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S A Boppart

Publications and source records attributed to S A Boppart.

At least 19 recordsLinked to original sources
PubMed2001

Real-time optical coherence tomography for minimally invasive imaging of prostate ablation.

OBJECTIVE: Numerous ablation techniques have been developed to alleviate urethral obstruction and improve urodynamics in benign prostatic hyperplasia. Most techniques, however, rely on visual observation of surface changes for ablation end points. The feasibility of using real-time optical coherence tomography (OCT) for minimally invasive imaging to guide and monitor prostate resection is demonstrated with representative techniques of laser and radiofrequency ablation. Empiric comparisons of ablation dynamics are made, and the use of OCT as a high-resolution, subsurface modality for image guidance is evaluated. MATERIALS AND METHODS: Optical coherence tomography is a high-resolution, high-speed near-infrared imaging technique analogous to ultrasound imaging, except that reflections of light are detected rather than sound. High-speed OCT is used to image the dynamic process of laser and radiofrequency ablation of in vitro human prostate tissue. OCT images of ablation sites are compared with corresponding histology. RESULTS: Based on comparisons between OCT images and corresponding histology, OCT imaged transurethral prostate tissue morphology, including urethral sinuses and submucosal glands. Real-time OCT imaging provided rapid feedback and control of ablation dynamics. The compact and portable OCT technology is amenable to minimally invasive beam-delivery devices. CONCLUSIONS: Optical coherence tomography offers a minimally invasive means of assessing transurethral prostate morphology. Real-time OCT has the potential to provide image guidance of prostate resection for many of the existing surgical treatments directed at alleviating urethral obstruction associated with benign prostatic hyperplasia.

Catheter Ablation↗
PubMed2000

Assessment of coronary plaque with optical coherence tomography and high-frequency ultrasound.

This study compares the ability of intravascular optical coherence tomography (OCT) and high-frequency intravascular ultrasound (IVUS) to image highly stenotic human coronary arteries in vitro. Current imaging modalities have insufficient resolution to perform risk stratification based on coronary plaque morphology. OCT is a new technology capable of imaging at a resolution of 5 to 20 microm, which has demonstrated the potential for coronary arterial imaging in prior experiments. Human postmortem coronary arteries with severely stenotic segments were imaged with catheter-based OCT and IVUS. The OCT system had an axial resolution of 20 microm and a transverse resolution of 30 microm. OCT was able to penetrate and image near-occlusive coronary plaques. Compared with IVUS, these OCT images demonstrated superior delineation of vessel layers and lack of ring-down artifact, leading to clearer visualization of the vessel plaque and intima. Histology confirmed the accuracy and high contrast of vessel layer boundaries seen on OCT images. Thus, catheter-based OCT systems are able to image near-occlusive coronary plaques with higher resolution than that of IVUS.

Coronary Artery Disease↗
PubMed2000

Feasibility of optical coherence tomography for high-resolution imaging of human gastrointestinal tract malignancies.

Optical coherence tomography (OCT) is a new imaging technology which can perform high-resolution, cross-sectional imaging of the internal microstructure of biological tissues. OCT is analogous to ultrasound, except that it measures the intensity of back-reflected infrared light rather than sound waves. OCT performs two- and three-dimensional imaging of tissue microstructure in situ and in real time. It can achieve image resolutions approaching the cellular level over approximately the same imaging depths as a conventional biopsy. In this article we examine the feasibility of OCT for high-resolution imaging of gastrointestinal malignancies with ex-vivo imaging of normal and pathologic microstructures. Tissue, both normal and neoplastic, was obtained from patients undergoing surgical resection after an initial diagnosis of a gastrointestinal malignancy. The tissue samples were imaged prior to fixation using a laboratory OCT system. The OCT system consists of a fiber optic-based Michelson interferometer, a commercially available amplified superluminscent light source, and a computer for data acquisition. The images were subsequently compared with histological cross-sections corresponding to the imaged areas. The stratified squamous epithelium of the normal esophagus was clearly visible in the OCT images and contrasted to the disorganized and non-uniform nature of the mucosal layers of Barrett's esophagus and squamous carcinoma. The columnar epithelial morphology as well as other mucosal structures in normal colon were distinctly visible using OCT. In contrast, disorganization of the normal mucosal layers and ulcerative lesions were identified in tissues from ulcerative colitis and adenocarcinoma of the colon. The ability of OCT to image tissue microstructure at high resolutions makes it a potentially powerful technology for minimally invasive assessment of the gastrointestinal tract and the evaluation of early neoplastic changes.

Adenocarcinoma↗
PubMed2000

Optical coherence tomography: advanced technology for the endoscopic imaging of Barrett's esophagus.

BACKGROUND AND STUDY AIMS: Endoscopic optical coherence tomography (OCT) is an emerging medical technology capable of generating high-resolution cross-sectional imaging of tissue microstructure in situ and in real time. We assess the use and feasibility of OCT for real-time screening and diagnosis of Barrett's esophagus, and also review state-of-the-art OCT technology for endoscopic imaging. MATERIALS AND METHODS: OCT imaging was performed as an adjunct to endoscopic imaging of the human esophagus. Real-time OCT (13-microm resolution) was used to perform image-guided evaluation of normal esophagus and Barrett's esophagus. Beam delivery was accomplished with a 1-mm diameter OCT catheter-probe that can be introduced into the accessory channel of a standard endoscope. Different catheter-probe imaging designs which performed linear and radial scanning were assessed. Novel ultrahigh-resolution (1.1-microm resolution) and spectroscopic OCT techniques were used to image in vitro specimens of Barrett's esophagus. RESULTS: Endoscopic OCT images revealed distinct layers of normal human esophagus extending from the epithelium to the muscularis propria. In contrast, the presence of gland- and crypt-like morphologies and the absence of layered structures were observed in Barrett's esophagus. All OCT images showed strong correlations with architectural morphology in histological findings. Ultrahigh-resolution OCT techniques achieved 1.1-microm image resolution in in vitro specimens and showed enhanced resolution of architectural features. Spectroscopic OCT identified localized regions of wavelength-dependent optical scattering, enhancing the differentiation of Barrett's esophagus. CONCLUSIONS: OCT technology with compact fiberoptic imaging probes can be used as an adjunct to endoscopy for real-time image-guided evaluation of Barrett's esophagus. Linear and radial scan patterns have different advantages and limitations depending upon the application. Ultrahigh-resolution and spectroscopic OCT techniques improve structural tissue recognition and suggest future potential for resolution and contrast enhancements in clinical studies. A new balloon catheter-probe delivery device is proposed for systematic imaging and screening of the esophagus.

Barrett Esophagus↗
PubMed1999

High-resolution optical coherence tomography-guided laser ablation of surgical tissue.

BACKGROUND: Optical coherence tomography (OCT) is a compact high-speed imaging technology which uses infrared light to acquire cross-sectional images of tissue on the micrometer scale. Because OCT images are based on the optical backscattering properties of tissue, changes in tissue optical properties due to surgical laser ablation should be detectable using this technique. In this work, we examine the feasibility of using real-time OCT imaging to guide the placement and observe the dynamics of surgical laser ablation in a variety of tissue types. MATERIALS AND METHODS: More than 65 sites on five ex vivo rat organ tissue types were imaged at eight frames per second before, during, and after laser ablation. Ablation was performed with a coincident continuous wave argon laser operating at 514-nm wavelength and varying exposure powers and durations. Following imaging, tissue registration was achieved using microinjections of dye followed by routine histologic processing to confirm the morphology of the ablation site. RESULTS: High-speed OCT imaging at eight frames per second permitted rapid tissue orientation and guided ablation in numerous organ specimens. Acquisition rates were fast enough to capture dynamic changes in optical backscatter which corresponded to thermal tissue damage during laser ablation. CONCLUSIONS: The ability of high-resolution high-speed OCT to guide laser ablation and image the dynamic changes suggests a role in image-guided surgical procedures, such as the ablation of neoplasms. Future in vivo studies are necessary to demonstrate performance intraoperatively.

Abdominal Muscles↗
PubMed1999

Optical imaging technology in minimally invasive surgery. Current status and future directions.

Optical engineering and imaging technology have played a major role in the evolving field of minimally invasive surgery (MIS) by making it possible to visualize the manipulation of tissue at remote internal sites. We assess and review the optical imaging technology used during a variety of MIS procedures from an engineering perspective. The field of MIS is evolving rapidly. Optic-based technologies have the potential to further improve diagnostic capabilities of MIS. Optical imaging technologies and instrument designs are discussed in relation to their current and future use in MIS procedures. Technical limitations in imaging technology are described, along with potential solutions. We review the current status and future role of optical imaging technology in MIS. In the future, synergistic benefits from engineering, imaging technology, and MIS are likely to improve diagnostic ability and patient care.

Equipment Design↗
PubMed1999

High resolution imaging of endometriosis and ovarian carcinoma with optical coherence tomography: feasibility for laparoscopic-based imaging.

High resolution imaging of gynaecological tissue offers the potential for identifying pathological changes at early stages when interventions are more effective. Optical coherence tomography (OCT) is a high resolution high speed optical imaging technology which is analogous to ultrasound B-mode imaging except reflections of light are detected rather than sound. The OCT technology is capable of being integrated with laparoscopy for real-time subsurface imaging. In this report, the feasibility of OCT for differentiating normal and pathologic laparoscopically-accessible gynaecologic tissue is demonstrated. Differentiation is based on architectural changes of in vitro tissue morphology. OCT has the potential to improve conventional laparoscopy by enabling subsurface imaging near the level of histopathology.

Endometriosis↗
PubMed1999

High resolution in vivo intra-arterial imaging with optical coherence tomography.

BACKGROUND: Optical coherence tomography (OCT) is a new method of catheter based micron scale imaging. OCT is analogous to ultrasound, measuring the intensity of backreflected infrared light rather than sound waves. OBJECTIVE: To demonstrate the ability of OCT to perform high resolution imaging of arterial tissue in vivo. METHODS: OCT imaging of the abdominal aorta of New Zealand white rabbits was performed using a 2.9 F OCT imaging catheter. Using an ultrashort pulse laser as a light source for imaging, an axial resolution of 10 micrometer was achieved. RESULTS: Imaging was performed at 4 frames/second and data were saved in either super VHS or digital format. Saline injections were required during imaging because of the signal attenuation caused by blood. Microstructure was sharply defined within the arterial wall and correlated with histology. Some motion artefacts were noted at 4 frames/second. CONCLUSIONS: In vivo imaging of the rabbit aorta was demonstrated at a source resolution of 10 micrometer, but required the displacement of blood with saline. The high resolution of OCT allows imaging to be performed near the resolution of histopathology, offering the potential to have an impact both on the identification of high risk plaques and the guidance of interventional procedures.

Animals↗
PubMed1999

High resolution imaging of transitional cell carcinoma with optical coherence tomography: feasibility for the evaluation of bladder pathology.

Significant challenges regarding patient morbidity and mortality remain in the management of transitional cell carcinoma (TCC). Among the most important of these challenges is the inability to identify early neoplastic changes and to assess the degree of tumour invasion into the bladder wall in vivo. Optical coherence tomography (OCT) has been recently developed to provide in situ, high resolution, catheter/endoscope based imaging. This study explored the feasibility of OCT for the evaluation of bladder pathology. Both in vitro and in vivo studies were performed. In vitro imaging of pathological human bladder was performed and compared with normal specimens and histopathology. In vivo imaging of normal rabbit bladder was also performed with our current catheter/endoscope based systems. In the in vitro studies, OCT was able to delineate normal microstructure of the bladder, such as the mucosa, submucosa and muscularis layers. This was in contrast to specimens of invasive carcinoma, where a disruption of the normal bladder wall architecture was seen. The in vivo experiment demonstrated current limitations of the catheter/endoscope based systems and provided valuable information for developing an improved system for bladder imaging. The ability of OCT to delineate microstructure of the bladder wall suggests feasibility for endoscopic based imaging. In particular, there is a potential role envisioned for OCT in the management of TCC, identifying pre-malignant states and the depth of tumour invasion.

Animals↗
PubMed1999

High resolution imaging of normal and osteoarthritic cartilage with optical coherence tomography.

OBJECTIVE: We describe optical coherence tomography (OCT), a high resolution micron scale imaging technology, for assessment of osteoarthritic articular cartilage microstructure. OCT is analogous to ultrasound, measuring the intensity of backreflected infrared light rather than acoustical waves. METHODS: OCT imaging was performed on over 100 sites on 20 normal and osteoarthritic cartilage specimens in vitro. RESULTS: Microstructures that were identified included fibrillations, fibrosis, cartilage thickness, and new bone growth at resolutions between 5 and 15 microm. In addition, the polarization sensitivity of imaging suggested a diagnostic role of polarization spectroscopy. CONCLUSION: OCT represents an attractive new technology for intraarticular imaging due to its high resolution (greater than any available clinical technology), ability to be integrated into small arthroscopes, compact portable design, and relatively low cost.

Arthrography↗
PubMed1999

High-resolution imaging of gynecologic neoplasms using optical coherence tomography.

BACKGROUND: A modality capable of imaging the female reproductive tract, at or near the cellular level, could lead to the detection of diseases at earlier stages than currently possible. Optical coherence tomography achieves high resolutions in the cellular range (4-20 microm) and could accomplish that level of detection. METHOD: Optical coherence tomography imaging of gynecologic tissue was studied in vitro on normal and neoplastic human cervical and uterine tissue. EXPERIENCE: The structures of the normal ectocervix and endocervix, including epithelium, basal membrane, and glands, were identified clearly. These findings were compared with changes associated with carcinoma in situ and invasive carcinoma. The optical coherence tomography images of the uterus also showed changes between microstructural features of normal tissue and endometrial adenocarcinoma. CONCLUSION: Optical coherence tomography of tissue microstructures showed potential for powerful, minimally invasive assessment of the female reproductive tract at a resolution greater than any current clinical imaging method.

Feasibility Studies↗
PubMed1998

Optical biopsy with optical coherence tomography.

A need exists in medicine for a technology capable of 'optical biopsy,' imaging at or near the resolution of histopathology without the need for excisional biopsy. Optical coherence tomography (OCT) is a recently developed imaging technology that uses infrared light to generate cross-sectional images on a micron scale. In this work, the feasibility of OCT for optical biopsy was confirmed with in vitro tissue from the skeletal and male reproductive systems. This work supports the hypothesis that OCT is an attractive technology for in vivo optical biopsy.

Biopsy↗
PubMed1998

New technology for high-speed and high-resolution optical coherence tomography.

Optical coherence tomography (OCT) is an optical imaging technique that is capable of performing micron-scale, cross-sectional imaging of internal microstructure in biological systems. OCT is analogous to ultrasound B mode imaging except that it uses light rather than sound and performs imaging by measuring the back-scattered intensity of light from structures in tissue. We describe recent advances in OCT technology including the application of short pulse solid state lasers based on Ti: Al2O3 and Cr: Mg2SiO4 to enable high-resolution, high-speed imaging as well as the development of OCT catheter/endoscope delivery to permit imaging of internal organ systems. OCT enables the nonexcisional, in situ, real-time imaging of tissue microstructure and is thus a powerful and promising technique for optical biopsy.

Animals↗
PubMed1998

Two- and three-dimensional high-resolution imaging of the human oviduct with optical coherence tomography.

OBJECTIVE: To evaluate the feasibility of optical coherence tomography, a new method of micron-scale imaging, for high-resolution assessment of the oviduct. Optical coherence tomography is analogous to ultrasound except that it measures the backreflection of infrared light rather than acoustical waves. DESIGN: The ampulla of a human fallopian tube was imaged in vitro using optical coherence tomography. Images were generated in 2 and 3 dimensions. SETTING: University. PATIENT(S): Samples were obtained from women who had undergone hysterectomy for leiomyomatosis. INTERVENTION(S): None MAIN OUTCOME MEASURE(S): The ability to perform imaging on a micron scale, which is a level of resolution higher than that of any currently available clinical technology. RESULT(S): Two- and three-dimensional data sets of the reflectance of a human fallopian tube were acquired. A volume of 5 x 5 x 2.5 mm (length x width x depth) was scanned. The axial resolution was 11 microm, and the lateral resolution at the focus was 20 microm. The data sets showed detailed structures of the fallopian tube. CONCLUSION(S): Our ability to obtain micron-scale two- and three-dimensional images of an in vitro oviduct suggests that it may be possible to identify and surgically treat tubal causes of infertility.

Diagnostic Imaging↗
PubMed1998

Optical biopsy in human pancreatobiliary tissue using optical coherence tomography.

Optical coherence tomography (OCT) is a new technique for performing high-resolution, cross-sectional tomographic imaging in human tissue. OCT is analogous to ultrasound B mode imaging except that it uses light rather than acoustical waves. As a result, OCT has over 10 times the resolution of currently available clinical high-resolution cross-sectional imaging technologies. In this work, we investigate the capability of OCT to differentiate the architectural morphology of pancreatobiliary tissues. Normal pancreatobiliary tissues, including the gallbladder, common bile duct, pancreatic duct, and pancreas were taken postmortem and imaged using OCT. Images were compared to corresponding histology to confirm tissue identity. Microstructure was delineated in different tissues, including tissue layers, glands, submucosal microvasculature, and pancreatic islets of Langerhans. The ability of OCT to provide high-resolution imaging of pancreatobiliary architectural morphology suggests the feasibility of using OCT as a powerful diagnostic endoscopic imaging technology to image early stages of pancreatobiliary disease.

Biliary Tract↗
PubMed1998

Optical coherence tomography for neurosurgical imaging of human intracortical melanoma.

OBJECTIVE: Intraoperative identification of brain tumors and tumor margins has been limited by either the resolution of the in vivo imaging technique or the time required to obtain histological specimens. Our objective was to evaluate the feasibility of using optical coherence tomography (OCT) as a high-resolution, real-time intraoperative imaging technique to identify an intracortical melanoma. INSTRUMENTATION: OCT is a new, noncontact, high-speed imaging technology capable of resolutions on the micrometer scale. OCT is analogous to ultrasound B-mode imaging, except that reflections of infrared light, rather than sound, are detected. OCT uses inherent tissue contrast, rather than enhancement with dyes, to differentiate tissue types. The compact, fiberoptic-based design is readily integrated with surgical instruments. METHODS: A portable handheld OCT surgical imaging probe has been constructed for imaging within the surgical field. Cadaveric human cortex with metastatic melanoma was harvested and imaged in two and three dimensions. Changes in optical backscatter intensity were used to identify regions of tumor and to locate tumor margins. Structures within the optical coherence tomographic images were compared with the histological slides. RESULTS: Two-dimensional images showed increased optical backscatter from regions of tumor, which was quantitatively used to determine the tumor margin. The images correlated well with the histological findings. Three-dimensional reconstructions revealed regions of tumor penetrating normal cortex and could be resectioned at arbitrary planes. Subsurface cerebral vascular structures could be identified and were therefore avoided. CONCLUSION: OCT can effectively differentiate normal cortex from intracortical melanoma based on variations in optical backscatter. The high-resolution, high-speed imaging capabilities of OCT may permit the intraoperative identification of tumor and the more precise localization of tumor margins.

Brain Neoplasms↗