title: Femoral Trochlear Groove Morphometry Assessed on Oblique Coronal MR Images.
abstract: OBJECTIVE
  The objective of our study as to assess several indexes relevant to patellofemoral instability (PFI) associated with femoral trochlear dysplasia as measured on oblique coronal MR images at three standardized reference levels.
  
  
  METHODS
  A total of 30 knee MRI examinations were selected as the study group of PFI patients. Sixty knee MRI examinations were included as a control group. MRI protocols included sagittal T2-weighted, axial proton density-weighted, and oblique coronal T2-weighted imaging. On a midline sagittal image, the following three levels of the femoral trochlear groove cartilage were determined: level 1 (one-fourth level of the trochlear groove in the midsagittal plane), level 2 (one-half level of the trochlear groove in the midsagittal plane), and level 3 (three-fourths level of the trochlear groove in the midsagittal plane). Three-level axial and oblique coronal images were selected using the sagittal image as a scout. Femoral trochlear indexes including the sulcus angle, sulcus depth, facet length, and trochlear groove area were measured on the axial and oblique coronal images.
  
  
  RESULTS
  Most indexes showed significant differences between the PFI and control groups in the axial and oblique coronal planes at all three levels (p < 0.05). Almost all indexes measured on the oblique coronal plane images were significantly different from those measured on the axial plane images (p < 0.05). Oblique coronal images showed little variability in the sulcus angle among the three levels in contrast to a marked decrease in the angle from the proximal to distal level on axial images.
  
  
  CONCLUSIONS
  Femoral trochlear indexes measured on oblique coronal knee MR images can be used to assess femoral trochlear dysplasia. Oblique coronal images showed less morphologic distortion of the distal femoral trochlear groove than axial images.
authors.affiliation: 1 All authors: Department of Radiology, Seoul National University College of Medicine, 101 Daehak-ro Jongno-gu, Seoul 110-744, Korea.
authors.forename: Minkyung
authors.initials: M
authors.lastname: Yi
authors.affiliation: 1 All authors: Department of Radiology, Seoul National University College of Medicine, 101 Daehak-ro Jongno-gu, Seoul 110-744, Korea.
authors.forename: Sung Hwan
authors.initials: SH
authors.lastname: Hong
authors.affiliation: 1 All authors: Department of Radiology, Seoul National University College of Medicine, 101 Daehak-ro Jongno-gu, Seoul 110-744, Korea.
authors.forename: Ja-Young
authors.initials: JY
authors.lastname: Choi
authors.affiliation: 1 All authors: Department of Radiology, Seoul National University College of Medicine, 101 Daehak-ro Jongno-gu, Seoul 110-744, Korea.
authors.forename: Hye Jin
authors.initials: HJ
authors.lastname: Yoo
authors.affiliation: 1 All authors: Department of Radiology, Seoul National University College of Medicine, 101 Daehak-ro Jongno-gu, Seoul 110-744, Korea.
authors.forename: Yusuhn
authors.initials: Y
authors.lastname: Kang
authors.affiliation: 1 All authors: Department of Radiology, Seoul National University College of Medicine, 101 Daehak-ro Jongno-gu, Seoul 110-744, Korea.
authors.forename: Jina
authors.initials: J
authors.lastname: Park
authors.affiliation: 1 All authors: Department of Radiology, Seoul National University College of Medicine, 101 Daehak-ro Jongno-gu, Seoul 110-744, Korea.
authors.forename: Heung Sik
authors.initials: HS
authors.lastname: Kang
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D002648:Child; D006801:Humans; D007593:Joint Instability / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D057071:Patellofemoral Joint / Q000473:pathology*; D012189:Retrospective Studies
keywords: MRI; femoral trochlear groove; oblique coronal scans; patellofemoral instability