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Time course of lesion development in patients with acute stroke: serial diffusion- and hemodynamic-weighted magnetic
L H Schwamm1, W J Koroshetz, A G Sorensen
1Departmentof Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, Mass. 02114, USA.
Background And Purpose:
We sought to characterize the evolution of acute ischemic stroke by MRI and its relationship to patients' neurological outcome.
Methods:
Fourteen patients with acute ischemic stroke underwent MRI within 13 hours of symptom onset (mean, 7.4+/-3 hours) and underwent repeated imaging and concurrent neurological examination at 8, 24, 36, and 48 hours and 7 days and >42 days after first imaging.
Results:
Diffusion-weighted imaging (DWI) lesion volumes increased between the first and second scans in 10 of 14 patients; scans with maximum DWI lesion volume occurred at a mean of 70.4 hours. Initial DWI lesion volume correlated with the largest T2 lesion volume (r=0.97; P<0.001). Final lesion volume was smaller than maximum lesion volume in 12 of 14 patients. There was positive correlation between the follow-up National Institutes of Health Stroke Scale score and the initial DWI lesion volume (r=0.67; P=0. 01) and maximum T2 lesion volume (r=0.77; P<0.01) and negative correlation with initial mean apparent diffusion coefficient ratio (ADCr) (r=-0.64; P<0.05). The ADCr was 0.73 at initial imaging and fell between the initial and second scans in 10 of 14 patients. Mean ADCr did not rise above normal until 42 days after stroke onset (P<0. 001).
Conclusions:
Serial MRI demonstrates the dynamic nature of progressive ischemic injury in acute stroke patients developing over hours to days, and it suggests that both primary and secondary pathophysiological processes can be valuable targets for neuroprotective interventions.
Insights
Serial MRI reveals acute ischemic stroke lesion evolution over days. Early diffusion-weighted imaging (DWI) lesion size predicts neurological outcome, highlighting targets for neuroprotection.
Area of Science:
- Neurology
- Radiology
- Neuroscience
Background:
- Acute ischemic stroke involves complex pathophysiological processes.
- Understanding stroke evolution is crucial for effective treatment.
Purpose of the Study:
- To characterize the temporal evolution of acute ischemic stroke using serial MRI.
- To investigate the relationship between MRI findings and patient neurological outcomes.
Main Methods:
- Fourteen acute ischemic stroke patients underwent serial MRI within 13 hours of symptom onset.
- Imaging and neurological examinations were performed at multiple time points: 8, 24, 36, 48 hours, 7 days, and >42 days.
Main Results:
- Diffusion-weighted imaging (DWI) lesion volumes increased in most patients, peaking around 70 hours.
- Initial DWI lesion volume correlated with final T2 lesion volume and neurological outcome (NIH Stroke Scale).
- Apparent diffusion coefficient ratio (ADCr) initially decreased and normalized after 42 days.
Conclusions:
- Serial MRI demonstrates the dynamic and progressive nature of ischemic injury in acute stroke.
- Both primary and secondary injury mechanisms are identifiable and represent potential targets for neuroprotective therapies.