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Acute cerebral infarction in monkeys: an experimental study using MR imaging
Abstract:
Magnetic resonance (MR) imaging was performed in five monkeys with experimentally induced acute cerebral infarction to define the MR imaging features and correlate these with computed tomographic (CT) findings, laboratory analysis, and histopathologic studies. Acute infarct (2-4 hours after embolization) was generally visible on MR images but not on CT scans. CT at 24 and 48 hours did show the infarcts. In all cases the infarct was more clearly depicted with MR imaging and was visualized as an area of high signal intensity on T2-weighted images. Spectrometric nuclear MR measurements of the postmortem cerebral tissue confirmed prolongation of both T1 and T2 values similar to that calculated from MR images. At postmortem laboratory testing, the area of infarction detected with MR imaging had decreased specific gravity and increased water content, reflecting edema.
Insights
Magnetic resonance (MR) imaging detects acute cerebral infarction earlier and more clearly than computed tomography (CT) scans. MR imaging reveals infarcts as high signal intensity on T2-weighted images, correlating with tissue edema.
Area of Science:
- Neurology
- Radiology
- Medical Imaging
Background:
- Acute cerebral infarction presents diagnostic challenges in early stages.
- Computed tomography (CT) may not reliably detect early ischemic changes.
- Magnetic resonance (MR) imaging offers potential for improved early infarct visualization.
Purpose of the Study:
- To define MR imaging features of acute cerebral infarction in a primate model.
- To correlate MR imaging findings with CT scans, laboratory analysis, and histopathology.
- To assess the utility of MR imaging in early stroke detection.
Main Methods:
- Experimental induction of acute cerebral infarction in five monkeys.
- Performance of serial MR imaging and CT scans.
- Postmortem histopathologic and spectrometric nuclear MR measurements of cerebral tissue.
Main Results:
- Acute infarcts (2-4 hours) were visible on MR imaging but not on initial CT scans.
- CT detected infarcts at 24 and 48 hours.
- MR imaging provided clearer depiction of infarcts as high signal intensity on T2-weighted images.
- Postmortem analysis confirmed prolonged T1 and T2 values and increased water content in infarct areas.
Conclusions:
- MR imaging is superior to CT for early detection of acute cerebral infarction.
- MR imaging findings correlate with histopathologic evidence of edema and tissue changes.
- T2-weighted MR sequences are sensitive for identifying early ischemic lesions.