Related Experiment Video
Updated: Jan 23, 2026
Ovine Lumbar Intervertebral Disc Degeneration Model Utilizing a Lateral Retroperitoneal Drill Bit Injury
Published on: May 25, 2017
Novel Application of the Pfirrmann Disc Degeneration Grading System to 9.4T MRI: Higher Reliability Compared to 3T
Idrees Sher1,2,3, Chris Daly1,2,3, David Oehme4
1Department of Neurosurgery, Monash Medical Centre, Clayton, Victoria, Australia.
Study Design:
Reliability study.
Objective:
To evaluate the applicability and reliability of 9.4T magnetic resonance imaging (MRI) in the assessment of degenerative disc disease compared with 3T MRI.
Summary Of Background Data:
MRI is a reliable indicator of biochemical changes in the intervertebral disc (IVD) including hydration status, proteoglycan content, and disc degeneration compared with anatomical and histological studies. High-field 9.4T MRI has been shown to provide superior resolution and anatomical detail. However, it has not been tested against current standard MRI techniques.
Methods:
Disc degeneration was initiated in 36 skeletally mature ewes 6 months prior to necropsy via validated surgical IVD injury models using either scalpel injury or drill-bit injury techniques at lumbar spine levels L2/3 and L3/4 with L1/2, L4/5, and L5/6 serving as control discs. All ex vivo IVDs were examined with 9.4T MRI and 3T MRI. All scans were analyzed using the Pfirrmann grading system by four independent observers. Intra- and interobserver reliability was assessed using kappa statistics and Spearman correlation.
Results:
Inter- and intraobserver agreement for 9.4T MRI was excellent, both at κ 0.91 (P < 0.001). Comparatively, 3T interobserver reliability demonstrated substantial agreement at κ 0.61 (P < 0.001). Complete agreement was obtained in 92.7% to 100% of discs at 9.4T compared with 69.7% to 83.1% at 3T. A difference of one grade or more occurred in 6.7% at 9.4T and 39.3% at 3T. 9.4T MRI scored 97.3% of discs as grade 1 to 2 compared with 71.3% at 3T. 3T MRI tended to over-score the extent of disc degeneration with 28.6% of discs scored as grade 3 or higher compared with 2.7% at 9.4T MRI.
Conclusion:
9.4T MRI study of IVD degeneration using the Pfirrmann grading system demonstrated excellent inter- and intraobserver reliability. Comparatively, 3T MRI demonstrated a tendency to over score the extent of disc degeneration. This improved reliability of 9.4T MRI holds great potential for its clinical applications.
Level Of Evidence:
3.
Insights
High-field 9.4T magnetic resonance imaging (MRI) shows excellent reliability for assessing intervertebral disc (IVD) degeneration, outperforming standard 3T MRI. This advanced imaging technique offers improved accuracy for clinical applications in diagnosing disc disease.
Area of Science:
- Biomedical Imaging
- Musculoskeletal Research
- Veterinary Science
Background:
- Magnetic resonance imaging (MRI) is crucial for evaluating intervertebral disc (IVD) health, including hydration and degeneration.
- High-field 9.4T MRI offers superior resolution compared to standard 3T MRI but requires validation for disc degeneration assessment.
Purpose of the Study:
- To compare the reliability and applicability of 9.4T MRI versus 3T MRI for assessing degenerative disc disease.
- To evaluate inter- and intraobserver agreement using the Pfirrmann grading system for both MRI techniques.
Main Methods:
- Degenerative disc disease was surgically induced in 36 ewes.
- Ex vivo intervertebral discs were imaged using both 9.4T and 3T MRI.
- Four independent observers graded disc degeneration using the Pfirrmann system; reliability was assessed via kappa statistics and Spearman correlation.
Main Results:
- 9.4T MRI demonstrated excellent inter- and intraobserver agreement (κ=0.91), with 92.7%-100% complete agreement.
- 3T MRI showed substantial interobserver agreement (κ=0.61), with 69.7%-83.1% complete agreement.
- 9.4T MRI had fewer grade discrepancies and tended to score discs as less severe compared to 3T MRI, which showed a tendency to overscore degeneration.
Conclusions:
- 9.4T MRI exhibits excellent reliability for assessing IVD degeneration using the Pfirrmann grading system.
- 3T MRI demonstrated a tendency to overscore disc degeneration compared to 9.4T MRI.
- The high reliability of 9.4T MRI suggests significant potential for clinical use in diagnosing and managing disc diseases.
Related Concept Videos
01:14Imaging Studies I: CT and MRI
Description of the Procedures
Computed Tomography (CT) scan:
Computed Tomography (CT) scans use X-ray technology to generate detailed images of bones, organs, and tissues. During the scan, the patient lies on a moving table...
01:30Radiological Investigation II: MRI and Ventilation Perfusion Scan
Magnetic Resonance Imaging (MRI) and Ventilation Perfusion Scans are two radiological investigations that offer detailed diagnostic images of the body, particularly lung structures.
MRI
MRI uses magnetic fields and radiofrequency signals to distinguish between normal and abnormal tissues. This technology provides a more detailed diagnostic image than CT scans, enabling it to characterize pulmonary nodules, stage bronchogenic carcinoma, and evaluate inflammatory activity in...
01:29Reliability and Validity
01:19Graded Potential
Graded potentials fall into two categories: depolarizing and hyperpolarizing. Depolarizing graded potentials typically occur when sodium (Na+) or...
01:15Types of Aggregate Grading
Well-graded aggregates include a complete range of necessary size fractions that fit together to create a dense matrix with minimal voids, represented by a smooth, continuous gradation curve. This type of grading ensures good...
01:25Distribution Reliability and Automation