Evaluation of Lumbar Intervertebral Disc and Facet Joint Degeneration Using Histogram Analysis of T2 and T2* Values

TL;DR

This study evaluates how T2 and T2* MRI values can help assess degeneration in the spine's intervertebral discs and facet joints.

Contribution

It introduces histogram analysis of T2 and T2* values as a novel method for grading spinal degeneration.

Findings

Histogram analysis of T2 and T2* values can distinguish normal from abnormal intervertebral discs.

Facet joint degeneration is more common than disc degeneration in people under 39 years old.

The reliability of histogram parameters varies between intervertebral discs and facet joints.

Abstract

Lumbar facet joint (LFJ) and intervertebral disc (IVD) degeneration are the common causes of low back pain. The aim of this study is to explore the feasibility of histogram analysis of T2 and T2* values on grading LFJ and IVD degeneration and to examine the correlation between the LFJ and IVD in the degenerative process.

420 IVDs and 840 LFJs of 87 subjects were examined using T2WI, T2 and T2* mapping. All IVDs and LFJs were classified, respectively, according to the Pfirrmann and Weishaupt grade and grouped by patient age. Histogram‐derived parameters based on T2 (T2‐HPs) and T2* (T2*‐HPs) values of IVDs and LFJs were compared among the different groups.

The interobserver agreement for Pfirrmann grade was good (κ = 0.732), and moderate for Weishaupt grading (κ = 0.474). For patients under 39 years old, the degeneration incidence (DI) of LFJ was higher than IVD (χ
2 = 16.436, p < 0.001; χ
2 = 5.210, p = 0.022). In the 50–59 and 60–69 years groups, the DI of LFJ was statistically significantly lower than that of IVD (χ
2 = 14.915, p < 0.001; χ
2 = 13.174, p < 0.001). The interobserver reliability of histogram parameters for IVDs was good to excellent with ICCs ranging from 0.825 to 0.985, and poor to excellent for LFJs (0.302–0.945). All T2‐HPs and T2*‐HPs had the ability to distinguish normal IVDs from abnormal discs, with the AUC varying from 0.562 to 0.824. For T2‐HPs, only SD and Entropy can not distinguish normal (Weishaupt grades 0 and 1) and abnormal (grades 2 and 3) LFJs, and all other parameters can distinguish them, with AUC changing from 0.551 to 0.615. For T2*‐HPs, only Mean and Entropy were reliable for identifying normal and abnormal LFJs with low AUC (0.572, 0.540, respectively).

Histogram analysis of T2/T2* values is feasible for detecting IVD degeneration, but the feasibility of grading LFJ is still controversial. The DI of LFJ is higher than that of IVD under 39 years old, challenging the commonly accepted paradigm of the degenerative process beginning at the IVDs.

Histogram Assessment of Lumbar Intervertebral Disc and Facet Joint Degeneration.

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