Table 3.
Neuroimaging studies investigating NP within the SCI cohort.
| References | Modality | Region of interest(s) | Statistical correction | Main findings |
|---|---|---|---|---|
| Jutzeler et al. (55) | sMRI | Whole brain; M1, S1, S2, PMC, insula, thalamus, ACC as regions of interests |
p < 0.05 FWE correction | SCI-NP vs. SCI-no NP: (Whole brain):↔ GMV (Regions of interest): ↑ GMV in L ACC and R M1 Pain intensity correlated positively with GMV in R M1 ↓ GMV in R S1 and bilateral thalamus. |
| Mole et al. (56) | sMRI | Whole brain: M1, S1, thalamus, L posterior cingulate, R insula as regions of interests |
p < 0.001 uncorrected; p < 0.05 FWE correction |
SCI-NP vs. SCI-no NP: ↓ GMV in bilateral S1. Pain intensity correlated negatively with GMV in S1 ↓ WMV deep to S2 |
| Min et al. (59)§ | rsfMRI | Bilateral M1, SMA, S1, S2, BG, dlPM, vlPM |
p < 0.05, k = 64 FDR correction |
SCI-pain vs. SCI-no pain: n/a |
| Yoon et al. (57) | sMRI DTI PET |
Whole brain |
sMRI and PET: p < 0.001 uncorrected, p < 0.05 SVC with 10 mm spheres; DTI: p < 0.05 TFCE |
SCI-NP vs. SCI-no NP: n/a |
| Gustin et al. (58) | DTI | Whole brain |
p < 0.005 uncorrected, k = 20 |
SCI-NP vs. SCI-no NP: ↓ MD of ventral pons to midbrain. ↑ MD of R PPC, R dorsolateral PFC, L anterior insula, mOFC, PMC, L amygdala, and R ventroposterior thalamus. MD values of dorsolateral PFC, PPC, anterior insula and PMC were positively correlated with pain intensity. MD values of amygdala and ventroposterior thalamus were negatively correlated with pain intensity. ↔ FA. |
| Widerström- Noga et al. (60) | MRS | Thalamus | Independent t tests p < 0.05 |
SCI-NP high pain vs. low pain:↓ NAA/Ins and Glx/Ins |
| Gustin et al. (61) | MRS | Thalamus | Independent t tests p < 0.05 |
SCI NP vs. SCI no NP:NAA/Cr and GABA/Cr |
| Widerström-Noga et al. (62) | MRS | ACC | Independent t tests p < 0.05 |
SCI-NP high pain vs. low pain:Ins, Cr and Cho ↓ NAA/Ins and Glx/Ins SCI-NP high pain vs. SCI no NP: ↓ Glx ↓ Glx/Ins |
| Stanwell et al. (63) | MRS | Thalamus, PFC, ACC | Wavelet-based significant testing p < 0.05 |
SCI-NP vs. SCI-no NP: PFC: Mean spectral differences, possible contributions: NAA, Glu, Glx, Cho, taurine and GABA. ACC: Mean spectral differences, possible contributions: Ins and Asp. Thalamus: not significant |
| Pattany et al. (64) | MRS | Thalamus | Post hoc t-tests p < 0.05 |
SCI-NP vs. SCI-no NP: ↓ NAA and NAA/Ins. Pain intensity correlated negatively with NAA levels. Pain intensity correlated positively with Ins levels |
Results of studies investigating differences between SCI-NP and SCI-no NP subjects unless stated otherwise. Study order is based on neuroimaging modality as reported in Table 1, starting with structural, DTI, rsfMRI, then MRS. ACC, anterior cingulate cortex; Asp, aspartate; BG, basal ganglia; CC, corpus callosum; Cho, choline; Cr, creatine; CST, corticospinal tract; DTI, diffusion tensor imaging; dlPM, dorsolateral premotor cortex; FA, fractional anisotropy; FC, functional connectivity; FDR, false-discovery rate; FWE, family-wise error; GABA, gamma (γ)-aminobutyric acid; Glu, glutamate; Glx, glutamate and glutamine; GMV, gray matter volume; Ins, Myo-inositol; k, minimum cluster size; L, left; M1, motor cortex; MD, mean diffusivity; mFG, medial frontal gyrus; mOFC, medial orbital frontal cortex; MRS, magnetic resonance spectroscopy; NAA, N-acetyl aspartate; PET, positron emission tomography; PFC, prefrontal cortex; PMC, premotor cortex; PPC, posterior parietal cortex; R, right; rsfMRI, resting-state fMRI; S1, somatosensory cortex 1; S2, somatosensory cortex 2; SCI, spinal cord injury; SLF, superior longitudinal fasciculus; SMA, supplementary motor area; sMRI, structural MRI; SCI NP, SCI subjects with NP; SCI no NP, SCI subjects without NP; SVC, small volume correction; TFCE, threshold-free cluster enhancement; vlPM, ventrolateral premotor cortex; WMV, white matter volume.
↔ No significant changes; ↑ significant increase; ↓ significant decrease.