Journal of neuroimaging : official journal of the American Society of Neuroimaging
-
Diffusion-weighted magnetic resonance imaging (DWI) detects acute ischemic infarcts with high lesion conspicuity. Determination of infarct age is difficult on DWI alone because infarct signal intensity (SIinfarct) on DWI is influenced by T2 properties ("T2 shine-through"). Maps of the apparent diffusion coefficient (ADC) reflect pure diffusion characteristics without T2 effects but have low lesion conspicuity. ⋯ All infarcts > 10 days old had an eDWI signal intensity lower than control tissue (hypointense appearance). The authors concluded that the use of eDWI, as a single set of images, reliably differentiates acute infarcts (< or = 5 days old) from infarcts > 10 days old. This feature would be expected to be helpful when the distinction between acute and nonacute infarction cannot be determined on clinical grounds.
-
The purpose of this study was to investigate cerebral arteriolar vasoreactivity function in preeclampsia. Preeclamptic (n = 26) and healthy pregnant (n = 22) women underwent transcranial Doppler sonography of the middle cerebral artery at rest and after 60 seconds of hyperventilation (HV). Systolic, diastolic, and mean blood flow velocities were recorded. ⋯ No difference could be detected in percentage change of middle cerebral artery blood flow velocities after HV between the two groups. There is no evidence of a small-vessel vasoconstriction among preeclamptic patients. The role of vasoconstriction of the large cerebral arteries and vasodilation of the resistance arterioles, as well as a combination of these 2 pathomechanisms, in determining cerebral blood flow in preeclampsia and eclampsia should be investigated in further studies.
-
The objective of this study was to examine cerebral hemodynamics changes during hypothermic circulatory arrest (HCA) with and without retrograde cerebral perfusion (RCP). Thirteen colony-bred hound dogs were placed on cardiopulmonary bypass (CPB) and cooled to 18 degrees C. Five dogs underwent 2 hours of HCA without RCP and 8 with RCP. ⋯ During hypothermic circulatory arrest, RCP provides CBFV in the MCA comparable to MCA CBFV during CPB. HCA dogs without RCP showed immediate hyperemia on reperfusion. The decreased CBFV and increased PI at 1 hour after postarrest CPB could be an indicator of progressive ischemic injury due to the increased intracranial pressure despite the implementation of RCP.
-
Regression of symptomatic intracranial atherostenosis is not known to be a common occurrence. In this case, delay of basilar reconstruction by endovascular means permitted serial angiographic assessment of plaque change. The use of high-dose atorvastatin over a 2-week period was associated with marked angiographic improvement. Medical programs of plaque stabilization may provide adjunctive benefit in patients with symptomatic intracranial disease.
-
To test the hypothesis that syndrome X is a systemic vascular disorder, the authors studied 40 patients with this diagnosis using technetium-99m hexamethylpropylene amine oxime and single photon emission computed tomography (SPECT) brain images. Twenty-three of 25 cases with definite myocardial perfusion defects diagnosed by thallium-201 myocardial perfusion SPECT also had multiple hypoperfusion areas in the brain versus 2 of 15 patients without thallium myocardial defects. The parietal lobes were the most common hypoperfusion areas, and cerebellum was the least common. Syndrome X is a systemic vascular disorder with a high incidence of hypoperfusion lesions of the brain and is usually coincident with myocardial defects.