Different anatomical variations of circle of Willis in adult patients on magnetic resonance angiography
Marium Amjad, Sarah Maryam, M. Zakir, S.M.Y Farooq, M. Riaz, A. Majeed, R. Riaz, A. Shahzad, A. Lutfullah, M. Umer, K Aftab
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ABSTRACT
Background: The COW shows
vast variations in different individuals. The aim of this study was to evaluate
and describe the prevalence and patterns of arterial variants and the different
morphological variations of the COW on MRA in adult Pakistanis.
Aim: To find the different anatomical variations
of Circle of Willis in adult patients on magnetic resonance angiography.
Methodology: In this descriptive study a total of 90
patients with ages 20-90 years, were selected for the study between July 2021
till October 2021. The adult patients were referred for screening MRA brain in
the Department of Radiology. The protocol selected to visualize the COW was
3D-TOF MRA.
Results: Data analysis demonstrates that out of total
90 patients, 51(56.7%) were males and 39(43.3%) were females. Overall,
66(79.5%) circles were complete in anatomical configuration and 24(20.5) were
incomplete. The anterior circle was complete in 73(81.1%) subjects and
incomplete in 17(18.9%) subjects. The posterior circle was complete in
83(92.2%) subjects and incomplete in 7(7.8%) subjects.The most common variation
of COW was hypoplasia/absence of segments of Circle of Willis. ACA was the most
frequent segment of Circle of Willis that was hypoplastic/absent followed by A1
segment of right ACA is absent in 6(7.2%) subjects and A1segment of right ACA
is hypoplastic in 6(7.2%) subjects.
Conclusion: The study
concludes that mostly the COW is complete in Pakistani adults. There are
variations particularly in anterior part as compared to the posterior part of
the COW. The most common variants are of A1 segment of Right ACA as compared to
other type of variants.
Keywords: Circle of Willis, 3D-TOF-MRA, Anterior
circulation, Posterior circulation, Complete circle, Incomplete circle,
ABSTRACT
Background: The COW shows
vast variations in different individuals. The aim of this study was to evaluate
and describe the prevalence and patterns of arterial variants and the different
morphological variations of the COW on MRA in adult Pakistanis.
Aim: To find the different anatomical variations
of Circle of Willis in adult patients on magnetic resonance angiography.
Methodology: In this descriptive study a total of 90
patients with ages 20-90 years, were selected for the study between July 2021
till October 2021. The adult patients were referred for screening MRA brain in
the Department of Radiology. The protocol selected to visualize the COW was
3D-TOF MRA.
Results: Data analysis demonstrates that out of total
90 patients, 51(56.7%) were males and 39(43.3%) were females. Overall,
66(79.5%) circles were complete in anatomical configuration and 24(20.5) were
incomplete. The anterior circle was complete in 73(81.1%) subjects and
incomplete in 17(18.9%) subjects. The posterior circle was complete in
83(92.2%) subjects and incomplete in 7(7.8%) subjects.The most common variation
of COW was hypoplasia/absence of segments of Circle of Willis. ACA was the most
frequent segment of Circle of Willis that was hypoplastic/absent followed by A1
segment of right ACA is absent in 6(7.2%) subjects and A1segment of right ACA
is hypoplastic in 6(7.2%) subjects.
Conclusion: The study
concludes that mostly the COW is complete in Pakistani adults. There are
variations particularly in anterior part as compared to the posterior part of
the COW. The most common variants are of A1 segment of Right ACA as compared to
other type of variants.
Keywords: Circle of Willis, 3D-TOF-MRA, Anterior
circulation, Posterior circulation, Complete circle, Incomplete circle,