The following is a summary of “Pretreatment Brain White Matter Integrity Associated with Neuropathic Pain Relief and Changes in Temporal Summation of Pain Following Ketamine,” published in the September 2024 issue of Pain by Mills et al.
Neuropathic pain (NP), a condition linked with central sensitization and may benefit from personalized treatment strategies based on neuroimaging biomarkers. However, the role of white matter (WM) properties is still undiscovered.
Researchers conducted a retrospective study to assess whether WM pathways of the default mode network (DMN: medial prefrontal cortex [mPFC],) and descending pain modulation system (periaqueductal gray [PAG]) are related with ketamine analgesia and attenuated temporal summation of pain (TSP) in NP.
They used a fixed-based analysis of diffusion-weighted imaging data to estimate WM microstructure (fiber density [FD]) and macrostructure (fiber bundle cross-section) within the DMN and mPFC-PAG pathways in 70 individuals who underwent magnetic resonance imaging and TSP testing; 35 with NP who underwent ketamine treatment with aged 35 and sex-matched pain-free individuals. Individuals with NP were evaluated before and 1 month after treatment; those with ≥30% pain relief were considered responders (n = 18), and others as nonresponders (n = 17).
The results showed that WM structure within the DMN and mPFC-PAG pathways had no similarity in responders from nonresponders. However, pretreatment FD in the anterior limb of the internal capsule was related to pain relief (r= .48). Additionally, pretreatment FD in the DMN (left mPFC-precuneus/posterior cingulate cortex; r = .52) and mPFC-PAG (r = .42) negatively correlated with changes in TSP, suggesting that WM microstructure in the DMN and mPFC-PAG pathway is linked with the degree to which ketamine reduces central sensitization.
They concluded that fixed metrics of WM structure may hold promise to predict ketamine treatment outcomes in neuropathic pain.
Source: sciencedirect.com/science/article/pii/S1526590024004565
