Ketotic hyperglycemia and epilepsia partialis continua.

Epilepsia partialis continua (EPC) may occur during nonketotic hyperglycemia but has not been described with diabetic ketoacidosis. The authors report a patient with EPC associated with ketotic hyperglycemia. Brain MRI showed two areas of abnormal signal intensity in the left precentral gyrus and in the right cerebellar hemisphere. Hyperglycemia may reduce seizure threshold because of the increase in gamma-aminobutyric acid metabolism and may trigger epileptic discharges.

Diffusion and perfusion MR imaging in cases of Alzheimer's disease: correlations with cortical atrophy and lesion load.

BACKGROUND AND PURPOSE: Perfusion and diffusion-weighted MR imaging are powerful new imaging techniques for evaluating tissue pathophysiology in association with many neurologic disorders, such as neurodegenerative diseases. The purpose of our study was to evaluate the sensitivity and specificity of dynamic susceptibility contrast-enhanced MR imaging and diffusion-weighted MR imaging in cases of Alzheimer's disease and to assess the role of atrophy in the quantification of cortical perfusion. METHODS: Thirty-nine participants were studied: 18 patients with moderate cognitive impairment with probable Alzheimer's disease, 16 patients with mild impairment with possible or probable Alzheimer's disease, and 15 group-matched elderly healthy comparison volunteers. Relative values of temporoparietal, sensorimotor, and hippocampal regional cerebral blood volume (rCBV) were measured as a percentage of cerebellar rCBV, and group classification was assessed with logistic regression. Brain atrophy was used as a covariate to assess its role in rCBV quantification. Regions of interest placed on orientation-independent apparent diffusion coefficient maps allowed the calculation of apparent diffusion coefficient values and relative anisotropic indices of the head of the caudate nuclei, thalamus, parietal, frontal, and hippocampal cortices bilaterally, genu and splenium of corpus callosum, and anterior and posterior white matter in patients with Alzheimer's disease and in control volunteers. RESULTS: Temporoparietal rCBV ratios were reduced bilaterally in the patients with Alzheimer's disease. Sensitivity was 91% in moderately affected patients with Alzheimer's disease and 90% in patients with mild cases. Specificity was 87% in healthy comparison volunteers. Lower values of sensitivity and specificity were obtained for sensorimotor (73%, 50%, and 67%, respectively) and hippocampal cortices (80%, 80%, and 65%, respectively). Using brain atrophy as a covariate, patients with Alzheimer's disease still showed a statistically significant reduction of rCBV compared with control volunteers. Diffusion-weighted MR imaging analysis only showed a trend, with no statistic significance, of reduction of anisotropy in posterior white matter. CONCLUSION: Dynamic susceptibility contrast-enhanced MR imaging of rCBV may be an alternative to nuclear medicine imaging for the evaluation of patients with Alzheimer's disease. When brain atrophy is used as a covariate, differences in rCBV still persist between patients with Alzheimer's disease and control volunteers, suggesting that perfusion impairment is unrelated to atrophy. No significant results for either white or gray matter were obtained using diffusion-weighted MR imaging.

[The clinical efficacy of magnetic resonance with diffusion-weighted sequences in the assessment of acute cerebral ischemia]. / Efficacia clinica della Risonanza Magnetica con sequenze pesate in diffusione nella valutazione dell'ischemia cerebrale acuta.

PURPOSE: To evaluate the efficacy of diffusion weighted Magnetic Resonance Imaging in the diagnosis of acute ischemic infarction and correlate the signal changes observed in the acute phase with final brain damage. MATERIAL AND METHODS: Fifteen patients (six women and nine men: mean age 68 years) with acute ischemic stroke (within 12 hours) underwent diffusion MRI. All the patients were selected on the basis of sudden focal neurologic symptoms and CT findings excluding other conditions than ischemia. MRI was performed with a 1.5 T magnet with echo-planar gradients. All the patients underwent follow-up CT and/or MRI. RESULTS: Diffusion MRI, performed in the acute phase, showed signal changes in all the patients whose infarction was later confirmed by CT or MRI. In 10 of 12 patients with positive diffusion imaging, CT was normal. FLAIR sequences showed the lesions in 4 of 12 cases. In the 2 patients with transient ischemic attack diffusion MRI was normal as well as follow-up examinations. Apparent Diffusion Coefficients values in the infarcted area were almost half those of the contralateral normal brain. Final damage (as assessed by CT or MRI) was larger than observed in acute diffusion images in all cases but one. CONCLUSION: Because of its high sensitivity and specificity, diffusion MRI is going to play a more important role in the management of acute ischemic stroke patients.

[An evaluation of the carotid bifurcation and of the intracranial circle by angio-spiral computed tomography]. / Valutazione della biforcazione carotidea e del circolo intracranico mediante angio-Tomografia Computerizzata spirale.

INTRODUCTION: Some clinical trials (NASCET, ECTS) have assessed that carotid endarterectomy is protective against stroke in patients with asymptomatic severe carotid stenosis. In order to decrease costs and risks, new diagnostic tools have been developed, such as Magnetic Resonance Angiography (MRA), duplex Ultrasound (US) and more recently Spiral Computed Tomography Angiography (CTA). CTA provides excellent 3D angiography images of the extracranial vessels using a volume rendering technique. This study was aimed at prospectively evaluating the accuracy of CTA in the diagnosis of carotid bifurcation. The circle of Willis was also studied during the same bolus injection. DSA was used as the gold standard technique. Surgery was also used for comparison. MATERIAL AND METHODS: Spiral CTA and DSA were performed in 106 carotid bifurcations. DSA was performed in all patients within 48-72 hours of CTA. The degree of internal carotid stenosis was evaluated according to NASCET criteria. Degree of stenosis, presence of calcifications, ulcerations and tandem lesions were reviewed by two different neuroradiologists blinded to each other and to the results of the other technique. In 19 cases the size of residual lumen of the ICA was surgically evaluated and correlated with CTA. RESULTS: There was an overall correlation between CTA and DSA in 94% of cases. Our data are in agreement with the results of the current literature. CT angiograms overrated by one category 6 cases (25%) of mild and one of moderate stenosis (7.14%). Calcifications were seen on spiral CT angiography in 69 (65.09%) carotid bifurcations while DSA detected the presence in 31 (29.24%). Ulcerations were missed by CTA in 3 cases. Five (4.71%) tandem lesions were visualized by DSA distal to bifurcation: 2 (1.88%) were also diagnosed by CTA. The patency of the circle of Willis was assessed in all cases. In 19 cases, the size of ICA stenosis evaluated at surgery was comparable with CTA findings. CONCLUSIONS: In conclusion CTA offers an outstanding alternative to catheter angiography in the evaluation of stenosis-occlusion of the carotid bifurcation. The intracranial circulation can be easily assessed by CTA as well, which allows the study of tandem lesions and of the circle of Willis.