Biomedical subjects

Tom Collier

Publications and source records attributed to Tom Collier.

6 recordsLinked to original sources

PubMed2002

Near real-time in vivo confocal imaging of mouse mammary tumors.

The goal of this study was to evaluate the ability of near real-time reflectance confocal microscopy to image tumor metastasis in vivo in an animal model. We used an epi-illumination confocal microscope to capture images of mouse mammary tumors in nude immunodeficient and Balb/C immunocompetent mice. In vivo confocal images and videos of normal and neoplastic areas were obtained before and after the application of a 6% acetic acid solution, with a lateral resolution of 0.8 microns and an axial resolution of 2-3 microns. Average imaging depths ranged from 150 microns to greater than 300 microns. We were able to differentiate between normal and abnormal tissue areas within the mammary gland, including areas of adipose tissue, fibroblasts and connective tissue, neoplastic tissue, and blood flow within blood vessels. Intravital imaging with reflectance confocal microscopy appears to be a useful tool to study tumor metastasis in vivo.

Animals↗

PubMed2002

Near real-time confocal microscopy of amelanotic tissue: detection of dysplasia in ex vivo cervical tissue.

RATIONALE AND OBJECTIVES: The authors performed this study to determine whether images of ex vivo tissue obtained with a near real-time confocal microscope can be used to differentiate between normal and dysplastic tissue. MATERIALS AND METHODS: Biopsy specimens of colposcopically normal and abnormal cervical tissue were obtained from 19 patients and imaged at various depths with a confocal microscope. Nuclear morphologic features were extracted from the confocal images; in addition, a group of reviewers examined the images and attempted to identify whether the specimen contained high-grade dysplasia. Results of both analyses were compared with the histopathologic findings of the same specimens provided by a board-certified pathologist with expertise in gynecologic pathology. RESULTS: The morphologic feature measurements compared well with the findings at pathologic examination. The use of the nuclear-cytoplasmic ratio to determine the presence of dysplasia resulted in a sensitivity of 100% and a specificity of 91%. The untrained reviewers had an average sensitivity of 95% and an average specificity of 69% in the determination of dysplasia. CONCLUSION: The results indicate the clinical potential of in vivo confocal imaging in the detection of dysplasia.

Carcinoma in Situ↗

PubMed2002

Fiber-optic confocal reflectance microscope with miniature objective for in vivo imaging of human tissues.

We have built a fiber-optic confocal reflectance microscope capable of imaging human tissues in near real time. Miniaturization of the objective lens and the mechanical components for positioning and axially scanning the objective enables the device to be used in inner organs of the human body. The lateral resolution is 2 micrometers and axial resolution is 10 micrometers. Confocal images of fixed tissue biopsies and the human lip in vivo have been obtained at 15 frames/s without any fluorescent stains. Both cell morphology and tissue architecture can be appreciated from images obtained with this microscope.

Biopsy↗

PubMed2002

Contrast agents for confocal microscopy: how simple chemicals affect confocal images of normal and cancer cells in suspension.

Normal and malignant human cervical cancer cells were imaged in vivo with confocal, phase contrast, and brightfield microscopies. Results were compared between cells in growth medium before and after addition of acetic acid, hypertonic saline solution, toluidine blue, and Lugol's iodine. The exogenous agents changed the backscattering characteristics of the cells when measured with confocal microscopy at 808 nm. A tendency toward higher scattering was observed in treated cells. Acetic acid and toluidine blue increased the brightness of the nucleus with respect to the cytoplasm in normal and cancer cells. Hypertonic saline solution made the cytoplasm brighter than the nucleus in both types of cells. The results indicate that simple chemicals can be used to enhance confocal microscopy's ability to differentiate intracellular components, such as nuclear size and shape. This can further confocal microscopy's ability to assess disease in cells and tissues.

Acetic Acid↗

PubMed2002

Endoscopic microscopy.

In vivo endoscopic optical microscopy provides a tool to assess tissue architecture and morphology with contrast and resolution similar to that provided by standard histopathology--without need for physical tissue removal. In this article, we focus on optical imaging technologies that have the potential to dramatically improve the detection, prevention, and therapy of epithelial cancers. Epithelial pre-cancers and cancers are associated with a variety of morphologic, architectural, and molecular changes, which currently can be assessed only through invasive, painful biopsy. Optical imaging is ideally suited to detecting cancer-related alterations because it can detect biochemical and morphologic alterations with sub-cellular resolution throughout the entire epithelial thickness. Optical techniques can be implemented non-invasively, in real time, and at low cost to survey the tissue surface at risk. Our manuscript focuses primarily on modalities that currently are the most developed: reflectance confocal microscopy (RCM) and optical coherence tomography (OCT). However, recent advances in fluorescence-based endoscopic microscopy also are reviewed briefly. We discuss the basic principles of these emerging technologies and their current and potential applications in early cancer detection. We also present research activities focused on development of exogenous contrast agents that can enhance the morphological features important for cancer detection and that have the potential to allow vital molecular imaging of cancer-related biomarkers. In conclusion, we discuss future improvements to the technology needed to develop robust clinical devices.

Cell Line, Tumor↗

PubMed2002

Detection of dysplasia with near real time confocal microscopy.

The use of high resolution, in vivo confocal imaging may offer a clinical tool to detect early neoplasia and reduce the incidence and mortality of cancer. Our laboratory is currently examining the feasibility of using confocal microscopy for non-invasive diagnosis of dysplasia and early carcinoma in epithelial tissue. We are performing a series of ex vivo studies investigating the optical properties of normal and abnormal biopsies to quantify the diagnostic capability of this technology to discriminate between normal and pre-cancerous tissue. These studies use a near real time reflectance confocal microscope to acquire images at various depths throughout the epithelium. To date, we have completed a twenty-five patient study of cervical biopsies and have acquired images from six patients of an approved twenty-two patient study in the oral cavity. The cervical study has shown a distinct difference between normal and dysplastic tissue which can be used diagnostically, while initial results from the oral cavity are promising even with increased keratin scattering. In conclusion, our examination of normal and precancerous biopsies has demonstrated the confocal microscope's ability to image sub-cellular morphology at a resolution making accurate diagnosis possible and supporting this technique's potential for in vivo assessment of dysplasia.

Biopsy↗