Ultrasound probe pressure but not maternal Valsalva maneuver alters Doppler parameters during fetal middle cerebral artery Doppler ultrasonography.
OBJECTIVE
To determine the effects of increased ultrasound probe pressure and maternal Valsalva maneuver (VM) on the middle cerebral artery (MCA) Doppler ultrasonography in fetuses.


METHODS
A total of 120 healthy pregnant women in second and third trimesters were enrolled in the study. MCA blood flow was measured by pulsed Doppler sonography in 60 fetuses (24 and 40 weeks' gestation) before and after the application of increased ultrasound probe pressure. In the other 60 fetuses (32 and 36 weeks' gestation), sonography was performed before and after maternal VM. Statistical analysis was performed by paired t-test.


RESULTS
The pressure induced by the ultrasound probe induced a significant increase in the pulsatility index (PI), resistance index (RI), and peak systolic velocity (PSV); however, a significant decrease was found in the end-diastolic velocity (EDV) (p < 0.05). No statistically significant difference was found in the mean flow velocity (MFV). Moreover, maternal VM did not have any effect on the PI, RI, EDV, or MFV.


CONCLUSIONS
Fetal MCA Doppler assessment is affected by increased probe pressure but not by maternal VM. Thus, the application of the MCA Doppler sonography should be undertaken in the head of fetuses without any probe pressure and without maternal VM.
Department of Ultrasound, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian, P R China.
Yi-Ming
YM
Su
Guo-Rong
GR
Lv
Xiao-Kang
XK
Chen
Shao-Hui
SH
Li
Hui-Tong
HT
Lin
D001783:Blood Flow Velocity / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D005260:Female; D005333:Fetus / Q000098:blood supply*; D006801:Humans; D007231:Infant, Newborn; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging*; D009035:Mothers; D011247:Pregnancy; D011262:Pregnancy Trimester, Second / Q000502:physiology; D011263:Pregnancy Trimester, Third / Q000502:physiology; D011312:Pressure / Q000009:adverse effects*; D018617:Ultrasonography, Doppler, Pulsed / Q000009:adverse effects* / Q000379:methods; D016216:Ultrasonography, Prenatal / Q000009:adverse effects* / Q000295:instrumentation / Q000379:methods; D014636:Valsalva Maneuver / Q000502:physiology*