Related Experiment Videos
[Does diffusion and perfusion MRI modify the diagnosis and management of cerebral ischemic accidents?]
C Marsault1, C Oppenheim, D Le Bihan
1Radiologie A. Neuroradiologie, Groupe hospitalier Pitié Salpêtrière, 47-83 bld de l'Hôpital-75651 Paris.
Abstract:
Since 25 years, CT has the capability to recognize hemorrhagic infarcts in emergency. On the other hand, cytotoxic oedema is visible only 12 or 24 hours after the onset of the ischemic stroke. T2 weighted MR-sequences are more sensitive and few hours after the onset, cytotoxic oedema appears as hypersignal, particularly using FLAIR sequences (Fluid Attenuated Inversion Recuperation). Described in 1986, diffusion-weighted MRI is a very sensitive technique to detect the cytotoxic oedema few minutes after the onset. The attenuation of the apparent diffusion coefficient must be evaluated with a map. This attenuation appears as hypersignal and its sensibility is close than 100%. The mismatch between data of perfusion MRI and diffusion MRI is the area of the ischemic penumbra. These new MRI techniques are easy to learn and must be available 24 h a day and 7 days a week in the stroke centers. They are simple, rapid and highly accurate for the diagnosis of acute ischemic stroke. They could be useful to select candidates to aggressive therapy during the first 3 or 6 hours. Potentially, they improve patient's outcome.
Insights
Diffusion-weighted MRI rapidly detects cytotoxic edema in ischemic stroke within minutes, offering a 100% sensitive diagnostic tool. This advanced imaging technique aids in early stroke diagnosis and treatment selection.
Area of Science:
- Neurology
- Radiology
- Medical Imaging
Context:
- Computed Tomography (CT) can identify hemorrhagic infarcts but struggles with early ischemic stroke detection.
- Cytotoxic edema, a key indicator of ischemic stroke, becomes visible on T2-weighted MRI sequences 12-24 hours post-onset.
- Fluid Attenuated Inversion Recovery (FLAIR) sequences enhance the visibility of cytotoxic edema on MRI.
Purpose:
- To evaluate the diagnostic capabilities of advanced MRI techniques, specifically diffusion-weighted MRI (DWI), for acute ischemic stroke.
- To highlight the speed and sensitivity of DWI in detecting cytotoxic edema compared to conventional CT and other MRI sequences.
- To emphasize the potential of DWI and perfusion MRI in identifying the ischemic penumbra and guiding therapeutic decisions.
Summary:
- Diffusion-weighted MRI (DWI) detects cytotoxic edema within minutes of ischemic stroke onset with nearly 100% sensitivity.
- Apparent diffusion coefficient (ADC) maps are crucial for evaluating the characteristic hypersignal indicating edema.
- The mismatch between perfusion MRI and DWI data defines the ischemic penumbra, a critical area for intervention.
Impact:
- These MRI techniques are simple, rapid, and highly accurate for diagnosing acute ischemic stroke.
- Availability of DWI and perfusion MRI in stroke centers 24/7 can significantly improve patient outcomes.
- Early identification of candidates for aggressive therapy within the first 3-6 hours of stroke onset is facilitated, potentially improving patient prognosis.