Reliability of doppler assessment of the middle cerebral artery in the near and far fields in healthy and anemic fetuses

Objectives-The purpose of this study was to assess the reliability of the middle cerebral artery pulsatility index (PI) and peak systolic velocity (PSV) at the proximal portions of the near- And far-field vessel sites in healthy and anemic fetuses. Methods-The middle cerebral artery PSV and PI were prospectively assessed in 50 normal singleton pregnancies. The Doppler waveforms for the middle cerebral artery PI and the PSV were recorded independently by 2 operators at the most proximal portions of the near- And far-field sites. Data for the PSV and PI at the proximal portions of both the near- And the far-field sites were also retrospectively collected in 7 anemic fetuses. Results-No significant difference between the operators was detected for the middle cerebral artery PSV (P = .60) and PI (P = .88) measured in the conventionally used near-field proximal site in the 50 healthy fetuses. No significant difference between the proximal portions of the near- And far-field sites was detected for the PSV (P = .53) and PI (P = .23) in healthy or anemic fetuses. Conclusions-The findings of this study suggest that the use of the far-field vessel is an acceptable alternative for measurement of the middle cerebral artery PI and PSV when investigation of the near-field vessel is technically difficult.