Background: In extremely premature newborns, the effect of ventriculomegaly, as seen on cranial ultrasound (CUS), on cerebral perfusion is not well studied. The resistive index (RI) (Figure-1) is a marker of change of the flow velocity on Doppler ultrasound that could be used to understand this effect.
Objective: To identify the following: 1- The normal RI values in premature infants without intraventricular hemorrhage (IVH), 2- The relation between the RI in the major intracerebral arteries and the ventricular size on CUS using the fronto-temporal horn ratio (FTHR) in newborns with and without IVH, and 3-The association with white matter injury on brain magnetic resonance imaging (MRI).
Design/Methods: A retrospective study at a tertiary care neonatal ICU. Inclusion criteria: 1) < 29 weeks gestational age (GA), 2) < 1500 grams birth weight (BW), 3) admitted in the first week of life with at least two cranial ultrasounds (CUS) performed, 4) brain MRI at term age equivalent. CUS images were reviewed to identify the IVH grade, FTHR, and RI values in the major intracerebral arteries [anterior cerebral (ACA), right and left middle cerebral (RMCA/LMCA)]. White matter injury on brain MRI was estimated using the Kidokoro score (2013).
Results: 100 newborns met the inclusion criteria between 2011- 2014: 37 had no IVH, 36 had grade 1-2 IVH, and 27 had grade 3-4 IVH. Median gestational age was 26 wks (range 23-28) and birth weight was 811g (range 410-1280). In newborns with no IVH, the RI values in the first week after birth were: ACA=0.75±0.1, RMCA=0.74±0.1, LMCA=0.74±0.1 and remained relatively stable throughout post menstrual age (PMA). FTHR for the whole sample positively correlated with RI ACA (p = 0.001), RI RMCA (p=0.08), RI LMCA (p=0.01) even after controlling for PMA and IVH group. Both FTHR and RI were significantly associated with moderate to severe cerebral injury (Kidokoro>8) on brain MRI. FTHR was a better predictor (AUROC: FTHR: 0.91, RI ACA: 0.64, RI RMCA: 0.63, RI LMCA: 0.61).
Conclusion(s): There are signs of change in cerebral blood flow velocity on Doppler ultrasound in the extremely premature newborns with ventriculomegaly. This will require further investigation to find the contribution to cerebral injury.
Obeid R, Jacobs M, Chang T, Massaro AN, Bulas D, Penn A. Cerebral perfusion using the resistive index on doppler ultrasound in extremely premature newborns with ventriculomegaly. Poster presented at: Pediatric Academic Societies, PAS 2021 Virtual. 2021, Phase I: April 30-May 4, Phase II: May 10-June 4; Virtual.