Capillary transit time heterogeneity inhibits cerebral oxygen metabolism in patients with reduced cerebrovascular reserve capacity from steno-occlusive disease.
Mark B VestergaardHelle K IversenSofie Amalie SimonsenUlrich LindbergStig P CramerUlrik B AndersenHenrik Bw LarssonPublished in: Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism (2022)
The healthy cerebral perfusion demonstrates a homogenous distribution of capillary transit times. A disruption of this homogeneity may inhibit the extraction of oxygen. A high degree of capillary transit time heterogeneity (CTH) describes that some capillaries have very low blood flows, while others have excessively high blood flows and consequently short transit times. Very short transit times could hinder the oxygen extraction due to insufficient time for diffusion of oxygen into the tissue. CTH could be a consequence of cerebral vessel disease. We examined whether patients with cerebral steno-occlusive vessel disease demonstrate high CTH and if elevation of cerebral blood flow (CBF) by administration of acetazolamide (ACZ) increases the cerebral metabolic rate of oxygen (CMRO 2 ), or if some patients demonstrate reduced CMRO 2 related to detrimental CTH. Thirty-four patients and thirty-one healthy controls participated. Global CBF and CMRO 2 were acquired using phase-contrast MRI. Regional brain maps of CTH were acquired using dynamic contrast-enhanced MRI. Patients with impaired cerebrovascular reserve capacity demonstrated elevated CTH and a significant reduction of CMRO 2 after administration of ACZ, which could be related to high CTH. Impaired oxygen extraction from CTH could be a contributing part of the declining brain health observed in patients with cerebral vessel disease.
Keyphrases
- cerebral blood flow
- subarachnoid hemorrhage
- cerebral ischemia
- end stage renal disease
- chronic kidney disease
- ejection fraction
- newly diagnosed
- contrast enhanced
- magnetic resonance imaging
- healthcare
- public health
- single cell
- brain injury
- prognostic factors
- magnetic resonance
- mental health
- computed tomography
- climate change
- blood brain barrier
- patient reported