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Selected Regional Changes in Brain Diffusivity in Isolated Mild Fetal Ventriculomegaly
Ronen Bercovitz M.A, Gal Yaniv M.D. PhD, Eldad Katorza M.D, Dafi Bergman B.Sc, Anat Biegon PhD, Chen Hoffmann M.D
Department of Diagnostic Imaging and Obstetrical & Gynecological Sheba Medical Center, Sackler School of Medicine, Tel Aviv University
Stony Brook University School of Medicine, Stony Brook, NY, USA
Background• Ventriculomegaly (VM) is a term used when the lateral
ventricles become dilated (Size>10 mm)
• The most common definition uses the atrium width of the lateral ventricle
• VM occurs in around 1% of pregnancies
Background
Ventriculomegaly
Mild ( 10-12 mm)
Moderate
( 13-15 mm)
Severe >(
15 mm )
• Traditionally VM was divided into three groups
Background
Ventriculomegaly
Mild ( 10-15 mm)
Severe >(
15 mm )
• Today it is also common to divide VM severity
Background• Isolated VM (IMVM) is defined as an enlargement
of ventricles without any additional pathology
Background• There is no consensus about the clinical
significance of IMVM
• The reported incidence of associated neurological pathology ranges from 0-36%
• We seek for imaging markers for better understanding the IMVM outcomes
Background• Apparent Diffusion Coefficient (ADC) values gradually
change during fetal life with a typical pattern
• Fetal brain ADC does not change significantly during the 3rd trimester
Purpose• To evaluate the impact of symmetric and asymmetric
Isolated Mild Ventriculomegaly (IMVM) on Apparent Diffusion Coefficient (ADC) values in the fetal brain
Symmetric IMVMAsymmetric IMVM
Materials and methods• 67 fetuses with IMVM were scanned
between 2009-2014
• MRI and – Ultrasound proven IMVM
• Compared to 38 normal feMRI scans matched for gestational age (controls).
Materials and methods• IMVM cases were divided into 3 groupes
• AVM- Asymmetrical ventriculomegaly• SVM- Symmetrical ventriculomegaly• AV1normal- Asymmetrical ventricles with one
normal-sized ventricle
Asymmetrical VM≥)2
mm difference in
atrial width
)Symmetrical VM
<)2
mm difference
in atrial width
)Asymmetrical
ventricles with one
normal-sized ventricle
Materials and methods• ADC measurements
• ROI locations: A: Frontal & Parietal lobe WM.B: Basal ganglia. C: Thalamus.D: Temporal & Occipital lobe WM. E: Cerebellum. F: Pons
Results: Elevated ADC values • ADC values were significantly elevated in the basal
ganglia (BG) of the AV1normal and SVM groups
• Results were compared to 38 normal feMRI scans matched for GA
SVMAV1normalControl
38
42
17
P <0.003**
*
Results: Elevated ADC values AV1normal Group
AV1normal group
• Results were compared to 38 normal feMRI scans matched for GA
• The ADC values in the BG were elevated only ipsilateral to the enlarged atrium
Results: Reduced ADC valuesAVM and SVM groups
• Frontal lobe ADC values were significantly reduced
• Results were compared to 38 normal feMRI scans matched for GA
SVMAVMControl
38
8
17
P <0.003*
*
*
Results: Reduced ADC valuesAVM group
• Temporal lobe ADC values were significantly reduced
• Results were compared to 38 normal feMRI scans matched for GA
AVM
Control
38 8
P <0.001*
*
Discussion• We identified distinct ADC value changes
in different brain regions in each IMVM group
basal ganglia Frontal lobe Temporal lobe
AV1normal group
SVM group
SVM group
AVM group
AVM group
Discussion• ADC value change analysis
ADC
Reduced ADC values
• Hyper-cellularity
• Acute ischemia
• Premature development )premature myelin synthesis)
Frontal lobe
SVM group
AVM group
Temporal lobe
AVM group
Discussion• ADC value change analysis
ADC
Elevated ADC values
• Hypo-cellularity
• Edema
• Developmental delay )delayed myelin synthesis)
basal ganglia
AV1normal group
SVM group
Conclusions
• Changes in ADC values may contribute to the understanding of different IMVM significance
• A clinco-pathological correlation between ADC changes and Vineland questioner score is needed
• Different IMVM subgroups are associated with distinct ADC values in different brain regions
Discussion
ADC
Reduced ADC values
• Hyper-cellularity
• Acute ischemia
• Premature development )premature myelin synthesis)
ADC
Elevated ADC values
• Hypo-cellularity
• Edema
• Developmental delay )delayed myelin synthesis)