Phase-based Electrical Conductivity as a Potential Imaging Marker of Treatment Effectiveness in Lumbar Intervertebral Disc Herniation

Motivation: Electrical conductivity (σ) of intervertebral disc (IVD) may show biological and structural changes associated with ultra-purified alginate (UPAL) gel implantation treatment for lumbar IVD degeneration. Goal(s): This study compared σ of lumbar IVD derived from electric properties tomography (EPT) between patients receiving standard discectomy and those receiving UPAL gel implantation. Approach: The major σ histogram metrics of each IVD were extracted and compared between the two treatment groups. Results: The minimum σ (σmin) significantly decreased following standard discectomy suggesting advancing degeneration. In contrast, the σ histogram metrics of the gel implantation group did not vary, suggesting its superiority over the standard discectomy. Impact: This is the first study which evaluated treatment effectiveness of surgery (standard discectomy and UPAL gel implantation) in lumbar IVD degeneration using a recently developed noninvasive quantitative MRI index, i.e., σ of IVD.