S.S. Kuznetsov

Multiphoton tomography and multimodal OCT for in vivo visualization of oral malignancy in the hamster cheek pouch

The main purpose of this work is to evaluate the possibility to distinguish in vivo benign papilloma, severe dysplasia and squamous cell carcinoma by establishing quantitative image characteristics of multiphoton tomography (MPT) and multimodal optical coherence tomography images (MM OCT). Specific features of papillomatous outgrowths at different stages were revealed using 7,12-dimethylbenz[a]anthracen (DMBA)-induced hamster oral carcinoma. Analysis of MPT images included assessment of nuclear-cytoplasmic (NC) ratio, nuclear density and heterogeneity parameter F. Crosspolarization OCT images were quantified via the integral depolarization factor (IDF). Analysis of OCT microvascular maps enabled differential analysis based on the number of smallest-diameter blood vessels present in a particular pathology. Both MPT and MM OCT metrics showed some difference between benign papilloma, dysplastic papilloma, and squamous cell carcinoma tissue states. The results suggested that combined use of MPT and MM OCT have great potential for in vivo differentiation between benign and malignant papillomas.

Visual assessment criteria of microstructural ex vivo co-and cross-polarized optical coherence tomography images in gliomas

Optical coherence tomography (OCT) is a promising method of glial tumors borders diagnostics. Nowadays it is possible to use hand-held and microscope mounted OCT devices during tumor removal. But still there are no clearly visual assessment criteria of OCT images, on the basis of which good differentiation between glioma tissue and white matter can be performed. This paper presents such criteria for crosspolarization OCT (CP OCT), which can detect both the scattering and polarization properties of tissues.

Multimodal OCT characterization of human breast cancer morphological types: preliminary study

Introduction of innovative noninvasive diagnostic techniques in clinical practice remains an actual topic of modern medicine. In the study, we assessed feasibility of multimodal OCT (MM OCT) that combines crosspolarization imaging and elastographic stiffness mapping to assess spatial structural organization and heterogeneity of breast cancer in the tumor center in comparison with normal mammary gland tissue. The research was carried out using human breast tissue mastectomy surgical samples including different histological types of breast cancer: ductal carcinoma in situ, invasive lobular and ductal carcinoma, fibroadenoma and normal tissue. The histological subtypes of breast cancer showed different structural and stiffness features of tumor tissue. In the case of invasive ductal carcinoma, the cross-polarization OCT image shows a more heterogeneous high-level OCT signal and higher stiffness in comparison with lobular breast cancer or fibroadenoma. These results indicate that assessing microstructures and elasticity changes yields complementary information about the microstructural features of breast cancer, which is important for selection of treatment tactics.

Multimodal OCT for assessment of vasculature-targeted PDT success

The main goal of the study was a vasculature targeted PDT. A new approach named M-mode-like OCT (MML OCT) was applied to monitor early response to PDT. Due to the chosen filtering parameters (96 Hz filter threshold), this approach visualizes only vessels with flowing blood. Without flowing blood even filled vessels are not visualized because flow-less blood causes speckle variations with significantly lower frequencies (<50 Hz corresponding to speckle decorrelation time for stationary blood). This feature allows us to detect thrombosis of blood vessels, the results of MML OCT and histological examination being perfectly coinciding. The advantages of MML OCT such as a simple and fast process of obtaining microvasculature images and label-free nature of the visualization makes this method perspective in routine clinical monitoring of antitumor therapies.

Optical and ultrasound methods for detection of chemotherapy-induced changes of breast tumors blood supply

The results of breast cancer oxygenation study under chemotherapy action obtained by diffuse optical spectroscopy and comparison with tumor pathologic response are presented. Capabilities of Ultrasonography as an additional method are demonstrated.

Human Fresh Tissue Optical Biopsy Using Multiphoton Microscopy for PDT Control

Capabilities of multiphoton microscopy for investigation of Photoditazin distribution in tumor cell line and in ex vivo human tumor is demonstrated. The preferential accumulation of PS in the stroma compared with cellular component is shown.

Diagnostics of radiation induced tissue damage and remodeling by laser scanning microscopy with second harmonic generation

Normal bladder mucosa has a high-contrast stratified structure with well-delineated epithelium, basal membrane and lamina propria. The urothelial cells form a smooth dense layer without connective tissue elements. Submucosal and muscle layers have a well expressed vessels network. Muscle fibers form bundles of an equal size in different directions. A small amount of connective tissue fibers form a scaffold of the tissue.