Brain Ischemia In Patients Research Articles

Etiology of Perfusion‐Diffusion Magnetic Resonance Imaging Mismatch Patterns

ABSTRACT Background and Purpose. Diffusion‐and perfusion‐weighted magnetic resonance imaging (DWI and PWI) are useful tools for the assessment of brain ischemia. Discrepancies between the extent of DWI and PWI abnormalities are thought to depend pre dominantly on time from symptom onset to magnetic resonance imaging (MRI) examination. However, underlying ischemic stroke etiology can also be important. A mismatch may indicate the presence of tissue at risk for infarction, whereas the rele vance of other DWI/PWI patterns is uncertain. The authors therefore investigated the etiology of brain ischemia in patients with different DWI/PWI patterns. Methods. Retrospective study of 130 patients with acute brain ischemia and detailed stroke workup, including MRI within a week after symptom onset (40 ± 39 hours). Patients were divided into the following groups: mis‐match (PWI > DWI), reverse mismatch (DWI > PWI), and match (<25% difference between PWI and DWI). Results. Mismatch occurred in 49% of patients, whereas 22% had reverse mis‐match and 29% matched lesions. Time from symptom onset to MRI examination was similar between the 3 groups. Largeartery atherosclerosis increased by almost 4‐fold the odds of mismatch (odds ratio: 3.89, 95% confidence interval: 1.72–8.78; P < .001), whereas patients with reverse mismatch were likely to have cryptogenic stroke. Patients with matched lesions were similarly distributed among different stroke subtypes. Con clusions. Ischemic stroke etiology appears to influence the development of specific DWI/PWI patterns. Prospective studies are needed to confirm these observations.

Etiology of Perfusion-Diffusion Magnetic Resonance Imaging Mismatch Patterns

Diffusion-and perfusion-weighted magnetic resonance imaging (DWI and PWI) are useful tools for the assessment of brain ischemia. Discrepancies between the extent of DWI and PWI abnormalities are thought to depend pre dominantly on time from symptom onset to magnetic resonance imaging (MRI) examination. However, underlying ischemic stroke etiology can also be important. A mismatch may indicate the presence of tissue at risk for infarction, whereas the relevance of other DWI/PWI patterns is uncertain. The authors therefore investigated the etiology of brain ischemia in patients with different DWI/PWI patterns. Retrospective study of 130 patients with acute brain ischemia and detailed stroke workup, including MRI within a week after symptom onset (40 +/- 39 hours). Patients were divided into the following groups: mis-match (PWI > DWI), reverse mismatch (DWI > PWI), and match (<25% difference between PWI and DWI). Mismatch occurred in 49% of patients, whereas 22% had reverse mis-match and 29% matched lesions. Time from symptom onset to MRI examination was similar between the 3 groups. Largeartery atherosclerosis increased by almost 4-fold the odds of mismatch (odds ratio: 3.89, 95% confidence interval: 1.72-8.78; P < .001), whereas patients with reverse mismatch were likely to have cryptogenic stroke. Patients with matched lesions were similarly distributed among different stroke subtypes. Ischemic stroke etiology appears to influence the development of specific DWI/PWI patterns. Prospective studies are needed to confirm these observations.

Cognitive dysfunction after coronary artery bypass graft surgery

Coronary artery bypass graft surgery (CABG) is one of the most commonly performed major surgical procedures. However, patients having undergone CABG may experience neurological problems such as stroke, delirium, and cognitive difficulties. Observations suggest that these complications are caused by several synergistic factors, most prominently brain ischemia secondary to cerebral hypoperfusion and/or embolization of heterogeneous endovascular debris. Embolic signals are commonly detected during surgery using intraoperative transcranial Doppler monitoring. After surgery, magnetic resonance imaging of the brain may detect scattered areas of brain ischemia in patients with or without delirium. The large majority of these patients do not exhibit focal neurological deficits suggestive of ischemic stroke. We review the literature pertaining to postoperative encephalopathy, with emphasis on prevention, diagnosis, and treatment.

Cerebral blood flow and sources of abnormal EEG activity (VARETA) in neurocysticercosis

Objectives: To compare two different functional procedures in the assessment of brain ischemia in patients with neurocysticercosis (NCC): (1) electroencephalography (EEG) evaluated by brain maps and EEG current sources in the frequency domain using variable resolution electromagnetic tomography and (2) blood flow analyzed by computerized tomography assessed with stable Xe (Xe-CT). Methods: Eleven patients with NCC at different evolution stages were studied. CT and Xe-CT scans, as well as quantitative electroencephalography with source calculation in the frequency domain, were obtained. All patients showed cysts and in 6 of them there were also vascular complications: two of them presented calcifications of the middle cerebral artery, two other subjects showed calcifications of the vessels in the circle of Willis and the remaining two had brain infarctions. Results: In the cyst areas important hypoperfused zones were observed, as intense as those observed in infarcted areas. Damage to the blood–brain barrier was originated by parasites in colloidal phase (final cysticerci stage) producing large areas of edema and hypoperfusion. Abnormal delta EEG activity was observed in very large lesions, probably generated by partial cortical deafferentation; and abnormal theta activity was mainly related to the presence of edema. Conclusions: Sources of abnormal EEG activity were very similar in topography to the hypoperfused areas.

52 Brain Ischemia in Patients with Intraventricle Hemorrhage due to Arterial Aneurysms Rupture

52 Brain Ischemia in Patients with Intraventricle Hemorrhage due to Arterial Aneurysms Rupture

Left ventricular myxoma: M-mode and two-dimensional echocardiographic features

Atrial myxoma may be associated with syncope or sudden death attributed to left-sided cardiac outflow obstruction or embolization caused by tumor dislodgement or thrombus formation. Definitive treatment for primary and secondary stroke prevention is surgical resection. The role of thrombolysis in acute brain ischemia in patients with atrial myxoma is not defined. There are few data available regarding safety and efficacy of thrombolytic therapy in acute ischemic strokes caused by atrial myxoma. Prior case reports described partial success using intra-arterial local thrombolysis; however, this is invasive and can be associated with significant complications. A previously reported case of systemic thrombolysis resulted in development of cerebral hemorrhage. We describe a young man who presented with syncope and a dense stroke developing as a complication of atrial myxoma, followed by a remarkable recovery after treatment with intravenous recombinant tissue plasminogen activator and urgent cardiac surgery. Contrary to some expert opinion, systemic thrombolytic therapy may be safely and effectively used to treat acute ischemic strokes from atrial myxoma.