KH
authors.lastname: Englmeier
authors.forename: M
authors.initials: M
authors.lastname: Reiser
authors.forename: F
authors.initials: F
authors.lastname: Eckstein
mesh_terms: D000328:Adult; D000465:Algorithms; D016477:Artifacts; D002358:Cartilage, Articular / Q000473:pathology*; D020342:Finite Element Analysis; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007719:Knee Joint / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests