Metabolic profile of complete spinal cord injury in pons and cerebellum: A 3T 1H MRS study.

The aim of this exploratory study was the assessment of the metabolic profiles of persons with complete spinal cord injury (SCI) in three region-of-interests (pons, cerebellar vermis, and cerebellar hemisphere), with magnetic resonance spectroscopy, and their correlations to clinical scores. Group differences and association between metabolic and clinical scores were examined. Fifteen people with chronic SCI (cSCI), five people with subacute SCI (sSCI) and fourteen healthy controls were included. Group comparison between cSCI and HC showed lower total N-acetyl-aspartate (tNAA) in the pons (p = 0.04) and higher glutathione (GSH) in the cerebellar vermis (p = 0.02). Choline levels in the cerebellar hemisphere were different between cSCI and HC (p = 0.02) and sSCI and HC (p = 0.02). A correlation was reported for choline containing compounds (tCho) to clinical scores in the pons (rho = - 0.55, p = 0.01). tNAA to total creatine (tNAA/tCr ratio) correlated to clinical scores in the cerebellar vermis (rho = 0.61, p = 0.004) and GSH correlated to the independence score in the cerebellar hemisphere (rho = 0.56, p = 0.01). The correlation of tNAA, tCr, tCho and GSH to clinical scores might be indicators on how well the CNS copes with the post-traumatic remodeling and might be further examined as outcome markers.

Functional connectivity and amplitude of low-frequency fluctuations changes in people with complete subacute and chronic spinal cord injury.

After spinal cord injury (SCI), reorganization processes and changes in brain connectivity occur. Besides the sensorimotor cortex, the subcortical areas are strongly involved in motion and executive control. This exploratory study focusses on the cerebellum and vermis. Resting-state functional magnetic resonance imaging (fMRI) was performed. Between-group differences were computed using analysis of covariance and post-hoc tests for the seed-based connectivity measure with vermis and cerebellum as regions of interest. Twenty participants with complete SCI (five subacute SCI, 15 with chronic SCI) and 14 healthy controls (HC) were included. Functional connectivity (FC) was lower in all subjects with SCI compared with HC in vermis IX, right superior frontal gyrus (pFDR = 0.008) and right lateral occipital cortex (pFDR = 0.036). In addition, functional connectivity was lower in participants with chronic SCI compared with subacute SCI in bilateral cerebellar crus I, left precentral- and middle frontal gyrus (pFDR = 0.001). Furthermore, higher amplitude of low-frequency fluctuations (ALFF) was found in the left thalamus in individuals with subacute SCI (pFDR = 0.002). Reduced FC in SCI indicates adaptation with associated deficit in sensory and motor function. The increased ALFF in subacute SCI might reflect reorganization processes in the subacute phase.

Intraarterial MR angiography and DSA in patients with peripheral arterial occlusive disease: prospective comparison.

PURPOSE: To prospectively evaluate the accuracy of intraarterial magnetic resonance (MR) angiography in the depiction of significant stenoses and occlusions, with intraarterial digital subtraction angiography (DSA) serving as the reference standard. MATERIALS AND METHODS: Approval of the local ethics committee and informed consent were obtained. Twenty patients (11 men; nine women; age range, 48-86 years; mean age, 69.5 years+/-11.2 [standard deviation]) with symptomatic peripheral arterial occlusive disease (PAOD) were prospectively enrolled. After percutaneous transluminal angioplasty (PTA), intraarterial MR angiography was performed in the thigh and the calf with a 1.5-T MR imager in two consecutive runs. Intraarterial MR angiography was performed with a low-dose injection protocol (ie, two 20-mL injections of a 50-mmol gadolinium-based contrast agent). Moderate stenoses (luminal narrowing50%) or vessel occlusions; 95% confidence intervals (CIs) were calculated for sensitivity and specificity. RESULTS: Intraarterial DSA revealed 78 moderate stenoses, 57 significant stenoses, and 28 occlusions. Sensitivity, specificity, and accuracy of intraarterial MR angiography in the characterization of significant stenoses or occlusions were 92% (95% CI: 72%, 99%), 94% (95% CI: 82%, 98%), and 93%, respectively, in femoropopliteal arteries and 93% (95% CI: 83%, 98%), 71% (95% CI: 51%, 86%), and 86%, respectively, in infrapopliteal arteries. The main artifact observed with intraarterial MR angiography was venous contamination (12%). CONCLUSION: Intraarterial MR angiography is an accurate method used to depict significant stenoses and occlusions in lower extremity arteries with a low-dose injection protocol.