Repeatability of Doppler ultrasound measurement of blood flow velocity and its variability in the supraclinoid segment of the internal carotid artery in preterm newborns.
Accuracy of transfontanellar Doppler ultrasound measurement of blood flow velocity and its variability in the supraclinoid segment of the internal carotid artery was studied in preterm newborns. Measurements were performed in duplicate, on a well defined site, under negligible angle of insonation, and during stable physical condition. The measurements included the base value and variability over 20 seconds, for: diastolic velocity; mean velocity; systolic velocity; resistance index; diastolic time interval; systolic time interval; heart beat duration. As a measure of accuracy the coefficient of repeatability was calculated for each parameter. Coefficients several times smaller than the range of measured values, were found for most parameters. These parameters and their coefficients include: diastolic velocity (base value 3.1 cm s-1, variability 1.6 cm s-1); mean velocity base value 3.1 cm s-1; systolic velocity base value 4.5 cm s-1; resistance index (base value 0.13, variability 0.08); diastolic time interval base value 25 ms; systolic time interval base value 27 ms; heart beat duration base value 27 ms. Thus, Doppler ultrasound enables differentiation within the biological variation of certain properties of cerebral blood flow.
Mullaart
R A
RA
Department of Child Neurology, University Hospital, The Netherlands.
Hopman
J C
JC
Daniels
O
O
Rotteveel
J J
JJ
De Haan
A F
AF
Vreuls
H J
HJ
D001783:Blood Flow Velocity; D002343:Carotid Artery, Internal; D002560:Cerebrovascular Circulation; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000502:physiology*; D015203:Reproducibility of Results; D014465:Ultrasonics; D014463:Ultrasonography