Background: Non-missile traumatic brain injury (nmTBI) without macroscopically detectable lesions often results in cognitive impairments that negatively affect daily life. Aim: To identify abnormal white matter projections in patients with nmTBI with cognitive impairments using diffusion tensor magnetic resonance imaging (DTI). Methods: DTI scans of healthy controls were compared with those of 23 patients with nmTBI who manifested cognitive impairments but no obvious neuroradiological lesions. DTI was comprised of fractional anisotropy analysis, which included voxel-based analysis and confirmatory study using regions of interest (ROI) techniques, and magnetic resonance tractography of the corpus callosum and fornix. Results: A decline in fractional anisotropy around the genu, stem and splenium of the corpus callosum was shown by voxel-based analysis. Fractional anisotropy values of the genu (0.47), stem (0.48), and splenium of the corpus callosum (0.52), and the column of the fornix (0.51) were lower in patients with nmTBI than in healthy controls (0.58, 0.61, 0.62 and 0.61, respectively) according to the confirmatory study of ROIs. The white matter architecture in the corpus callosum and fornix of patients with nmTBI were seen to be coarser than in the controls in the individual magnetic resonance tractography. Conclusions: Disruption of the corpus callosum and fornix in patients with nmTBI without macroscopically detectable lesions is shown. DTI is sensitive enough to detect abnormal neural fibres related to cognitive dysfunction after nmTBI.

The aim of this study was to explore the regional cerebral glucose metabolism (rCM) in patients with chronic stage traumatic brain injury (TBI) compared with normal controls. We also investigated the relationship between regional cerebral glucose metabolism and cognitive function. We performed 2-[(18)F]fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) study using statistical parametric mapping (SPM) analysis in 36 diffuse axonal injury (DAI) patients (mean age +/- SD, 36.3 +/- 9.8 years). At 6 months or more after head injury, all patients underwent FDG-PET study and neuropsychological batteries to assess cognitive function. Thirty healthy, gender-matched control subjects who were comparable in age were also studied. Between the TBI patients and normal controls, group comparisons showed regional metabolic decreases in the bilateral frontal lobes, temporal lobes, thalamus, as well as the right cerebellum in the TBI group. Only full-scale Intelligence Quotient (IQ) (mean +/- SD, 78.5 +/- 11.9) correlated positively with rCM in the right cingulate gyrus and the bilateral medial frontal gyrus. In other examinations, the correlation was not provided. DAI may induce functional disconnection and decreased neuronal activity, and finally lead to diffuse glucose hypometabolism. Low full-scale IQ scores may be related to significantly different underlying cognitive impairment. In supporting cognitive function following TBI, which showed diffuse cerebral metabolic reduction compared with normal controls, medial prefrontal cortex and anterior cingulate cortex may be an important component.

We conducted a study to evaluate the degree of corticospinal tract (CST) dysfunction associated with diffuse axonal injury (DAI) through analyses of both diffusion-tensor magnetic resonance imaging (DTMRI) and motor-evoked potential (MEP). Using DTMRI and MEP with transcranial magnetic stimulation, we evaluated 138 instances of CST in 52 patients with severe chronic DAI and compared them with the findings in 17 normal volunteers. We determined values of fractional anisotropy (FA) on FA maps obtained with DTMRI of six regions of interest (ROIs) in the CST, consisting of the semioval center, coronal radiation, posterior limb of internal capsule, midbrain, pons and medulla oblongata. The lowest value of %FA for each of the six ROIs in each CST was defined as the minimum %FA, and the lowest magnetic stimulation strength that produced MEP was defined as the minimum threshold for MEP. The mean minimum %FA for CSTs in which MEP could not be obtained even with maximum magnetic stimulation (the MEP- group) was significantly lower than that of CSTs in which MEP could be obtained (the MEP+ group). ROIs with the lowest %FA value were the midbrain in the MEP+ group and the medulla oblongata in the MEP- group. In the MEP+ group, a serial decrease in the minimum %FA value significantly correlated with a serial increase in minimum threshold for MEP. These results show that in patients with chronic DAI, physiological motor dysfunction as revealed by MEP correlates significantly with morphological damage to the CST as detected by DTMRI. This strongly suggests that DTMRI can be a valuable tool for evaluating aberrant motor function and for estimating its severity in DAI.

No abstract

Objective: To assess the selection of carotid endarterectomy (CEA) or carotid artery stenting (CAS) and the choice of embolic protection device (EPD) on the basis of a preoperative magnetic resonance (MR) plaque image such as Sp/Sm (signal intensity ratio of carotid plaque against sternocleidomastoid muscle). Methods:Between August 2011 and August 2015, 180 patients who underwent CEA or CAS at our institution were retrospectively analyzed. CEA was selected when soft plaque was suspected by a plaque image of Sp/Sm ≥2, in contrast, CAS was indicated for patients with a surgically high-risk condition and for patients with a plaque image of Sp/Sm <2.Moreover, EPD was chosen by means of the plaque characterization such as Angioguard XP for Sp/Sm <2, Filter wire EZ or Spider FX for 2 ≤ Sp/Sm <3, and balloon (GuardWire PS/Mo.Ma Ultra) for 3 ≤ Sp/Sm. Then, we compared the peri-operative complication rate and hyperintensity rate on diffusion-weighted image (DWI) post-operatively. Results:In 80 cases with 3 ≤ Sp/Sm, CEA was performed for 30 cases and CAS using balloon for 50 cases. In 88 cases with 2 ≤ Sp/Sm <3, CEA was performed for nine cases and CAS using Filter wire EZ or Spider FX for 79 cases. The residual 12 cases with Sp/Sm <2 were treated with CAS using Angioguard XP. The complication rate was 2.1% in CAS and 0% in CEA. Asymptomatic hyperintensities on DWI after revascularization were detected in 24% of CAS patients and 0% of CEA patients. As for EPD, 27 of 79 CAS patients treated with Filter wire EZ or Spider FX had hyperintensities on DWI and hyperintensities were mostly observed in 21 of 39 patients with 2 ≤ Sp/Sm <3 on both T1-and T2-weighted imaging, but not in 6 of 40 patients with 2≤ Sp/Sm <3 on either T1-or T2-weighted imaging. Conclusion:The clinical outcome of patients treated with CEA was acceptable regardless of their carotid plaque components, if SAPPHIRE CEA high-risk group is accurately excluded. Considering that balloon protection should be used as EPD against soft plaque with 2 ≤ Sp/Sm <3 on both T1-and T2-weighted imaging, selection of CEA or CAS and EPD based on the MR plaque characteristics such as Sp/Sm is a useful strategy.