Journal of Ultrasound in Medicine, Vol 17, Issue 12 769-773, Copyright © 1998 by American Institute of Ultrasound in Medicine
Superior mesenteric artery blood flow velocimetry: cross-sectional Doppler sonographic study in normal fetuses
R. Achiron, R. Orvieto, S. Lipitz, S. Yagel and Z. Rotstein
Department of Obstetrics and Gynecology, The Chaim Sheba Medical Center, Tel Hashomer, Sackler School of Medicine, Tel Aviv University, Israel.
Our objectives were to describe the flow velocity waveform of the fetal
superior mesenteric artery and to establish a nomogram for its pulsatility
index. In a cross-sectional study using color Doppler ultrasonography,
superior mesenteric artery flow velocimetry was investigated prospectively
in 96 healthy fetuses of between 14 and 37 weeks of gestation. In normal
fetuses the pulsatility index measurements showed a slight but
insignificant increase over the course of gestation (r = 0.26; P > 0.5).
The lowest mean +/- standard deviation for pulsatility index in the
superior mesenteric artery was 1.86 +/- 0.45 (95% confidence interval
1.67-2.06), recorded between 18 and 21 weeks' gestation. Thereafter the
pulsatility index increased to 1.94 +/- 6.4 (95% confidence interval
1.74-2.8) at 22 to 25 weeks, and from weeks 26 to 29 it increased to 2.18
+/- 0.52 (95% confidence interval 1.91-2.46). During the third trimester
and at term, the mean pulsatility index of 2.23 +/- 0.32 (95% confidence
interval 1.43-3.03) did not change significantly with gestational age. In
normal fetuses, except for the early stages, a relatively stable vascular
resistance of the intestinal circulation was found. The application of this
nomogram in clinical practice may facilitate evaluation of intestinal
perfusion in compromised fetuses with blood flow centralization.
