Stroke in Latin America.

Stroke is one of the leading causes of mortality in Latin America, with variable incidence and prevalence throughout the continent reflecting regional socioeconomic differences. In Latin America, uncontrolled hypertension is one of the major causes of stroke, but other modifiable risk factors also play a role, such as heavy alcohol consumption and smoking. Intracerebral hemorrhage and lacunar stroke are more frequent in Latin America than in North America and Europe. There are multiple causes of stroke that are endemic to Latin America, including neurocysticercosis, Chagas' disease, sickle cell anemia, malaria, hemorrhagic fever, and snake bites.

[Asymmetric cortical high signal on diffusion weighted-MRI in a case of Creutzfeldt-Jakob disease].

High signal in the cerebral cortex and/or basal ganglia on diffusion-weighted magnetic resonance imaging (DW-MRI) has been described as a good diagnostic marker for sporadic Creutzfeldt-Jakob disease (sCJD). We report a case of sCJD with atypical clinical evolution and unusual DW-MRI findings. A 53-year-old man was seen with a 2-year history of a rapidly progressive dementia and cerebellar ataxia. Cerebrospinal fluid analysis, including the test for 14-3-3 protein, was normal. EEG did not show periodic activity. However, DW-MRI showed gyriform hyperintensity involving practically the entire cortical ribbon of the left hemisphere, whilst being limited to the posterior cingulate gyrus in the right hemisphere. DNA analysis showed no mutations or insertions in the prion protein gene, and homozigozity for methionine in codon 129. A subsequent brain biopsy confirmed the diagnosis of CJD. Thus, high signal on DW-MRI may be limited to the cerebral cortex and may present a very asymmetric distribution in sCJD.

Asymmetric cortical high signal on diffusion weighted-MRI in a case of Creutzfeldt-Jakob disease

Hipersinal no cortex cerebral e/ou nos gânglios da base observado com a técnica de difusão da ressonância magnética (RM-DIF) tem sido descrito como bom marcador diagnóstico da doença de Creutzfeldt-Jakob esporádica (DCJe). Relatamos caso de DCJe com evolução clínica atípica e achados incomuns na RM-DIF. Homem de 53 anos foi examinado com história de dois anos de demência rapidamente progressiva e ataxia cerebelar. Exame do líquido cefalorraqueano, incluindo pesquisa da proteína 14-3-3, foi normal; EEG não revelou atividade periódica; RM-DIF mostrou hiperintensidade nos giros que afetava quase inteiramente o manto cortical do hemisfério cerebral esquerdo e que no hemisfério direito se limitava à parte posterior do giro cíngulo. Análise do DNA revelou ausência de mutação ou de inserção no gene da proteína priônica e a presença de homozigose para metionina no códon 129. Biópsia cerebral confirmou o diagnóstico de DCJ. Hipersinal na RM-DIF pode ser limitado ao córtex cerebral e pode distribuir-se de modo muito assimétrico na DCJe.

Proton MR spectroscopy in Wilson disease: analysis of 36 cases.

BACKGROUND AND PURPOSE: Wilson disease (WD) is rare but one of the few metabolic disorders that can possibly benefit from effective available treatments. The literature regarding proton MR spectroscopy (MRS) in WD is scarce and controversial. The purpose of this study was to determine the brain metabolic changes due to WD by using MRS. To our knowledge, this is the first time that MRS was performed in such a large sample of patients with WD. METHODS: Thirty-six patients with WD and 37 healthy volunteers were examined with MRS in the parieto-occipital cortex, frontal white matter, and basal ganglia (BG). Ratios of the following metabolites were calculated in relation to creatine (Cr): N-acetylaspartate (NAA), choline (Cho), myo-inositol (mI), and glutamine/glutamate (Glx). The mean peak line width was measured on each spectrum. RESULTS: Compared with control subjects, patients with WD had significantly decreased NAA/Cr ratios in the three studied areas (P < .005) and an increased mI/Cr ratio in the BG (P < .001). Cho/Cr and Glx/Cr did not differ between the groups. The mean peak line in the BG was wider in patients than in control subjects. CONCLUSION: WD is unequivocally associated with MRS changes that could possibly be assigned to neuronal loss (in the three studied areas), to gliosis, and to iron and/or copper deposition in the BG.

Diffusion-weighted MR imaging of cystic lesions of neurocysticercosis: a preliminary study

Neurocysticercosis is an endemic disease in some developing countries. It has pleomorfic clinical and imaging findings, which are variable from patient to patient. In this preliminary note, we studied the magnetic resonance (MR) diffusion-weighted images (DWI) of sixteen patients presenting with cystic lesions of this disease diagnosed by clinical and laboratorial findings. All the lesions had hypointense signal and the similar apparent diffusion coeficient (ADC) values as the cerebrospinal fluid (CSF)

Brain spect in dementia: a clinical-scintigraphic correlation

The aim of this study was to compare the accuracy of computed tomography (CT) and single photon emission computerized tomography (SPECT) in the diagnosis of dementia. Fifty-two patients with clinical diagnosis of dementia and 11 controls were studied. The scans were interpreted by one experienced neuroradiologist and one nuclear radiologist, both blinded to the clinical data. In the diagnosis of dementia, CT and SPECT showed equal sensitivity (82.7 per cent) and statistically similar specificity (63.8 and 81.8 per cent, respectively). The specificity of SPECT in diagnosing Alzheimer's disease (100 per cent) was statistically superior to CT (69 per cent). However, both methods showed similar sensitivity in detecting Alzheimer's disease. In conclusion, SPECT and CT showed similar accuracy in the diagnosis of dementia. The quite high specificity of SPECT in Alzheimer's disease may be useful for confirming that diagnosis, particularly for patients with presenile onset of the disease.