[Development of method for measurement of pulsatile change in arterial diameter in the fetus]

The present study was designed to evaluate perfusion dynamics of organs by measuring pulsatile change in arterial diameter concomitant with flow velocity determination. An ultrasonic phased locked echo tracking system equipped with a real time linear array scanner was used to measure pulsatile change in arterial diameter. The distance from the transducer to a distal or proximal point on the inner vessel wall can be defined as the relative time difference of the zero cross for each reflective wave. The pulsatile change in the arterial diameter was a reflection of intra-arterial pressure change which was confirmed by simultaneous measurement of direct pressure in the adult brachial, femoral and descending aorta (DA) by arterial catheterization. The accuracy of measurement of arterial diameter and pulsatile change were confirmed by the coefficient of variation (C.V) in the diameter of than 4% in the former and less than 8% in the later in both inter- and intra-assay variance. In normal growth fetuses, the pulsatile changes in the DA were within the range of about 10% of the minimum arterial diameter. Intrauterine growth retarded fetuses (IUGR) who had a high pulsatility index (PI) were 7.26 +/- 0.36% (n = 5, p < 0.01 v.s. normal growth group) and showed discrete figures between pulsatile and blood flow velocity waveforms. Furthermore, large for date fetuses (LFD) who had a high PI were 12.20 +/- 0.50% (n = 3, p < 0.05 v.s. normal growth group) and had similar figures in pulsatile and blood flow velocity waveforms.(ABSTRACT TRUNCATED AT 250 WORDS)