Kensuke Shiga

Microbleeds in Alzheimer Disease Are More Related to Cerebral Amyloid Angiopathy than Cerebrovascular Disease

Cerebral amyloid angiopathy (CAA) is one of the cardinal pathological features in the vascular components of Alzheimer’s disease (AD). CAA itself results in disrupted microvasculature, mainly in the cerebral cortex, eventually leading to a brain cortical or subcortical hemorrhage in a population of elderly people, but clinically overt brain hemorrhages are not so frequent in AD patients. Here we assessed 50 AD patients and 26 controls to detect latent brain hemorrhages with gradient-echo T2*-weighted images, a sensitive magnetic resonance imaging technique to detect hemosiderin components in the brain. Microbleeds, demarcated as low-intensity spots in T2*-weighted images, were detected in 16.7% of AD patients without cerebrovascular disease (CVD) and in 12.5% of those with CVD, while no microbleeding was detected in the control subjects. No significant difference was observed between the microbleed-positive group and the microbleed-negative counterpart in their clinical background, such as hypertension, the use of antiplatelet drugs and smoking. In addition, white matter high intensities in the T2-weighted image were significantly more confluent in the microbleed-positive AD group than its negative counterpart. In conclusion, our evaluation of AD brains revealed that latent microbleeds in AD patients are more frequent than in normal controls. Microbleeds not being related to common hemorrhagic risk factors, but being significantly related to white matter pathologies suggested that microbleeds in AD may be associated with CAA, but not with hypertension or CVD.

Local tissue anisotropy decreases in cerebellopetal fibers and pyramidal tract in multiple system atrophy

BackgroundOne of the cardinal features in multiple system atrophy (MSA) is the white matter pathology: loss of myelin, astrocytosis, and glial cytoplasmic inclusions. The pathological changes of tissue microstructure can modify the diffusion behavior of water molecules, which can be assessed by diffusion tensor imaging (DTI).Objectives To explore the hypothesis of white matter degeneration in MSA.MethodsWe studied 11 patients with clinically probable MSA and 10 age–matched controls. DTI was performed in both groups to measure fractional anisotropy (FA) in various regions of interest: the inferior cerebellar peduncle (ICP), middle cerebellar peduncle (MCP), superior cerebellar peduncle (SCP), basis pontis, internal capsule, and corpus callosum.ResultsFA values in SCP and corpus callosum showed no significant difference between the MSA group and controls. By contrast, FA values decreased in the MSA group in the MCP, basis pontis and internal capsule. In addition, FA values in the MCP were negatively correlated with ataxia severity in the MSA group.ConclusionThe areas showing decreased tissue anisotropy in DTI corresponded well with pathologically vulnerable areas in MSA. In addition, the local tissue anisotropy of MCP decreased in accordance with functional disability. These observations implied that DTI is a feasible method for in vivo evaluation of the white matter pathology in MSA.

Fiber-Tracking Method Reveals Sensorimotor Pathway Involvement in Stroke Patients

BACKGROUND AND PURPOSE We tested the feasibility of a new MRI technique that provides visualization of the sensorimotor tracts in vivo in a group of stroke victims. SUMMARY OF REPORT Fourteen patients with small infarctions involving the white matter of the supratentorial brain were evaluated. Sensorimotor tracts on the lesional and contralesional sides were successfully depicted in all cases. The position of the sensorimotor tracts relative to the infarct was in good agreement with clinical symptoms. The overall sensitivity and specificity for sensorimotor tract involvement were 100% and 77%, respectively. CONCLUSIONS Our proposed fiber-tracking method was shown to be a clinically feasible technique that correlates well with clinical symptoms.

Nerve ultrasound depicts peripheral nerve enlargement in patients with genetically distinct Charcot-Marie-Tooth disease

Objective To elucidate the ultrasound (US) features of peripheral nerves including nerve roots in patients with different types of Charcot-Marie-Tooth disease (CMT), and the association between US findings, clinical features and parameters of nerve conduction studies (NCS) in CMT1A. Methods US of median, sural and great auricular nerves and the C6 nerve root was performed in patients with CMT1A (n=20), MPZ-associated CMT (n=3), NEFL-associated CMT (n=4), EGR2-associated CMT (n=1), ARHGEF10-associated CMT (n=1) and in controls (n=30). In patients with CMT1A, we analysed the correlations between US findings and the following parameters: age, CMT Neuropathy Score (CMTNS) and NCS indices of the median nerve. Results Cross-sectional areas (CSAs) of all the nerves were significantly increased in patients with CMT1A compared with that in controls. In MPZ-associated CMT, increased CSAs were found in the median nerve at wrist and in the great auricular nerve, whereas it was not increased in patients with NEFL-associated CMT. In patients with CMT1A, there was a positive correlation between CMTNS and the CSAs in the median nerves or great auricular nerves. In median nerves in patients with CMT1A, we found a negative correlation between the nerve conduction velocity and the CSA. Conclusions Nerve US may aid in differentiating among the subtypes of CMT in combination with NCS. In CMT1A, the median nerve CSA correlates with the disease severity and peripheral nerve function.

Contrasting echogenicity in flexor digitorum profundus–flexor carpi ulnaris: A diagnostic ultrasound pattern in sporadic inclusion body myositis

Introduction: In this study we aimed to clarify whether muscle ultrasound (US) of the forearm can be used to differentiate between patients with sporadic inclusion body myositis (s‐IBM) and those with s‐IBM–mimicking diseases. Methods: We compared the echo intensity (EI) of the flexor digitorum profundus (FDP) muscle and the flexor carpi ulnaris (FCU) muscles in patients with s‐IBM (n = 6), polymyositis/dermatomyositis (PM/DM; n = 6), and amyotrophic lateral sclerosis (ALS; n = 6). Results: We identified EI abnormalities in 100% of patients with s‐IBM, 33% of those with PM/DM, and 33% of those with ALS. An “FDP–FCU echogenicity contrast,” a US pattern involving a higher EI in the FDP than in the FCU, was observed in all patients with s‐IBM, but in none of those with PM/DM or ALS. Conclusions: FDP–FCU echogenicity contrast in muscle US is a sensitive diagnostic indicator of s‐IBM. Muscle Nerve 49: 745–748, 2014

White Matter Loss in the Splenium of the Corpus callosum in a Case of Posterior Cortical Atrophy: A Diffusion Tensor Imaging Study

There have been several functional imaging studies using PET and SPECT to investigate posterior cortical atrophy (PCA). These studies have suggested dysfunction of corticocortical connections which is consistent with the occipitoparietal stream. However, there are no reports suggesting disturbance of the white matter that interconnects the temporal, parietal and occipital cortices. We measured fractional anisotropy (FA) in the genu and splenium of the corpus callosum and created color maps using diffusion tensor imaging (DTI), which is a relatively new MRI technique that allows visualization of the directionality of water diffusion, in a patient with PCA and compared these findings with those in 5 typical Alzheimer disease (AD) patients. The PCA patient was a 75-year-old man presenting with progressive complex visual disorder who satisfied the clinical diagnostic criteria for PCA. In 5 typical AD patients, the FA index in the splenium was higher than that in the genu; however, in the PCA patient, the FA index in the splenium was significantly lower than that in the genu. A DTI-based color map of the PCA patient showed reduction of anisotropy and fiber volume in the splenium. These findings suggest that the splenium of the corpus callosum secondarily degenerated due to neuronal degeneration of the temporal, parietal and occipital cortices and suggest that reduction of the FA in the splenium is one of the characteristics of PCA.

Wallerian degeneration of the inferior cerebellar peduncle depicted by diffusion weighted imaging

Wallerian degeneration of the inferior cerebellar peduncle has never been demonstrated on imaging studies. We describe a case in which it was depicted by thin slice diffusion weighted imaging. Location to the inferior cerebellar peduncle was confirmed by a fibre tracking method.

Discrepancy between clinical and pathological diagnoses of CBD and PSP

Progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD) are often clinically confused with each other. Moreover, the discrepancy between clinical and pathological diagnoses of CBD and PSP are still controversial. We report here two atypical cases of PSP and CBD. A 73–yearold woman was admitted with right hand rigidity, limb kinetic apraxia and cortical sensory loss. Brain atrophy, hypoperfusion and hypometabolism predominantly in the left frontoparietal lobes indicated CBD clinically. Pathological studies revealed neuronal loss and spongy change without ballooned neurons (BN) in the cerebral cortex. Modified Gallyas–Braak (G–B) staining revealed neurofibrillary tangles (NFTs) and tufted astrocytes, indicating pathological diagnosis of PSP. A 75–year–old man admitted with vertical gaze palsy, neck dystonia, parkinsonism and dementia. Atrophy of the frontal lobes and tegmentum of the midbrain and symmetrical frontal hypoperfusion in SPECT indicated PSP. However, neuronal loss and BN in the frontal lobes and clusters of astrocytic plaques indicated CBD pathologically. The G–B staining was useful for differentiating between CBD and PSP, but our atypical cases bring up a new issue about differential diagnosis of CBD and PSP.

Renin-angiotensin system gene polymorphism in Japanese stroke patients

Abstract A role of deletion (D)/insertion (I) polymorphism in angiotensin converting enzyme (ACE) gene or A/C polymorphism in angiotensin II type 1 receptor (AT1R) gene polymorphism on ischemic stroke or leukoaraiosis were assessed in 129 Japanese ischemic stroke patients and 27 normal control subjects. Ischemic stroke patients were divided into three groups, including lacunar, atherothrombotic and cardio-embolic infarction. Leukoaraiosis was assessed with the grade of periventricular high intensity (PVH) and deep white matter lesion (DWL). The D allele of ACE gene (ACE*D) increased by 2.57-fold the risk of lacunar infarction although ACE*D did not significantly increase the risk of atherothrombotic and cardio-embolic infarction. ACE*D also had a 2.82- and 2.95-fold increased risk of PVH and DWL, respectively. AT1R polymorphism showed no significant effect on ischemic stroke and leukoaraiosis. ACE*D increased the risk of normotensive lacunar infarction significantly although other risks except current smoking showed no significant effect on normotensive lacunar infarction. The findings of this study suggested a role of ACE polymorphism on lacunar infarction independent of hypertension.

Metamorphopsia and visual hallucinations restricted to the right visual hemifield after a left putaminal haemorrhage.

The physiological response to hypothermia is controlled by the hypothalamus, involving peripheral vasoconstriction and shivering. In hypothalamic hypothermia these systems fail with loss of reactive peripheral vasoconstriction to reduce heat loss and loss of the shivering response to produce heat. It is the failure of these systems that contributes to the hypothermia and also produces diagnostic difficulty, with the patient feeling warm to the touch and not shivering. The ECG showing the pathognomonic J waves, with absence of shiver waves mirrored the hypothalamic cause of the hypothermia. This is the first description of hypothermia in a patient with multiple sclerosis with a proved hypothalamic plaque and no other identifiable cause for hypothermia.