Abby Vogel

Using noninvasive multispectral imaging to quantitatively assess tissue vasculature

This research describes a noninvasive, noncontact method used to quantitatively analyze the functional characteristics of tissue. Multispectral images collected at several near-infrared wavelengths are input into a mathematical optical skin model that considers the contributions from different analytes in the epidermis and dermis skin layers. Through a reconstruction algorithm, we can quantify the percent of blood in a given area of tissue and the fraction of that blood that is oxygenated. Imaging normal tissue confirms previously reported values for the percent of blood in tissue and the percent of blood that is oxygenated in tissue and surrounding vasculature, for the normal state and when ischemia is induced. This methodology has been applied to assess vascular Kaposis sarcoma lesions and the surrounding tissue before and during experimental therapies. The multispectral imaging technique has been combined with laser Doppler imaging to gain additional information. Results indicate that these techniques are able to provide quantitative and functional information about tissue changes during experimental drug therapy and investigate progression of disease before changes are visibly apparent, suggesting a potential for them to be used as complementary imaging techniques to clinical assessment.

Advances in Optical Spectroscopy and Imaging of Breast Lesions

A review is presented of recent advances in optical imaging and spectroscopy and the use of light for addressing breast cancer issues. Spectroscopic techniques offer the means to characterize tissue components and obtain functional information in real time. Three-dimensional optical imaging of the breast using various illumination and signal collection schemes in combination with image reconstruction algorithms may provide a new tool for cancer detection and treatment monitoring.

Quantitative assessment of tumor vasculature and response to therapy in kaposi's sarcoma using functional noninvasive imaging.

Two noninvasive methods, thermography and laser Doppler imaging (LDI), were assessed for their ability to quantitatively assess parameters of vascularity in lesions of HIV-associated Kaposis sarcoma (KS). Thermography and LDI images of a representative KS lesion were recorded in 16 patients and compared to normal skin either adjacent to the lesion or on the contralateral side. Eleven of the 16 patients had greater than 0.5 °C increased temperature and 12 of the 16 patients had increased flux (measured by LDI) as compared to normal skin. There was a strong correlation between these two parameters (R = 0.81, p < 0.001). In ten patients, measurements were obtained prior to therapy and after receiving a regimen of liposomal doxorubicin and interleukin-12. After 18 weeks of therapy, temperature and blood flow of the lesions were significantly reduced from the baseline (p = 0.004 and 0.002 respectively). These techniques hold promise to assess physiologic parameters in KS lesions and their changes with therapy.

Using Quantitative Imaging Techniques to Assess Vascularity in AIDS-Related Kaposi's Sarcoma

Three quantitative and non-invasive techniques were used to monitor angiogenesis in Kaposis sarcoma patients: thermography, laser Doppler imaging (LDI), and near-infrared spectroscopy. Before and after combination cytotoxic and anti-angiogenesis therapy, blood volume, oxygenated hemoglobin, temperature, and blood flow were analyzed. These three techniques are objective, easy to perform, and appear to be very sensitive in assessing changes in the lesions upon administration of therapy

Noninvasive infrared imaging for quantitative assessment of tumor vasculature and response to therapy

In this study we are investigating three infrared imaging techniques, thermography, multispectral imaging and Laser Doppler imaging (LDI) to assess parameters of vascularity in lesions of Kaposis sarcoma (KS) and response to therapy. Thermography, multispectral imaging and LDI were recorded over the lesion and compare to normal skin either adjacent to the lesion or on the contralateral side. The KS lesions generally had increased temperature, blood volume (as measured by multispectral imaging) and blood flux (as measured by LDI) as compare to normal skin. After the treatment with experimental antiKS drug, temperature, blood volume and blood flow of the lesion were significantly reduced from the baseline. These techniques hold promise to assess physiological parameter in KS lesion and their changes with therapy.

Noninvasive Multimodality Imaging Techniques to Assess Kaposi's Sarcoma

We evaluated three non-invasive method, thermography, laser Doppler imaging and near infrared multi-spectral imaging to quantitatively assess parameters of vascularity in Kaposis sarcoma. The KS lesion generally has increased temperature, blood velocity and blood deoxy-hemoglobin. There is a strong correlation between temperature and blood velocity (R= 81, p<0.001). After treatment with experimental drug (liposomal doxorubicin and interleukin-12), temperature, blood velocity, blood volume and deoxy-hemoglobin of the lesions are reduced from the baseline at week 18. The techniques are objective, easy to perform, and appear to be very sensitive in assessing improvement in the lesions upon administration of therapy

Optical quantification of epithelial layer thickness as a measure of oral inflammation

For individuals with cancer risk factors, reducing tissue inflammation may reduce the risk of developing cancer. This is the basis of several clinical trials evaluating potential chemoprevention drugs. These trials require quantitative assessments of inflammation which, for the oral epithelium, are traditionally provided by punch biopsies. To reduce patient discomfort and morbidity, we have developed a non-invasive alternative using diffuse reflectance spectroscopy. Though any optical system has the potential for probing near-surface structures, traditional methods of accounting for scattering of photons are generally invalid for typical epithelial thicknesses. We have previously developed a theory that is valid in this regime and validated it with Monte Carlo simulations. We use a differential measure with acute sensitivity to small changes in layer scattering coefficients. To assess the capability of the approach to quantify epithelial thickness, detailed Monte Carlo simulations and measurements on phantom models of a two layered structure have been performed. Preliminary results from this work show that our key feature varies less than 20 percent despite four-fold changes in scattering coefficients and ten-fold changes in absorption coefficients. This indicates that the method will be of practical clinical value for quantifying epithelial thickness in vivo.

Optical Diagnostic Imaging from Bench to Bedside

This PDF file contains the editorial “Guest Editorial: Optical Diagnostic Imaging from Bench to Bedside” for JBO Vol. 12 Issue 05