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Suter MJ, Lam S, Brenner M. Optical techniques in pulmonary medicine. SPIE photonics West. Expert Rev Respir Med 2012; 6:143-5. [PMID: 22455486 DOI: 10.1586/ers.12.11] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
There is ongoing interest in the emerging field of pulmonary photonic-based diagnostics. Potential clinical need areas that are being actively investigated at this time include airway and peripheral lung cancer diagnostics, pulmonary parenchymal and interstitial disorders, alveolar structure function, inhalation injury, ciliary function analysis, asthma and obstructive lung diseases.
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Gora M, Yoo H, Suter MJ, Gallagher KA, Bouma BE, Nishioka NS, Tearney GJ. Optical frequency domain imaging system and catheters for volumetric imaging of the human esophagus. PHOTONICS LETTERS OF POLAND 2011; 3:144-146. [PMID: 22924122 PMCID: PMC3425351 DOI: 10.4302/plp.2011.4.06] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Barrett's esophagus (BE) is a metaplastic disorder that can undergo dysplastic progression, leading to esophageal adenocarcinoma. Upper endoscopy is the standard of care for screening for BE, but this technique has a relatively low diagnostic accuracy and high cost due to the requirement of conscious sedation. Optical frequency domain imaging (OFDI) is a high-speed imaging modality that generates cross-sectional images of tissues with a resolution of approximately 10μm that is sufficient for detecting microscopic tissue architecture. In combination with a balloon-centering catheter, this method enables BE diagnosis over the entire distal esophagus.
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Suter MJ, Nadkarni SK, Weisz G, Tanaka A, Jaffer FA, Bouma BE, Tearney GJ. Intravascular optical imaging technology for investigating the coronary artery. JACC Cardiovasc Imaging 2011; 4:1022-39. [PMID: 21920342 PMCID: PMC3583353 DOI: 10.1016/j.jcmg.2011.03.020] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2010] [Revised: 03/04/2011] [Accepted: 03/14/2011] [Indexed: 12/14/2022]
Abstract
There is an ever-increasing demand for new imaging methods that can provide additional information about the coronary wall to better characterize and stratify high-risk plaques, and to guide interventional and pharmacologic management of patients with coronary artery disease. While there are a number of imaging modalities that facilitate the assessment of coronary artery pathology, this review paper focuses on intravascular optical imaging modalities that provide information on the microstructural, compositional, biochemical, biomechanical, and molecular features of coronary lesions and stents. The optical imaging modalities discussed include angioscopy, optical coherence tomography, polarization sensitive-optical coherence tomography, laser speckle imaging, near-infrared spectroscopy, time-resolved laser induced fluorescence spectroscopy, Raman spectroscopy, and near-infrared fluorescence molecular imaging. Given the wealth of information that these techniques can provide, optical imaging modalities are poised to play an increasingly significant role in the evaluation of the coronary artery in the future.
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Choma MA, Suter MJ, Vakoc BJ, Bouma BE, Tearney GJ. Physiological homology between Drosophila melanogaster and vertebrate cardiovascular systems. Dis Model Mech 2010; 4:411-20. [PMID: 21183476 PMCID: PMC3097462 DOI: 10.1242/dmm.005231] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The physiology of the Drosophila melanogaster cardiovascular system remains poorly characterized compared with its vertebrate counterparts. Basic measures of physiological performance remain unknown. It also is unclear whether subtle physiological defects observed in the human cardiovascular system can be reproduced in D. melanogaster. Here we characterize the cardiovascular physiology of D. melanogaster in its pre-pupal stage by using high-speed dye angiography and optical coherence tomography. The heart has vigorous pulsatile contractions that drive intracardiac, aortic and extracellular-extravascular hemolymph flow. Several physiological measures, including weight-adjusted cardiac output, body-length-adjusted aortic velocities and intracardiac shear forces, are similar to those in the closed vertebrate cardiovascular systems, including that of humans. Extracellular-extravascular flow in the pre-pupal D. melanogaster circulation drives convection-limited fluid transport. To demonstrate homology in heart dysfunction, we showed that, at the pre-pupal stage, a troponin I mutant, held-up2 (hdp2), has impaired systolic and diastolic heart wall velocities. Impaired heart wall velocities occur in the context of a non-dilated phenotype with a mildly depressed fractional shortening. We additionally derive receiver operating characteristic curves showing that heart wall velocity is a potentially powerful discriminator of systolic heart dysfunction. Our results demonstrate physiological homology and support the use of D. melanogaster as an animal model of complex cardiovascular disease.
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Kang DK, Suter MJ, Boudoux C, Yachimski PS, Puricelli WP, Nishioka NS, Mino-Kenudson M, Lauwers GY, Bouma BE, Tearney GJ. Co-registered spectrally encoded confocal microscopy and optical frequency domain imaging system. J Microsc 2010; 239:87-91. [PMID: 20629914 DOI: 10.1111/j.1365-2818.2010.03367.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Spectrally encoded confocal microscopy and optical frequency domain imaging are two non-contact optical imaging technologies that provide images of tissue cellular and architectural morphology, which are both used for histopathological diagnosis. Although spectrally encoded confocal microscopy has better transverse resolution than optical frequency domain imaging, optical frequency domain imaging can penetrate deeper into tissues, which potentially enables the visualization of different morphologic features. We have developed a co-registered spectrally encoded confocal microscopy and optical frequency domain imaging system and have obtained preliminary images from human oesophageal biopsy samples to compare the capabilities of these imaging techniques for diagnosing oesophageal pathology.
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Waxman S, Freilich MI, Suter MJ, Shishkov M, Bilazarian S, Virmani R, Bouma BE, Tearney GJ. A case of lipid core plaque progression and rupture at the edge of a coronary stent: elucidating the mechanisms of drug-eluting stent failure. Circ Cardiovasc Interv 2010; 3:193-6. [PMID: 20407116 DOI: 10.1161/circinterventions.109.917955] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Choma MA, Suter MJ, Vakoc BJ, Bouma BE, Tearney GJ. Heart wall velocimetry and exogenous contrast-based cardiac flow imaging in Drosophila melanogaster using Doppler optical coherence tomography. JOURNAL OF BIOMEDICAL OPTICS 2010; 15:056020. [PMID: 21054114 PMCID: PMC2994925 DOI: 10.1117/1.3503418] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Revised: 08/31/2010] [Accepted: 08/31/2010] [Indexed: 05/22/2023]
Abstract
Drosophila melanogaster (fruit fly) is a central organism in biology and is becoming increasingly important in the cardiovascular sciences. Prior work in optical imaging of the D. melanogaster heart has focused on static and dynamic structural anatomy. In the study, it is demonstrated that Doppler optical coherence tomography can quantify dynamic heart wall velocity and hemolymph flow in adult D. melanogaster. Since hemolymph is optically transparent, a novel exogenous contrast technique is demonstrated to increase the backscatter-based intracardiac Doppler flow signal. The results presented here open up new possibilities for functional cardiovascular phenotyping of normal and mutant D. melanogaster.
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Hariri LP, Bouma BE, Waxman S, Shishkov M, Vakoc BJ, Suter MJ, Freilich MI, Oh WY, Rosenberg M, Tearney GJ. An automatic image processing algorithm for initiating and terminating intracoronary
OFDI pullback. BIOMEDICAL OPTICS EXPRESS 2010; 1:566-573. [PMID: 21258490 PMCID: PMC3017988 DOI: 10.1364/boe.1.000566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2010] [Revised: 07/28/2010] [Accepted: 08/08/2010] [Indexed: 05/30/2023]
Abstract
Intracoronary optical frequency domain imaging (OFDI) provides high resolution, three-dimensional views of coronary artery microstructure, but requires a non-occlusive saline/contrast purge to displace blood for clear artery views. Recent studies utilized manual pullback initiation/termination based on real-time image observation. Automated pullback initiation/termination by real-time OFDI signal analysis would enable more efficient data acquisition. We evaluate the use of simple imaging parameters to automatically and robustly differentiate between diagnostic-quality clear artery wall (CAW) versus blood-obstructed fields (BOF). Algorithms are tested using intracoronary OCT human data retrospectively and intracoronary OFDI swine and human data prospectively. In prospective analysis of OFDI swine data, the sensitivity and specificity of the ratio of second and first moments (contrast parameter) were 99.6% and 97.2%, respectively. In prospective analysis of OFDI clinical data, the contrast parameter yielded 96.0% sensitivity and 94.5% specificity. Accuracy improved further by analyzing sequential frames. These results indicate the algorithm may be utilized with intracoronary OFDI for initiating and terminating automated pullback and digital data recording.
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Meyerholz DK, Stoltz DA, Namati E, Ramachandran S, Pezzulo AA, Smith AR, Rector MV, Suter MJ, Kao S, McLennan G, Tearney GJ, Zabner J, McCray PB, Welsh MJ. Loss of cystic fibrosis transmembrane conductance regulator function produces abnormalities in tracheal development in neonatal pigs and young children. Am J Respir Crit Care Med 2010; 182:1251-61. [PMID: 20622026 DOI: 10.1164/rccm.201004-0643oc] [Citation(s) in RCA: 147] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
RATIONALE Although airway abnormalities are common in patients with cystic fibrosis (CF), it is unknown whether they are all secondary to postnatal infection and inflammation, which characterize the disease. OBJECTIVES To learn whether loss of the cystic fibrosis transmembrane conductance regulator (CFTR) might affect major airways early in life, before the onset of inflammation and infection. METHODS We studied newborn CFTR⁻(/)⁻ pig trachea, using computed tomography (CT) scans, pathology, and morphometry. We retrospectively analyzed trachea CT scans in young children with CF and also previously published data of infants with CF. MEASUREMENTS AND MAIN RESULTS We discovered three abnormalities in the porcine CF trachea. First, the trachea and mainstem bronchi had a uniformly small caliber and cross-sections of trachea were less circular than in controls. Second, trachealis smooth muscle had an altered bundle orientation and increased transcripts in a smooth muscle gene set. Third, submucosal gland units occurred with similar frequency in the mucosa of CF and control airways, but CF submucosal glands were hypoplastic and had global reductions in tissue-specific transcripts. To learn whether any of these changes occurred in young patients with CF, we examined CT scans from children 2 years of age and younger, and found that CF tracheas were less circular in cross-section, but lacked differences in lumen area. However, analysis of previously published morphometric data showed reduced tracheal lumen area in neonates with CF. CONCLUSIONS Our findings in newborn CF pigs and young patients with CF suggest that airway changes begin during fetal life and may contribute to CF pathogenesis and clinical disease during postnatal life.
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Suter MJ, Jillella PA, Vakoc BJ, Halpern EF, Mino-Kenudson M, Lauwers GY, Bouma BE, Nishioka NS, Tearney GJ. Image-guided biopsy in the esophagus through comprehensive optical frequency domain imaging and laser marking: a study in living swine. Gastrointest Endosc 2010; 71:346-53. [PMID: 19879573 PMCID: PMC2857407 DOI: 10.1016/j.gie.2009.07.007] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Accepted: 07/03/2009] [Indexed: 02/08/2023]
Abstract
BACKGROUND Random biopsy esophageal surveillance can be subject to sampling errors, resulting in diagnostic uncertainty. Optical frequency domain imaging (OFDI) is a high-speed, 3-dimensional endoscopic microscopy technique. When deployed through a balloon-centering catheter, OFDI can automatically image the entire distal esophagus (6.0 cm length) in approximately 2 minutes. OBJECTIVE To test a new platform for guided biopsy that allows the operator to select target regions of interest on an OFDI dataset, and then use a laser to mark the esophagus at corresponding locations. The specific goals include determining the optimal laser parameters, testing the accuracy of the laser marking process, evaluating the endoscopic visibility of the laser marks, and assessing the amount of mucosal damage produced by the laser. DESIGN Experimental study conducted in 5 swine in vivo. SETTING Massachusetts General Hospital. MAIN OUTCOME MEASUREMENTS Success rate, including endoscopic visibility of laser marks and accuracy of the laser marking process for selected target sites, and extent of the thermal damage caused by the laser marks. RESULTS All of the laser-induced marks were visible by endoscopy. Target locations were correctly marked with a success rate of 97.07% (95% confidence interval, 89.8%-99.7%). Thermal damage was limited to the superficial layers of the mucosa and was observed to partially heal within 2 days. LIMITATIONS An animal study with artificially placed targets to simulate pathology. CONCLUSIONS The study demonstrates that laser marking of esophageal sites identified in comprehensive OFDI datasets is feasible and can be performed with sufficient accuracy, precision, and visibility to guide biopsy in vivo.
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Kang D, Suter MJ, Boudoux C, Yoo H, Yachimski PS, Puricelli WP, Nishioka NS, Mino-Kenudson M, Lauwers GY, Bouma BE, Tearney GJ. Comprehensive imaging of gastroesophageal biopsy samples by spectrally encoded confocal microscopy. Gastrointest Endosc 2010; 71:35-43. [PMID: 19922916 PMCID: PMC3135336 DOI: 10.1016/j.gie.2009.08.026] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2009] [Accepted: 08/23/2009] [Indexed: 02/06/2023]
Abstract
BACKGROUND Spectrally encoded confocal microscopy (SECM) is a high-speed reflectance confocal microscopy technique that has the potential to be used for acquiring comprehensive images of the entire distal esophagus endoscopically with subcellular resolution. OBJECTIVE The goal of this study was to demonstrate large-area SECM in upper GI tissues and to determine whether the images contain microstructural information that is useful for pathologic diagnosis. DESIGN A feasibility study. SETTING Gastrointestinal Unit, Massachusetts General Hospital. PATIENTS Fifty biopsy samples from 36 patients undergoing routine EGD were imaged by SECM, in their entirety, immediately after their removal. RESULTS The microstructure seen in the SECM images was similar to that seen by histopathology. Gastric cardia mucosa was clearly differentiated from squamous mucosa. Gastric fundic/body type mucosa showed more tightly packed glands than gastric cardia mucosa. Fundic gland polyps showed cystically dilated glands lined with cuboidal epithelium. The presence of intraepithelial eosinophils was detected with the cells demonstrating a characteristic bilobed nucleus. Specialized intestinal metaplasia was identified by columnar epithelium and the presence of goblet cells. Barrett's esophagus (BE) with dysplasia was differentiated from specialized intestinal metaplasia by the loss of nuclear polarity and disorganized glandular architecture. LIMITATIONS Ex vivo, descriptive study. CONCLUSIONS Large-area SECM images of gastroesophageal biopsy samples enabled the visualization of both subcellular and architectural features of various upper GI mucosal types and were similar to the corresponding histopathologic slides. These results suggest that the development of an endoscopic SECM probe is merited.
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Goldberg BD, Vakoc BJ, Oh WY, Suter MJ, Waxman S, Freilich MI, Bouma BE, Tearney GJ. Performance of reduced bit-depth acquisition for optical frequency domain imaging. OPTICS EXPRESS 2009; 17:16957-68. [PMID: 19770914 PMCID: PMC2785457 DOI: 10.1364/oe.17.016957] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
High-speed optical frequency domain imaging (OFDI) has enabled practical wide-field microscopic imaging in the biological laboratory and clinical medicine. The imaging speed of OFDI, and therefore the field of view, of current systems is limited by the rate at which data can be digitized and archived rather than the system sensitivity or laser performance. One solution to this bottleneck is to natively digitize OFDI signals at reduced bit depths, e.g., at 8-bit depth rather than the conventional 12-14 bit depth, thereby reducing overall bandwidth. However, the implications of reduced bit-depth acquisition on image quality have not been studied. In this paper, we use simulations and empirical studies to evaluate the effects of reduced depth acquisition on OFDI image quality. We show that image acquisition at 8-bit depth allows high system sensitivity with only a minimal drop in the signal-to-noise ratio compared to higher bit-depth systems. Images of a human coronary artery acquired in vivo at 8-bit depth are presented and compared with images at higher bit-depth acquisition.
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Desjardins AE, Vakoc BJ, Suter MJ, Yun SH, Tearney GJ, Bouma BE. Real-time FPGA processing for high-speed optical frequency domain imaging. IEEE TRANSACTIONS ON MEDICAL IMAGING 2009; 28:1468-72. [PMID: 19336296 PMCID: PMC2883772 DOI: 10.1109/tmi.2009.2017740] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
We present a novel algorithm for reconstructing interferograms acquired in optical frequency domain imaging (OFDI). The algorithm was developed specifically for processing in field programmable gate arrays (FPGAs) and featured the use of a finite-impulse-response (FIR) filter implementation of B-spline interpolation for efficiently re-sampling k-space. When implemented in FPGAs, the algorithm allowed for real-time processing of interferograms acquired with a high-speed OFDI system at 54 kHz and a sampling rate of 100 MS/s.
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Tearney GJ, Waxman S, Shishkov M, Vakoc BJ, Suter MJ, Freilich MI, Desjardins AE, Oh WY, Bartlett LA, Rosenberg M, Bouma BE. Three-dimensional coronary artery microscopy by intracoronary optical frequency domain imaging. JACC Cardiovasc Imaging 2009; 1:752-61. [PMID: 19356512 DOI: 10.1016/j.jcmg.2008.06.007] [Citation(s) in RCA: 252] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2008] [Revised: 05/22/2008] [Accepted: 06/03/2008] [Indexed: 11/25/2022]
Abstract
OBJECTIVES We present the first clinical experience with intracoronary optical frequency domain imaging (OFDI) in human patients. BACKGROUND Intracoronary optical coherence tomography (OCT) is a catheter-based optical imaging modality that is capable of providing microscopic (approximately 7-microm axial resolution, approximately 30-microm transverse resolution), cross-sectional images of the coronary wall. Although the use of OCT has shown substantial promise for imaging coronary microstructure, blood attenuates the OCT signal, necessitating prolonged, proximal occlusion to screen long arterial segments. OFDI is a second-generation form of OCT that is capable of acquiring images at much higher frame rates. The increased speed of OFDI enables rapid, 3-dimensional imaging of long coronary segments after a brief, nonocclusive saline purge. METHODS Volumetric OFDI images were obtained in 3 patients after intracoronary stent deployment. Imaging was performed in the left anterior descending and right coronary arteries with the use of a nonocclusive saline purge rates ranging from 3 to 4 ml/s and for purge durations of 3 to 4 s. After imaging, the OFDI datasets were segmented using previously documented criteria and volume rendered. RESULTS Good visualization of the artery wall was obtained in all cases, with clear viewing lengths ranging from 3.0 to 7.0 cm at pullback rates ranging from 5 to 20 mm/s. A diverse range of microscopic features were identified in 2 and 3 dimensions, including thin-capped fibroatheromas, calcium, macrophages, cholesterol crystals, bare stent struts, and stents with neointimal hyperplasia. There were no complications of the OFDI procedure. CONCLUSIONS Our results demonstrate that OFDI is a viable method for imaging the microstructure of long coronary segments in patients. Given its ability to provide microscopic information in a practical manner, this technology may be useful for studying human coronary pathophysiology in vivo and as a clinical tool for guiding the management of coronary artery disease.
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Bouma BE, Yun SH, Vakoc BJ, Suter MJ, Tearney GJ. Fourier-domain optical coherence tomography: recent advances toward clinical utility. Curr Opin Biotechnol 2009; 20:111-8. [PMID: 19264475 DOI: 10.1016/j.copbio.2009.02.007] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2008] [Revised: 02/09/2009] [Accepted: 02/10/2009] [Indexed: 12/20/2022]
Abstract
With the advent of Fourier-domain techniques, optical coherence tomography (OCT) has advanced from high-resolution 'point' imaging over small fields-of-view to comprehensive microscopic imaging over three-dimensional volumes that are comparable to the dimensions of luminal internal organs. This advance has required the development of new lasers, improved spectrometers, minimally invasive catheters and endoscopes, and novel optical and signal processing strategies. In recent cardiovascular, ophthalmic, and gastrointestinal clinical studies, the capabilities of Fourier-domain OCT have enabled a new paradigm for diagnostic screening of large tissue areas, which addresses the shortcomings of existing technologies and focal biopsy.
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Boudoux C, Leuin SC, Oh WY, Suter MJ, Desjardins AE, Vakoc BJ, Bouma BE, Hartnick CJ, Tearney GJ. Optical Microscopy of the Pediatric Vocal Fold. ACTA ACUST UNITED AC 2009; 135:53-64. [DOI: 10.1001/archoto.2008.518] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Suter MJ, Vakoc BJ, Yachimski PS, Shishkov M, Lauwers GY, Mino-Kenudson M, Bouma BE, Nishioka NS, Tearney GJ. Comprehensive microscopy of the esophagus in human patients with optical frequency domain imaging. Gastrointest Endosc 2008; 68:745-53. [PMID: 18926183 PMCID: PMC2715833 DOI: 10.1016/j.gie.2008.05.014] [Citation(s) in RCA: 151] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2008] [Accepted: 05/05/2008] [Indexed: 02/08/2023]
Abstract
BACKGROUND Optical coherence tomography (OCT) is a cross-sectional, high-resolution imaging modality that has been shown to accurately differentiate esophageal specialized intestinal metaplasia (SIM) from gastric cardia at the squamocolumnar junction (SCJ) and diagnose high-grade dysplasia and intramucosal carcinoma in patients with SIM. The clinical utility of OCT has been limited, however, by its inability to acquire images over large areas. OBJECTIVE The aim of this study was to use recently developed high-speed OCT technology, termed optical frequency domain imaging (OFDI), and a new balloon-centering catheter (2.5 cm diameter) to demonstrate the feasibility of large area, comprehensive optical microscopy of the entire distal esophagus (approximately 6.0 cm) in patients. DESIGN A pilot feasibility study. SETTING Massachusetts General Hospital. PATIENTS Twelve patients undergoing routine EGD. RESULTS Comprehensive microscopy of the distal esophagus was successfully performed in 10 patients with the OFDI system and balloon catheter. There were no complications resulting from the imaging procedure. Volumetric data sets were acquired in less than 2 minutes. OFDI images at the SCJ showed a variety of microscopic features that were consistent with histopathologic findings, including squamous mucosa, cardia, SIM with and without dysplasia, and esophageal erosion. LIMITATIONS Inability to obtain direct correlation of OFDI data and histopathologic diagnoses. CONCLUSIONS Comprehensive volumetric microscopy of the human distal esophagus was successfully demonstrated with OFDI and a balloon-centering catheter, providing a wealth of detailed information about the structure of the esophageal wall. This technique will support future studies to compare OFDI image information with histopathologic diagnoses.
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Suter MJ, Reinhardt JM, McLennan G. Integrated CT/bronchoscopy in the central airways: preliminary results. Acad Radiol 2008; 15:786-98. [PMID: 18486014 DOI: 10.1016/j.acra.2008.03.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2007] [Revised: 01/29/2008] [Accepted: 03/07/2008] [Indexed: 11/30/2022]
Abstract
RATIONALE AND OBJECTIVES Many imaging modalities and methodologies exist for evaluating the pulmonary airways. Individually, each modality provides insight to the state of the airways; however, alone they do not necessarily provide a comprehensive description. The goal of this work is to integrate complementary medical imaging datasets to form a synergistic description of the airways. MATERIALS AND METHODS Two digital bronchoscopic techniques were used to evaluate the pulmonary mucosa. A digital color bronchoscopic system was used to detect mucosal color alterations, and a fluorescence detection system was used to assess the microvasculature of the bronchial mucosa. Study participants were also imaged with a multidetector row computed tomographic (MDCT) scanner. Virtual bronchoscopic and image registration techniques were exploited to combine three-dimensional surface renderings, extracted from the MDCT data, together with the two-dimensional digital bronchoscopic images. Validation of the fusion process was performed on a rubber phantom of an adult airway with 4 embedded metal beads. RESULTS The fusion of the MDCT extracted airway tree and the digital bronchoscopic datasets were presented for three study participants. In addition, the detected accuracy of the registration method to reliably align the MDCT and bronchoscopic image datasets was determined to be 1.98 mm in the phantom airway model. CONCLUSION We have demonstrated that merging of three distinct digital datasets to provide a single synergistic description of the airways is possible. This is a pilot project in the field of eidomics, the process of combining digital image datasets and image-based processes together. We anticipate that in the future eidomics will provide a universal and predictive imaging language that will change health care delivery.
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Vakoc BJ, Shishko M, Yun SH, Oh WY, Suter MJ, Desjardins AE, Evans JA, Nishioka NS, Tearney GJ, Bouma BE. Comprehensive esophageal microscopy by using optical frequency-domain imaging (with video). Gastrointest Endosc 2007; 65:898-905. [PMID: 17383652 PMCID: PMC2705339 DOI: 10.1016/j.gie.2006.08.009] [Citation(s) in RCA: 150] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2006] [Accepted: 08/07/2006] [Indexed: 12/27/2022]
Abstract
BACKGROUND Optical coherence tomography (OCT) has been used for high-resolution endoscopic imaging and diagnosis of specialized intestinal metaplasia, dysplasia, and intramucosal carcinoma of the esophagus. However, the relatively slow image-acquisition rate of the present OCT systems inhibits wide-field imaging and limits the clinical utility of OCT for diagnostic imaging in patients with Barrett's esophagus. OBJECTIVE This study describes a new optical imaging technology, optical frequency-domain imaging (OFDI), derived from OCT, that enables comprehensive imaging of large esophageal segments with microscopic resolution. DESIGN A prototype OFDI system was developed for endoscopic imaging. The system was used in combination with a balloon-centering catheter to comprehensively image the distal esophagus in swine. RESULTS Volumetric images of the mucosa and portions of the muscularis propria were obtained for 4.5-cm-long segments. Image resolution was 7 microm in depth and 30 microm parallel to the lumen, and provided clear delineation of each mucosal layer. The 3-dimensional data sets were used to create cross-sectional microscopic images, as well as vascular maps of the esophagus. Submucosal vessels and capillaries were visualized by using Doppler-flow processing. CONCLUSIONS Comprehensive microscopic imaging of the distal esophagus in vivo by using OFDI is feasible. The unique capabilities of this technology for obtaining detailed information of tissue microstructure over large mucosal areas may open up new possibilities for improving the management of patients with Barrett's esophagus.
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Yun SH, Tearney GJ, Vakoc BJ, Shishkov M, Oh WY, Desjardins AE, Suter MJ, Chan RC, Evans JA, Jang IK, Nishioka NS, de Boer JF, Bouma BE. Comprehensive volumetric optical microscopy in vivo. Nat Med 2006; 12:1429-33. [PMID: 17115049 PMCID: PMC2709216 DOI: 10.1038/nm1450] [Citation(s) in RCA: 283] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2006] [Accepted: 06/20/2006] [Indexed: 11/09/2022]
Abstract
Comprehensive volumetric microscopy of epithelial, mucosal and endothelial tissues in living human patients would have a profound impact in medicine by enabling diagnostic imaging at the cellular level over large surface areas. Considering the vast area of these tissues with respect to the desired sampling interval, achieving this goal requires rapid sampling. Although noninvasive diagnostic technologies are preferred, many applications could be served by minimally invasive instruments capable of accessing remote locations within the body. We have developed a fiber-optic imaging technique termed optical frequency-domain imaging (OFDI) that satisfies these requirements by rapidly acquiring high-resolution, cross-sectional images through flexible, narrow-diameter catheters. Using a prototype system, we show comprehensive microscopy of esophageal mucosa and of coronary arteries in vivo. Our pilot study results suggest that this technology may be a useful clinical tool for comprehensive diagnostic imaging for epithelial disease and for evaluating coronary pathology and iatrogenic effects.
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Ruckstuhl S, Suter MJ, Giger W. Rapid determination of sulfonated naphthalenes and their formaldehyde condensates in aqueous environmental samples using synchronous excitation fluorimetry. Analyst 2001; 126:2072-7. [PMID: 11763094 DOI: 10.1039/b104090c] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Sulfonated naphthalenes and their formaldehyde condensates (SNFC) were determined in aqueous environmental samples by spectrofluorimetry. A clean-up step using n-hexane to extract possibly interfering nonpolar compounds such as naphthalene is the only preparatory procedure. Synchronous excitation mode with a gammalambda of 105 nm allows the determination of SNFC in environmental samples without additional clean-up or analyte enrichment. Interferences by humic acids and nitrate occurred only at concentrations higher than 1 mg C L(-1) and 10 mg NO3- L(-1), respectively. The limit of detection was 0.2 microg L(-1), the average recovery was 104% and the confidence interval (95% certainty) was 24%. The response factor for the quantitative determination of total SNFC, depending on the distribution of the different SNFC components, was validated for groundwater from two field sites using an HPLC-FD (fluorescence detection) method as a reference method.
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Acero JL, Haderlein SB, Schmidt TC, Suter MJ, von Gunten U. MTBE oxidation by conventional ozonation and the combination ozone/hydrogen peroxide: efficiency of the processes and bromate formation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2001; 35:4252-4259. [PMID: 11718338 DOI: 10.1021/es010044n] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The present study investigates the oxidation of methyl tert-butyl ether (MTBE) by conventional ozonation and the advanced oxidation process (AOP) ozone/hydrogen peroxide under drinking water treatment conditions. The major degradation products identified were tert-butyl formate (TBF), tert-butyl alcohol (TBA), 2-methoxy-2-methyl propionaldehyde (MMP), acetone (AC), methyl acetate (MA), hydroxyisobutyraldehyde (HiBA), and formaldehyde (FA). The rate constants of the reaction of ozone and OH radicals with MTBE were found to be 0.14 and 1.9 x 10(9) M(-1) s(-1), respectively. The rate constants for the same oxidation processes were also measured for the degradation products TBF, MMP, MA, and HiBA (k(O3-TBF) = 0.78 M(-1) s(-1); k(OH-TBF) = 7.0 x 10(8) M(-1) s(-1); k(O3-MMP) = 5 M(-1) s(-1); k(OH-MMP) = 3 x 10(9) M(-1) s(-1), k(O3-MA) = 0.09 M(-1) s(-1), k(O3-HiBA) = 5 M(-1) s(-1); k(OH-HiBA) = 3 x 10(9) M(-1) s(-1)). Since all compounds reacted slowly with molecular ozone, only the degradation pathway of MTBE with OH radicals has been determined, including the formation of primary degradation products. In experiments performed with several natural waters, the efficiency of MTBE elimination and the formation of bromate as disinfection byproduct have been measured. With a bromide level of 50 microg/L, only 35-50% of MTBE could be eliminated by the AOP O3/H2O2 without exceeding the current drinking water standard of bromate (10 microg/L). The transient concentrations of MTBE and its primary degradation products were modeled using a combination of kinetic parameters (degradation product distribution and rate constants) together with the ozone and OH radical concentration and were in good agreement with the experimental results.
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Reichenbecher W, Philipp B, Suter MJ, Schink B. Hydroxyhydroquinone reductase, the initial enzyme involved in the degradation of hydroxyhydroquinone (1,2,4-trihydroxybenzene) by Desulfovibrio inopinatus. Arch Microbiol 2000; 173:206-12. [PMID: 10763753 DOI: 10.1007/s002039900130] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The recently isolated sulfate reducer Desulfovibrio inopinatus oxidizes hydroxyhydroquinone (1,2,4trihydroxybenzene; HHQ) to 2 mol acetate and 2 mol CO2 (mol substrate)-1, with stoichiometric reduction of sulfate to sulfide. None of the key enzymes of fermentative HHQ degradation, i.e. HHQ-1,2,3,5-tetrahydroxybenzene transhydroxylase or phloroglucinol reductase, were detected in cell-free extracts of D. inopinatus, indicating that this bacterium uses a different pathway for anaerobic HHQ degradation. HHQ was reduced with NADH in cell-free extracts to a nonaromatic compound, which was identified as dihydrohydroxyhydroquinone by its retention time in HPLC separation and by HPLC-mass spectrometry. The compound was identical with the product of chemical reduction of HHQ with sodium borohydride. Dihydrohydroxyhydroquinone was converted stoichiometrically to acetate and to an unknown coproduct. HHQ reduction was an enzymatic activity which was present in the cell-free extract at 0.25-0.30 U (mg protein)-1, with a pH optimum at 7.5. The enzyme was sensitive to sodium chloride, potassium chloride, EDTA, and o-phenanthroline, and exhibited little sensitivity towards sulfhydryl group reagents, such as copper chloride or p-chloromercuribenzoate.
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Zipper C, Bolliger C, Fleischmann T, Suter MJ, Angst W, Müller MD, Kohler HP. Fate of the herbicides mecoprop, dichlorprop, and 2,4-D in aerobic and anaerobic sewage sludge as determined by laboratory batch studies and enantiomer-specific analysis. Biodegradation 2000; 10:271-8. [PMID: 10633543 DOI: 10.1023/a:1008396022622] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Aerobic degradation experiments with the racemic mixtures of mecoprop and dichlorprop revealed that activated sludge collected from the aeration tank of a municipal waste water treatment plant degraded both enantiomers of mecoprop and dichlorprop within 7 days, albeit in an enantioselective manner; the (S) enantiomers were preferentially degraded. Mecoprop, dichlorprop, and 2,4-D were completely metabolized under aerobic conditions, as shown by the 86-98% elimination of dissolved organic carbon. Under anaerobic conditions, the concentration of 2,4-D decreased exponentially with a first-order reaction rate constant of 0.24 per day and without a lag-phase. After an incubation time of 17 days, 2,4-D was completely removed. 2,4-Dichlorophenol was the main metabolite of anaerobic 2,4-D degradation; only traces of 4-chlorophenol were detected. In contrast, the chiral phenoxypropionic acid herbicides mecoprop and dichlorprop persisted under anaerobic conditions during 49 days of incubation.
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Koller-Lucae SK, Suter MJ, Rentsch KM, Schott H, Schwendener RA. Metabolism of the new liposomal anticancer drug N4-octadecyl-1-beta-D-arabinofuranosylcytosine in mice. Drug Metab Dispos 1999; 27:342-50. [PMID: 10064564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023] Open
Abstract
Metabolism and excretion of the new antitumor drug N4-octadecyl-1-beta-D-arabinofuranosylcytosine (NOAC) was investigated in mice. Mice were injected i.v. with tritium-labeled liposomal NOAC (4 micromol/mouse). Analysis of HPLC-purified extracts of liver homogenates by liquid chromatography coupled with mass spectrometry revealed only the presence of unmetabolized drug. To study the excretion of the administered drug, mice were injected with tritium-labeled liposomal NOAC or as comparison with 1-beta-D-arabinofuranosylcytosine (ara-C; 4 micromol/mouse) and housed up to 48 h in metabolic cages. Urine and feces were collected at different time points and the kinetics of excreted radioactivity were determined. After 48 h, 39% of the injected [5-3H]NOAC radioactivity was excreted in urine and 16% in feces, whereas ara-C radioactivity was only found in urine with 48% of the injected dose. Feces extracts and urine were purified by HPLC and radioactive fractions were further analyzed by liquid chromatography coupled with mass spectrometry. The radioactivity of feces extracts of NOAC-treated mice was composed of unmetabolized NOAC, hydroxylated NOAC (NOAC + OH), its sulfated derivative (NOAC + OSO3H), and unidentified metabolites, whereas in urine, the hydrophilic molecules ara-C and ara-U were found. During the period of 48 h only 2% of the injected NOAC was eliminated in its unmetabolized form, whereas 25% was identified as main metabolite ara-C. Urine collected during 48 h in ara-C-treated mice contained 33% of the injected dose as unmetabolized drug and 13% as the main metabolite ara-U. Thus, NOAC is metabolized by two major pathways, one leading to the hydrophilic metabolites ara-C and ara-U and the other to hydroxylated and sulfated NOAC.
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