Gudrun Fazekas

Estrogen replacement therapy in older women: a neuropsychological and brain MRI study.

OBJECTIVE: To determine if postmenopausal women receiving estrogen perform better on demanding cognitive tests than women without estrogen replacement and if this beneficial effect on cognition is caused by estrogen‐related prevention of silent ischemic brain damage.

Brain MRI findings and cognitive impairment in patients undergoing chronic hemodialysis treatment

Although both morphologic cerebral damage and cognitive dysfunction are known to occur in patients on chronic hemodialysis (CHD) their extent and possible relation have been rarely studied. We therefore performed magnetic resonance imaging of the brain and neuropsychological testing in 30 consecutive CHD patients (mean age 58 years; range 37-69) and in an equal number of asymptomatic volunteers matched for age, sex and major cerebrovascular risk factors. Twenty-four (80%) of the CHD patients were demented according to the criteria of the Diagnostic and Statistical Manual of Mental Disorders IIIR and their mean scores on the Mini Mental State Examination (22.9 +/- 4 vs. 27.9 +/- 1.4; p < 0.001) and Mattis Dementia Rating Scale (112.3 +/- 21.5 vs. 141.9 +/- 2.3); p < 0.001) were significantly lower than those of controls. The brains of CHD patients showed significantly more atrophy on visual rating and semiquantitative morphometric measures. Multiple lacunes or confluent white matter hyperintensities predominated in 10 (33%) patients, three showed territorial infarcts and two a combination of both. Clinically these findings were unexpected in almost half of individuals. Marked cognitive impairment was associated with more extensive enlargement of the third ventricle (5.8 +/- 1.8 vs. 7.3 +/- 2 mm; p < 0.04) and the temporal horns (3.5 +/- 1.6 vs. 5.1 +/- 1.8 mm; p < 0.02) but not with the presence of cerebral ischemic lesions or any difference in laboratory data. These results call attention to a very high rate of cerebral damage in individuals undergoing CHD and suggest brain degeneration of probably toxic-metabolic etiology to be associated with severe cognitive impairment of these patients.

Magnetic Resonance Imaging Correlates of Transient Cerebral Ischemic Attacks

BACKGROUND AND PURPOSE MRI of patients with a transient ischemic attack (TIA) may provide more detailed morphological insights than CT. We therefore studied the frequency and type of TIA-related infarcts shown by MRI, examined the utility of intravenous contrast material, and searched for potential predictors of infarct occurrence. METHODS We performed 1.5-T MRI of the brain of 52 patients (age range, 28 to 93 years; mean, 61 years) with a hemispheric TIA. Contrast material (Gd-DTPA) was given to 45 individuals. We recorded type, number, size, and location of ischemic brain lesions and related the presence of acute infarction to features of clinical presentation and probable causes for the TIA. RESULTS MRI showed focal ischemic lesions in 50 patients (81%), but an acute TIA-associated infarct was seen in only 19 subjects (31%). In patients with an acute lesion, the infarcts were smaller than 1.5 cm in 13 (68%), purely cortical in 11 (58%), and multiple in 7 (37%) individuals. Contrast enhancement contributed to the delineation of an acute lesion in only 2 of 45 patients (4%). Acute infarction was unpredictable by clinical TIA features, but the frequency of identifiable vascular or cardiac causes was significantly higher in those patients with TIA-related morphological damage (odds ratio, 5.2 [95% confidence interval, 1.6 to 17.3]). CONCLUSIONS More than two thirds of TIA patients showed no associated brain lesion even when MRI and contrast material were used, but the overall frequency of ischemic damage was high. TIA-related infarcts on MRI were mostly small and limited to the cortex and tended to consist of multiple lesions. A positive MRI underscores the need for comprehensive diagnostic workup since evidence of infarction appears to be associated with a higher frequency of significant vascular or cardiac disorders.

Superficial siderosis of the central nervous system: MRI findings and clinical significance

We reviewed a 7-year series of brain MRI examinations to determine the frequency and clinical significance of superficial siderosis of the central nervous system (SS). SS was defined by widespread bilateral signal loss at the surfaces of the cerebral or cerebellar hemispheres, the brain stem and the spinal cord on T2-weighted images. Clinical data comprised a neurological examination of identified patients and a review of their case notes. Among 8843 consecutive studies we identified 13 (0.15 %) patients with MRI evidence of SS. Only 2 had symptoms or signs characteristic of SS, such as cerebellar ataxia, hearing loss, myelopathy and dementia. Haemosiderin deposition was most widespread in both symptomatic individuals. A definite cause for SS was detected in 9 patients (69 %). None of them had a full clinical picture of SS. These data indicate SS per se to be much more frequent than may be assumed from the literature. It appears to become symptomatic only with extensive amounts of widespread iron deposition which develop preferentially with cryptic or unidentified causes of bleeding.

Magnetic Resonance Imaging and Spectroscopy Findings After Focal Status Epilepticus

Summary: The etiology of cerebral abnormalities after focal status epilepticus (SE) is unknown. Possible causes include hypoxia and the excessive release of excitatory amino acids. Magnetic resonance imaging (MRI) of a 21–year‐old patient with “cryptogenic” continuous motor seizures showed swelling and signal hyperintensity of the contralateral panetotemporal cortex, the thalamus, and the ipsilateral cerebellum on T2‐weighted images. These regions are connected by glutamatergic pathways. Proton magnetic resonance spectroscopy (MRS) of the cortical lesion yielded a signal peak at the resonance frequency of 2.29 ppm, suggesting a focal increase of glutamate or its degradation product glutamine. At 3–month follow‐up, structural alterations had disappeared, but the N‐acetylaspartatelcholine ratio was still reduced in the previously abnormal area. These findings are the first to demonstrate the contribution of MRS to pathophysiologic studies of focal SE in humans and, in combination with the pattern of imaging abnormalities, support a major role of glutamate for seizure‐related brain damage.

Pattern of cerebral blood flow and cognition in patients undergoing chronic haemodialysis treatment

SummaryWe studied 20 patients aged 46–69 years (mean 57 years) undergoing long-term haemodialysis (HD) and 20 age- and sex-matched controls with single photon emission tomography (SPET) and 99Tcm-hexamethyl-propyleneamine-oxime to look for regional abnormalities in cerebral blood flow (CBF) and their relation to cognitive dysfunction. Global hemispheric tracer uptake relative to the cerebellum was similar in both groups, but regional over cerebellar activity was significantly reduced in the frontal cortex (85.9 ± 5.1 vs 90.4 ± 5.3; P = 0.01) and thalamus (99.2 ± 8.8 vs 104.9 ± 8.4; P = 0.05) of the HD patients. Normalization to whole-brain activity also showed the frontal cortex to be hypoactive in the HD patients, while tracer uptake was increased occipitally. These regional differences were not explained by the presence of atrophy or cerebrovascular damage seen on brain magnetic resonance imaging. The HD patients scored significantly worse on cognitive tests such as the Mini Mental State Examination (23 ± 4 vs 28 ± 1; P < 0.001) and Mattis Dementia Rating Scale (114 ± 24 vs 143 ± 1; P < 0.001). Regional activity ratios did not correlate with cognitive test scores, however. Our results indicate a disturbed pattern of CBF in HD patients, although regional SPET abnormalities did not correspond to the severity of cognitive dysfunction.