title: 3D-imaging of the knee with an optimized 3D-FSE-sequence and a 15-channel knee-coil.
abstract: OBJECTIVE
  To evaluate the clinical usefulness of an optimized 3D-Fast-Spin-Echo-sequence (3D-SPACE) in combination with a 15-channel knee-coil for 3D-imaging of the knee at 3T.
  
  
  METHODS
  15 volunteers and 50 consecutive patients were examined at 3 T with fat-saturated moderately T2-weighted 3D-SPACE (Voxel-size (VS): 0.6 mm×0.5 mm×0.5 mm/acquisition-time (AT) 10:44 min) using a 15-channel knee-coil. Flip angle optimization and radial k-space reordering were applied. Signal- and contrast-to-noise-ratios (SNR, CNR) were compared to non-optimized 3D-SPACE (8-channel knee-coil) and conventional 2D-FSE (VS: 0.4 mm×0.4 mm×3 mm/total AT: 12 min). Two radiologists independently rated depiction of internal knee structures and assessed detection and depiction of cartilage and meniscus abnormalities compared to conventional 2D-FSE-sequences. Sensitivity and specificity were calculated for a subgroup with arthroscopy as reference standard. Statistical analysis was performed with paired t-tests, confidence intervals and weighted-κ-coefficients.
  
  
  RESULTS
  SNR and CNR particularly of fluid/cartilage of optimized 3D-SPACE were significantly higher (p<0.05) than of the non-optimized 3D-sequence and conventional 2D-sequence. Blurring and image inhomogeneity were reduced in the optimized sequence. The thin slice-thickness was beneficial for depiction of problematical anatomical structures such as meniscal roots. 3D-SPACE showed significantly higher diagnostic confidence (p<0.05) for diagnosis of cartilage lesions of the femoral trochlea. Overall sensitivity and specificity of 3D-SPACE and 2D-FSE for cartilage lesions was 82.3%/80.2% and 79.4%/84.2% and 100%/86.4% and 92.3%/81.8% for meniscus lesions.
  
  
  CONCLUSIONS
  Optimized 3D-SPACE provides significantly higher signal and contrast compared to conventional 2D-FSE, particularly for fluid and cartilage, leading to improved diagnostic confidence, particularly in problematic areas, such as the femoral trochlea.
authors.affiliation: Department of Clinical Radiology, University Hospitals Munich, Marchioninistrasse 15, 81377 Munich, Germany. mike.notohamiprodjo@med.uni-muenchen.de
authors.forename: Mike
authors.initials: M
authors.lastname: Notohamiprodjo
authors.forename: Annie
authors.initials: A
authors.lastname: Horng
authors.forename: Bernhard
authors.initials: B
authors.lastname: Kuschel
authors.forename: Dominik
authors.initials: D
authors.lastname: Paul
authors.forename: Guobin
authors.initials: G
authors.lastname: Li
authors.forename: Jose G
authors.initials: JG
authors.lastname: Raya
authors.forename: Maximilian F
authors.initials: MF
authors.lastname: Reiser
authors.forename: Christian
authors.initials: C
authors.lastname: Glaser
mesh_terms: D000328:Adult; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000295:instrumentation* / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000295:instrumentation* / Q000379:methods*; D007718:Knee Injuries / Q000473:pathology*; D007719:Knee Joint / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation* / Q000379:methods; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity