Fetal cerebral blood flow and volume Juriy Wladimiroff, MD, PhD FRCOG, FCYNGOF, FEBCOG, FISUOG, FAIUM, FAOGU, Dr h.c.

l Fetal growth restriction Fetal undernutrition Fetal hypoxaemia Restricted liver growth Protected brain growth Hemodynamic redistribution e.g. brain sparing US: Liver volume Brain volume Brain/liver vol ratio! Umbilical venous volume flow l

COLOUR FLOW IMAGE OF MIDDLE CEREBRAL ARTERY

MIDDLE CERBRAL ARTERY: NORMAL WAVEFORM

MIDDLE CEREBRAL ART.: ABNORMAL WAVEFORM: BRAIN SPARING

Fetal middle cerebral artery Pulsatility Index

Fetal anterior/middle/posterior cerebral art PI

Middle cerebral art. mean blood flow velocity cm/sec

Scherjon et al; Pediatrics, 2005; 205:385-391 (ISUOG;Brezinka,2011)

Umbilical venous cross-sectional area

Umbilical venous volume flow (ml/min) = 0 Umbilical venous volume flow (ml/min) = 0.06 x (time averaged velocity (mm/s) x cross-sectional area (mm2) )

Umbilical venous blood flow (ml/min)

Umbilical venous blood flow/kg fetus

Umbilical artery Pulsatility Index Mean SD SGA with normal volume flow/kg fetus 1.7  0.9 SGA with reduced volume flow/kg fetus 3.2  2.2 p-value <0.05

BRAIN /LIVER VOLUME RATIO WAT HAPPENS TO THE BRAIN TO LIVER VOLUME RATIO IN THE PRESENCE OF UTERO-PLACENTAL INSUFFIENCY AS EXPRESSED BY UMBILICAL VENOUS BLOOD FLOW ?

Brain volume measured with 3DUS Glabella Opisthion ‘Vocal mode’

Fetal Liver volume (ml)

Normal fetal brain volume relative to gestational age age BV(ml)= 1/12  x (HC / )3

Estimated brain/liver volume ratio relative to umbilical venous volume flow/ kg fetal weight

In the presence of fetal growth restriction umbilical venous volume flow is significantly reduced When taking into account umbilical venous volume flow data standardised for fetal weight, reduced values are associated with raised umbilical artery pulsatility index values indicating raised fetal placental downstream impedance due to progressive fetal hypoxaemia In fetal growth restriction, fetal brain/liver volume ratio starts to increase at umbilical venous volume flow levels of as low as 70-80 ml/l when standardised for fetal weight

Management of Rhesus disease

Mari et al NEJM 2001 Moving from amnio + Liley chart to fetal blood typing from maternal blood and non-invasive MCA Doppler PSV has revolutionized the management of Rhesus disease Amniocentesis almost never performed; cordocentesis only as a prelude to transfusion: Far fewer invasive tests 27

Fetal hemodynamic adaptive changes related to intrauterine growth Fetal hemodynamic adaptive changes related to intrauterine growth. The Generation R study Depts Obstetrics & Gynaecology, Division of Obstetrics & Perinatal Medicine; Epidemiology & Biostatistics; Pediatrics, Erasmus university Medical School. Authors: BO Verburg VWV Jaddoe JW Wladimiroff A Hofman JCM Witteman EAP Steegers

Umbilical venous cross-sectional area

Umbilical venous blood flow (ml/min)

Umbilical venous blood flow/kg fetus

Brain volume measured with 3DUS Glabella Opisthion ‘Vocal mode’

Conclusions Fetal growth restriction is characterised by centralisation of the circulation with preferential blood supply/oxygenation of fetal brain,( heart and adrenals); Fetal cerebral bloodflow: increased diastolic blood flow indicates fetal brain sparing; increased systolic blood flow indicates fetal anaemia; Reduction of umbilical venous bloodflow to 60-80ml/kg/min is associated with an increase in fetal brain/liver volume ratio

Umbilical artery Pulsatility Index Mean SD SGA with normal volume flow/kg fetus 1.7  0.9 SGA with reduced volume flow/kg fetus 3.2  2.2 p-value <0.05

Umbilical venous TA velocity (mm/s)

Umbilical venous area (mm2)

Fetal descending aorta PI

Estimated brain/liver volume ratio relative to umbilical venous volume flow/ kg fetal weight

CONCLUSIONS Normal umbilical venous volume flow increases approximately 7-fold during the second half of pregnancy A gestational age related decrease exists for umbilical venous volume flow per kg fetus, that is standardised for fetal weight

Blood supply to the fetal brain