Costas Pitris | PubMed Health

PubMed2005

Transillumination spatially modulated illumination microscopy.

The diagnostic utility of a conventional transillumination microscope, the most common imaging modality in clinical use today, is limited by the microscope's resolution. It is, however, possible to achieve lateral resolution well beyond the classical limit by using laterally structured illumination in a wide-field, nonconfocal microscope. In this method, the spatially modulated illumination (SMI) makes high-resolution information that is normally inaccessible visible in the observed image. Previously presented SMI microscopy systems operated in epifluorescence mode. We describe the design, construction, and testing of a novel transillumination SMI microscope. As transillumination is necessary for most medical applications, such as histopathologic evaluation of biopsy tissue and chromosomal analysis, such a system should have a significant diagnostic effect.

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PubMed2005

High-resolution optical coherence tomographic imaging of osteoarthritic cartilage during open knee surgery.

This study demonstrates the first real-time imaging in vivo of human cartilage in normal and osteoarthritic knee joints at a resolution of micrometers, using optical coherence tomography (OCT). This recently developed high-resolution imaging technology is analogous to B-mode ultrasound except that it uses infrared light rather than sound. Real-time imaging with 11-microm resolution at four frames per second was performed on six patients using a portable OCT system with a handheld imaging probe during open knee surgery. Tissue registration was achieved by marking sites before imaging, and then histologic processing was performed. Structural changes including cartilage thinning, fissures, and fibrillations were observed at a resolution substantially higher than is achieved with any current clinical imaging technology. The structural features detected with OCT were evident in the corresponding histology. In addition to changes in architectural morphology, changes in the birefringent or the polarization properties of the articular cartilage were observed with OCT, suggesting collagen disorganization, an early indicator of osteoarthritis. Furthermore, this study supports the hypothesis that polarization-sensitive OCT may allow osteoarthritis to be diagnosed before cartilage thinning. This study illustrates that OCT, which can eventually be developed for use in offices or through an arthroscope, has considerable potential for assessing early osteoarthritic cartilage and monitoring therapeutic effects for cartilage repair with resolution in real time on a scale of micrometers.

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