Images of embolic stroke
See also: Cover
image
This patient was studied by me and colleagues in
the McConnell Brain Imaging Center at the Montreal
Neurological Institute. He was in the acute phase of
a devastating embolic stroke. Positron emission
tomography was used to measure cerebral blood flow
(CBF, upper left), the cerebral metabolic rates for
oxygen (CMRO2, upper right) and glucose
(CMRGlu[N], lower left), and the brain pH (CPH, lower
right). The intensity of any function can be
estimated from the colour, with lower to higher
values going from purple to blue to yellow and red.
Although this patient's entire right hemisphere is
suffering a drop in blood perfusion, relatively
smaller brain regions are showing a drop in metabolic
function, resulting from a combination of increased
extraction fractions for oxygen and glucose, and a
switch to anaerobic glycolysis. The latter leads to
the accumulation of lactate, which results in the
acidosis noted in the CPH image. Such imaging studies
not only improve our understanding of stroke
pathophysiology but can also be used to test the
effectiveness of therapeutic measures. -- Antoine
Hakim, MD, PhD
