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

Background• ADC values are a useful tool for assessing brain

pathology and development

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

Thank You

Contact us:

chen.hoffmann@sheba.health.gov.ilronen.bercovitz@sheba.health.gov.ilwww.imaging.sheba.co.il

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)

Limitations• Some of our study groups are small

(AVM and SVM groups)

• Lack of clinical follow up of fetuses

• Lack of definitive explanation to results

SVMAVMControl38

8

17