Keywords:
Vascular, Neuroradiology brain, Arteries / Aorta, MR-Angiography, Computer Applications-3D, Imaging sequences, Radiobiology, Image verification
Authors:
J. Sidorova, A. I. Gromov, I. Krinina, A. Kudryavtseva; Moscow/RU
DOI:
10.26044/ecr2019/C-1916
Conclusion
The obtained data on the combination of anatomical variants of COW with the presence of Pcomm prove the hypothesis of the appointment of Pcomm to represent the collateral blood flow of the brain.
Variants that reflect the decrease in blood flow in the anterior and posterior cerebral circulation - ACA hypoplasia and VA hypoplasia were most often combined with the presence of Pcomm (80% and 100%,
respectively).
It was noted the prevalence of Pcomm larger diameter in case combination with ACA or VA hypoplasia.
Moreover,
the dominant frequency of ipsilateral Pcomm at VA hypoplasia and contralateral Pcomm at ACA hypoplasia reflects a hemodynamic feature in patients with variant anatomy of COW.
Hypoplasia VA causes a circulatory deficit in the ipsilateral PCA and increases the need for additional blood flow through the ipsilateral Pcomm.
With A1 segment ACA hypoplasia is needed blood flow compensation in remaining segments of ACA which occurs through the Pcomm on the contralateral side [figure 11].
Fig. 11: Scheme of collateral blood flow in hypoplasia’s A1 segment of ACA (A) and VA (B). Small wavy arrows show the blood flow reduction due to hypoplasia of the artery, the arrowheads show the direction of collateral compensation of blood flow. Pink circles indicate the area in need of replenishment of blood flow.
References: Department of Radiology, MEDSI, Botkin hospital, Moscow
The surveillance ischemic cortical stroke in patient having VA aplasia and underdeveloped Pcomm on the side of stroke further confirm the hypothesis of compensatory appointment of Pcomm.
However,
the fact of detection of ischemia in the flow of variant anatomy during the weak compensation of the cerebral circle,
as well as the fact of compensation of VA hypoplasia by the means of fetal Pcomm suggests that collateral blood supply development in the case of variant anatomy more likely of congenital rather than acquired origin.
This raises the needs to revise the hypothesis of the ability of the posterior connective arteries to hypertrophy with acquired stenosis of the arteries supplying of the brain for example carotid as reported by some researchers [7,
8].
In any case,
to obtain evidence of acquired compensatory hypertrophy of the posterior connective arteries further well-designed trials with larger sample sizes are needed.