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Clinical and hemodynamic aspects of low-flow infarcts
C Weiller1, E B Ringelstein, W Reiche
1Neurologische Klinik, Rheinisch-Westfälische Technische Hochschule, Aachen, FRG.
Insights
Cerebral blood flow is altered in stroke patients. Low-flow infarcts, linked to carotid artery disease, show significantly reduced perfusion reserve and vasomotor reactivity compared to territorial infarcts.
Area of Science:
- Neurology
- Radiology
- Vascular Medicine
Background:
- Stroke is a leading cause of disability, with infarcts classified morphologically as low-flow or territorial.
- Understanding the hemodynamic differences between these infarct types is crucial for diagnosis and treatment.
Purpose of the Study:
- To compare cerebral hemodynamics, including cerebral blood flow (CBF), cerebral blood volume (CBV), cerebral perfusion reserve (CPR), and hemispheric vasomotor reactivity (VMR), between low-flow and territorial infarcts.
- To investigate the relationship between infarct type, carotid artery disease, and hemodynamic changes.
Main Methods:
- Single-photon emission computed tomography (SPECT) was used to measure CBF, CBV, and CPR.
- Transcranial Doppler sonography (TCD) with CO2 stimulation assessed VMR.
- CT and MRI differentiated infarct types in 37 patients and controls.
Main Results:
- Both infarct types showed decreased CBF and increased CBV in affected areas compared to controls.
- Territorial infarcts with carotid occlusions and low-flow infarcts exhibited significantly reduced CPR and VMR.
- Low-flow infarcts demonstrated more extensive reductions in CPR and VMR than territorial infarcts.
- Patients with cardiac embolic territorial infarcts had normal CPR and VMR.
Conclusions:
- Low-flow infarcts are associated with severe extracranial carotid artery disease and significant hemodynamic compromise.
- Hemodynamic changes in territorial infarcts are generally localized, while low-flow infarcts show wider perfusion deficits.
- SPECT and TCD are valuable tools for characterizing hemodynamic alterations in different stroke types.
Abstract:
We used single-photon emission computed tomography to measure cerebral blood flow, cerebral blood volume, and cerebral perfusion reserve and transcranial Doppler sonography with CO2 stimulation to assess hemispheric vasomotor reactivity in 37 patients and in normal controls. Computed tomography and magnetic resonance imaging were performed to differentiate morphologically low-flow infarcts (n = 17) from territorial infarcts (n = 20). In patients with either type of infarct, blood flow was decreased and blood volume was increased in the infarcted areas compared with the same areas in the controls. Perfusion reserve and vasomotor reactivity were significantly reduced in patients with territorial infarcts and carotid artery occlusions (n = 12) and even more reduced in patients with low-flow infarcts (p less than 0.001). Both parameters were normal in patients with cardiac embolic territorial infarcts (n = 8). In patients with territorial infarcts, blood flow and perfusion reserve changes were restricted to the infarcted areas, whereas in patients with low-flow infarcts, regions of decreased perfusion reserve considerably exceeded the area of the infarct. Low-flow infarcts are related to the hemodynamic effects of severe extracranial carotid artery disease.