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Optical Coherence Tomography To Evaluate Changes In Vasculature
Of The Murine Fetal Brain In Utero Due To Prenatal Alcohol
Exposure
Raksha Raghunathan1, Chen Wu1, Manmohan Singh1, Chih-Hao Liu1, Rajesh C. Miranda2, and Kirill V. Larin1,*
1Department
of Biomedical Engineering, University of Houston
2Department of Neuroscience and Experimental Therapeutics, TAMHSC College of Medicine
*Contact author: University of Houston, 2026 SERC, Houston, TX 77204.
Email: [email protected] Ph:No: 832-842-8834
Fetal Alcohol Syndrome Disorder
• Fetal Alcohol Syndrome (FAS):
 First described in 1973 [1].
 Was defined as a pattern of birth defects associated with prenatal alcohol exposure.
• However due to the broad spectrum of developmental and behavioral effects, fetal alcohol syndrome disorder
(FASD) was a general term coined for any adverse effect caused with prenatal alcohol exposure [2].
• FASD includes:
 FAS
 Partial FAS
 Alcohol- related birth defects (ARBD)
 Alcohol related neurodevelopmental disorder (ARND)
 Neurobehavioral disorder associated with prenatal alcohol exposure (ND-PAE).
• However, the term FASD is not used for clinical diagnosis.
1. Jones, K. and D. Smith, Recognition of the Fetal Alcohol Syndrome in Early Infancy. The Lancet, 1973. 302(7836): p. 999-1001.
2. Williams, J.F. and V.C. Smith, Fetal Alcohol Spectrum Disorders. Pediatrics, 2015. 136(5): p. e1395.
Common Facial Defects Associated With
FASD
3. Smith, S.M., Alcohol-Induced Cell Death in the Embryo. Alcohol Health Res World, 1997. 21(4): p. 287-97.
Effects Of Ethanol On Fetal Neurogenesis
• Second trimester is a critical period for fetal neurogenesis and brain angiogenesis.
• Ethanol is known to directly affect several aspects of neural development including:
 Biology of stem cells [4]
 Neuronal migration [5]
• Also known to cause behavioral deficits.
• Vasculature development in the brain during this stage is of great importance. [6]
How does maternal ethanol consumption affect this vasculature development?
4. C. Camarillo, and R. C. Miranda, "Ethanol exposure during neurogenesis induces persistent effects on neural maturation: evidence from an ex vivo model of fetal cerebral cortical
neuroepithelial progenitor maturation," Gene Expr 14(3), 159-171 (2008).
5. B. M. Altura et al., "Ethanol promotes rapid depletion of intracellular free Mg in cerebral vascular smooth muscle cells: Possible relation to alcohol-induced behavioral and stroke-like
effects," Alcohol 10(6), 563-566 (1993).
6. M. G. Norman, and J. R. O'Kusky, "The growth and development of microvasculature in human cerebral cortex," J Neuropathol Exp Neurol 45(3), 222-232 (1986).
Previously Used Imaging Modalities For Brain Imaging To Study FASD
Histology:
• Traditional method
• Time consuming
• Cannot be performed in vivo
Micro-Magnetic resonance imaging (MRI) [7]:
• requires external contrast agent (may harm the embryos)
• Long acquisition times
Micro-Computed tomography (CT) [8]:
• Uses ionizing radiation (may harm the embryos)
Ultrasound(US) [9]:
• Low spatial resolution.
7. V. W. Swayze et al., "Magnetic Resonance Imaging of Brain Anomalies in Fetal Alcohol Syndrome," Pediatrics 99(2), 232 (1997).
8. Belma, D., et al. (2007). "Digimouse: a 3D whole body mouse atlas from CT and cryosection data." Physics in Medicine and Biology 52(3): 577.
9. Sudheendran, N., S. Bake, R.C. Miranda, and K.V. Larin, Comparative Assessments of the Effects of Alcohol Exposure on Fetal Brain Development Using Optical Coherence Tomography and
Ultrasound Imaging. J Biomed Opt, 2013. 18(2): p. 20506.
Optical Coherence Tomography
• Well established optical imaging modality based on low coherence interferometry [10].
• Optical analog of ultrasound.
• Capable of label-free, noninvasive, depth-resolved imaging of tissue with micrometer-scale spatial resolution.
• Widely used in many applications today including:
 Ophthamology [11]
 Dermatology [12]
 Cardiology [13]
 Cancer imaging [14]
 Embryology [15]
10. Huang, D., et al. (1991). "Optical coherence tomography." Science 254(5035): 1178-1181
11. Drexler, W., et al. (2003). "Enhanced visualization of macular pathology with the use of ultrahigh-resolution optical coherence tomography." Arch Ophthalmol 121(5): 695-706.
12. Sattler, E., et al. (2013). "Optical coherence tomography in dermatology." J Biomed Opt 18(6): 061224.
13. Jang, I. K., et al. (2005). "In vivo characterization of coronary atherosclerotic plaque by use of optical coherence tomography." Circulation 111(12): 1551-1555.
14. Vakoc, B. J., et al. (2012). "Cancer imaging by optical coherence tomography: preclinical progress and clinical potential." Nat Rev Cancer 12(5): 363-368.
15. Raghunathan, R., et al. (2016). "Optical coherence tomography for embryonic imaging: a review." Journal of Biomedical Optics 21(5): 050902-050902.
Why Use Optical Coherence Tomography In
Embryology?
• Ability to provide cross sectional images
• Noninvasive nature
 Live imaging of embryos possible
• High spatial and temporal resolution
• Rapid acquisition speeds
[9]
Resolution comparison of an a)OCT image
b)Ultrasound image
16. Wang, S., D.S. Lakomy, M.D. Garcia, A.L. Lopez, 3rd, K.V. Larin, and I.V. Larina, Four-Dimensional Live Imaging of Hemodynamics in Mammalian Embryonic Heart with Doppler
Optical Coherence Tomography. J Biophotonics, 2016.
[16]
Overview of The Study
• Acute vasculature changes in the embryonic brain after maternal alcohol exposure.
• In utero imaging using OCT.
• Speckle variance OCT (SVOCT) [17, 18] was used to image the vasculature changes.
• Pregnant mice at E 14.5 were used.
• SVOCT measurements were taken before and upto 45 minutes after the gavage.
 Intervals of 5 minutes.
• Gavage: 95% ethanol at a volume of 3g/ kg.
• Preliminary results have been shown.
17. Mariampillai, A., et al. (2008). "Speckle variance detection of microvasculature using swept-source optical coherence tomography." Opt Lett 33(13): 1530-1532.
18. Sudheendran, N., et al. (2011). "Speckle variance OCT imaging of the vasculature in live mammalian embryos." Laser Physics Letters 8(3): 247-252.
OCT System Setup
Home built OCT system:
• A-line rate: 30kHz
• Central wavelength:: ~1310 nm
• Bandwidth: 150 nm
• Output power: ~39 mW
• Axial resolution: ~11 um in air
• 600 A-lines per B-scan
• 500 B-scans per volume
Results
Pre-ethanol
A
45 minutes post- ethanol
vessels on the
uterus
A
B
B
Mouse 1
A
B
0.5 mm
A
Mouse 2
% Decrease in Vessel Diameter 45 mins. After
Ethanol
Artifacts caused
due to bulk
motion
correction
0.5 mm
B
A
vessels on the
uterus
0.5 mm
0.5 mm
Summary and Discussion
• OCT was used to evaluate the effects of maternal ethanol consumption on the fetal brain.
• SVOCT measurements were taken before and after maternal ethanol consumption.
• Pregnant mice at gestational stage 14.5 dpc were used.
• Preliminary results show a significant decrease in the vessel diameter of the fetal brain 45 minutes after
maternal alcohol consumption.
• This suggests that ethanol might act as a vasoconstrictor on the fetal brain.
Future work:
• Quantification of other parameters such as vessel area density, and vessel length fraction.
• Doppler OCT to verify flow speeds before and after maternal alcohol consumption.
Thank you, questions?!