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Optimized System for Cerebral Perfusion Monitoring in the Rat Stroke Model of Intraluminal Middle Cerebral Artery Occlusion
Published on: February 17, 2013
Stability of large diffusion/perfusion mismatch in anterior circulation strokes for 4 or more hours
R Gilberto González1, Reza Hakimelahi, Pamela W Schaefer
1Neuroradiology Division, Department of Radiology, Massachusetts General Hospital, Boston, Harvard Medical School, Boston, MA 02114, USA. rggonzalez@partners.org
Background:
The stability of hypoperfused brain tissue in stroke patients with major artery occlusions is unknown. The purpose of this study was to determine the persistence of a diffusion/perfusion mismatch in patients with ICA or proximal MCA occlusions.
Methods:
Fourteen patients with ICA and/or proximal MCA occlusion and a diffusion/perfusion mismatch at presentation were studied. All were enrolled in a pilot randomized study of normobaric oxygen therapy. None received thrombolytic therapy; 8 received normobaric oxygen and 6 room air. Diffusion/perfusion MRI was performed at baseline, 4 hours, 24 hours, and 1 week. Abnormal DWI, ADC, and MTT volumes were determined using standard image analysis methods.
Results:
The mean time from symptom onset to baseline MRI was 7.5 +/- 1 hours. Across all 4 time points there was a significant difference in DWI lesion (ANOVA, P < 0.0001) and abnormal MTT volumes (ANOVA, P < 0.01) with the 24 hour and 1 week abnormal volumes different from the earlier studies. However, comparing baseline and 4 hour scans, there was no significant interval change in the mean abnormal DWI volume (29.4 +/- 8.2 ml vs. 28.1 +/- 7.4 ml) or abnormal MTT volumes (137 +/- 17.7 ml vs. 130.9 +/- 13.8). By 24 hours, only 2 patients did not maintain a mismatch of 20% or greater.
Conclusions:
Patients who present outside the time window for thrombolytic therapy, and who have a large diffusion/perfusion mismatch on MRI may have a stable mismatch for 4 or more hours.
Insights
Brain tissue with a diffusion/perfusion mismatch in stroke patients with major artery occlusions may remain stable for hours. This stability is crucial for patients outside the thrombolytic therapy window.
Area of Science:
- Neurology
- Radiology
- Stroke Medicine
Background:
- The stability of hypoperfused brain tissue in stroke patients with major artery occlusions remains unclear.
- Understanding this stability is critical for managing patients outside the acute treatment window.
Purpose of the Study:
- To determine the persistence of a diffusion/perfusion mismatch in patients with internal carotid artery (ICA) or middle cerebral artery (MCA) occlusions.
Main Methods:
- Fourteen patients with ICA/proximal MCA occlusion and a diffusion/perfusion mismatch underwent diffusion/perfusion MRI at baseline, 4 hours, 24 hours, and 1 week.
- Patients were part of a pilot study for normobaric oxygen therapy; none received thrombolytics.
- Abnormal diffusion-weighted imaging (DWI), apparent diffusion coefficient (ADC), and mean transit time (MTT) volumes were quantified.
Main Results:
- No significant interval change in mean abnormal DWI or MTT volumes was observed between baseline and 4-hour scans.
- Significant differences in DWI lesion and abnormal MTT volumes were noted across all time points by 24 hours and 1 week.
- By 24 hours, most patients maintained a diffusion/perfusion mismatch of 20% or greater.
Conclusions:
- A large diffusion/perfusion mismatch on MRI may indicate stable hypoperfused brain tissue for at least 4 hours in stroke patients.
- This finding is particularly relevant for patients presenting beyond the typical time window for thrombolytic therapy.
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