RESUMEN
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.
Asunto(s)
Arterias Cerebrales/anomalías , Edad Gestacional , HumanosRESUMEN
The arteries of the circle of Willis in fetal brains of 20-40 weeks of gestational age were studied with the operating microscope. The majority of fetuses were between 24-32 weeks of age. Our findings were as follows: 1) the average diameters of all segments were 4-5 times narrower than the average diameters in adults, and the average lengths of the same segments were 2-2.5 times shorter than the same lengths in adults; 2) the number of perforators corresponded with the perforating arteries in adults; 3) hypoplastic segments, as well as anomalies and variations, were identified; 4) calibers almost equal in size between the right and left corresponding segments were found in a high proportion of cases; 5) in the majority of cases a polygon, much like the "precarious" circle in adults, was dissected. The "fetal" or the "ideal" circles were found in a low proportion of cases.