In this age when we are witnessing a veritable explosion in new
modalities in diagnos- tic imaging we continue to have a great need for
detailed studies of the vascularity of the brain in patients who have
all types of cerebral vascular disease. Much of the understanding of
cerebral vascular occlusive lesions which we developed in the last two
decades was based on our ability to demonstrate the vessels that were
affected. Much experimental work in animals had been done where major
cerebral vessels were obstructed and the effects of these obstructions
on the brain observed pathologically. However, it was not until cerebral
angiography could be performed with the detail that became possible in
the decades of the '60 's and subsequently that we could begin to
understand the relationship of the obstructed vessels observed
angiographically to the clinical findings. In addition, much physiologic
information was obtained. For instance, the concept ofluxury perfusion
which is used to describe non-nutritional flow through the tissues was
observed first angiographically although the term was not used until
LASSEN described it as a pathophysiological phenomenon observed during
cerebral blood flow studies with radioactive isotopes. The concept of
embolic occlusions of the cerebral vessels as against thrombosis was
clarified and the relative frequency of thrombosis versus embolism was
better understood. The concept of collateral circulation of the brain
through so-called meningeal end-to- end arterial anastomoses was vastly
better understood when serial angiography in obstructive cerebral
vascular disease was carried out with increasing frequency.
