TABLE 1.
Parameters for magnetic resonance (MR) images evaluation
| Parameters | Definition | Qualifications |
|---|---|---|
| IVD height | Qualitative assessment of the IVD height in comparison to control IVD (L4‐L5) |
Normal Decreased Collapsed |
| Annular fissure | Loss of the morphology of the AF characterized by separation between the annular fibers on T2 images representing fluid or granulation tissue. |
Absent Present |
| End plate changes |
Signs of degenerative or inflammatory changes involving the vertebral endplates characterized by change in signal intensity and/or morphology. Classified based on the location of the changes in regard to the endplates of the IVD being evaluated. |
Absent Upper Lower Both |
| IVD bulging |
Presence of disc tissue extending beyond the edges of the ring apophyses, throughout the circumference of the disc (not considered a form of herniation). When present, the bulging can be further classified as diffuse, if all the disc tissues are involved, or asymmetric when the disc tissue greater bulging is ≤50% of the disc circumference. |
Absent Diffuse Asymmetric |
| IVD herniation |
Defined as a focal displacement of disc material (≤ 25% of the disc circumference) beyond the limits of the intervertebral disc space. When present, the herniated disc can be further classified as contained, if the displaced portion is covered by outer annulus fibers and/or the posterior longitudinal ligament; or uncontained when there is no such covering. |
Absent Contained Uncontained |
| IVD protrusion | With IVD herniation, Presence of herniation of nucleus material through the original defect or through another location in the annulus resulting in a focal “out‐pouching” of the disc contour beyond the normal outer limits of the disc 37 |
Absent Present |
| IVD extrusion | With IVD herniation, Presence of herniation of disc material through the original defect or through another location in the annulus such that disc material breaks through the confines of the annulus fibrosus 37 |
Absent Present |
Note: Parameters used for comprehensive MR‐images evaluation of control and injured IVD.