Related Experiment Video
Updated: Jul 19, 2026
A Magnetic Resonance Imaging Protocol for Stroke Onset Time Estimation in Permanent Cerebral Ischemia
Published on: September 16, 2017
Patients with diffusion-perfusion mismatch on magnetic resonance imaging 48 hours or more after stroke symptom onset:
Angelica Perez1, Lucas Restrepo, Jonathan T Kleinman
1Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
Background:
Abnormalities in diffusion-weighted (DWI) and perfusion-weighted (PWI) magnetic resonance imaging (MRI) are thought to reflect the presence of brain tissue at risk for ischemic stroke. Many patients with acute ischemic stroke have a mismatch pattern in which the PWI volume is larger than the DWI lesion. This mismatch typically resolves over 24-48 hours. Little is known about the presence of DWI-PWI mismatch in later stages of stroke.
Methods:
This is a retrospective study of 122 patients admitted with a diagnosis of acute ischemic stroke who had DWI and PWI abnormalities on studies performed within 7 days of onset of symptoms. Patients were divided into two groups: those with MRI performed <48 hours and those with MRI performed >or=48 hours from onset of symptoms.
Results:
Among 42 patients with MRI performed >or=48 hours after onset of stroke symptoms, 15 of 42 (36%) showed a mismatch pattern, compared to 45 of 80 (56%) in the <48 hours group (P < 0.05). Most of the patients in the >or=48 hours group with mismatch had large artery occlusive disease and many had neurological fluctuations. A subset of these patients were treated with induced hypertension and showed clinical improvement.
Conclusions:
Some patients have persistent DWI-PWI mismatch up to several days after stroke onset. Further studies are needed to determine if these patients should be candidates for reperfusion therapy.
Insights
Some patients with acute ischemic stroke show persistent diffusion-weighted (DWI) and perfusion-weighted (PWI) MRI mismatch beyond 48 hours. This finding suggests potential for later reperfusion therapy in select stroke cases.
Area of Science:
- Neurology
- Radiology
- Stroke Medicine
Background:
- Diffusion-weighted (DWI) and perfusion-weighted (PWI) MRI abnormalities indicate brain tissue at risk for ischemic stroke.
- A common finding is DWI-PWI mismatch, where PWI volume exceeds the DWI lesion, typically resolving within 24-48 hours.
- Limited data exists on DWI-PWI mismatch in later stroke stages.
Purpose of the Study:
- To investigate the presence and characteristics of DWI-PWI mismatch in acute ischemic stroke patients beyond 48 hours from symptom onset.
Main Methods:
- Retrospective analysis of 122 acute ischemic stroke patients with DWI and PWI MRI within 7 days of symptom onset.
- Patients categorized into two groups: MRI performed <48 hours and MRI performed ≥48 hours from symptom onset.
Main Results:
- 15 of 42 patients (36%) in the ≥48 hours group exhibited DWI-PWI mismatch, compared to 45 of 80 (56%) in the <48 hours group (P < 0.05).
- Patients with later mismatch often had large artery occlusive disease and neurological fluctuations.
- A subset treated with induced hypertension showed clinical improvement.
Conclusions:
- Persistent DWI-PWI mismatch can be observed for several days post-stroke onset.
- Further research is warranted to identify these patients as potential candidates for reperfusion therapy.
Related Concept Videos
01:17Assessment of Diffusion and Perfusion
The Role of Diffusion in Respiration
Diffusion is the process by which molecules move from an area of higher concentration to an area of lower concentration. In the respiratory system, this principle...
01:24Magnetic Resonance Imaging