Role of the advanced MRI sequences in predicting the outcome of preterm neonates
Creators: name: TORTORA, DOMENICO
Publisher: name: Universit� degli studi di Genova
Year: 2019

description: AIM
The aim of the project is to evaluate the role of advanced MRI sequences
(susceptibility weight imaging (SWI), diffusion tensor imaging (DTI), and arterial
spin labeling (ASL) perfusion) in detecting early changes that affect preterm neonatal
brain, especially in those patients without lesions at conventional MRI or with small
brain injuries (i.e. low grade germinal matrix-intraventricular hemorrhage (GMHIVH)),
and to correlate these subtle brain abnormalities with neurodevelopmental
outcome at 24 months.
METHODS
Since November 2015 until June 2017, 287 preterm neonates and 108 term neonates
underwent a 3T or 1.5T MRI study at term corrected age (40�1 weeks). SWI, DTI
and ASL sequences were performed in all neonates. SWI sequences were evaluated
using both a qualitative (SWI venography) and quantitative (Quantitative
Susceptibility Map analysis (SWI-QSM)) approach. DTI data were analyzed using a
Tract-Based Spatial Statistics analysis (TBSS). ASL studies were processed to
estimate Cerebral Blood Flow (CBF) maps. Perinatal clinical data were collected for
all neonates. Neurodevelopmental data were evaluated at 24 months in 175 neonates
using 0-2 Griffiths Developmental Scales.
RESULTS
The analysis performed on SWI-venography revealed differences in subependymal
veins morphology between preterm and term neonates with normal brain MRI, with
a higher variability from the typical anatomical pattern in preterm neonates. The same
analysis performed in preterm neonates with GMH-IVH revealed that the anatomical
features of subependymal veins may play a potential role as predisposing factor for
GMH-IVH. Moreover, the SWI-QSM analysis revealed a greater paramagnetic
susceptibility in several periventricular white matter (WM) regions in preterm
neonates with GMH-IVH than in healthy controls. This finding is likely related to the
accumulation of hemosiderin/ferritin following the diffusion of large amounts of
intraventricular blood products into the WM, and it is also supposed to trigger the
cascade of lipid peroxidation and free radical formation that promote oxidative and
inflammatory injury of the WM in neonatal brain after GMH-IVH. The TBSS
analysis confirmed that microstructural WM injury can occur in preterm neonates
with low grade GMH-IVH even in the absence of overt signal changes on
conventional MRI, with different patterns of WM involvement depending on
gestational age. Moreover, the distribution of these WM microstructural alterations after GMH-IVH correlates with specific neurodevelopmental impairments at 24
months of age. Finally, the analysis of brain perfusion at term-corrected age revealed
lower CBF in preterms with sub-optimal neuromotor development, reinforcing the
hypothesis that impaired autoregulation of CBF may contribute to the development
of brain damage in preterm neonates.
CONCLUSION
Advanced MRI sequences can assist the standard perinatal brain imaging in the early
diagnosis of preterm neonatal brain lesions and can provide new insights for
predicting the neurodevelopmental trajectory. However, detailed and serial imaging
of carefully chosen cohorts of neonates coupled with longer clinical follow-up are
essential to ensure the clinical significance of these novel findings.