All about MCA Doppler

. MCA :- A) MCA/umbilical PI ratio is designated as abnormal when such ratio is as low as  < 1.08;  The ratio is  defined as abnormal when  MCA/uterine artery PI  < 5^th percentile. However , NICU, neonatal intensive care unit; are not increased at this stage ( not significant; SGA,) What do we mean by small‐for‐gestational age? If EFW is below the < 5^th centile) as per customized Growth chart prepared from Ht, Wt of mother, sex, Ethnicity. 

Normally  MCA/uterine artery PI ratio decreases with gestational age. Abnormally low MCA/ uterine artery PI ratios are related to unfavorable pregnancy outcome. The predictive value of the MCA/uterine artery PI ratio is similar to that of the MCA/umbilical artery PI ratio. Normal MCA/uterine artery PI ratios decreased with advancing gestational age. Redistribution of the fetal circulation indicated by a low MCA/uterine artery PI ratio was seen in 30% of the mild (n=15) and 46% of the severe (n=30) pre-eclamptic cases.

MCA PI shows a wider range than previously reported in the literature.

How to  construct normal ranges for A) umbilical artery pulsatility index (UA PI), B) middle cerebral artery pulsatility index (MCA PI) and C)  cerebroplacental ratio (CPR)  construct normal ranges for umbilical artery pulsatility index (UA PI), middle cerebral artery pulsatility index (MCA PI) and cerebroplacental ratio (CPR) in prolonged pregnancies according to strict methodological criteria using polynomial regression analysis.

MCA PI/Umb artery Doppler calculation:” Values below the 5th percentile or an MCA/umbilical artery PI ratio lower than 1.08 were defined as brain-sparing. low MCA/uterine artery PI ratio was seen in 30% of the mild and 46% of the severe  pre-eclamptic cases.