Stroke is one of the leading causes of death in patients undergoing chronic dialysis. However, few clinical studies have so far examined stroke, especially brain infarction, under such conditions. We retrospectively evaluated the clinical features and risk factors for brain infarction in 33 patients undergoing hemodialysis (hemodialysis, 29 patients; continuous ambulatory peritoneal dialysis, 4 patients; male : female ratio, 25 : 8) between May 2003 and August 2006. The mean age was 68.5±10.9 (mean±SD) years. The basal renal diseases were chronic glomerulonephritis (n=16), diabetes mellitus (n=10) and other diseases (n=7). The mean duration of maintenance dialysis before the onset of stroke was 5.6±5.2 years. All 33 patients developed brain infarction, including the atherothrombotic (n=13), lacunar (n=9) and cardioembolic (n=11) types. The complications included a high frequency of hypertension (79%) in all groups, diabetes mellitus (36%) and atrial fibrillation (21%). Four of the patients, 2 with lacunar and 2 with atherothrombotic infarction, developed brain infarction within 3 hours after hemodialysis. Hemodynamic changes might have caused the infarction in these patients. The proportion of patients with a modified Rankin Scale grade of 4-6 at discharge was 42%, and the mortality rate was high (15%). The prognosis of brain infarction was poorer in patients with hemodialysis than in those without.

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Left ventricular assist devices (LVADs) have been widely used in terminal heart failure patients waiting for cardiac transplantation. However, complications, including embolism, infection, and mechanical problems, can occur incidentally in LVAD-treated patients. We investigated the clinical characteristics of 4 patients who developed stroke after an LVAD operation performed at our hospital. The participants (3 men, 1 woman) ranged in age from 7 to 46 years. All cases were diagnosed as having dilated cardiomyopathy; based on clinical criteria, they all developed cardioembolic stroke. The stroke occurred at 7 days after the LVAD operation in 1 case (a 7-year-old girl) and between 5 months and a year in the other 3 cases. Two cases complained of headache at the onset of stroke. All cases were treated by oral anticoagulant therapy using warfarin to attain a prothrombin time-international normalized ratio (PT-INR) of 2.0-3.0.

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We report a case of cerebral infarction caused by occlusion of a median callosal artery. A 55-year-old man was admitted to our hospital because of right motor weakness and sensory disturbance, and disorientation, followed by sensory disturbance of the left upper limb, and motor weakness of the left lower leg. Diffusion weighted images of MRI demonstrated high intensity over an extended area of the corpus callosum and bilateral medial parietal cortex. T1, T2 weighted and FLAIR images revealed a thrombus in the median callosal artery as hyperintensity spots. On comparison with MRA images obtained in a previous stroke attack, occlusion of the median callosal artery was identified in the new MRA series. The patient developed intermanual conflicts and compulsive manipulation in both arms, motor apraxia and constructive disorder in the right hand, and sensory misperception and ideomotor apraxia in the left hand. These symptoms were considered to represent callosal alien hand signs mixed with posterior alien hand signs in the left hand, and anterior alien hand signs in the right hand. Since the median callosal artery makes various contributions to the blood supply of the corpus callosum and bilateral hemispheres, it is important to investigate both the neurological symptoms and neuroradiological findings carefully in detail.

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We report a case of cerebral embolism with a patent foramen ovale and atrial septal aneurysm. A 28-year-old man was admitted to our hospital due to left hemiparesis, sensory loss and dysarthria. He had a past history of migraine with aura, and he sometimes drove for long distances. Upon arrival at hospital, he presented with an unsteady gait and his NIHSS was 0. He underwent a 3 Tesla brain MRI at 2 hours after the onset. Diffusion-weighted images showed a high intensity area in the right corona radiata and insula. T2^*-weighted images revealed a dot signal with a very low intensity on the right MCA, suggesting an embolus in the MCA. Funicular low signals in the right parietal lobe were regarded as medullary veins enhanced by increased deoxyhemoglobin. These findings were important since they could indicate an ischemic lesion. On MRA and cerebral angiography, the right MCA was actually seen to be occluded in the M2 portion. Transesophageal echocardiography demonstrated a patent foramen ovale and atrial septal aneurysm with right to left shunt. 3 Tesla T2^*-weighted MRI was thus useful for assessing the mechanism of the cerebral ischemic events.

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An 86-year-old woman with a history of hypertension and non-valvular atrial fibrillation developed cardioembolic stroke with symptoms of consciousness disturbance and left hemiparesis. We detected an oscillating thrombus at a proximal site of the internal carotid artery by carotid ultrasonography. The end-diastolic flow velocity of the right internal carotid artery was 0cm/s. To prevent against recurrence of cardioembolic stroke, administration of intravenous heparin was commenced. The oscillating thrombus disappeared at 3 days after the onset; however, the side-to-side ratio of the end-diastolic velocity still remained high, which suggestes occlusion of the distal internal carotid artery. The side-to-side ratio of the end-diastolic velocity decreased at 13 days after the onset, which indicated recanalization of the right internal carotid artery. Observation of the carotid artery and measurements of the flow velocity of the internal carotid artery by carotid ultrasonography are useful for detecting an oscillating thrombus and subsequent recanalization of the internal carotid artery.

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A 75-year-old man with hypertension and type 2 diabetes mellitus was admitted to our hospital because of acute onset of dizziness, diplopia, and difficulty in walking. Neurological examinations disclosed right median longitudinal fascicle (MLF) syndrome, left unilateral cerebellar ataxia, and a tendency to fall to the left on walking. Cranial routine diffusion and T2 weighted magnetic resonance imaging (MRI) with horizontal section on admission revealed no abnormality in the brainstem. However, serial diffusion and T2 weighted MRI with coronal section demonstrated a right paramedian infarction of lacunar size located in the tegmentum of the caudal mesencephalon. The patient was therefore diagnosed as having a pure midbrain infarction and was treated by anti-platelet therapy. He was discharged on the 13th day as the MLF syndrome had almost disappeared, and his stability in walking was improved. One month later, the MLF syndrome had completely vanished and the cerebellar ataxia was further improved. We conclude that thin slice coronal MRI examinations can be useful for the diagnosis of small brainstem infarction.

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Adult Still's disease (ASD) is a relatively rare rheumatoid disorder. We report a case of ASD with cerebral infarction. A 33-year-old woman had a 3-year history of ASD. She was hospitalized with dysarthria and right hemiparesis at 2 weeks after delivery, although her ASD remained inactive. Magnetic resonance imaging revealed cerebral infarction of the left pons. She was treated medically with aspirin and she improved remarkably. ASD-associated cerebral ischemia is quite rare, and may result from vasculitis of the cerebral arterioles and/or a hypercoagulable state after delivery.

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