. Author manuscript; available in PMC: 2018 Nov 3.

Published in final edited form as: J Perinatol. 2018 Aug 30;38(11):1431–1443. doi: 10.1038/s41372-018-0209-5

Table 3.

Definitions of head ultrasound ventricle size measurements and resistive index [10–1,5, 34, 50]

Measurements of ventricle size, resistive index on HUS
Ventricular index (VI)	Distance from lateral wall of the lateral ventricle body to the falx
Anterior horn width (AHW)	Distance from medial wall to floor of lateral ventricle at the level of the interventricular foramina of Monro
Thalamooccipital distance (TOD)	Depth of the occipital horn, or distance from outermost point of the thalamus at its junction with the choroid plexus to the outermost part of the occipital horn posteriorly in the oblique parasagittal view
Ventricle/brain (V/B) ratio	(Vl-left + VI-right)/biparietal diameter
Resistive index (RI)^a	(Systolic pressure—diastolic pressure)/systolic pressure

Preterm infants have statistically significant higher baseline RI values in comparison to term infants (0.7 in preterm, 0.66 in term). With compression these numbers remain stable (0.71 and 0.68, respectively), indicating effective autoregulation regardless of gestational age