Reliability of CT Perfusion-Derived CBF in Relation to Hemodynamic Compromise in Patients with Cerebrovascular Steno-Occlusive Disease: A Comparative Study with ¹⁵O PET

Abstract

In the bolus tracking technique with computed tomography (CT) or magnetic resonance imaging, cerebral blood flow (CBF) is computed from deconvolution analysis, but its accuracy is unclear. To evaluate the reliability of CT perfusion (CTP)-derived CBF, we examined 27 patients with symptomatic or asymptomatic unilateral cerebrovascular steno-occlusive disease. Results from three deconvolution algorithms, standard singular value decomposition (sSVD), delay-corrected SVD (dSVD), and block-circulant SVD (cSVD), were compared with (15)O positron emission tomography (PET) as a reference standard. To investigate CBF errors associated with the deconvolution analysis, differences in lesion-to-normal CBF ratios between PET and CTP were correlated with prolongation of arterial-tissue delay (ATD) and mean transit time (MTT) in the lesion hemisphere. Computed tomography perfusion results strongly depended on the deconvolution algorithms used. Standard singular value decomposition showed ATD-dependent underestimation of CBF ratio, whereas cSVD showed overestimation of the CBF ratio when MTT was severely prolonged in the lesions. The computer simulations reproduced the trend observed in patients. Deconvolution by dSVD can provide lesion-to-normal CBF ratios less dependent on ATD and MTT, but requires accurate ATD maps in advance. A practical and accurate method for CTP is required to assess CBF in patients with MTT-prolonged regions.

Cerebral venous collaterals: A new fort for fighting ischemic stroke?

“…Additionally, CTV helps to avoid venous injury during surgery for intracranial neoplasm. However, because of radiation exposure and the possible influence with the fetus thyroid, its application is limited in pregnant women and children (Ibaraki et al, 2015).…”

Comparison of [15O] H2O positron emission tomography and functional magnetic resonance imaging in activation studies

“…The deconvolution method is used to work out the MTT,[ 10 ] but the CBF image relies in large part on the deconvolution algorithm, so its reliability is low. [ 11 ] In organs other than the brain (such as cardiac muscle) the contrast agent leaks from capillaries perfuses the tissue, thus by determining the rate constant, we are able to determine blood flow. [ 12 ]…”

Identifying perfusion deficits on CT perfusion images using temporal similarity perfusion (TSP) mapping

“…As well, thus far we have not yet compared the performance of TSP to transit-delay insensitive algorithms such as delaycorrected singular value decomposition (dSVD), block-circulant SVD, maximum slope, or inverse filter which are known to perform better when it comes to final infarct prediction [4]. Delay-corrected SVD-derived CBF maps are known to be less dependent on arterial-tissue delay and mean transit time than standard SVD [19]. Thereby, future work will compare delay-insensitive maps to TSP maps and will incorporate the CBF map in its analysis to determine whether TSP maps are indeed more specific for penumbra than the MTT or TTP maps.…”

“…The cerebral blood volume (CBV) is determined based on the area under the time attenuation curve. The software also provides a cerebral blood flow (CBF) map as output, but given the sensitivity of SVD CBF maps to both arterial-tissue delay and mean transit time, we decided not to incorporate the CBF map into our analysis [19].…”