Aims and objectives
Computed tomography perfusion (CTP) is a key component in the diagnosis of cerebral ischemic stroke[1-4]; however,
quantitative stability and variation among algorithms have previously been reported.
A newly introduced Bayesian algorithm is expected to provide quantitatively accurate measurements in CTP[6-9].
Although we previously reported CTP tends to demonstrate reduced cerebral blood flow (CBF) at low radiation doses,
the Bayesian algorithm is expected to improve quantitative accuracy in this respect.
We evaluated quantitative diagnostic accuracy at low radiation doses among CTP parameters of the reformulated singular...
Methods and materials
We retrospectively investigated 6 consecutive cases of suspected AIS,
including 4 with penumbra;16 auto-segmented areas of each middle cerebral artery territory were categorized into normal tissue,
acute ischemic lesion,
chronic ischemic lesion,
and old infarction at the final diagnosis.
We calculated the CBF,
cerebral blood volume (CBV),
mean transit time (MTT),
and time to peak (TTP),
excluding the infarcted lesions.
Perfusion scan was performed on a 320-rows area detector CT (Aquilion ONE,
Canon Medical Systems,
Japan) with rotation speed 0.5 s/rotation and scan intervals...
Although both the rSVD and Bayesian algorithms indicated significantly increased CBV and prolonged MTT and TTP values in penumbra than in normal perfusion tissues (p< 0.001),
no significant difference in CBF was found between penumbra and normal tissue measured using both algorithms (p= 0.13 using rSVD,p= 0.12 using Bayesian)(Figure 2).
Much discussion has been held regarding the quantitative thresholds for penumbra and ischemic core.
CBF is gradually reduced throughout all stages of ischemia; consequently,
it is occasionally difficult to define a clearthreshold between infarct and penumbra based on CBF.
On the other hand,
CBV increases during ischemic penumbra,
whereas CBV decreases during irreversible tissue damage.
Therefore,decreased CBV was used to define an infarcted core.Although the quantitative stability of CBF is worse than that of CBV,
decreased CBF is has been considered an accurate definition of...
Perfusion measurements of the brain: using dynamic CT for the quantitative assessment of cerebral ischemia in acute stroke,
European journal of radiology 30(3) (1999) 170-184.
Dynamic CT perfusion imaging of acute stroke,
AJNR Am J Neuroradiol 21(8) (2000) 1441-9.