TY - JOUR
T1 - From perviousness to permeability, modelling and measuring intra-thrombus flow in acute ischemic stroke
AU - Arrarte Terreros, Nerea
AU - Tolhuisen, Manon L.
AU - Bennink, Edwin
AU - de Jong, Hugo W. A. M.
AU - Beenen, Ludo F. M.
AU - Majoie, Charles B. L. M.
AU - van Bavel, Ed
AU - Marquering, Henk A.
PY - 2020/10/9
Y1 - 2020/10/9
N2 - Thrombus permeability determines blood flow through the occluding thrombus in acute ischemic stroke (AIS) patients. The quantification of thrombus permeability is challenging since it cannot be directly measured nor derived from radiological imaging data. As a proxy of thrombus permeability, thrombus perviousness has been introduced, which assesses the amount of contrast agent that has penetrated the thrombus on single-phase computed tomography angiography (CTA). We present a method to assess thrombus permeability rather than perviousness. We follow a three-step approach: (1) we propose a theoretical channel-like structure model describing the thrombus morphology. Using Darcy's law, we provide an analytical description of the permeability for this model. According to the channel-like model, permeability depends on the number of channels in the thrombus, the radius of the occluded artery, and the void fraction representing the volume available for the blood to flow; (2) we measure intra-thrombus blood flow and velocity on dynamic CTA; and (3) we combine the analytical model with the dynamic CTA measurements to estimate thrombus permeability. Analysis of dynamic CTA data from 49 AIS patients showed that the median blood velocity in the thrombus was 0.58 (IQR 0.26–1.35) cm/s. The median flow within the thrombus was 3.48 · 10−3 (IQR 1.71 · 10−3–9.21 · 10−3) ml/s. Thrombus permeability was of the order of 10−3–10−5 mm2, depending on the number of channels in the thrombus. The channel-like thrombus model offers an intuitive way of modelling thrombus permeability, which can be of interest when studying the effect of thrombolytic drugs.
AB - Thrombus permeability determines blood flow through the occluding thrombus in acute ischemic stroke (AIS) patients. The quantification of thrombus permeability is challenging since it cannot be directly measured nor derived from radiological imaging data. As a proxy of thrombus permeability, thrombus perviousness has been introduced, which assesses the amount of contrast agent that has penetrated the thrombus on single-phase computed tomography angiography (CTA). We present a method to assess thrombus permeability rather than perviousness. We follow a three-step approach: (1) we propose a theoretical channel-like structure model describing the thrombus morphology. Using Darcy's law, we provide an analytical description of the permeability for this model. According to the channel-like model, permeability depends on the number of channels in the thrombus, the radius of the occluded artery, and the void fraction representing the volume available for the blood to flow; (2) we measure intra-thrombus blood flow and velocity on dynamic CTA; and (3) we combine the analytical model with the dynamic CTA measurements to estimate thrombus permeability. Analysis of dynamic CTA data from 49 AIS patients showed that the median blood velocity in the thrombus was 0.58 (IQR 0.26–1.35) cm/s. The median flow within the thrombus was 3.48 · 10−3 (IQR 1.71 · 10−3–9.21 · 10−3) ml/s. Thrombus permeability was of the order of 10−3–10−5 mm2, depending on the number of channels in the thrombus. The channel-like thrombus model offers an intuitive way of modelling thrombus permeability, which can be of interest when studying the effect of thrombolytic drugs.
KW - Acute ischemic stroke
KW - Blood flow quantification
KW - Dynamic CTA
KW - Thrombus permeability
UR - http://www.scopus.com/inward/record.url?scp=85090143352&partnerID=8YFLogxK
U2 - https://doi.org/10.1016/j.jbiomech.2020.110001
DO - https://doi.org/10.1016/j.jbiomech.2020.110001
M3 - Article
C2 - 32896744
SN - 0021-9290
VL - 111
JO - Journal of Biomechanics
JF - Journal of Biomechanics
M1 - 110001
ER -