Posterior disk displacement: morphologic assessment and measurement reliability--cervical spine

Area of Science:

• Radiology
• Spinal Imaging
• Diagnostic Accuracy

Background:

• Magnetic resonance imaging (MRI) is crucial for assessing disk displacement post-manipulation.
• Limited data exists on the incidence of iatrogenic herniations and the size variations of disk displacements.
• Evaluating the reliability of chiropractic radiologists and measurement tools is essential.

Purpose of the Study:

• To determine average measurements for normal and displaced cervical disks.
• To assess the reliability of measurements made by chiropractic radiologists.
• To compare measurement devices used in disk displacement assessment.

Main Methods:

• An intraobserver and interobserver reliability study was conducted on 106 cervical MRI scans.
• Three evaluators assessed six categories of disk displacement and compared measurements.
• Scans were reassessed for intraobserver reliability, and variations were analyzed.

Main Results:

• Interexaminer reliability for measurement devices ranged from 0.80 to 0.84; intraexaminer reliability ranged from 0.58 to 0.94.
• Agreement for disk displacement presence was 86% (interexaminer) and 78-85% (intraexaminer).
• Clear mean size differences were observed between different types of disk displacement, with high correlation (0.96) between ruler and digitizer measurements.

Conclusions:

• Chiropractic radiologists demonstrated good to very good agreement in measurements and fair to good agreement in disk assessments.
• Distinct mean size differences exist among various types of disk displacement.
• Measurement devices (ruler and digitizer) showed no significant difference in results.