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Time course of the apparent diffusion coefficient (ADC) abnormality in human stroke
G Schlaug1, B Siewert, A Benfield
1Department of Neurology and Radiology, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA.
Neurology
|July 1, 1997
Summary
Diffusion-weighted MRI reveals acute stroke injury through reduced apparent diffusion coefficient (ADC) values. This reduction persists for at least 96 hours, indicating cytotoxic edema in early stroke stages.
Area of Science:
- Neuroimaging
- Radiology
- Neurology
Background:
- Diffusion-weighted MRI (DW-MRI) detects acute cerebral ischemic injury via hyperintense signals.
- Apparent diffusion coefficient (ADC) declines in acute injury and elevates in chronic stages due to altered water content.
Purpose of the Study:
- To characterize the temporal evolution of ADC changes in acute human stroke.
- To differentiate between cytotoxic and vasogenic edema based on ADC kinetics.
Main Methods:
- Analysis of 157 DW-MRI studies from 101 patients with ischemic stroke.
- Measurement of relative ADC (rADC) by comparing lesion to control regions.
- Correlation of rADC values with time elapsed since stroke onset.
Main Results:
- A significant reduction in rADC (mean 58.3% of control) was observed, persisting for at least 96 hours post-stroke (p < 0.005).
- A trend towards pseudonormalization and elevation of rADC was noted at subacute to chronic time points (≥7 days).
Conclusions:
- The sustained rADC reduction in the initial four days suggests a dominant role of cytotoxic edema.
- ADC changes provide a dynamic marker for edema evolution and tissue injury in acute stroke.