Persistent Periventricular Echogenicities in Preterms Are Not Related to Smaller Brains at Term-Equivalent Age

Abstract

Background: Periventricular white matter (PWM) is particularly vulnerable in very preterm infants. Non-cystic white matter injury, known as non-cystic periventricular leukomalacia (ncPVL), is the commonest ‘lesion' affecting the preterm brain. There is no consensus about whether ncPVL can be reliably identified from cerebral ultrasound (cUS) or whether there is any reliable correlate of ncPVL on cUS at term-equivalent age (TEA). Objective: To compare brain volumes and linear measures at TEA in infants with and without a diagnosis of ncPVL. Methods: Preterm infants of ≤32 weeks' gestation without major lesions were serially assessed using cUS. ncPVL was defined as PWM echogenicity comparable to the choroid plexus on two scans at least 2 weeks apart after the first postnatal week. At TEA, infants were scanned for the estimation of brain volume and ventricular and tissue dimensions. Head circumference was measured. The data were compared between those with/without ncPVL. Observer agreement was assessed using kappa statistic. Results: Of 63 eligible infants 29% had ncPVL. Significant differences were found between those with/without ncPVL for 5 min Apgar score, CRIB score, invasive ventilation rates and chronic lung disease but not for other relevant clinical data. No significant differences were found for estimated brain volume, ventricular size, corpus callosum length/thickness or central grey matter width. Intra-observer reliability was moderate (kappa = 0.51-0.56); inter-observer reliability was poor (kappa = 0.20-0.32). Conclusions: This study indicates that an ultrasound diagnosis of ncPVL should not be used as a sole predictor of lower brain growth detectable at TEA.

Enlarged subarachnoid space on cranial ultrasound in preterm infants: Neurodevelopmental implication

“…White matter injuries on MRI at term-equivalent age in very preterm infants are reportedly associated with grey matter abnormalities (including reduction in cerebral cortical grey matter volume) and future neurological impairment 7,8 . However, periventricular echogenicity greater than that of the choroid plexus, or inhomogeneous flares, which is often considered a possible US finding of non-cystic PVL 9,10 , has presented inconsistent association with punctate or diffuse white matter injuries or decreased brain volumes on MRI at term-equivalent age 11–13 or future adverse neurological outcomes 14–16 . Rather, other combined cUS findings supportive of cerebral atrophy showed an association with neurodevelopmental outcome in previous literature 14 , with enlarged subarachnoid space (ESS) being one of them.…”

What is the exact mechanism underlying periventricular echogenicity?

“…Although periventricular echogenicity (PVE) is more common than PVL, the effect of PVE on the neurologic outcome has not yet been clearly understood. 1…”