Dr. Roberto Romero Profile

Dr. Roberto Romero

at National Institutes of Health

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Publications (3)

Proceedings Article | 6 March 2023 Presentation

Monitoring of fetal heart rate using near-infrared spectroscopy

Thien Nguyen, Sooongho Park, Dahiana Gallo, Tomi Kanninen, Zeyu Zhang, George Downey, Roberto Romero, Amir Gandjbakhche

Proceedings Volume PC12375, PC123750B (2023) https://doi.org/10.1117/12.2661534

KEYWORDS: Fetus, Heart, Near infrared spectroscopy, Ultrasonography, Doppler effect, Signal detection, Electronic filtering, Sensors, Medicine, Light sources

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Proceedings Article | 5 March 2021 Presentation

Oxygenation measurement of placenta tissue during pregnancy using near infrared spectroscopy

Thien Nguyen, Kosar Khaksari, Siddharth Khare, Roberto Romero, Amir Gandjbakhche

Proceedings Volume 11638, 1163804 (2021) https://doi.org/10.1117/12.2582790

KEYWORDS: Near infrared spectroscopy, Fetus, Tissue optics, Tissues, Uterus, Ultrasonography, Skin, Scattering, Oxygen, Monte Carlo methods

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SPIE Journal Paper | 5 November 2020 Open Access

Evaluation of the human placenta optical scattering properties using continuous wave and frequency-domain diffuse reflectance spectroscopy

Siddharth Khare, Thien Nguyen, Afrouz Anderson, Brian Hill, Roberto Romero, Amir Gandjbakhche

JBO, Vol. 25, Issue 11, 116001, (November 2020) https://doi.org/10.1117/12.10.1117/1.JBO.25.11.116001

KEYWORDS: Scattering, Tissue optics, Fetus, Near infrared spectroscopy, Diffuse reflectance spectroscopy, Blood, Tissues, Light scattering, Absorption, Optical properties

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Significance: Placenta is an essential organ for fetal development and successful reproduction. Placental insufficiency can lead to fetal hypoxia and, in extreme cases anoxia, leading to fetal death. Of the 145 million deliveries per year worldwide, ∼15 million neonates are small for gestational age and, therefore, at risk for antepartum and intrapartum hypoxia. Clinical methods to assess placental function largely rely on the assessment of fetal heart rate changes but do not assess placental oxygenation. Near-infrared spectroscopy (NIRS) allows non-invasive, real-time assessment of tissue oxygenation in intact organs, which can be used to assess placental oxygenation. However, tissue optical properties can affect the accuracy of methods to measure tissue oxygenation. Aim: This study was performed to estimate the scattering coefficient of the human placenta. We have computed the scattering coefficients of the human placenta for the range of 659 to 840 nm using two methods of diffuse reflectance spectroscopy (DRS). Approach: Measurements were performed using an in-house DRS device and a well-established frequency-domain diffuse optical spectroscopic system (DOSI). Measurements were performed in eight placentas obtained after cesarean deliveries. Placentas were perfused with normal saline to minimize the effects of absorption due to blood. Three sites per placenta were measured. Absorption and scattering coefficients were then calculated from the measured reflectance using the random walk theory for DRS and frequency-domain algorithm for DOSI. Results: Average reduced scattering coefficient (μs ′ ) was 0.943 ± 0.015 mm − 1 at 760 nm and 0.831 ± 0.009 mm − 1 at 840 nm, and a power function μs ′ = 1.6619 (λ/500 nm) − 1.426 was derived for the human placental scattering coefficient. Conclusion: We report for the first time the scattering coefficient of the human placenta. This information can be used to assess baseline scattering and improve measurements of placental oxygen saturation with NIRS.

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