Optics@Martinos at Photonics West 2019

This year we presented several work at the SPIE Photonics West. Below is the list of abstracts:

Connecting theory to the signal dynamics of interferometric diffuse correlation spectroscopy Mitchell B. Robinson, Stefan A. Carp, Davide Tamborini, David A. Boas, Maria Angela Franceschini 2 February 2019 • 4:00 – 4:20 PM | Part of SPIE BiOS Abstract: Diffuse correlation spectroscopy (DCS) is an emerging technique that allows for the monitoring of moving particles present in tissue. Traditionally, the instrumentation required to detect the multiply scattered photons has made these systems more expensive and the heavily attenuated signal at increased source to detector separations is difficult to resolve even utilizing single photon counting detectors. Here we detail an investigation of a DCS system that takes advantage of an interferometric approach to increase the detectable signal and reduce the cost of the detection instrumentation.

Optimization of portable, time-domain diffuse correlation spectroscopy system Davide Tamborini, Kimberly A. Stephens, Melissa Wu, Bernhard Zimmermann, Kuan-Cheng Wu, Megan Blackwell, Andrew M. Siegel, David A. Boas, Stefan A. Carp, Maria A. Franceschini 2 February 2019 • 4:20 – 4:40 PM | Part of SPIE BiOS Abstract: We will present a bedside TD-DCS system based on commercially available pulsed laser and single-photon detectors. We will discuss how to optimize the design of the system to overcome the limitation of current commercially available components and to translate the TD-DCS technique into portable system. We’ll present our current portable TD-DCS system, comprising the probe, the required data analysis steps to compute BFi and a full validation study, starting from phantom-based experiment up to preliminary in-vivo measurements.

Creation of infant brainstem atlas using optical coherence tomography Caroline V. Magnain, Jean C. Augustinack, Camilo Jaimes Cobos, Robin Haynes, Brian Edlow, Luiz Fernando Ferraz da Silva, Hannah Kinney, Bruce Fischl, Lilla Zollei 5 February 2019 • 6:00 – 8:00 PM | Part of SPIE BiOS Abstract: The arousal deficit hypothesis is a leading hypothesis for the sudden infant death syndrome. The arousal ascending network in the brainstem is made of nuclei and tracts that are not all visible in MRI due to their small size and the limited myelin, resulting in lack of resolution and contrast, respectively. We used optical coherence tomography coupled to a vibratome to reconstruct the brainstem at 2.9 μm resolution. The segmentation of brainstem nuclei and tracts were performed on the OCT volume and transferred to MRI data to analyze the brainstem connectivity.

Detectors challenges for diffuse correlation spectroscopy at 1064 nm Davide Tamborini, Kuan-Cheng Wu, Kimberly A. Stephens, Melissa Wu, Oleg Shatrovoy, Niyom Lue, Megan Blackwell, Vikas Anant, Stefan A. Carp, Maria A. Franceschini 6 February 2019 • 8:50 – 9:20 AM | Part of SPIE BiOS Abstract: Diffuse correlation spectroscopy (DCS) measures a microvascular blood flow index (BFi) by illuminating the tissue with a long coherence length laser, detecting fluctuations in the speckle pattern and fitting a physical model to the measured intensity autocorrelation curves. We will present the advantage of using light at 1064 nm and we will discuss the limitation due to the available single-photon detectors at this wavelength. We will present measurements using both Silicon and InGaAs/InP SPADs, and SnSPD to validate the advantage of DCS at 1064 

Measuring blood flow and oxidative metabolism in the exercising muscle using diffuse correlation spectroscopy and frequency domain near infrared spectroscopy Parisa Farzam, Valentina Quaresima, Pamela Anderson, Daniel Wiese, Alessandro Babini, Stefan Carp, Marco Ferrari, Maria Angela Franceschini 6 February 2019 • 9:20 – 9:40 AM | Part of SPIE BiOS Abstract:Eighteen athletes were recruited to investigate rectus femoris blood flow and oxidative metabolism responses during incremental cycling exercise at exhaustion. MetaOx (ISS, Champaign, IL) frequency domain was used to measure tissue scattering and absorption, from which hemoglobin concentrations and oxygenation were estimated. Blood flow, obtained by diffuse correlation spectroscopy, was utilized to derive oxidative metabolism changes. Moreover, at each cycling power increment, blood lactate concentration was measured to assess the muscle transition from aerobic to anaerobic metabolism. During high power exercise, the blood flow reached a plateau whilst lactate concentration continued to increase indicating progressive involvement of the anaerobic metabolism.

Cerebral blood flow measurement in adults during hypercapnia using continuous wave and time domain diffuse correlation spectroscopy Stefan A. Carp, Davide Tamborini, Melissa Wu, Parya Farzam, Kimberly Stephens, Suk-Tak Chen, Jason Z. Qu, Maria A. Franceschini 6 February 2019 • 11:10 – 11:30 AM | Part of SPIE BiOS Abstract:Cerebral blood flow assessment using non-invasive diffuse correlation spectroscopy techniques offers the potential to improve critical care for patients undergoing procedures that may impact brain health. In this work we characterize the performance of continuous wave (CW) and time domain (TD) diffuse correlation spectroscopy measurements in assessing cerebral blood flow through measurements on several healthy volunteers during CO2 inhalation. We report on the noise performance and cerebral sensitivity of the two DCS approaches, as well as compare the optical blood flow change estimates with MRI arterial spin labeling data.

Quantitative depth selective measurements of flow using acousto-optic diffuse correlation spectroscopy. Mitchell B. Robinson, Stefan A. Carp, David A. Boas, Maria Angela Franceschini 6 February 2019 • 4:00 – 4:15 PM | Part of SPIE BiOS Abstract: Diffuse correlation spectroscopy (DCS) has emerged as a non-invasive technique to measure the hemodynamics of the brain. By monitoring the time course of speckle intensity, information about the motion of the blood cells can be estimated. Non-invasive optical measurements of the brain suffer from contamination of the signal by the blood flow in the scalp. Here we present a method of depth discrimination of the source of the DCS signal using pulsed ultrasound for the determination of motion at different depths within the sample.

Three-dimensional breast shape acquisition and co-registration method for multimodal dynamic DOT and digital breast tomosynthesis Bin Deng, Lance Barcelona, Kathleen Deabill, Siyuan Wei, Jayne Cormier, Qianqian Fang, Mansi Saksena, Stefan A. Carp 6 February 2019 • 5:20 – 5:40 PM | Part of SPIE BiOS Abstract:    The ill-posed nature of the DOT inverse problem makes this technique particularly susceptible to model errors when the data-acquisition conditions do not fully match the assumptions built into the image reconstruction process. In this paper, we describe the use of a set of auxiliary devices in conjunction to a multimodal DOT/x-ray system to capture accurate breast shape information and a 3D surface registration method that spatially co-registers separately acquired clinical DBT scans with DOT measurements for guided optical image reconstruction. We demonstrate the performance of this method by imaging patients presenting with benign or malignant lesions during stepwise breast compression.