To investigate the mechanisms underlying the evolution of unilateral spatial neglect (USN) due to cerebral infarction, the cerebral oxygen metabolism was measured quantitatively by positron emission tomography (PET). Out of 189 consecutive patients with right hemisphere lesions who underwent PET, we recruited 13 patients (group A) who exhibited USN at the time of PET examination, 11 patients (group B) who had already recovered from USN, and 27 patients (group C) with right hemisphere infarction who failed to present with USN throughout. Eight normal volunteers (group NV) served as controls. Statistical comparisons were performed on the local values of the cerebral metabolic rate of oxygen (CMRO₂) from the region of interest (ROI) in the right dorsolateral frontal lobe, superior temporal gyrus, inferior parietal lobule, cingulate gyrus, basal ganglia and thalamus which are associated with USN. We also obtained CMRO₂ values for the contralateral areas. As compared with group C or NV, there were significant decreases in CMRO2 in the right frontal, right temporal and right parietal lobes, right basal ganglia, right thalamus and bilateral cingulate gyri in groups A and B. Except for the left inferior parietal lobule, no significant differences in regional CMRO₂ were noted between groups A and B. These findings indicate that extensive right hemisphere lesions may produce USN, but no specific brain region is associated with its recovery. Different from aphasics, no definite relationship is evident between recovery from USN and the role of the contralateral left hemisphere. This could be explained partly by the complexity of the pathogenetic mechanisms underlying USN.

View full abstract

The utility of DWI (diffusion-weighted imaging) has been established in acute ischemic stroke. However, some patients with acute stroke show no abnormal signals on DWI, despite the presence of infarction (false-negative DWI). We analyzed the relationship between false-negative DWI and the clinical manifestations of acute ischemic stroke in 151 DWI-positive (89%) and 19 false-negative DWI (11%) patients. We performed MRI within 24 hours after onset at our hospital. Non-specific clinical manifestations, including vertigo and nausea, were frequently observed in false-negative DWI patients. As regards the vascular territory, false-negative DWI was noted in 15.3% of 59 patients with infarctions within the territory of the vertebrobasilar artery. Concerning the duration from onset to initial imaging, 73.7% of the patients with false-negative DWI findings underwent MRI examination within 6 hours after onset. Of the patients with false-negative DWI, 84.2% had lacunar infarction (X²=16.4, P<0.001). In conclusion, false negative DWI is more frequently observed in lacunar infarction than in atherothrombotic infarction or cardiogenic embolism. It is important to examine carefully the neurological changes occurring in patients who present with acute stroke, but have negative DWI findings.

View full abstract

There is no direct evidence as to whether antiplatelet therapy should be discontinued or not when patients with cerebrovascular diseases undergo surgery or invasive examinations. We therefore examined the platelet aggregability as a marker for determining the adequate period to discontinue the antiplatelet agents. 22 patients who underwent surgery or examination were discontinued on antiplatelet agents (9 patients on aspirin and 13 patients on ticlopidine) for 14 days before the operation. The aggregability in the aspirin group was significantly increased on the 3^rd day as compared to that before the discontinuance (14.0±8.5% vs. 48.1±31.2%; p<0.05). The aggregability in the ticlopidine group was significantly increased on the 14^th day (19.5±11.4% vs. 58.4±30.8%; p<0.05). We conclude that it is desirable to pause aspirin for 3 days and ticlopidine for 2 weeks, in terms of the platelet aggregability.

View full abstract

The present study analyzed the functional outcome of patients with cardioembolic stroke in relation to the length of time from disease onset to the start of treatment with edaravone. The study involved 51 con-secutive cases with proximal occlusion of the middle cerebral artery. All patients were admitted to our hospital during the four-year period from August 2001 to August 2005. The patients were divided into three groups according to the length of time from disease onset to the start of treatment ; Group A (within 3 hours, n=16), Group B (3-6 hours, n=16) and Group C (6-24 hours, n=19). Edaravone was administered for 7-14 days (60 mg/day). Inter-group comparisons of the functional outcome were performed using the Japan Stroke Scale (JSS), the NIH Stroke Scale (NIHSS) and the modified Rankin Scale (mRS). The degree of functional improvement evaluated at 28 days after disease onset using the JSS was correlated with the edaravone dosing period (r=-0.7602, p<0.001). In terms of the NIHSS and mRS scores on day 28, the percentage of cases showing improvement was higher in Group A than in Groups Band C (p<0.001). These findings suggest that functional recovery is more likely to be achieved if edaravone therapy is initiated immediately after cardioembolic stroke.

View full abstract

We report a 61-year-old woman with embolic basilar artery occlusion, who developed transient cardiac dysfunction. The initial neurological findings were diplopia, but she suddenly developed coma. Her blood pressure decreased from 160/78 mmHg to 70/58 mmHg immediately after the deterioration of consciousness. Her ECG demonstrated inverted T waves, and echocardiography showed left ventricular apical ballooning akinesis and basal hyperkinesis, which normalized 7 days later. We diagnosed the patient as Takotsubo cardiomyopathy. Subarachnoid hemorrhage or supratentorial ischemic stroke are sometimes associated with Takotsubo cardiomyopathy. This is the first report of Takotsubo cardiomyopathy associated with embolic basilar artery occlusion.

View full abstract

A 65-year-old woman was admitted to our hospital with chorea in her right arm and leg. Neurological examinations showed mild right hemiparesis and hemichorea. The blood glucose level was 123 mg/dl, glycosylated hemoglobin Alc 15.2 mmol/l, and plasma osmotic pressure 297 mOsm/kg. Brain CT demonstrated high density and magnetic resonance (MR) showed a high signal intensity on T1-weighted images, low signal intensity on T2-weighted images and FLAIR images, partly low signal intensity on T2-weighted images, and mildly low signal intensity on diffusion weighted images in the left striatum. Proton MR spectroscopy revealed for the left putamen a decreased N-acetyl aspartic acid/Crea ratio (0.96), normal Colin/Crea ratio (1.19), and not a rise of lactic acid. ¹²³I-IMP SPECT showed normal blood flow. The patient's diabetes was controlled with insulin, and the hemichorea improved on treatment with haloperidol at 3 mg and clonazepam at 0.5 mg per day. The MRI and MRS findings in our patient suggested petechial hemorrhage, although gliosis has been reported in biopsy and autopsy cases. The striatal hyperactivity may have been associated with the onset of hemichorea in our patient.

View full abstract

We report a case of cerebral infarction due to nonbacterial thrombotic endocarditis (NBTE) associated with ovarian cancer. This 38-year-old woman hed begun to notice transient visual loss with pain in her right eye once a week since August 2002. Each episode continued for approximately 30 sec, and then spontaneously dissolved. In September, she had suddenly noticed difficulty in speaking. She consulted us in October 2002. Brain MRI revealed evidence of new acute ischemic strokes in the bilateral cerebrum. Transesophageal echo-cardiography demonstrated a mass on the mitral valve thought to represent a thrombus or vegetation. Pelvic MRI revealed massive ascites with an ovarian mass. Although empiric treatment with intravenous antibiotics and anti-coagulation therapy (warfarin and aspirin) was started, the size of mass attached to the mitral valve gradually enlarged. The patient then underwent surgery for removal of the mass on the mitral valve. De-bridement and plasty of the mitral valve were achieved with preservation of valvular function. Pathological examinations of the surgical material confirmed a diagnosis of NBTE. Two months after the cardiac operation, an operation for the ovarian mass was performed. The pathology revealed a poorly differentiated adenocarcinoma in the right ovary. Immunohistochemical studies for mucin showed that the tumor cells were positive for MUC1, MUC4, and MUC16, but negative for MUC2, MUC3, MUC5AC, and MUC6. NBTE associated with cancer should be considered as one of the causes of brain infarction.

View full abstract

A case of a 38-year-old woman with sinus thrombosis caused by low-dose (third-generation) oral contraceptives is reported. She suffered from seizures and headache. T2 weighted MR imaging showed disappearance of flow void of the superior sagittal sinus and magnetic resonance venography (MRV) revealed dural sinus thrombosis. Diffusion weighted MR imaging demonstrted an increased signal in the left parietal region. A single photon emission computed tomographic scan of the cerebral blood flow reveled a marked decrease of flow in this area. The patient was treated with propofol-coma and continuous intravenous heparin injection followed by oral anticoagulant (warfarin). Repeat MRV demonstrated sinus re-canalization. Her symptoms except for dysesthesia in both hands improved and her life became completely independent within one month. She has been followed up subsequently with no further problems.

View full abstract

A 43-year-old woman with hypertension, hyperlipidemia, smoking and a familial history as risk factors of cerebral infarction was admitted to our hospital because of left hemiparesis. Brain MRI demonstrated multiple fresh infarctions in the right frontotemporal lobes. A carotid arterial doppler echogram revealed mild atherosclerotic changes in the proximal portion of the left internal carotid artery. An MRA performed on admission could not be assessed because of the presence of motional artifacts. Although the patient's hospital course was satisfactory for a while, her left hemiparesis suddenly exacerbated on the 14th hospital day : this turned out to have been caused by a recurrence of a large hemorrhagic infarction in the right middle cerebral artery territory. A brain CT performed on the 16th hospital day revealed a transtentorial cerebral herniation, and the patient died on the 18th hospital day. An autopsy disclosed a large right hemispheric hemorrhagic infarction with severe edema. Histopathologically, there were discontinuities of the internal elastic lamina and aneu-rysmal changes due to thinning or dissection of the media in the right middle cerebral artery. Similar vessel lesions were evident in other body regions as well, leading us to make a pathological diagnosis of fibromuscular dysplasia. It appeared that the cerebral infarctions had been caused by luminal stenosis or occlusion of the main cerebral arteries due to medial dissections based on this condition.

View full abstract

An 88-year-old woman was admitted to our hospital with left hemiparesis. A recent infarction was detected in the right middle cerebral artery. She was diagnosed as having a cardiogenic cerebral embolism with atrial fibrillation on electrocardiography. Two months later she was again admitted to our hospital, this time for tetraplegia and consciousness disturbances. Three-dimensional computed tomographic angiography failed to show the basilar artery. After admission, no symptoms suggestive of recurrent cerebral infarction were observed. Follow-up computed tomography revealed bilateral infarction over the entire cerebral hemisphere. Areas of the bilateral cerebral hemisphere lesions were thought to be ischemic at the time of her second admission to the hospital.

View full abstract