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Microembolic signals and diffusion-weighted MR imaging abnormalities in acute ischemic stroke
K Kimura1, K Minematsu, M Koga
1Cerebrovascular Division, Department of Medicine, National Cardiovascular Center, 5-7-1 Fujishirodai, Suita, Osaka 565-8565, Japan.
Background And Purpose:
The clinical significance of microembolic signals (MESs) detected by transcranial Doppler sonography (TCD) in acute ischemic stroke remains unclear. The purpose of the present study was to assess the findings of diffusion-weighted MR imaging (DWI) and other clinical characteristics in patients with acute ischemic stroke and MESs.
Methods:
We performed TCD and DWI within 48 hours and 7 days, respectively, after stroke onset in 28 patients with acute brain infarction. The relationship between the number of MESs and DWI findings, risk factors for stroke, National Institutes of Health Stroke Scale (NIHSS) score on admission, and arterial disease was examined.
Results:
Ten patients had MESs detected by TCD (MES group) and 18 had no MESs (control group). The frequency of hypertension, diabetes mellitus, hyperlipidemia, and smoking; NIHSS score; blood-coagulation parameters; and interval between stroke onset and DWI study did not differ between the two groups. However, arterial disease was more frequent in the MES group than in the control group. Small, multifocal ischemic lesions (<10 mm in diameter) on DWI were more frequent in the MES group than in the control group. Conventional CT and MR imaging often failed to show these lesions.
Conclusion:
Small, often asymptomatic DWI abnormalities were more frequent in patients with MESs detected by TCD and with large-vessel occlusive diseases than in stroke patients without MESs. TCD and DWI may provide early clues to the mechanism of stroke in the acute phase.
Insights
Microembolic signals (MESs) detected by transcranial Doppler sonography (TCD) in acute ischemic stroke patients are associated with more frequent small, multifocal lesions on diffusion-weighted MRI (DWI), suggesting early clues to stroke mechanisms.
Area of Science:
- Neuroimaging
- Cerebrovascular Disease
- Diagnostic Ultrasound
Background:
- The clinical significance of microembolic signals (MESs) detected via transcranial Doppler sonography (TCD) in acute ischemic stroke is not fully understood.
- Assessing MESs in conjunction with advanced imaging may clarify their role in stroke pathophysiology.
Purpose of the Study:
- To evaluate diffusion-weighted MR imaging (DWI) findings and clinical characteristics in acute ischemic stroke patients with detected MESs.
- To correlate MES detection with stroke etiology and early imaging markers.
Main Methods:
- Transcranial Doppler (TCD) and diffusion-weighted MRI (DWI) were performed on 28 acute brain infarction patients within 48 hours and 7 days of stroke onset, respectively.
- The study examined the relationship between MESs, DWI findings, stroke risk factors, NIHSS scores, and arterial disease.
Main Results:
- Ten patients (MES group) had detectable MESs, while 18 (control group) did not. No significant differences were observed in stroke risk factors or NIHSS scores between groups.
- Arterial disease was more prevalent in the MES group.
- Small, multifocal ischemic lesions (<10 mm) on DWI were significantly more frequent in the MES group, often undetected by conventional CT/MRI.
Conclusions:
- Patients with MESs detected by TCD and evidence of large-vessel occlusive disease showed a higher frequency of small DWI abnormalities compared to stroke patients without MESs.
- Combined TCD and DWI may offer early insights into acute stroke mechanisms, particularly in cases involving large vessel disease.