CVR Project (2011-2018)
Measurement of Cerebral Vascular Reserve using Functional
Magnetic Resonance Imaging
In healthy people, when the brain
requires more oxygen and nutrients the blood vessels dilate and
there is an increase in the volume of blood flowing to the brain.
Cerebral vascular reserve (CVR) is a measure of this ability of the
blood vessels supplying the brain to respond to increasing demand.
In some people the cerebral vascular reserve is impaired and the
blood supply does not increase when the brain requires more
oxygen.
Assessment of CVR is thought to be
clinically important; it could help identify patients at increased
risk of stroke and determine the best course of treatment. One
method currently used to measure CVR is to use radioactive tracers
to measure the blood flow in the brain but this technique requires
the use of expensive tracers and needs the patient to attend the
hospital on two separate days.
A technique called
Blood-Oxygen-Level-Dependent functional MRI (fMRI BOLD) has been
shown to measure changes in blood flow to the brain. We are
investigating whether fMRI can measure CVR in place of the existing
technique. It does not use radioactivity and can be completed
during one scanning session. The patient is asked to lie in the
scanner and to carry out a series of breath holds (for up to 20s)
while being scanned.
We undertook a pilot study in which 5
patients and 3 normal volunteers were scanned. The data showed that
when analysising the patient population with breath-hold BOLD fMRI
the data can be very different to the standard model, which could
have implications for the accuracy of the analysis of this data in
the future.
For more detail on the project, click
here.
Figure 1 SPM8 analysis of fMRI BOLD
in a healthy volunteer Figure 2 Functional data
overlaid on a structural MRI
scan
For more information, contact:
Sian.Curtis@UHBW.nhs.uk,
Claire.Doody@NBT.nhs.uk
