Quantitative susceptibility map analysis in preterm neonates with germinal matrix‐intraventricular hemorrhage

• Published in: Journal of magnetic resonance imaging Vol. 48; no. 5; pp. 1199 - 1207
• Main Authors: Tortora, Domenico, Severino, Mariasavina, Sedlacik, Jan, Toselli, Benedetta, Malova, Mariya, Parodi, Alessandro, Morana, Giovanni, Fato, Marco Massimo, Ramenghi, Luca Antonio, Rossi, Andrea
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01-11-2018
• Subjects: Age; Basal ganglia; Blood; Brain; Cerebellum; Covariance; Degradation products; Diamagnetism; Ferritin; Field strength; Ganglia; germinal matrix hemorrhage; Gestational age; Hemoglobin; Hemorrhage; Image processing; intraventricular hemorrhage; Iron; Magnetic resonance imaging; Magnetic susceptibility; neonate; Neonates; Neuroimaging; Population (statistical); preterm; quantitative susceptibility map; Spatial distribution; Statistical analysis; Statistical tests; Substantia grisea; Tissues; Ventricle; Ventricles (cerebral); preterm; germinal matrix hemorrhage; neonate; magnetic susceptibility; intraventricular hemorrhage; quantitative susceptibility map
• ISSN: 1053-1807; 1522-2586
• DOI: 10.1002/jmri.26163

Background
Germinal matrix‐intraventricular hemorrhage (GMH‐IVH) is a common form of intracranial hemorrhage occurring in preterm neonates that may affect normal brain development. Although the primary lesion is easily identified on MRI by the presence of blood products, its exact extent may not be recognizable with conventional sequences. Quantitative susceptibility mapping (QSM) quantify the spatial distribution of magnetic susceptibility within biological tissues, including blood degradation products.
Purpose/Hypothesis
To evaluate magnetic susceptibility of normal‐appearing white (WM) and gray matter regions in preterm neonates with and without GMH‐IVH.
Study Type
Retrospective case‐control.
Population
A total of 127 preterm neonates studied at term equivalent age: 20 had mild GMH‐IVH (average gestational age 28.7 ± 2.1 weeks), 15 had severe GMH‐IVH (average gestational age 29.3 ± 1.8 weeks), and 92 had normal brain MRI (average gestational age 29.8 ± 1.8 weeks).
Field Strength/Sequence
QSM at 1.5 Tesla.
Assessment
QSM analysis was performed for each brain hemisphere with a region of interest‐based approach including five WM regions (centrum semiovale, frontal, parietal, temporal, and cerebellum), and a subcortical gray matter region (basal ganglia/thalami).
Statistical Tests
Changes in magnetic susceptibility were explored using a one‐way analysis of covariance, according to GMH‐IVH severity (P < 0.05).
Results
In preterm neonates with normal brain MRI, all white and subcortical gray matter regions had negative magnetic susceptibility values (diamagnetic). Neonates with severe GMH‐IVH showed higher positive magnetic susceptibility values (i.e. paramagnetic) in the centrum semiovale (0.0019 versus ‐0.0014 ppm; P < 0.001), temporal WM (0.0011 versus ‐0.0012 ppm; P = 0.037), and parietal WM (0.0005 versus ‐0.0001 ppm; P = 0.002) compared with controls. No differences in magnetic susceptibility were observed between neonates with mild GMH‐IVH and controls (P = 0.236).
Data Conclusion
Paramagnetic susceptibility changes occur in several normal‐appearing WM regions of neonates with severe GMH‐IVH, likely related to the accumulation of hemosiderin/ferritin iron secondary to diffusion of extracellular hemoglobin from the ventricle into the periventricular WM.
Level of Evidence: 4
Technical Efficacy: Stage 3
J. Magn. Reson. Imaging 2018;47:1199–1207.