Keywords:
CT-Angiography, Neuroradiology brain, Experimental investigations, Ischaemia / Infarction
Authors:
M. A. Rios Vives1, P. Coscojuela2, V. Wijk2, S. Boned2, A. García-Tornel2, M. Muchada2, M. Ribo2, C. Molina2, M. Rubiera2; 1BARCELONA, BA/ES, 2Barcelona/ES
DOI:
10.26044/ecr2019/C-3784
Aims and objectives
The presence of a favorable leptomeningeal collateral circulation (CC) is a strong predictor of neuroimaging outcomes and early and long-term clinical evolution after acute ischemic stroke.
Leptomeningeal circulation refers to a network of small vessels that interconnect the distal arteries of the brain.
In a sense,
they act as bridges that partially connect the different distal circulation systems of the brain (i.e.
median cerebral artery (MCA) with the anterior and posterior cerebral artery territories).
When there is an occlusion of the main arteries of the circle of Willis,
leptomeningeal CC provides an alternative blood route to irrigate the ischemic brain tissue.
Therefore,
CC has demonstrated to extend the therapeutic window for reperfusion therapies and to reduce or even prevent infarct progression.
Evaluation of CC has been added to most acute stroke imaging protocols by computerized tomography angiography (CTA).
Even though leptomeningeal collaterals cannot be effectively visualized by CTA,
the enhancement of the vessels on the ischemic brain tissue distal to the large artery occlusion can be evaluated.
Furthermore,
recent studies have demonstrated that CC evaluation by CTA is improved when the multiphase CTA (mCTA) technique is performed.
mCTA consists in one single contrast injection,
followed by 3 CTA acquisitions each separated-by 10 seconds.
A dynamic evaluation of the contrast evolution within the ischemic tissue is obtained this way.
However,
CTA does not increase brain parenchymal ischemic information over non-contrast CT.
Therefore,
multimodal evaluation of acute stroke patients usually includes a brain perfusion CT (CTP).
CTP consists on an intravenous injection of iodinated contrast and evaluation of its pass through the brain tissue at risk.
Circumvolution maps are obtained from different time and intensity parameters,
and an estimation of the already irreversible damaged tissue (core) and hypoperfused but still salvageable tissue is provided.
Both CTA and CTP provide information of the contrast pass through the ischemic tissue.
Therefore,
CTP,
with a continued acquisition over time during the administration of IV contrast,
could theoretically be a similar or even better method for evaluating blood flow through the leptomeningeal CC than CTA or mCTA.
However,
previous techniques to evaluate CC by CTP are complicated and time-consuming,
so their use is not spread in real-life practice.
In our study,
we aim to identify a quick and accurate method to evaluate CC status by CTP.