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Relationship between magnetic resonance arterial patency and perfusion-diffusion mismatch in acute ischemic stroke
I A Staroselskaya1, C Chaves, B Silver
1Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA.
Background:
In patients with acute ischemic stroke the magnetic resonance (MR) perfusion-diffusion mismatch pattern (perfusion lesion at least 20% larger than the lesion on diffusion-weighted imaging) may indicate ischemically threatened but viable tissue. To our knowledge, the relationship of this MR pattern to serial changes in MR angiography (MRA) has not been reported.
Objectives:
To investigate the relationship between MRA changes and patterns of diffusion-weighted imaging and perfusion abnormalities and to determine if the information obtained could be used in clinical management.
Methods:
The MR studies of 35 patients who had undergone sequential multimodality MR imaging studies within the first 4 days of stroke were reviewed. All lesions were in the internal carotid artery territory distribution. Magnetic resonance angiographies were read by 2 observers blinded to the clinical data.
Results:
During the first 24 hours a perfusion-diffusion mismatch was present in 22 (92%) of the 24 patients with an MRA arterial occlusive lesion. (At this time 5 [46%] of the 11 patients with a normal MRA [P =.006] also had a mismatch.) Two to 4 days after stroke, of these 22 patients resolution of the mismatch occurred in 8 (87%) of 9 patients with recanalization on MRA compared with 5 (39%) of 13 patients without arterial recanalization (P =.03). Resolution of mismatch occurred in 3 (60%) of 5 patients with a normal MRA and a mismatch at the first time point.
Conclusions:
Concordance between MRA and the MR perfusion-diffusion mismatch pattern provides supportive evidence for an arterial vascular basis for this MR signature in acute stroke. Discordance between MRA lesions and mismatch may result from arterial branch occlusions undetected by MRA or from an alternate mechanism for the mismatch. The MR imaging patterns identified extend our understanding of the pathophysiology of stroke and may contribute to the improvement of stroke management in the future.
Insights
The MR perfusion-diffusion mismatch pattern in acute ischemic stroke correlates with arterial occlusive lesions seen on MRA. This finding helps understand stroke pathophysiology and may improve clinical management.
Area of Science:
- Neurology
- Radiology
- Medical Imaging
Background:
- The perfusion-diffusion mismatch pattern on MRI may identify viable brain tissue in acute ischemic stroke.
- The relationship between this MRI pattern and serial changes in MR angiography (MRA) has not been previously reported.
Purpose of the Study:
- To investigate the relationship between MRA changes and diffusion-weighted imaging/perfusion abnormalities.
- To determine if this information can aid in clinical stroke management.
Main Methods:
- Reviewed MR studies of 35 acute ischemic stroke patients within 4 days of stroke onset.
- All lesions were in the internal carotid artery territory.
- MRA was interpreted by two blinded observers.
Main Results:
- A perfusion-diffusion mismatch was present in 92% of patients with MRA arterial occlusive lesions within 24 hours.
- Mismatch resolution occurred in 87% of patients with MRA recanalization versus 39% without recanalization (2-4 days post-stroke).
Conclusions:
- Concordance between MRA and the MR perfusion-diffusion mismatch supports an arterial vascular basis for this stroke imaging signature.
- Discordance may indicate undetected arterial branch occlusions or alternative mechanisms.
- These MR imaging patterns enhance understanding of stroke pathophysiology and may improve future stroke management.