Neurosurgery Surgical Research Laboratory
Treatment of Post-Surgical Vasoconstriction
Dr Zervas | Recent
Publications | Links
Research in Cerbral Vasospasm
Dr Zervas's Lab -
PET Imaging of CBF, CBV, O2M, OEF and GluMetab
Images courtesy of Anna-Liisa
Brownell, PhD in collaboration on a study of CNS tissue metabolism (rGMR, rCMRO2, rOEF,
rCBF, rCBV) during cerebral vasospasm. (For more info.)
Functional CT Studies
Images courtesy of CIPR (Center for
Imaging and Pharmaceutical Research) as part of a collaboration with the CNS project group. The
images are the work of George Hunter, MD and
Leena Hamberg,
PhD as part of a study on peripheral tissue perfusion (CBV, TTT, CBFi) during cerebral
vasospasm. (For more info.)
Dr Zervas's &
Dr Peterson's Labs -
Studies in laser-induced
pulsed-fluid wave treatment of vasospastic cerebral arteries.
MGH Laser Center
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Despite intensive laboratory and clinical research efforts over the past l5 years,
delayed chronic cerebral vasospasm remains a major source of morbidity and mortality
following subarachnoid hemorrhage (SAH). Research efforts in my laboratory have taken two
related paths: (1) In vitro efforts to define the basic mechanisms which underlie the
pathogenesis of cerebral vasospasm, and (2) In vivo studies to identify pharmacological
methods of prophylactic and/or therapeutic relief of cerebral vasospasm. In the course of
this project, we developed and characterized the animal model of post-SAH cerebral
vasospasm which has become the worldwide standard in vasospasm research. Over 40
laboratories internationally use the "doubleSAH canine model" routinely.
Most recently, innovations in the clinical management of subarachnoid hemorrhage
patients has led to marked improvement in their general clinical outcome, except for those
patients with a demonstrable severe focal constriction in some particular cerebral
arterial perfusion zone. A new collaborative effort with the Wellman Laser Applications
Group holds great promise for the treatment of these patients.
Using both in vitro systems and our well-established animal model, we have recently
shown that very brief pulses of low energy laser energy applied intraluminally to
constricted cerebral arteries can create a localized expansive fluid wave capable of
forcibly dilating the artery. While the method is, in principle, similar then to balloon
angioplasty: it has several features which represent distinct improvements. Since the
pulsed fluid wave can be made to propagate over a significant distance intraluminally, it
is not necessary to directly catheterize the injured vessels. That is, approach to within
a few centimeters distally is adequate, thus reducing possible injury to already "at
risk" arteries. Secondly, and perhaps most importantly, the pulsed-fluid wave will
propagate from the lumen of major conducting vessels to smaller branch vessels and perhaps
deep into the zones of reduced cerebral perfusion. We are currently working
collaboratively with several imaging groups (PET and CIPR) to establish the parameters of
laser-induced pulsed-fluid wave treatment which successfully reestablished normal levels
of cerebral perfusion in our animal model. The diffuse spread of vasodilation into
constricted microcirculatory beds by pulsed-wave application is in result unobtainable by
balloon angioplasty. Our research in this new methodology holds great promise for
developing a new and successful treatment modality for cerebral vasospasm.
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