title: Thoracolumbar junction: morphologic characteristics, various variants and significance.
abstract: This study aimed to assess the types of vertebral segments at the thoracolumbar junction, as they relate to the most caudal ribs, to evaluate the reliability of this assessment using axial CT with curved planar reformatting (CPR) images, to describe the morphologic characteristics of a thoracolumbar transitional vertebra (TLTV), to introduce a new classification system for the TLTV and to evaluate the reliability of the classification system using axial CT with CPR images.
  This was a retrospective review of 744 consecutive patients who underwent spine CT imaging that included the thoracolumbar junction. Two radiologists (Readers 1 and 2) independently evaluated the axial CT with CPR images for all cases (n = 744). Each radiologist differentiated the vertebral segments at the thoracolumbar junction as TLTV or non-TLTV (thoracic segment or lumbar segment). In addition, each radiologist classified the 94 patients with the TLTV using a novel classification system. Interobserver agreement between the two radiologists regarding the differentiation of vertebral segments at the thoracolumbar junction was analysed with kappa statistics. Similarly, intra- and interobserver agreement regarding TLTV classification was analysed with kappa statistics.
  Interobserver agreement between the two readers with respect to the differentiation of vertebral segments at the thoracolumbar junction via axial CT with CPR images was nearly perfect (κ-value: 0.959). Interobserver agreement between the two readers with respect to TLTV classification using axial CT with CPR images was nearly perfect (κ-value: 0.846). In addition, intraobserver agreement for Reader 1 was also nearly perfect (κ-value: 0.877).
  Morphologic analysis of the thoracolumbar junction may help accurate spinal enumeration.
  Consideration of various variants at the thoracolumbar junction should help radiologists and clinicians to interpret the morphology of the thoracolumbar junction. This may facilitate communication with the referring clinician, thereby reducing the error in spinal enumeration.
authors.affiliation: Department of Radiology, Kosin University Gospel Hospital, Busan, South Korea.
authors.forename: Se K
authors.initials: SK
authors.lastname: Park
authors.affiliation: Department of Radiology, Kosin University Gospel Hospital, Busan, South Korea.
authors.forename: Jung G
authors.initials: JG
authors.lastname: Park
authors.affiliation: Department of Radiology, Kosin University Gospel Hospital, Busan, South Korea.
authors.forename: Beom S
authors.initials: BS
authors.lastname: Kim
authors.affiliation: Department of Radiology, Kosin University Gospel Hospital, Busan, South Korea.
authors.forename: Jin D
authors.initials: JD
authors.lastname: Huh
authors.affiliation: Department of Radiology, Kosin University Gospel Hospital, Busan, South Korea.
authors.forename: Hee
authors.initials: H
authors.lastname: Kang