Thoracolumbar junction: morphologic characteristics, various variants and significance

Area of Science:

• Radiology
• Anatomy
• Medical Imaging

Background:

• Accurate spinal enumeration is crucial for clinical diagnosis and treatment.
• Variations in vertebral morphology, particularly at the thoracolumbar junction, can lead to enumeration errors.

Purpose of the Study:

• To assess vertebral segments at the thoracolumbar junction in relation to caudal ribs.
• To evaluate the reliability of axial CT with curved planar reformatting (CPR) for this assessment.
• To introduce and validate a novel classification system for thoracolumbar transitional vertebrae (TLTV).

Main Methods:

• Retrospective review of 744 spine CT scans including the thoracolumbar junction.
• Independent evaluation by two radiologists using axial CT with CPR images.
• Differentiation of TLTV and non-TLTV, and classification of TLTV using a new system.
• Inter- and intraobserver agreement analysis using kappa statistics.

Main Results:

• Nearly perfect interobserver agreement for differentiating vertebral segments (κ=0.959).
• Nearly perfect interobserver agreement for TLTV classification (κ=0.846).
• Nearly perfect intraobserver agreement for TLTV classification (κ=0.877).

Conclusions:

• Morphologic analysis of the thoracolumbar junction aids accurate spinal enumeration.
• The proposed TLTV classification system is reliable for use with axial CT and CPR.
• Improved interpretation of thoracolumbar morphology can reduce spinal enumeration errors.