Perfusion-MRI in cerebral infarct

PURPOSE: To investigate the hemodynamic changes in patients with acute cerebral stroke by perfusion MRI. MATERIAL AND METHODS: In 12 patients with acute stroke in the territory of the middle cerebral artery, perfusion MRI was performed. Peak time, mean transit time, regional cerebral blood volume and regional cerebral blood flow were calculated in the infarction, the peri-infarction area and the contralateral hemisphere. RESULTS: In the infarction the mean blood flow was 29 ml/100 g/min, compared to about 40 ml/100 g/min in the peri-infarction area and the contralateral hemisphere. In two patients increased cortical blood flow was found in the infarction due to luxury perfusion. The cerebral blood volume was reduced in the infarction, but significantly increased, to 7.3 ml/100 g, in the peri-infarction tissue. CONCLUSION: Perfusion MRI allows one to differentiate various patterns of perfusion disorders in patients with acute cerebral stroke. The resulting data may be helpful in describing the pathophysiologic mechanisms of compensation.     

Seizures in cerebral malaria

The authors proposed a new application of helical CT, namely, CT-ventriculography that can obtain 2D and 3D images of different cardiac phases. CT-ventriculography could assess wall motion, systolic thickening and chamber volume. From a single breath hold helical CT 50-rotation), about 500 transaxial slices were obtained by applying overlapping reconstruction (0.1 pitch, 0.08 sec = 0.2 mm interval). All transaxial slices were recordered to separate different cardiac phases. Then, long and short axial 2D tomograms and 3D images in different cardiac phases were reformatted. CT-ventriculography is a promising new application for the assessment of heart function.     

Acute prognosis and differentiation of various cerebral infarct groups in comparison with cerebral hemorrhage

For clinical trials classification of stroke should be possible at the bedside by simple methods that are available every where. In this study are 1105 patients with every first ischaemic strokes and 130 patients with intracerebral haemorrhages. The differences between severity of clinical symptoms, outcome and risk factors of intracerebral haemorrhages, ischaemic stroke caused by cerebral microangiopathy, ischaemic stroke combined with extracranial carotid stenosis, cardiogenic brain embolism and atherothrombotic stroke, were analysed. Intracerebral haemorrhages show the poorest outcome of all groups (mortality 23.8%), due to increased intracranial pressure. Cardiogenic brain embolism is more frequent in older women (mean age 77.8 y.). Main risk factor is atrial fibrillation with absolute arrhythmia. The outcome of this group is the worst of all subgroups of ischaemic stroke and survivors most often in need of institutionalization. Patients with ischaemic stroke combined with extracranial carotid stenosis are significantly younger (mean age 67.6 y.), predominantly male, and smokers. Their mortality is low (0.63%), but recovery of paresis is slower than in other subgroups. Ischaemic strokes caused by cerebral microangiopathy with hypertension as main risk factor recover most quickly but acute mortality is higher than in ischaemic stroke combined with extracranial carotid stenosis because of higher age (mean age 74.5 y.). Institutionalization is more frequent too because of higher incidence of dementia in this subgroup. The main prognostic factors of all groups are age and severity of clinical symptoms. A special subgroup are infratentorial ischaemic strokes.(ABSTRACT TRUNCATED AT 250 WORDS)     

Regional cerebral blood volume after severe head injury in patients with regional cerebral ischemia

OBJECTIVE: Recent early cerebral blood flow (CBF) studies in cases of severe head injury have revealed ischemia in a substantial number of patients with a variety of computed tomographically demonstrated diagnoses. The underlying derangements causing this early ischemia are unknown, but cerebral blood volume (CBV) measurements might offer some insight into this pathological abnormality. METHODS: For this purpose, stable xenon-enhanced computed tomography was used for assessment of CBF, and a dynamic computed tomographic imaging technique was used for determining CBV. Based on the occurrence of regional ischemia (CBF < 20 ml/100 g/min), seven patients with varying anatomic lesions revealed by computed tomography were identified for comparison between CBF and CBV in ischemic and nonischemic areas. RESULTS: Both CBF (15+/-4.3 versus 34+/-11 g/min, P < 0.002) and CBV (2.5+/-1.0 versus 4.9+/-1.9 ml/100 g) exhibited significantly lower values in the ischemic zones than in the nonischemic zones (means+/-standard deviations). Among 26 patients with or without ischemia observed during their initial follow-up studies, which were conducted between Days 2 and 8, all patients showed CBF and CBV values within the low-normal range. CONCLUSION: These data evidently support the suggestion that compromise of the microvasculature is the cause of early ischemia, rather than vasospasm of the larger conductance vessels.     

Strabismus in children with cerebral palsy

In 48 children with cerebral palsy the characteristics of the squint and amblyopia were analyzed, also with respect to the features of cerebral palsy and to birth weight. Strabismus of congenital esotropia type was found to be common, as was also exotropia of early onset. Spontaneous alternation or an accommodative component of the squint was present only in a few cases. There was no evidence of an accumulation of any strabismus type in the different subgroups of cerebral palsy, whereas amblyopia or an obvious risk for amblyopia was found in the great majority of the cases. Some kind of amblyopia treatment was given to 34. Most of them showed improvement of the visual capacity which encourages treatment of amblyopia, even in children with cerebral palsy.     

Experimental animal models in cerebral ischemia

This paper describes the potential markers of cell death and connective tissue degradation which might serve as markers of periodontal disease activity. The first section deals with enzymes released by dead and degenerating cells. Firstly, it describes how these pass from the periodontal tissues into gingival crevicular fluid (GCF) and explains that these enzymes have been used as markers of cell death in medicine for several decades. It then discusses the main enzymes in this group, aspartate amino transferase (AST) and lactate dehydrogenase (LDH) and reviews those studies which have attempted to relate these enzymes to periodontal disease severity and activity. Secondly, it describes the potential markers of connective tissue degradation, fibronectin, hydroxyproline-containing peptides and glycosaminoglycans (GAGs) and explains how these are produced. Finally, it describes the only commercial test kit for markers in this group (GCF-AST).     

MRI findings in cerebral fat embolism

The purpose of this retrospective study was to demonstrate the MRI features of cerebral manifestations in patients with fat embolism syndromes in comparison with cerebral CT (CCT). Magnetic resonance imaging was performed according to standard protocols revealing multiple small non-confluent hyperintense intracerebral lesions larger than 2 mm on proton-density and T2-weighted images to various extents in three of four patients with clinically suspected cerebral fat embolism. Cerebral CT was negative in all patients. Our findings confirm that MRI can detect cerebral fat embolism with a higher sensitivity than CCT. Thus, MRI should be the first choice for imaging of cerebral fat embolism.     

Calcific cerebral embolism in systemic calciphylaxis

Calciphylaxis represents a rare complication of end-stage renal disease with hyperparathyroidism. We report the case of a 26-year-old woman with systemic calciphylaxis secondary to chronic renal failure who developed mitral annular calcification and a right middle cerebral artery stroke. The high-density lesion seen on CT scan of the brain probably represents a calcified cerebral embolus originating from the mitral valve.     

Analysis of IMP-SPECT in cerebral infarcts

We performed single photon emission computed tomography with N-isopropyl[123I]-p-iodoamphetamine in 22 normal volunteers (mean age, 68.3 +/- 9.5 years) and 190 patients with unilateral cerebral infarcts (66.1 +/- 11.4 years). We then compared visual and semiquantitative assessment of the left/right ratio of the early images. Cerebral blood flow in the patients with cerebral infarcts was compared with data from normal volunteers. An abnormal left/right ratio was recognized in 110 of 136 (81%) patients in whom X-ray computed tomography (CT) showed an abnormality, while visual inspection revealed abnormalities in only 99 (73%). In 54 patients no abnormality on CT, an abnormal left/right ratio was found in 28 (52%), and visual abnormalities in only 9 (17%). Altogether, the left/right ratio was abnormal in 138 of 190 (73%) patients, and abnormalities were detected visually in 108 (57%). Of 95 patients, 56 (59%) showed markedly larger lesions using the left/right ratio method than with the visual method.     

Immunopathological changes in human cerebral malaria

Pathogenic mechanisms in human cerebral malaria remain unclear. We reevaluate the role of cell-mediated immune mechanisms in the pathogenesis of this disease based on autopsy findings in a 34-year-old Caucasian male. Histologic examination of brain tissue showed typical features of severe malaria infection (sequestration of Plasmodium falciparum-infected erythrocytes in vessels, cerebral oedema, petechial lesions and Dürck granulomas). In addition to these classical changes, we found that leukocytes that stained positively in immunohistochemistry for CD68 and tumor necrosis factor-alpha (TNF) coexisted with infected erythrocytes in capillaries, whereas in venules the monocyte population outnumbered the erythrocytes. Notable expression of ICAM-1 on endothelial cell surface was detected by immunohistochemistry in vessels with sequestered cells but not in unaffected vessels. These changes are identical to those of the murine model of the disease, in which cell-mediated immune mechanisms and TNF have been implicated. In vitro, ICAM-1 has been shown to be a potential ligand for P. falciparum-infected erythrocytes. In malaria patients, high serum TNF levels, which have been detected in close correlation with disease severity, may thus favor adhesion to endothelial cells of either red or white blood cells via enhanced ICAM-1 expression. The present observations are further evidence for a role of cell-mediated immunity in the pathogenesis of human cerebral malaria.     

Nutrition in children with cerebral palsy

The previously reported earlier onset of pituitary tumours in cross-bred mice inheriting a mutant Rb-1 allele paternally has been ascribed to imprinting of an Rb-1-linked gene. Here, we demonstrate that, as predicted from this mechanism, there is no effect of the parent of origin of the mutation in inbred mice.     

Radiation-associated cerebral blindness

PURPOSE: To report a case of blindness caused by a white-matter injury after whole brain irradiation for metastatic renal cell carcinoma. METHODS: Case report. We performed comprehensive serial neuro-ophthalmologic examinations. RESULTS: Four to 5 months after resection of renal cell metastasis in the left occipital cortex, interleukin-2 therapy, and whole brain irradiation with 3,000 cGy plus a 1,500-cGy boost to the posterior third of the brain, the patient developed a progressive decline in visual acuity in both eyes to hand motions. Magnetic resonance imaging disclosed signal abnormalities without mass effect in the white matter of the parietal and occipital lobes bilaterally, including the optic radiations. CONCLUSION: This case is a unique example of cortical blindness secondary to radiation injury in the occipital lobes and optic radiations.