One of the most common surgical oncology procedures is breast lumpectomy. This is a clinical paradigm where x-ray imaging of the resected specimen is done, but optical imaging has a major potential role to play in helping to identify if there is residual tumor. The goal is to have a healthy margin of tissue around the identified malignancy, and the surgeon needs better real-time tools to help confirm if this is the case. Current methods in x-ray imaging only visualize the mass roughly and the localization wire, whereas optical scanning tools can increase the fidelity of imaging the surfaces, to see if the margins are clear. However, the largest challenge is the one of logistics of imaging highly amorphous tissue volumes which can have high blood content, high heterogeneity of optical properties, ink marking or embedded wires. Additionally the imaging and guidance must be accomplished in minutes. Thus, wide field high sensitivity imaging tools are needed for optical scanning.

We present a dual-modality instrument that utilizes a paddle-shaped probe to conduct OCT imaging and a/LCI nuclear size measurements simultaneously to provide both structural and functional information in a single device during an endoscopic procedure. The probe is 3D printed using biocompatible material to deliver both modalities to the same location on the esophageal epithelium as a means to detect pre-cancerous tissues. We will present an update of our current clinical study at the University of North Carolina Center for Esophageal Diseases and Swallowing (UNC CEDAS) with a target of 40 total patients with and without esophageal dysplasia.

Altered mechanical properties of tissue have emerged as both the cause and the consequence of tumorigenesis. Therefore, mapping the viscoelastic properties of tissue microenvironment provides crucial insights into micro-mechanical drivers of carcinogenesis. Here, we introduce laser Speckle rHEologicAl micRoscopy (SHEAR) that capture the time series of speckle patterns formed by multiple scattering of coherent light from tissue. We demonstrate that SHEAR rapidly maps the complex shear modulus, G*(x,y,ω), with 10’s µm resolution over multiple cm2, covering tumor epithelium, invasive front, and stroma. We further establish that G*(x,y,ω) maps yield micro-mechanical heterogeneity indices that closely correspond with tumor histopathology and prognosis.

Re-excision procedures are frequent in breast-conserving surgery due to residual tumor left behind after initial resection. Projection radiography and volumetric X-ray imaging are used to assess margin adequacy, but X-ray imaging lacks contrast between healthy, abnormal benign, and malignant fibrous tissues important for surgical decision making. The purpose of this study was to compare micro-CT and optical scatter imagery of surgical breast specimens and to demonstrate enhanced contrast to intra-tumoral morphologies and tumor boundary features revealed by optical scatter imaging. Results suggest that optical scatter imaging reveals additional tissue features that could improve margin assessment over X-ray imaging alone.

Optical coherence tomography (OCT) is a popular noninvasive technique for obtaining depth-resolved information about tissue. By applying a windowing technique to the OCT interferogram, spectrum-dependent optical properties can be measured in order to identify tissue optical properties such as scattering attenuation coefficient and scattering power. By mapping the distinct ranges of these optical properties for different morphologies and stages of human colorectal adenoma tissues, rapid classification of disease is possible, potentially allowing for better identification of their malignant potential when performing surveillance colonoscopy.

Detecting early-stage glaucoma remains a challenge in current clinical practice. In this study we assessed the ability of the optical attenuation coefficient (AC) of the retinal nerve fiber layer (RNFL) to detect early-stage glaucoma, evaluated the effectiveness of the AC against the conventional RNFL thickness measurement, and introduced new depth-dependent diagnostic parameters. Our results showed statistically significant differences between ACs extracted from the RNFL of healthy eyes and early-stage glaucoma eyes, including glaucoma suspects and mild open-angle glaucoma. We also showed that depth-dependent AC analysis is an even more sensitive measure to monitor and detect early signs of glaucoma.

Nanoscale changes in the nuclear structure have been shown to play a critical role in genetic and transcriptional alterations and are a hallmark of neoplasia. Genomic processes are regulated by chromatin packing density, thus underlying the significance of understanding the subnuclear structure and its role in the regulation of molecular processes. However, the dynamic and multiscale aspects of these phenomena have remained an open problem. The key reason is the lack of technologies for label-free nanoscale-sensitive measurements in live cells. We have developed confocal light absorption and scattering spectroscopic (CLASS) microscopy for label-free chromatin sensing in live cells.

Dynamic changes in cellular morphology and subcellular structure are the result of underlying biochemical activity and molecular signaling pathways controlling cellular function. I will present two cellular imaging methods that directly encode and quantify the morphological and physical properties of cells. First, I present optical scatter imaging as a means of tracking sub-wavelength changes in organelle morphology in situ. We have conceived, developed and used this label-free technique to quantify mitochondrial fission in response intracellular calcium overload and apoptosis. Then, I present the prospects of utilizing a fluorescent molecular tension probe to map intracellular forces. We are currently utilizing this technique to study dendrtitic branching in neuronal cells. Our ultimate goal is to combine these microscopic technologies to enable the discovery of novel physical markers that will enhance the quantitative analysis and diagnosis of cellular function.

When laser speckle contrast imaging (LSCI) is applied to in-vivo imaging in a mouse brain, the light scattering from tissue background is found to vary on millisecond time scales. Instead of treating background scattering as static, we present a method of LSCI analysis that fully incorporates the dynamics of background scattering. Fast and slow scattering components are distinguished by a method of clustering, enabling a determination of their relative weights. We further show that the speckle correlation time can be directly reconstructed rather than fitted to a model, thus achieving much faster processing speed.

The dynamic nature of scattering media, such as living tissues, greatly degrades the images of hidden objects reconstructed by deep neural networks. We show that if the dynamic scattering medium is followed closely, the relationship between distorted reconstructed images and objects can nevertheless be found by generative adversarial networks. We numerically verify this method in a general case where the dynamic scattering medium is formulated as an evolving transmission matrix. Then we experimentally apply the method in imaging cell samples through a disordered optical fiber system with imaging depth variations. Increased robustness in imaging is observed in both cases.

We present the first feasibility study of a new optical device for assisted venipuncture based on partially-coherent wide-field speckle decorrelation. Using a pseudo-thermal light source, we can vary the degree of spatial coherence, in order to change the ratio of singly- to multiply-scattered light detected by the system. This leads to an improvement in the localization of the decorrelation contrast, and therefore in the delineation of deep veins, as compared to conventional laser speckle imaging (LSI) systems. The results obtained so far make us believe that our spatial coherence-gated LSI imaging architecture can find widespread application beyond venipuncture.

Diffuse correlation spectroscopy (DCS) is an emerging noninvasive optical technique used to measure an index of blood flow index (BFI). However, accurate quantification of BFI relies on a priori knowledge of the optical properties of tissue, namely, the absorption and reduced scattering coefficients. Traditionally, optical properties are measured with a separate near-infrared spectroscopy (NIRS) system, which can add appreciable cost to the measurements. Alternatively, optical properties are assumed from literature, which can induce significant errors in the estimation of BFI. Recently, a handful of “stand-alone” DCS methods have been proposed that employ multi-distance and/or multi-wavelength measurements to simultaneously estimate both optical properties and BFI, thereby reducing the need for reliance on costly NIRS systems. In this work, we employ in silico simulations to investigate the performance of these stand-alone DCS methods across a wide range of physiologically relevant tissue optical properties and BFI. We find that all methods are highly sensitive to even modest noise at large (> 2 cm) source-detector separations, making their clinical utility for deep tissue monitoring suspect. However, the multi-wavelength, multi-distance stand-alone method performs well at SDS 1.5-2.5cm when the reduced scattering coefficient < 7 cm^-1, suggesting a possible role for the modality in tissue types with low scattering, e.g., muscle perfusion or assessment of cerebral blood flow in preterm infants.