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Cerebral blood flow and cerebrovascular reserve capacity: estimation by dynamic magnetic resonance imaging
W G Schreiber1, F Gückel, P Stritzke
1Department of Radiology, German Research Cancer Center, Heidelberg.
Insights
Dynamic MRI offers a novel pixel-by-pixel method to assess regional cerebral blood flow (rCBF) and cerebrovascular reserve capacity. This technique provides crucial hemodynamic insights for patients with occlusive cerebrovascular disease and acute stroke.
Area of Science:
- Neurology
- Radiology
- Medical Imaging
Background:
- Cerebrovascular diseases like internal carotid artery (ICA) occlusion and stroke significantly impact brain hemodynamics.
- Accurate assessment of regional cerebral blood flow (rCBF) and cerebrovascular reserve capacity is vital for diagnosis and management.
Purpose of the Study:
- To introduce and validate a new dynamic MRI method for pixel-by-pixel estimation of rCBF and cerebrovascular reserve capacity.
- To evaluate the hemodynamic status in patients with ICA occlusion/stenosis and acute stroke using this novel MRI technique.
Main Methods:
- Dynamic susceptibility-weighted contrast-enhanced MRI was performed on healthy volunteers and patients with cerebrovascular conditions.
- Indicator dilution theory and deconvolution analysis were employed to calculate maps of rCBF, regional cerebral blood volume, and mean transit time (MTT).
- Cerebrovascular reserve capacity was assessed by measuring rCBF changes after acetazolamide stimulation in patients with ICA occlusion/stenosis.
Main Results:
- In patients with ICA occlusion/stenosis, decreased rCBF and increased MTT were observed ipsilateral to the occlusion.
- Reduced cerebrovascular reserve capacity was detected in a majority of patients with ICA occlusion after acetazolamide challenge.
- In acute stroke, severely reduced rCBF was found in the ischemic core, with altered hemodynamics in the peri-infarct region.
Conclusions:
- Dynamic MRI provides essential clinical information regarding the hemodynamic state of brain tissue in patients with occlusive cerebrovascular disease.
- The developed pixel-by-pixel method enables detailed assessment of rCBF and cerebrovascular reserve capacity, aiding in the evaluation of stroke and ICA stenosis.
- This technique holds promise for improving the diagnostic accuracy and therapeutic guidance in cerebrovascular disorders.
Abstract:
We have developed a new method for estimation of regional CBF (rCBF) and cerebrovascular reserve capacity on a pixel-by-pixel basis by means of dynamic magnetic resonance imaging (MRI). Thirteen healthy volunteers, 8 patients with occlusion and/or high grade stenosis of the internal carotid artery (ICA), and 2 patients with acute stroke underwent dynamic susceptibility-weighted contrast enhanced MRI. Using principles of indicator dilution theory and deconvolution analysis, maps of rCBF, regional cerebral blood volume, and of the mean transit time (MTT) were calculated. In patients with ICA occlusion/stenosis, cerebrovascular reserve capacity was assessed by the rCBF increase after acetazolamide stimulation. Mean gray and white matter rCBF values in normals were 67.1 and 23.7 mL x 100 g(-1) x min(-1), respectively. Before acetazolamide stimulation, six of eight patients with ICA occlusions showed decreased rCBF values; and in seven patients increased MTT values were observed in tissue ipsilateral to the occlusion. After acetazolamide stimulation, decreased cerebrovascular reserve capacity was observed in five of eight patients with ICA occlusion. In acute stroke, rCBF in the central core of ischemia was less than 8 mL x 100 g(-1) x min(-1). In peri-infarct tissue, rCBF and MTT were higher than in unaffected tissue but rCBF was normal. Dynamic MRI provides important clinical information on the hemodynamic state of brain tissue in patients with occlusive cerebrovascular disease or acute stroke.