Segmental duplications (also termed ‘fenestrations’)
of
the fetal anterior cerebral artery are a relatively rare
anomaly. Their occurrence was studied in 200 fetuses at 20–40 wk
gestational age. Duplications were found
in 21 of the 200 fetuses, i.e. 10.5%. In 2 fetuses, i.e. 1%, the
duplications were bilateral. In 1 case, i.e.
0.5%, 2 duplications were found on the left anterior cerebral artery.
There were 15 segmental duplications
on the left anterior cerebral artery, i.e. 62.5% of all duplications,
and 9 on the right, i.e. 37.5%. The
duplications were located in the distal part of the A1 segment
in 45.7%,
at the level of the anterior
communicating artery (A1–A2) in 37.7%,
and in the initial part of the A2 segment in 16.6%. The
duplications had 4 different forms namely oviform, fissured, triangular
and punctate.