title: 3.0T MR imaging of the ankle: Axial traction for morphological cartilage evaluation, quantitative T2 mapping and cartilage diffusion imaging-A preliminary study.
abstract: OBJECTIVE
  To determine the impact of axial traction during high resolution 3.0T MR imaging of the ankle on morphological assessment of articular cartilage and quantitative cartilage imaging parameters.
  
  
  METHODS
  MR images of n=25 asymptomatic ankles were acquired with and without axial traction (6kg). Coronal and sagittal T1-weighted (w) turbo spin echo (TSE) sequences with a driven equilibrium pulse and sagittal fat-saturated intermediate-w (IMfs) TSE sequences were acquired for morphological evaluation on a four-point scale (1=best, 4=worst). For quantitative assessment of cartilage degradation segmentation was performed on 2D multislice-multiecho (MSME) SE T2, steady-state free-precession (SSFP; n=8) T2 and SSFP diffusion-weighted imaging (DWI; n=8) images. Wilcoxon-tests and paired t-tests were used for statistical analysis.
  
  
  RESULTS
  With axial traction, joint space width increased significantly and delineation of cartilage surfaces was rated superior (P<0.05). Cartilage surfaces were best visualized on coronal T1-w images (P<0.05). Differences for cartilage matrix evaluation were smaller. Subchondral bone evaluation, motion artifacts and image quality were not significantly different between the acquisition methods (P>0.05). T2 values were lower at the tibia than at the talus (P<0.001). Reproducibility was better for images with axial traction.
  
  
  CONCLUSIONS
  Axial traction increased the joint space width, allowed for better visualization of cartilage surfaces and improved compartment discrimination and reproducibility of quantitative cartilage parameters.
authors.affiliation: Department of Radiology, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich, Germany. Electronic address: pia.jungmann@tum.de.
authors.forename: Pia M
authors.initials: PM
authors.lastname: Jungmann
authors.affiliation: Department of Radiology, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich, Germany. Electronic address: thomas.baum@tum.de.
authors.forename: Thomas
authors.initials: T
authors.lastname: Baum
authors.affiliation: Department of Radiology, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich, Germany; Musculoskeletal Imaging, Kantonsspital Graubuenden, Loestrasse 170, CH-7000 Chur, Switzerland. Electronic address: schaeffeler@me.com.
authors.forename: Christoph
authors.initials: C
authors.lastname: Schaeffeler
authors.affiliation: Department of Trauma Surgery, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich, Germany; Department of Orthopaedic Sports Medicine, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich, Germany. Electronic address: martin.sauerschnig@mri.tum.de.
authors.forename: Martin
authors.initials: M
authors.lastname: Sauerschnig
authors.affiliation: Department of Orthopaedic Sports Medicine, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich, Germany. Electronic address: peter.brucker@lrz.tu-muenchen.de.
authors.forename: Peter U
authors.initials: PU
authors.lastname: Brucker
authors.affiliation: Department of Radiology, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich, Germany; Department of Orthopaedic Sports Medicine, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich, Germany. Electronic address: abmann@onlinemed.de.
authors.forename: Alexander
authors.initials: A
authors.lastname: Mann
authors.affiliation: Department of Radiology, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich, Germany. Electronic address: cganter@tum.de.
authors.forename: Carl
authors.initials: C
authors.lastname: Ganter
authors.affiliation: Division of Radiological Physics, Department of Radiology, University of Basel Hospital, Petersgraben 4, 4031 Basel, Switzerland. Electronic address: oliver.bieri@unibas.ch.
authors.forename: Oliver
authors.initials: O
authors.lastname: Bieri
authors.affiliation: Department of Radiology, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich, Germany. Electronic address: ernst.rummeny@tum.de.
authors.forename: Ernst J
authors.initials: EJ
authors.lastname: Rummeny
authors.affiliation: Department of Radiology, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich, Germany. Electronic address: klaus.woertler@tum.de.
authors.forename: Klaus
authors.initials: K
authors.lastname: Woertler
authors.affiliation: Department of Radiology, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich, Germany; Department of Neuroradiology, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich, Germany. Electronic address: jsb@tum.de.
authors.forename: Jan S
authors.initials: JS
authors.lastname: Bauer
mesh_terms: D000328:Adult; D000843:Ankle Joint / Q000033:anatomy & histology*; D002358:Cartilage, Articular / Q000033:anatomy & histology*; D038524:Diffusion Magnetic Resonance Imaging; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D012016:Reference Values; D015203:Reproducibility of Results; D055815:Young Adult
keywords: Ankle; Cartilage; Magnetic resonance imaging; Traction