Table 1.

Doppler indices of cerebral blood flow.

Doppler Ultrasound Finding	Definition	Significance	Congenital Heart Disease
Cerebral Pulsatility Index (CPI)	(SV-DV)/MV	Lower value associated with higher mortality, growth retardation, and poor neurological outcome	Lower in HLHS and higher in right-sided obstruction lesions compared to normal [44] Lower in TGA [46] Lower in CHD with intracardiac mixing [47] Lower in CHD fetuses with CHF [48]
Cerebral Resistance Index (CRI)	(SV-DV)/SV	Lower value associated with growth retardation	Lower in CHD infants compared to normal [42]
Cerebral/Umbilical Pulsatility Ratio	CPI/UPI	Ratio <1 associated with growth retardation and poor perinatal outcome	No difference [44] Increased in CHD [48]
Cerebral/Umbilical Resistance Ratio	CRI/URI	Ratio <1 associated with growth retardation	Lower in CHD infants compared to normal Lowest in HLHS (58% with ratio <1) [42]
Reversal of diastolic flow in the aortic isthmus	Blood flow away from the descending aorta	Predicts poor neurological outcome	Present in HLHS and severe left ventricular (LV) outflow obstruction with LV failure