Fetal MRI is an important tool for the prenatal diagnosis of brain malformations and is often requested after second‐trimester ultrasonography reveals a possible abnormality. Despite the immature ...state of the fetal brain at this early stage, early suggestive signs of the presence of brain malformations can be recognized. To differentiate between the normal dynamics of the growing brain and the developing pathological conditions can be challenging and requires extensive knowledge of normal central nervous system developmental stages and their neuroradiological counterparts at those different stages. This article reviews the second‐trimester appearances of some commonly encountered brain malformations, focusing on helpful tricks and subtle signs to aid in the diagnosis of such conditions as rhombencephalosynapsis, various causes of vermian rotation, molar tooth spectrum anomalies, diencephalic‐mesencephalic junction dysplasia, ganglionic eminence anomalies, and the most common malformations of cortical development.
Fetal MRI is an important tool for the prenatal diagnosis of brain malformations and is often requested after second‐trimester ultrasonography reveals a possible abnormality. Despite the immature state of the fetal brain at this early stage, early suggestive signs of the presence of brain malformations can be recognized.
The basal ganglia and thalami are paired deep grey matter structures with extensive metabolic activity that renders them susceptible to injury by various diseases. Most pathological processes lead to ...bilateral lesions, which may be symmetric or asymmetric, frequently showing characteristic patterns on imaging studies. In this comprehensive pictorial review, the most common and/or typical genetic, acquired metabolic/toxic, infectious, inflammatory, vascular and neoplastic pathologies affecting the central grey matter are subdivided according to the preferential location of the lesions: in the basal ganglia, in the thalami or both. The characteristic imaging findings are described with emphasis on the differential diagnosis and clinical context.
Objectives
To evaluate white matter (WM) microstructural changes in preterm neonates (PN) with mild germinal matrix-intraventricular haemorrhage (mGMH-IVH) (grades I and II) and no other associated ...MRI abnormalities, and correlate them with gestational age (GA) and neurodevelopmental outcome.
Methods
Tract-based spatial-statistics (TBSS) was performed on DTI of 103 patients studied at term-equivalent age, to compare diffusional parameters (fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), axial diffusivity (AD)) between mGMH-IVH neonates (24/103) and controls matched by GA at birth and sex. The relationship between DTI abnormalities, GA and neurodevelopmental outcome assessed with Griffiths’ Developmental Scale-Revised:0-2 was explored using TBSS and Spearman-correlation analysis (
p
< .05).
Results
Affected neonates had lower FA, higher RD and MD of the corpus callosum, limbic pathways and cerebellar tracts. Extremely preterm neonates (GA < 29 weeks) presented more severe microstructural impairment (higher RD and MD) in periventricular regions. Neonates of GA ≥ 29 weeks had milder WM alterations (lower FA), also in subcortical WM. DTI abnormalities were associated with poorer locomotor, eye-hand coordination and performance outcomes at 24 months.
Conclusions
WM microstructural changes occur in PN with mGMH-IVH with a GA-dependent selective vulnerability of WM regions, and correlate with adverse neurodevelopmental outcome at 24 months.
Key Points
•
DTI-TBSS analysis identifies WM microstructural changes in preterm neonates with mGMH-IVH.
•
Extremely preterm neonates with mGMH-IVH presented more severe impairment of WM microstructure.
•
Extremely preterm neonates with mGMH-IVH presented microstructural impairment of periventricular WM.
•
mGMH-IVH affects subcortical WM in preterm neonates with gestational age ≥ 29 weeks.
•
WM microstructural alterations are related to neurodevelopmental impairments at 24 months.
Purpose
In moyamoya vasculopathy, prolonged arterial transit time may increase the arterial spin labeling (ASL) signal heterogeneity, which can be quantitatively expressed by the spatial coefficient ...of variation of ASL-CBF (ASL-sCoV). The aim was to compare the accuracy of ASL-sCoV and ASL-CBF with dynamic susceptibility contrast (DSC)-CBF and time-to-peak (DSC-TTP) in the evaluation of perfusion changes and clinical outcome after encephalo-duro-arterio-myo-synangiosis (EDAMS) in pediatric moyamoya patients.
Methods
A total of 37 children with moyamoya vasculopathy (mean age 6.31 years (1.12–15.42)) underwent ASL and DSC perfusion imaging at 3T before and up to 24 months after EDAMS. Mean DSC-CBF, mean DSC-TTP, mean ASL-CBF, and ASL-sCoV were calculated in middle cerebral artery territories. Generalized linear model analyses were used to evaluate temporal variations of postoperative perfusion changes and to compare these variations between patients developing valid pial collateralization and those without angiographic improvement. Relationship between perfusion parameters and clinical outcome after surgery was tested using multivariate regression analysis.
Results
Significant reduction was observed after EDAMS for ASL-sCoV (
P
= .002; eta-squared (η
2
) = 0.247) and DSC-TTP (
P
< .001; η
2
= 0.415), whereas only a trend of increase was observed for DSC-CBF and ASL-CBF, with larger discrepancy before and 6 months after surgery. At last follow-up, children developing pial collateralization showed lower absolute ASL-sCoV (
P
= .002 Cohen’s d = 0.84) and DSC-TTP (
P
= .027; Cohen’s d = 0.64) and higher DSC-CBF (
P
= .002; Cohen’s d = − 0.55) compared with those without vascular improvement. Low preoperative and early post-surgical ASL-sCoV predicted better long-term neurological outcome (
P
< .001; ß = − 0.631).
Conclusions
ASL-sCoV may contribute to predict surgical outcomes in pediatric moyamoya patients undergoing EDAMS.
Purpose
The aim of this study was to investigate MRI-derived diffusion weighted imaging (DWI) and arterial spin labeling (ASL) perfusion imaging in comparison with
18
F–dihydroxyphenylalanine (DOPA) ...PET with respect to diagnostic performance in tumor grading and outcome prediction in pediatric patients with diffuse astrocytic tumors (DAT).
Methods
We retrospectively analyzed 26 children with histologically proven treatment naïve low and high grade DAT who underwent ASL and DWI performed within 2 weeks of
18
F–DOPA PET. Relative ASL-derived cerebral blood flow max (rCBF max) and DWI-derived minimum apparent diffusion coefficient (rADC min) were compared with
18
F–DOPA uptake tumor/normal tissue (T/N) and tumor/striatum (T/S) ratios, and correlated with World Health Organization (WHO) tumor grade and progression-free survival (PFS). Statistics included Pearson’s chi-square and Mann-Whitney U tests, Spearman’s rank correlation, receiver operating characteristic (ROC) analysis, discriminant function analysis (DFA), Kaplan-Meier survival curve, and Cox analysis.
Results
A significant correlation was demonstrated between rCBF max, rADC min, and
18
F–DOPA PET data (
p
< 0.001). Significant differences in terms of rCBF max, rADC min, and
18
F–DOPA uptake were found between low- and high-grade DAT (
p
≤ 0.001). ROC analysis and DFA demonstrated that T/S and T/N values were the best parameters for predicting tumor progression (AUC 0.93,
p
< 0.001). On univariate analysis, all diagnostic tools correlated with PFS (
p
≤ 0.001); however, on multivariate analysis, only
18
F–DOPA uptake remained significantly associated with outcome (
p
≤ 0.03), while a trend emerged for rCBF max (
p
= 0.09) and rADC min (
p
= 0.08). The combination of MRI and PET data increased the predictive power for prognosticating tumor progression (AUC 0.97,
p
< 0.001).
Conclusions
DWI, ASL and
18
F–DOPA PET provide useful complementary information for pediatric DAT grading.
18
F–DOPA uptake better correlates with PFS prediction. Combining MRI and PET data provides the highest predictive power for prognosticating tumor progression suggesting a synergistic role of these diagnostic tools.
Purpose
The long-term impact of low-grade germinal matrix-intraventricular hemorrhage (GMH-IVH) on brain perfusion has not been fully investigated. We aimed to compare cortical and deep gray matter ...(GM) cerebral blood flow (CBF) obtained with pseudo-continuous arterial spin labeling (pCASL), among preterm neonates with and without low-grade GMH-IVH and full-term controls.
Methods
3T-pCASL examinations of 9 healthy full-term neonates (mean gestational age 38.5 weeks, range 38–39) and 28 preterm neonates studied at term-equivalent age were analyzed. Eighteen preterm neonates presented normal brain MRI (mean gestational age 30.50 weeks, range 29–31) and 10 low-grade GMH-IVH according to Volpe’s grading system (mean gestational age 32 weeks, range 28–34). A ROI-based mean CBF quantification was performed in 5 cortical (frontal, parietal, temporal, insula, occipital), and 4 subcortical GM regions (caudate, putamen, pallidum, thalamus) for each cerebral hemisphere. CBF differences were explored using a nonparametric analysis of covariance.
Results
Low-grade GMH-IVH hemispheres showed consistently lower CBF in all GM regions when compared with healthy preterm neonates, after controlling the confounding effect of gestational age, postmenstrual age, and birth weight
P
< .001, η
2
= .394. No significant differences were observed between neonates with low-grade GMH and full-term controls. Healthy preterm neonates showed significantly higher CBF than full-term controls in parietal (
P
= .032), temporal (
P
= .016), and occipital cortex (
P
= .024), and at level of thalamus (
P
= .023) and caudate nucleus (
P
= .014).
Conclusion
Low-grade GMH-IVH is associated with lower CBF in posterior cortical and subcortical gray matter regions in preterm neonates, suggesting regional vulnerability of these developing brain structures.
Purpose
The aim of this study was to compare arterial spin labeling (ASL) and dynamic susceptibility contrast (DSC) MRI perfusion with respect to diagnostic performance in tumor grading in pediatric ...patients with low- and high-grade astrocytic tumors (AT).
Methods
We retrospectively analyzed 37 children with histologically proven treatment naive low- and high-grade AT who underwent concomitant pre-operative ASL and DSC MRI perfusion. Studies were performed on a 1.5 T scanner, and a pulsed technique was used for ASL. DSC data were post-processed with a leakage correction software. Normalization of tumor perfusion parameters was performed with contralateral normal appearing gray matter. Normalized cerebral blood volume (nCBV) values in the most perfused area of each neoplasm were compared with normalized DSC-derived cerebral blood flow (nDSC-CBF) and ASL-derived cerebral blood flow (nASL-CBF) data, and correlated with WHO tumor grade. Statistics included Pearson’s chi-square and Mann-Whitney
U
tests, Spearman’s rank correlation, and receiver operating characteristic (ROC) analysis.
Results
A significant correlation was demonstrated between DSC and ASL data (
p
< 0.001). Significant differences in terms of DSC and ASL data were found between low- and high-grade AT (
p
< 0.001). ROC analysis demonstrated similar performances between all parameters in predicting tumor grade (nCBV: AUC 0.96,
p
< 0.001; nDSC-CBF: AUC 0.98,
p
< 0.001; nASL-CBF: AUC 0.96,
p
< 0.001).
Conclusions
Normalized pulsed ASL performed with a 1.5 T scanner provides comparable results to DSC MRI perfusion in pediatric AT and may allow distinction between high- and low-grade AT.
Morning glory disc anomaly is a congenital abnormality of the optic disc and peripapillary retina reported as an isolated condition or associated with various anomalies, including basal ...encephaloceles and moyamoya vasculopathy. However, the co-occurrence of these three entities is extremely rare and the pathogenesis is still poorly understood. Moreover, data on the surgical management and long-term follow-up of the intracranial anomalies are scarce. Here, we describe the case of a 11-year-old boy with morning glory disc anomaly, transsphenoidal cephalocele, and moyamoya vasculopathy, who underwent bilateral indirect revascularization with encephalo-duro-myo-arterio-pericranio-synangiosis at the age of 2 years, and endoscopic repair of the transsphenoidal cephalocele at the age of 6 years. A rare missense variant (c.1081T>C,p.Tyr361His) was found in
OFD1
, a gene responsible for a X-linked ciliopathy, the oral-facial-digital syndrome type 1 (OFD1; OMIM 311200). This case expands the complex phenotype of OFD1 syndrome and suggests a possible involvement of
OFD1
gene and
Shh
pathway in the pathogenesis of these anomalies.
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