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Detection of hyperacute parenchymal hemorrhage of the brain using echo-planar T2*-weighted and diffusion-weighted MRI
M Wiesmann1, T E Mayer, I Yousry
1Department of Radiology, Medizinische Universität zu Lübeck, 23538 Lübeck, Germany.
Abstract:
We investigated the usefulness of echo-planar imaging (EPI) as well as T2*-weighted and diffusion-weighted MRI (DWI) to identify hyperacute hemorrhage (within 24 h after ictus) in the brain. Seven patients were examined 3.5 to 24 h after onset of symptoms using a whole-body 1.5-T MR system. Two diffusion-weighted sequences were run to obtain isotropic and anisotropic diffusion images. Apparent diffusion coefficients (ADC) were calculated from the isotropic diffusion images. All DWI images as well as the T2*-weighted EPI images showed the hematomas as either discrete, deeply hypointense homogeneous lesions, or as lesions of mixed signal intensity containing hypointense areas. We conclude that even in the early phase after hemorrhage, sufficient amounts of paramagnetic deoxyhemoglobin are present in intracerebral hemorrhages to cause hypointensity on EPI T2*-weighted and DWI images; thus, use of ultrafast EPI allows identification of intracerebral hemorrhage.
Insights
Echo-planar imaging (EPI) and diffusion-weighted MRI (DWI) can identify hyperacute brain hemorrhage within 24 hours. These MRI techniques detect hypointense lesions caused by deoxyhemoglobin in early-stage hemorrhages.
Area of Science:
- Radiology
- Neuroimaging
Background:
- Hyperacute intracranial hemorrhage detection is crucial for timely treatment.
- Conventional MRI sequences may have limitations in identifying very early-stage hemorrhages.
Purpose of the Study:
- To evaluate the utility of echo-planar imaging (EPI), T2*-weighted, and diffusion-weighted MRI (DWI) for identifying hyperacute brain hemorrhage within 24 hours of symptom onset.
Main Methods:
- Seven patients with suspected hyperacute hemorrhage underwent MRI scans 3.5 to 24 hours post-symptom onset.
- Utilized a 1.5-T MR system with EPI, T2*-weighted, and DWI sequences, including isotropic and anisotropic diffusion imaging.
- Calculated apparent diffusion coefficients (ADC) from isotropic diffusion images.
Main Results:
- All DWI and T2*-weighted EPI images successfully identified hematomas.
- Lesions appeared as discrete, deeply hypointense or mixed-intensity areas on the images.
- The presence of paramagnetic deoxyhemoglobin in early hemorrhages contributed to lesion hypointensity.
Conclusions:
- Ultrafast EPI sequences, including T2*-weighted and DWI, are effective for identifying intracerebral hemorrhage in the hyperacute phase.
- The paramagnetic effects of deoxyhemoglobin enable early detection of hemorrhage via MRI.