title: Significance of Coronal Proset Magnetic Resonance Imaging to Detect Hidden Zone of the Mid-Zone Stenosis in the Lumbar Spine and Morphometric Analysis of the Mid-Zone Stenosis.
abstract: METHODS
  Retrospective exploratory imaging study.
  
  
  OBJECTIVE
  To investigate the significance of the coronal magnetic resonance imaging (MRI) using Proset technique to detect the hidden zone in patients with mid-zone stenosis by comparing with conventional axial and sagittal MRI and to explore the morphologic characteristic patterns of the mid-zone stenosis.
  
  
  BACKGROUND
  Despite advancements in diagnostic modalities such as computed tomography and MRI, stenotic lesions under the pedicle and pars interarticularis, also called the mid-zone, are still difficult to definitely detect with the conventional axial and sagittal MRI due to its inherited anatomical peculiarity.
  
  
  METHODS
  Of 180 patients scheduled to undergo selective nerve root block, 20 patients with mid-zone stenosis were analyzed using MRI. Characteristic group patterns were also explored morphologically by comparing MRI views of each group after verifying statistical differences between them. Hierarchical cluster analysis was performed to classify morphological characteristic groups based on three-dimensional radiologic grade for stenosis at all three zones.
  
  
  RESULTS
  At the mid-zone, the stenosis of grade 2 or more was found in 14 cases in the coronal image,13 cases in the sagittal image, and 9 cases in the axial image (p<0.05). Especially, mid-zone stenosis was not detected in six of 20 cases at the axial images. At the entrance and exit-zone, coronal image was also associated with more accurate detection of hidden zone compared to other views such as axial and sagittal images. After repeated statistical verification, the morphological patterns of hidden zone were classified into 5 groups: 6 cases in group I; 1 case in group II; 4 cases in group III; 7 cases in group IV; and 2 cases in group V.
  
  
  CONCLUSIONS
  Coronal MRI using the Proset technique more accurately detected hidden zone of the mid-zone stenosis compared to conventional axial and sagittal images.
authors: Department of Orthopaedic Surgery, Yeungnam University Hospital, Yeungnam University College of Medicine, Daegu, Korea.
authors: Hyo-Sae
authors: HS
authors: Ahn
authors: Department of Orthopaedic Surgery, Yeungnam University Hospital, Yeungnam University College of Medicine, Daegu, Korea.
authors: Whee Sung
authors: WS
authors: Son
authors: Department of Orthopaedic Surgery, Yeungnam University Hospital, Yeungnam University College of Medicine, Daegu, Korea.
authors: Ji-Hoon
authors: JH
authors: Shin
authors: Department of Orthopaedic Surgery, Yeungnam University Hospital, Yeungnam University College of Medicine, Daegu, Korea.
authors: Myun-Whan
authors: MW
authors: Ahn
authors: Department of Orthopaedic Surgery, Yeungnam University Hospital, Yeungnam University College of Medicine, Daegu, Korea.
authors: Gun Woo
authors: GW
authors: Lee
keywords: Lumbar vertebrae; Magnetic resonance imaging; Mid zone; Proset; Spinal stenosis