Assessment of the Fetal Cerebral Artery: Importance of Doppler Preset Settings.

ABSTRACT

OBJECTIVES: The Doppler assessment of the middle cerebral artery (MCA) has a central role in the monitoring of high-risk pregnancies. The objective of this study was to investigate the importance of Doppler preset settings for measurement of the peak systolic velocity (PSV) and pulsatility index (PI) of the MCA. METHODS: The PI and PSV of the MCA were determined prospectively in 350 healthy fetuses between 19 and 42 weeks of pregnancy. The first measurement of the MCA (MCA.S) was performed with the conventional settings and the second (MCA.O) with an optimized setting of the maximum achievable frame rate. For the MCA.O measurement, the width of the B-mode image and the color Doppler window were adjusted as narrowly as possible. In addition, the MCA was shown in optimized high-definition zoom. Resulting values were compared with commonly used reference values. RESULTS: The PSV and PI values and frame rates of the MCA.O setting were noticeably greater than those of the MCA.S setting (P < .001 for all). For both settings, the PSV and PI values were increased compared to common reference values. CONCLUSIONS: The assessment of the MCA with the optimized Doppler default setting yielded increased PSV and PI values compared to the commonly used measurement technique. Moreover, the resulting median curves differed from the established median reference curves. Therefore, an updated standardization for measuring the MCA should be set out, and current reference values should be adjusted.