When an artery in the neck or brain becomes occluded, the pressure in the branches beyond the occlusion may fall, depending on the adequacy of collateral sources of blood flow. The first response of the cerebrovasculature to a fall in intra-luminal pressure is reflex autoregulatory vasodilation. This serves to reduce the resistance to arterial inflow and maintain a normal level of cerebral blood flow. When autoregulatory capacity is overcome, the brain can increase the fraction of oxygen extracted from the blood as it passes by in order to maintain normal oxygen delivery and consequently, normal brain function. The presence of increased oxygen extraction in the brain beyond an occluded artery has recently been proven by our group (see Grubb, et al., below) to be a powerful and independent risk factor for subsequent stroke. Hemodynamic factors are also likely to be play an important role in the pathogenesis of stroke in patients with other cerebrovascular disorders, such as vasospasm after subarachnoid hemorrhage, intracranial atherosclerotic disease, and ischemia due to increased venous pressure. The presence of the compensatory responses of the cerebrovasculature to reduced pressure (autoregulatory vasodilation and increased oxygen extraction) can be accurately and non-invasively measured in living humans with positron emission tomography (PET) and short-lived radiotracers.
The main focus of my research is the hemodynamic and metabolic effects of different cerebrovascular diseases on the brain, as well as the effects of medical or endovascular treatment of these disorders on cerebral blood flow, autoregulatory vasodilation, and oxygen extraction. These measurements primarily utilize PET. One currently funded investigation is on role of impaired hemodynamics on the risk of stroke in patients with Moyamoya phenomenon, an uncommon cause of arterial narrowing and occlusion. The aim of another NIH-funded investigation is to develop techniques using magnetic resonance imaging to provide similar regional and quantitative measurements of blood flow, blood volume and oxygen extraction that are currently only obtainable with PET. My research closely parallels my clinical interests, which involves the diagnosis and treatment of cerebrovascular disease. My clinical specialty is the endovascular (within the blood vessels) treatment of cerebral aneurysms, arteriovenous malformations, embolic stroke, and atherosclerotic stenoses of the vessels of the head and neck.
Research Photos (Click to Enlarge)
Research Publications
Hallemeier CL, Rich KM, Grubb RL Jr, Chicoine MR, Moran CJ, Cross DT 3rd, Zipfel GJ, Dacey RG Jr, Derdeyn CP (2006 Jun). Clinical features and outcome in North American adults with moyamoya phenomenon. Stroke. 37 (6): 1490-6. Full Article >
Strom RG, Derdeyn CP, Moran CJ, Cross DT, Esper GJ, Mazumdar A, Al-Lozi M, Lopate G, Pestronk A (2006 Mar 28). Frequency of spinal arteriovenous malformations in patients with unexplained myelopathy. Neurology. 66 (6): 928-31. Full Article >
Grubb RL Jr, Powers WJ, Derdeyn CP, Adams HP Jr, Clarke WR (2003 Mar 15). The Carotid Occlusion Surgery Study. Neurosurg Focus. 14 (3): e9. Full Article >
Derdeyn CP, Videen TO, Yundt KD, Carpenter DA, Fritsch SM, Grubb RL Jr, Powers WJ. Variability of cerebral blood volume and oxygen extraction fraction: Stages of haemodynamic impairment revisited. Brain 2002;125: 595-607. Full Article >
Derdeyn CP. Physiological neuroimaging: emerging clinical applications. JAMA. 2001 Jun 27;285(24):3065-8. Full Article >
Derdeyn CP, Grubb RL Jr., Powers WJ. Cerebral hemodynamic impairment: methods of measurement and association with stroke risk. Neurology 1999;53:251-259 Full Article >
Contact Info
Colin Derdeyn, M.D.
Office Location: 510 South Kingshighway Blvd
Office Phone: (314) 362-5949
Lab Phone: (314) 362-9056
Campus Box: 8131
Fax: (314) 362-4886
derdeync@wustl.edu
http://www.nil.wustl.edu/~inr/Derdeyn.html
