Futoshi Mori

Quantitative susceptibility mapping (QSM) has been proposed to assess intraplaque hemorrhage (IPH) in the carotid artery. The purpose of this study was to compare the diagnostic accuracy of preoperative QSM with that of the conventional T1-weighed (T1W) three-dimensional (3D)-FSE sequence for detecting IPH in cervical ICA stenosis in patients undergoing carotid endarterectomy (CEA) using histology as the reference standard. Carotid T1W 3D-FSE and QSM images were obtained from 16 patients with cervical ICA stenosis before CEA. Relative signal intensity (RSI) and susceptibility of the ICA were measured on three axial images including the location of most severe stenosis on T1W 3D-FSE and QSM images, respectively. Three transverse sections of carotid plaques excised by CEA, which corresponded with images on MRI, were stained with H&E, antibody against glycophorin A and Prussian blue, and the relative area (RA) of histologic IPH was calculated. The correlation coefficient was significantly greater between susceptibility and RA-histologic IPH (ρ = 0.691) than between RSI and RA-histologic IPH (ρ = 0.413; P = .0259). The areas under the receiver operating characteristic curves for detecting histologic sections consisting primarily of IPH (RA-histologic IPH > 40.7%) tended to be greater for susceptibility (0.964) than for T1WI FSE-RSI (0.811). Marginal homogeneity was observed between susceptibility and histologic sections consisting primarily of IPH (P = .0412) but not between T1W FSE-RSI and histologic sections consisting primarily of IPH (P = .1824). Pre-CEA QSM detects histologic IPH in cervical ICA stenosis more accurately than preoperative T1W 3D-FSE imaging. QSM = quantitative susceptibility mapping; IPH = intraplaque hemorrhage; T1W = T1-weighed; 3D = three-dimensional; CEA = carotid endarterectomy; RSI = relative signal intensity; RA = relative area.

Background: While type 2 diabetes (T2D) is a major risk for ischemic stroke, the associated vessel wall characteristics remain essentially unknown. This study aimed to clarify intracranial vascular changes on three-dimensional vessel wall imaging (3D-VWI) using fast spin echo by employing 7Tesla (7T) magnetic resonance imaging (MRI) in T2D patients without advanced atherosclerosis as compared to healthy controls. Methods: In 48 T2D patients and 35 healthy controls, the prevalence of cerebral small vessel diseases and intracranial plaques were evaluated by 3D-VWI with 7T MRI. Results: The prevalence rate of lacunar infarction was significantly higher in T2D than in controls (n = 8 in T2D vs. n = 0 in control, p = 0.011). The mean number of intracranial plaques in both anterior and posterior circulation of each subject was significantly larger in T2D than in controls (2.23 in T2D vs. 0.94 in control, p < 0.01). In T2D patients, gender was associated with the presence of intracranial plaques. Conclusion: This is the first study to demonstrate the high prevalence of intracranial plaque in T2D patients with neither confirmed atherosclerotic disease nor symptoms by performing intracranial 3D-VWI employing 7TMRI. Investigation of intracranial VWI with 7T MRI is expected to provide novel insights allowing early intensive risk management for prevention of ischemic stroke in T2D patients.

[Purpose] This study investigated whether inhibition of unilateral vestibular function by transcranial direct current stimulation (tDCS) facilitates center-of-gravity (CoG) displacement. [Participants and Methods] Ten healthy individuals participated in this study. During a CoG displacement task, the subjects received 3 minutes cathodal tDCS applied to the right mastoid (tDCS condition) or first 30 seconds sham stimulation. The center of pressure (CoP), the weight load ratio, and the EMG of the lower leg were compared between pre- and post-stimulation. [Results] CoP and weight load ratio were significantly shifted to the right by the tDCS. [Conclusion] Vestibular tDCS might be a possible clinical intervention for the correction of displaced standing posture.

Lack of attention to obstacles on the floor or walking path may cause trip and fall accidents. The preparatory activity in the motor cortex to the perturbation associated with obstacle avoidance movements with cognitive task is still unclear. The purpose of this study was to investigate the motor cortical activity involved in the preparation and execution of concurrent obstacle avoidance movement and cognitive task. Twenty young adults were required to step over obstacles that were projected on the floor while performing a cognitive task. The electroencephalogram was recorded, and the movement-related cortical potentials (MRCP) aligned by foot dorsiflexion were evaluated. There was no significant difference in the number of contacts between the toe and the obstacle between the obstacle avoidance task and obstacle avoidance with cognitive task; however, the distance between the toe and the obstacle just before obstacle avoidance movement was significantly extended in the latter task. The amplitude and the onset of MRCP during the dual task were decreased and delayed, respectively, compared with the simple obstacle avoidance movement task. These results suggest that the young participants changed their clearance strategy to stepping over the obstacle during the concurrent motor and cognitive dual task to reduce motor cortical activity.

Objectives Nasal passages adjust the temperature of inhaled air to reach the required body temperature for the lungs. The nasal regions of primates including humans are believed to have experienced anatomical modifications that are adaptive to effective conditioning of the atmospheric air in the habitat for a given species. Measurements of the nasal temperature are required to understand the air‐conditioning performance for a given species. Unfortunately, repeated direct measurements within the nasal passage have been technically precluded in most nonhuman primates. Materials and methods Computational fluid dynamics (CFD) simulation is a potential approach for examining the temperature profile in the nasal passage without any direct measurements. The CFD simulation model mainly comprises a computational model to simulate physiological mechanisms and a wall model to simulate the nasal passage's anatomical and physical properties. We used a computational model developed for humans and examined corrections for the developed wall model based on human properties for predicting its performance in Japanese macaques. Results This study confirmed that the epithelium layer thickness of the wall model affects the accuracy of the predictions for macaques. A convenient correction of the thickness based on body mass allows us to simulate the actual air temperature profile in macaques' nasal passage. Discussion The CFD simulations of the wall model corrected with body mass can be applied to other nonhuman primates and mammals. This convenient corrective approach allows us to examine the functional contributions of a specific morphology to the air‐conditioning performance without any direct measurements to improve our understanding of primates' functional morphology and physical adaptations to the temperature environment in their habitat.

Background and Aim: We evaluated whether diffusion kurtosis and tensor imaging (DKI/DTI) could reveal microstructural alterations in the brains of patients with functional gastrointestinal disorders (FGIDs), and whether imaging findings were correlated with health‐related quality of life (HRQOL).Methods: Twelve patients with FGIDs fulfilling the Rome IV criteria, and seven healthy controls were examined using a 3 T magnetic resonance (MR) scanner. Tract‐based spatial statistics and regions of interest analyses were performed to compare the mean kurtosis (MK), fractional anisotropy (FA), and mean diffusivity (MD) between patients with FGIDs versus controls. HRQOL was assessed in patients with FGIDs using the eight‐item short form of the Medical Outcome Study Questionnaire (SF‐8) and the Gastrointestinal Symptom Rating Scale.Results: Patients with FGIDs had extensive, widespread regions of reduced MD in the white matter in comparison with healthy controls, whereas no significant differences were observed in MK and FA. No significant differences in deep gray matter for the MK, FA, and MD values were observed between patients with FGIDs and controls. In patients with FGIDs, the FA values in the globus pallidus had a significant and negative correlation with SF‐8 (a mental component summary) (r = −0.797, P = 0.01 uncorrected for multiple comparisons).Conclusions: DKI/DTI can help identify microstructural white matter alterations in patients with FGIDs. The FA values in the globus pallidus may be useful for a severity assessment of FGIDs.

Stent placement for cerebral aneurysms leads to a decrease in blood flow. This occurs not only through the direct obstruction of flow but also by the expansion of the parent artery. The latter has been observed in several clinical studies. The goal of this study was to clarify the effects of parent artery expansion after stent treatment on the following: 1) decrease in blood flow to an aneurysm, 2) wall shear stress (WSS), and 3) oscillatory shear index (OSI). The parent artery geometry constructed U-shape. The aneurysm location with respect to the U-shaped parent artery was determined according to previous clinical data. We performed calculations in unsteady-state situations using constructed models. Parent artery expansion with stent reduces blood inflow to an aneurysm and WSS of the aneurysm wall, in addition to increasing OSI. The aneurysm position affects the decrease of the inflow rate and WSS ratio and increases the OSI ratio. Expansion causes the majority of effects on flow reduction inside an aneurysm model. Thus, the expansion effects of all samples should not be neglected. These data suggest that parent artery expansion and its effect should be measured and included in the total decrease in blood flow. Parent artery expansion may induce intimal hyperplasia, thus increasing the thickness of the aneurysm wall.