[Preliminary study on the variability of the fetal cerebral velocimetry in various vessels of the Circle of Willis].

The authors have tried to analyse in a small series, the possibility as well as the variability of blood flow velocity waveforms in the different vessels of the circle of willis using colour Doppler. Fourteen patients were assessed. The 14 fetuses were of normal growth and/or had normal umbilical arterial blood flow velocity waveforms as well as normal uterine blood flow. The mean term at the time of examination was 23.8 +/- 2.9 standard deviation with the extremes going from 28.5 standard deviation to 40.5. The examinations were carried out using colour Doppler (Acuson) machine by the abdominal route with a 3.5-5 MHz bi-frequency sound. The vessels that were explored were the middle cerebral artery (CM), posterior cerebral artery (CP), the internal carotid artery (CI), the anterior cerebral artery (CA) in the region of the circle of Willis. CM and CA were able to be recorded in 100% of the cases, CP and CI in 93% of cases (13 out of 14 cases). The difference between he mean index (D/S, D = residual velocity in the diastole, S = maximum velocity in the systole) in each of these vessels was not statistically significant. In 3 out of 16 measurements (19%) the CP index was considered to be pathological while the index in the other vessels was normal, or when a different form of measurement was carried out in the region of CP, it was normal. This was also the case once for CA, but never for CM or CI.(ABSTRACT TRUNCATED AT 250 WORDS)