Biomedical subjects

Ruikang K Wang

Publications and source records attributed to Ruikang K Wang.

21 records · Page 2Linked to original sources

PubMed2002

Propylene glycol as a contrasting agent for optical coherence tomography to image gastrointestinal tissues.

BACKGROUND AND OBJECTIVE: Optical coherence tomography (OCT) is a recently developed imaging technique that has the potential to advance the early diagnosis of diseases in the human gastrointestinal (GI) tract. How ever, the high scattering nature of GI tissue limits its imaging depth and contrast. For more effective diagnosis using OCT, a concurrent improvement of imaging depth and contrast is, therefore, needed. In this work, we investigate the administration of chemical agents to the tissue as a means of improving the capability of OCT imaging of clinically relevant microstructures of the GI tract. STUDY DESIGN/MATERIALS AND METHODS: Normal human GI tissues, including stomach and oesophagus were obtained from patients in hospital, and were imaged with OCT within 0.5-2 hours of removal. Immediately after the first imaging of the specimens with OCT, about 0.5 ml of 80% propylene glycol solution was applied onto the tissue surface and the tissue allowed to absorb the chemical compounds for 20 minutes. Another image was then taken at the same position. The specimens were then embedded and stained in preparation for histologic evaluation. Co-registration of the images obtained using OCT before and after the topical application of the propylene glycol solution, and standard histopathologic processing provided basis for comparison. RESULTS: More detailed micro-structures, including the basal layer position and the cellular composition of the mucosal layer of GI tract tissues were observed after the topical application of propylene glycol solution, while these structures were not resolvable in the conventional OCT images. CONCLUSIONS: Propylene glycol could be used as a contrasting agent for OCT imaging of human GI tract tissues, allowing an increased capability of OCT for rapid clinical diagnosis in vivo.

Algorithms↗

PubMedDate not supplied

The potential role of optical coherence tomography in the evaluation of vulnerable carotid atheromatous plaques: a pilot study.

PURPOSE: The decision to intervene surgically in patients with carotid artery disease is based on the presence of symptoms, along with the severity of carotid artery stenosis as assessed by ultrasound or X-ray computed tomography (CT). Optical coherence tomography (OCT) is a relatively new imaging technique that offers potential in the identification of, as well as the distinction between, stable and unstable atherosclerotic plaques. The purpose of our study was to evaluate whether OCT can be used as a noninvasive diagnostic tool to reveal the morphology of carotid stenosis from the adventitial surface of the carotid artery. To achieve this aim, excised atheromatous plaques were scanned by OCT from the external surface. METHODS: Plaques removed at carotid endarterectomy were scanned by OCT from the external surface within 72 hr of surgery and then examined histologically. The images of the histologic slides and the scans were then compared. RESULTS: We examined 10 carotid endarterectomy specimens and were able to identify calcification, cholesterol crystal clefts, and lipid deposits in the OCT images with histologic correlation. The strong light scattering from the calcified tissue and cholesterol crystal clefts limited the depth of light penetration, making observation of the intimal surface and the detail of the fibrous cap difficult. However, we were able to confidently identify the absence of an atherosclerotic plaque by OCT scans even from the external surface. CONCLUSION: The results of this pilot study demonstrate that OCT can reveal the main features of carotid stenosis but that plaque vulnerability cannot be reliably and precisely assessed if scanned from the external surface with OCT in its present form.

Calcinosis↗

PubMedDate not supplied

Dynamic optical clearing effect of tissue impregnated with hyperosmotic agents and studied with optical coherence tomography.

The depth of light penetration into highly scattering tissues can be improved by the application of biocompatible and osmotically active chemical agents. We compare the dynamics of optical clearing of tissue by the topical application of glycerol and dimethyl sulfoxide (DMSO) using optical coherence tomography (OCT). It is demonstrated experimentally that both agents can largely improve the OCT imaging depth for porcine stomach tissue. During a period of approximately 20 to 30 min after the application of glycerol image contrast is also enhanced. This enhancement disappears over time. Such enhancement of image contrast is not observed with DMSO. Glycerol causes a higher degree of dehydration of the tissue than DMSO does. We suggest that these phenomena are caused by a two-stage diffusion of the chemicals. The first stage of diffusion is from the top tissue to the intercellular space, and the second is into the cell matrix. During the first stage, the imaging contrast could be improved by dehydration.

Animals↗