Instability of Doppler cerebral blood flow in monochorionic twins.
OBJECTIVE
The purpose of this study was to evaluate Doppler flow velocity changes in cerebral vessels of monochorionic twins with twin-twin transfusion syndrome (TTTS).


METHODS
Repeated Doppler umbilical and cerebral blood flow studies were performed in 7 twin pairs with TTTS. Eight monochorionic twin pairs and 11 dichorionic twin pairs served as control groups. The following Doppler parameters were assessed: umbilical artery pulsatility index (PI), middle cerebral artery (MCA) PI, cerebroplacental ratio, delta PI between the umbilical artery and MCA, and peak systolic velocity (PSV) in the MCA.


RESULTS
Significant variations in PSV in the MCA and cerebral indices were found in the study group of monochorionic twins with TTTS. Periods of high PSV with low PI in the MCA were followed by lower PSV in the same fetus. Repeated measurements in the comparison groups were stable without significant variations. The delta cerebroplacental ratio was significantly higher in the study group (0.38 versus 0.09 and 0.19 in the comparison groups; P < .02).


CONCLUSIONS
Significant changes in Doppler flow velocity and indices suggest instability of cerebral blood flow with episodes of "hyperperfusion" in monochorionic twins with TTTS. Further studies are needed to elucidate the relationship of these transient changes to neurologic sequelae in the neonate.
Department of Obstetrics and Gynecology, Bnei-Zion Medical Center, Ruth and Baruch Rappaport Faculty of Medicine, Technion- Institute of Technology, Haifa, Israel. sdegani@tx.technion.ac.il
Shimon
S
Degani
Zvi
Z
Leibovitz
Israel
I
Shapiro
Ron
R
Gonen
Gonen
G
Ohel
D001783:Blood Flow Velocity; D001921:Brain / Q000098:blood supply* / Q000196:embryology*; D002560:Cerebrovascular Circulation; D002823:Chorion / Q000002:abnormalities* / Q000000981:diagnostic imaging; D015150:Echocardiography, Doppler / Q000379:methods*; D004453:Echoencephalography / Q000379:methods; D005260:Female; D005330:Fetofetal Transfusion / Q000000981:diagnostic imaging*; D006801:Humans; D011247:Pregnancy; D011263:Pregnancy Trimester, Third; D016216:Ultrasonography, Prenatal / Q000379:methods*