Related Experiment Videos
Diffusion-weighted MR imaging in hypertensive encephalopathy: clues to pathogenesis
R B Schwartz1, R V Mulkern, H Gudbjartsson
1Department of Radiology, Brigham and Women's Hospital, Boston, MA 02115, USA.
AJNR. American Journal of Neuroradiology
|June 5, 1998
Summary
Diffusion-weighted MRI reveals that hypertensive encephalopathy edema is vasogenic, not ischemic. This finding is crucial for understanding and treating this neurological condition.
Area of Science:
- Neurology
- Radiology
- Medical Imaging
Background:
- Hypertensive encephalopathy involves acute blood pressure rise causing neurological symptoms.
- The origin of edema in this condition is debated: vasospasm with ischemia/infarction or autoregulation breakthrough with interstitial edema.
Purpose of the Study:
- To determine if edema in hypertensive encephalopathy is cytotoxic or vasogenic using diffusion-weighted MR imaging.
- To differentiate between ischemic/infarction and vasogenic edema in hypertensive encephalopathy.
Main Methods:
- Diffusion-weighted imaging (DWI) was performed on seven patients with hypertensive encephalopathy using a 1.5-T MR system.
- Apparent diffusion coefficient (ADC) maps and low/high b-factor images were acquired.
- ADC values in edematous regions were compared to normal white matter using a paired Student's t-test.
Main Results:
- DWI showed increased signal in edematous brain regions, corresponding to T2 signal.
- Quantitative ADC values in abnormal T2 signal regions were significantly higher (1.36 +/- 0.14 µm²/ms) than in normal white matter (0.80 +/- 0.05 µm²/ms).
- High b-factor DWI images did not reveal abnormal signals in these regions.
Conclusions:
- Diffusion-weighted MR imaging demonstrates that the edema in hypertensive encephalopathy is vasogenic in origin.
- The findings exclude ischemia or infarction as the cause of edema in these cases.
- This distinction has potential therapeutic implications for managing hypertensive encephalopathy.