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1.
J Surg Case Rep ; 2023(11): rjad628, 2023 Nov.
Article in English | MEDLINE | ID: mdl-38026739

ABSTRACT

Among intraabdominal lymphangiomas, colonic lymphangiomas are rare. These cystic tumors are generally asymptomatic and incidentally found but may present with bleeding or obstructive symptoms. Intussusception by such tumors is scarcely reported, with only nine previously reported cases listed in Pubmed. We report a case of a 41-year-old female Asian patient who presented with acute abdomen and was diagnosed with colonic intussusception caused by lymphangioma. She received emergent right hemicolectomy, recovered well without complications, and was discharged on the 5th postoperative day.

2.
IEEE Trans Med Robot Bionics ; 5(2): 335-342, 2023 May.
Article in English | MEDLINE | ID: mdl-37312886

ABSTRACT

MR-guided focal cryoablation of prostate cancer has often been selected as a minimally-invasive treatment option. Placing multiple cryo-needles accurately to form an ablation volume that adequately covers the target volume is crucial for better oncological/functional outcomes. This paper presents an MRI-compatible system combining a motorized tilting grid template with insertion depth sensing capabilities, enabling the physician to precisely place the cryo-needles into the desired location. In vivo animal study in a swine model (3 animals) was performed to test the device performance including targeting accuracy and the procedure workflow. The study showed that the insertion depth feedback improved the 3D targeting accuracy when compared to the conventional insertion technique (7.4 mm vs. 11.2 mm, p=0.04). All three cases achieved full iceball coverage without repositioning the cryo-needles. The results demonstrate the advantages of the motorized tilting mechanism and real-time insertion depth feedback, as well as the feasibility of the proposed workflow for MRI-guided focal cryoablation of prostate cancer.

3.
J Hazard Mater ; 451: 131101, 2023 06 05.
Article in English | MEDLINE | ID: mdl-36878030

ABSTRACT

Phytoremediation of metals from water (WM) and nutrient (NM) media exposed to waste metal cutting fluid (WMCF) along with temperature (T) and humidity (H) stress was tested using Azolla imbricata (Roxb.) Nakai. In the absence of WMCF, biomass was higher in NM than in WM during all tests. Surprisingly, opposite results were noted in the presence of WMCF, with growth failing at exposure to > 0.1% and > 0.5% in NM and WM, respectively. Further, correlation analysis of the growth data following WM exposure revealed that biomass was affected positively by T and negatively by H and metal accumulation. Simultaneously, metal accumulation was affected negatively by T and positively by H. The average accumulations of Al, Cd, Cr, Fe, Pb, and Zn across all T/H tests were 540, 282, 71, 1645, 2494 and 1110 mg·kg-1, respectively. The observed bioconcentration factor indicated that A. imbricata acts as a hyperaccumulator or accumulator of Zn (>10) and as either accumulator (>1) or excluder (<1) of the other metals. Overall, the phytoremediation performance of A. imbricata in multi-metal-contaminated WMCF was high in WM under all environmental conditions. Therefore, the use of WM is an economically feasible approach for the removal of metals from WMCF.


Subject(s)
Metals, Heavy , Soil Pollutants , Metals, Heavy/analysis , Biodegradation, Environmental , Humidity , Temperature , Water/analysis , Soil Pollutants/analysis
4.
Transl Biophotonics ; 4(3)2022 Aug.
Article in English | MEDLINE | ID: mdl-36176918

ABSTRACT

Noninvasive assessment of skin lesions, especially of basal cell carcinoma (BCC), has benefited more recently from the use of optical imaging techniques such as optical coherence tomography (OCT) and reflectance confocal microscopy (RCM). While RCM provides submicron scale resolution and thus enables identification of skin morphological changes of the skin, with the downside of limited penetration depth, OCT imaging of the same lesion brings the benefit of better resolving its depth of invasion. OCT and RCM can be used either individually or combined within the same instrument for the noninvasive diagnosis of nonmelanoma skin cancers (NMSCs). Their combined use has shown to provide certain benefits such as better characterization of the lesion's margins, both in depth and laterally, as well as improved sensitivity and specificity, as previously demonstrated by our team. In this paper we report a new "fiber-based" implementation of the second-generation RCM-OCT hand-held probe. The fiber-based implementation of both imaging modalities enabled the construction of a smaller footprint/lower weight hand-held probe. Its preliminary evaluation on the skin of healthy volunteers is reported here, demonstrating improved capabilities for resolving sub-cellular structures and image skin morphology with micron-scale resolution to a higher depth than in the previous implementation, while also enabling the construction of angiography maps showing vascular remodeling.

5.
J Periodontol ; 93(12): 1929-1939, 2022 12.
Article in English | MEDLINE | ID: mdl-35357007

ABSTRACT

BACKGROUND: Our objective was to develop and test a combined Raman microspectroscopy (RMS) and micro-optical coherence tomography (µOCT) approach for chairside quantification of gingival collagen, DNA, epithelium, and connective tissue. We hypothesized that a high-resolution RMS/µOCT can characterize healthy and inflamed periodontal tissues for diagnosis and disease activity monitoring. METHODS: A prototype instrument was developed, tested ex vivo on gingival specimens and optimized for in vivo intraoral use. The primary outcome measures were the ratios of oral epithelium to connective tissue thickness (OE:CT) and the amount of DNA to collagen type I (DNA/Col 1), and the thickness of sulcular epithelium (SE). For ex vivo testing, eight subjects with healthy periodontal tissues or with Stage II to IV periodontitis were included in the study and underwent crown-lengthening or periodontal surgical procedures, respectively. Gingival biopsies were scanned by RMS/µOCT and histometric analyses were performed. The proof-of-concept study included OE/CT, DNA/Col 1, and SE assessed in six volunteers with or without signs of gingival inflammation (n = 3/group). RESULTS: The spatially co-registered RMS spectra revealed opposing changes in the collagen and DNA peaks of inflamed compared with healthy tissues (P <0.05). Combined RMS/µOCT analysis showed that OE/CT, DNA/Col, and SE are significantly different between healthy and inflamed sites (P <0.05). Histological assessments confirmed the differences detected by RMS/µOCT. Qualitative analysis of DNA/Col 1 ratios indicated Col I content as the main distinguishing feature for health and DNA content for periodontitis. CONCLUSION: Results suggest that combined RMS/µOCT chairside imaging may distinguish between healthy and diseased sites by evaluating marginal periodontal morphological and biochemical features.


Subject(s)
Periodontitis , Tomography, Optical Coherence , Humans , Tomography, Optical Coherence/methods , Pilot Projects , Gingiva/diagnostic imaging , Gingiva/pathology , Periodontitis/pathology , Periodontium/diagnostic imaging , Periodontium/pathology
6.
Eur Surg Res ; 63(3): 123-131, 2022.
Article in English | MEDLINE | ID: mdl-34864732

ABSTRACT

PURPOSE: This study investigated the antiadhesive effects of Mediclore®, rosuvastatin, and a combination of Mediclore and rosuvastatin in a rat adhesion model. METHODS: The adhesion models (a total of 58 adult male rats) were divided into 4 groups. The control group (group C) received no special materials except for a saline. The experimental groups were treated with 5 mL of Mediclore (group M), rosuvastatin (group R), or rosuvastatin and Mediclore (group RM), and these materials were intraperitoneally placed under the incision. At postoperative day 14, the rats underwent re-laparotomy and adhesiolysis. Three investigators blinded to group assignment scored the extent of adhesion formation, the numbers of remote adhesions, and the extent of acute/chronic inflammation, fibrosis, edema, and congestion on resected specimens via histologic examination. RESULTS: The macroscopic adhesion score in group RM (7.27 ± 3.51) was significantly lower than those in groups C (13.36 ± 2.24) and R (11.71 ± 1.98); group M (9.13 ± 4.09) had a significantly lower adhesion score than group C. The number of remote adhesions was significantly lower in groups R and RM than in group C. The acute inflammation score, chronic inflammation score, and fibrosis score in group RM; the acute inflammation score in group R; and the fibrosis score in group M were significantly lower than those in group C. CONCLUSION: The intraperitoneal application of Mediclore and a combination of Mediclore and rosuvastatin effectively reduced postoperative adhesions.


Subject(s)
Hydroxymethylglutaryl-CoA Reductase Inhibitors , Animals , Disease Models, Animal , Fibrosis , Hydroxymethylglutaryl-CoA Reductase Inhibitors/pharmacology , Inflammation/drug therapy , Inflammation/pathology , Inflammation/prevention & control , Male , Postoperative Complications/prevention & control , Rats , Rosuvastatin Calcium/pharmacology , Tissue Adhesions/prevention & control
7.
Environ Pollut ; 289: 117311, 2021 Nov 15.
Article in English | MEDLINE | ID: mdl-34015691

ABSTRACT

Studies in the literature concern the toxicity of nanoparticles either in a Petri dish or in agar media-based tests. Therefore, for environmental relevance, individual and binary mixtures of metal oxide nanoparticles (M-NPs) cadmium oxide (CdO-NP) and copper oxide (CuO-NP) were tested in this study for their effect on Vigna radiata in soil with and without the addition of sawdust. Seed germination was 67% in 100 mg CuO-NP in soil without sawdust. Seeds failed to germinate in 100 mg CdO +100 mg CuO-NPs in soil without the addition of sawdust and germination was 83% at the same concentration in soil with sawdust. In sawdust added to soil, when compared with control (soil without M-NPs), the maximum reduction in shoot (82%) and root (80%) length and wet (61%) and dry (54%) weight of plant was recorded in CdO-NP treated soil. Similarly, compared with control (soil without sawdust and M-NPs), the percent reduction in shoot (61%) and root (70%) length and wet (44%) and dry (48%) weight was highest in CdO-NP treated soil not supplemented with sawdust. In a binary mixture test (CdO-NP + CuO-NP), the addition of sawdust promoted the above plant growth parameters compared with individual CdO-NP and CuO-NP tests. Cadmium (511 mg kg-1 for individual and 303 mg kg-1 for binary mixture tests) and Cu (953 mg kg-1 for individual and 2954 mg kg-1 for binary mixture tests) accumulation was higher in plants grown in soil without sawdust. The beneficial effect of sawdust addition was observed in seed germination, plant growth, and metal accumulation. With or without sawdust, the binary mixture of CdO and CuO was antagonistic. These results indicate that sawdust can prevent M-NP-induced toxicity and reduce metal accumulation in plant tissues.


Subject(s)
Metal Nanoparticles , Nanoparticles , Vigna , Cadmium/toxicity , Copper/toxicity , Metal Nanoparticles/toxicity , Oxides , Seeds
8.
Med Phys ; 48(5): 2553-2565, 2021 May.
Article in English | MEDLINE | ID: mdl-33651407

ABSTRACT

PURPOSE: Magnetic resonance imaging (MRI)-guided transperineal prostate biopsy has been practiced since the early 2000s. The technique often suffers from targeting error due to deviation of the needle as a result of physical interaction between the needle and inhomogeneous tissues. Existing needle guide devices, such as a grid template, do not allow choosing an alternative insertion path to mitigate the deviation because of their limited degree-of-freedom (DoF). This study evaluates how an angulated needle insertion path can reduce needle deviation and improve needle placement accuracy. METHODS: We extended a robotic needle-guidance device (Smart Template) for in-bore MRI-guided transperineal prostate biopsy. The new Smart Template has a 4-DoF needle-guiding mechanism allowing a translational range of motion of 65 and 58 mm along the vertical and horizontal axis, and a needle rotational motion around the vertical and horizontal axis ± 30 ∘ and a vertical rotational range of - 30 ∘ , + 10 ∘ , respectively. We defined a path planning strategy, which chooses between straight and angulated insertion paths depending on the anatomical structures on the potential insertion path. We performed (a) a set of experiments to evaluate the device positioning accuracy outside the MR-bore, and (b) an in vivo experiment to evaluate the improvement of targeting accuracy combining straight and angulated insertions in animal models (swine, n = 3 ). RESULTS: We analyzed 46 in vivo insertions using either straight or angulated insertions paths. The experiment showed that the proposed strategy of selecting straight or angulated insertions based on the subject's anatomy outperformed the conventional approach of just straight insertions in terms of targeting accuracy (2.4 mm [1.3-3.7] vs 3.9 mm [2.4-5.0] {Median IQR } ); p = 0.041 after the bias correction). CONCLUSION: The in vivo experiment successfully demonstrated that an angulated needle insertion path could improve needle placement accuracy with a path planning strategy that takes account of the subject-specific anatomical structures.


Subject(s)
Prostatic Neoplasms , Robotics , Animals , Humans , Image-Guided Biopsy , Magnetic Resonance Imaging , Male , Needles , Prostate/diagnostic imaging , Prostatic Neoplasms/diagnostic imaging , Swine
9.
PLoS One ; 16(2): e0245334, 2021.
Article in English | MEDLINE | ID: mdl-33571221

ABSTRACT

Providing surgical margin information during breast cancer surgery is crucial for the success of the procedure. The margin is defined as the distance from the tumor to the cut surface of the resection specimen. The consensus among surgeons and radiation oncologists is that there should be no tumor left within 1 to maximum 2 mm from the surface of the surgical specimen. If a positive margin remains, there is substantial risk for tumor recurrence, which may also result in potentially reduced cosmesis and eventual need for mastectomy. In this paper we report a novel multimodal optical imaging instrument based on combined high-resolution confocal microscopy-optical coherence tomography imaging for assessing the presence of potential positive margins on surgical specimens. Since rapid specimen analysis is critical during surgery, this instrument also includes a fluorescence imaging channel to enable rapid identification of the areas of the specimen that have potential positive margins. This is possible by specimen incubation with a cancer specific agent prior to imaging. In this study we used a quenched contrast agent, which is activated by cancer specific enzymes, such as urokinase plasminogen activators (uPA). Using this agent or a similar one, one may limit the use of high-resolution optical imaging to only fluorescence-highlighted areas for visualizing tissue morphology at the sub-cellular scale and confirming or ruling out cancer presence. Preliminary evaluation of this technology was performed on 20 surgical specimens and testing of the optical imaging findings was performed against histopathology. The combination of the three imaging modes allowed for high correlation between optical image analysis and histological ground-truth. The initial results are encouraging, showing instrument capability to assess margins on clinical specimens with a positive predictive value of 1.0 and a negative predictive value of 0.83.


Subject(s)
Breast Neoplasms , Image Processing, Computer-Assisted/methods , Margins of Excision , Microscopy, Confocal , Optical Imaging , Breast/diagnostic imaging , Breast/pathology , Breast Neoplasms/diagnostic imaging , Breast Neoplasms/surgery , Feasibility Studies , Female , Humans , Microscopy, Confocal/instrumentation , Microscopy, Confocal/methods , Optical Imaging/instrumentation , Optical Imaging/methods
10.
Biomed Opt Express ; 10(9): 4450-4461, 2019 Sep 01.
Article in English | MEDLINE | ID: mdl-31565501

ABSTRACT

Voice disorders affect a large number of adults in the United States, and their clinical evaluation heavily relies on laryngeal videostroboscopy, which captures the medial-lateral and anterior-posterior motion of the vocal folds using stroboscopic sampling. However, videostroboscopy does not provide direct visualization of the superior-inferior movement of the vocal folds, which yields important clinical insight. In this paper, we present a novel technology that complements videostroboscopic findings by adding the ability to image the coronal plane and visualize the superior-inferior movement of the vocal folds. The technology is based on optical coherence tomography, which is combined with videostroboscopy within the same endoscopic probe to provide spatially and temporally co-registered images of the mucosal wave motion, as well as vocal folds subsurface morphology. We demonstrate the capability of the rigid endoscopic probe, in a benchtop setting, to characterize the complex movement and subsurface structure of the aerodynamically driven excised larynx models within the 50 to 200 Hz phonation range. Our preliminary results encourage future development of this technology with the goal of its use for in vivo laryngeal imaging.

11.
Surg Laparosc Endosc Percutan Tech ; 29(6): 543-547, 2019 Dec.
Article in English | MEDLINE | ID: mdl-31568256

ABSTRACT

Laparoscopic appendectomy (LA) is perceived as a procedure requiring a short hospital stay; however, some patients require prolonged hospitalization because of postoperative ileus and pain; therefore, we introduced clipless LA, using only an ultrasonic energy device only for coagulation. A total of 1013 patients (clipless LA; n=290 and conventional LA; n=723) who underwent LA at our hospital between January 2015 and February 2018 were analyzed. The mean operative time was shorter (P<0.001), and postoperative pain score at 24 hours was lower (P<0.001) for clipless than for conventional LA. There were no significant differences in postoperative complications, except with regard to early postoperative ileus (clipless LA; 18.1% vs. conventional LA; 31.6%, P=0.025), and the operative method had significantly influenced early postoperative ileus (relative risk, 0.505; 95% confidence interval, 0.257-0.994; P=0.048). Clipless LA is comparable to conventional LA with regard to operative safety but results in significantly less pain and postoperative ileus.


Subject(s)
Appendectomy/methods , Appendicitis/surgery , Ileus/prevention & control , Laparoscopy/methods , Pain, Postoperative/prevention & control , Suture Techniques , Adult , Female , Follow-Up Studies , Humans , Ileus/epidemiology , Incidence , Length of Stay/trends , Male , Pain, Postoperative/epidemiology , Republic of Korea/epidemiology , Retrospective Studies , Risk Factors , Time Factors , Treatment Outcome
12.
Biomed Opt Express ; 9(2): 694-704, 2018 Feb 01.
Article in English | MEDLINE | ID: mdl-29552405

ABSTRACT

We report the development and the pre-clinical testing of a new technology based on optical coherence tomography (OCT) for investigating tissue composition at the tip of the core biopsy needle. While ultrasound, computed tomography, and magnetic resonance imaging are routinely used to guide needle placement within a tumor, they still do not provide the resolution needed to investigate tissue cellularity (ratio between viable tumor and benign stroma) at the needle tip prior to taking a biopsy core. High resolution OCT imaging, however, can be used to investigate tissue morphology at the micron scale, and thus to determine if the biopsy core would likely have the expected composition. Therefore, we implemented this capability within a custom-made biopsy gun and evaluated its capability for a correct estimation of tumor tissue cellularity. A pilot study on a rabbit model of soft tissue cancer has shown the capability of this technique to provide correct evaluation of tumor tissue cellularity in over 85% of the cases. These initial results indicate the potential benefit of the OCT-based approach for improving the success of the core biopsy procedures.

13.
J Biomed Opt ; 22(7): 76006, 2017 07 01.
Article in English | MEDLINE | ID: mdl-28697233

ABSTRACT

We present a hand-held implementation and preliminary evaluation of a combined optical coherence tomography (OCT) and reflectance confocal microscopy (RCM) probe for detecting and delineating the margins of basal cell carcinomas (BCCs) in human skin

Subject(s)
Carcinoma, Basal Cell/diagnostic imaging , Microscopy, Confocal , Tomography, Optical Coherence , Cross-Sectional Studies , Humans , Pilot Projects
14.
Biomed Opt Express ; 7(9): 3184-3197, 2016 Sep 01.
Article in English | MEDLINE | ID: mdl-27699091

ABSTRACT

Multimodal imaging probes a variety of tissue properties in a single image acquisition by merging complimentary imaging technologies. Exploiting synergies amongst the data, algorithms can be developed that lead to better tissue characterization than could be accomplished by the constituent imaging modalities taken alone. The combination of optical coherence tomography (OCT) with fluorescence lifetime imaging microscopy (FLIM) provides access to detailed tissue morphology and local biochemistry. The optical system described here merges 1310 nm swept-source OCT with time-domain FLIM having excitation at 355 and 532 nm. The pulses from 355 and 532 nm lasers have been interleaved to enable simultaneous acquisition of endogenous and exogenous fluorescence signals, respectively. The multimodal imaging system was validated using tissue phantoms. Nonspecific tagging with Alexa Flour 532 in a Watanbe rabbit aorta and active tagging of the LOX-1 receptor in human coronary artery, demonstrate the capacity of the system for simultaneous acquisition of OCT, endogenous FLIM, and exogenous FLIM in tissues.

15.
Biomed Opt Express ; 7(5): 2000-15, 2016 May 01.
Article in English | MEDLINE | ID: mdl-27231638

ABSTRACT

It is known that the progression of oral cancer is accompanied by changes in both tissue biochemistry and morphology. A multimodal imaging approach combining functional and structural imaging modalities could therefore provide a more comprehensive prognosis of oral cancer. This idea forms the central theme of the current study, wherein this premise is examined in the context of a multimodal imaging system that combines fluorescence lifetime imaging (FLIM) and optical coherence tomography (OCT). Towards this end, in the first part of the present study, the diagnostic advantage obtained by using both fluorescence intensity and lifetime information is assessed. In the second part of the study, the diagnostic potential of FLIM-derived biochemical features is compared with that of OCT-derived morphological features. For an objective assessment, several quantitative biochemical and morphological features from FLIM and OCT data, respectively, were obtained using signal and image processing techniques. These features were subsequently used in a statistical classification framework to quantify the diagnostic potential of different features. The classification accuracy for combined FLIM and OCT features was estimated to be 87.4%, which was statistically higher than accuracy based on only FLIM (83.2%) or OCT (81.0%) features. Moreover, the complimentary information provided by FLIM and OCT features, resulted in highest sensitivity and specificity for the combined FLIM and OCT features for discriminating benign (88.2% sens., 92.0% spec.), pre-cancerous (81.5% sens., 96.0% spec.), and cancerous (90.1% sens., 92.0% spec.) classes.

16.
Biomed Opt Express ; 7(2): 238-50, 2016 Feb 01.
Article in English | MEDLINE | ID: mdl-26977336

ABSTRACT

We report the development of a novel otoscopy probe for assessing middle ear anatomy and function. Video imaging and phase-sensitive optical coherence tomography are combined within the same optical path. A sound stimuli channel is incorporated as well to study middle ear function. Thus, besides visualizing the morphology of the middle ear, the vibration amplitude and frequency of the eardrum and ossicles are retrieved as well. Preliminary testing on cadaveric human temporal bone models has demonstrated the capability of this instrument for retrieving middle ear anatomy with micron scale resolution, as well as the vibration of the tympanic membrane and ossicles with sub-nm resolution.

17.
Biomed Opt Express ; 6(6): 2246-57, 2015 Jun 01.
Article in English | MEDLINE | ID: mdl-26114043

ABSTRACT

We demonstrate a miniature, tunable, minimally invasive endoscope for diagnosis of the auditory system. The probe is designed to sharply image anatomical details of the middle ear without the need for physically adjusting the position of the distal end of the endoscope. This is achieved through the addition of an electrowetted, tunable, electronically-controlled lens to the optical train. Morphological imaging is enabled by scanning light emanating from an optical coherence tomography system. System performance was demonstrated by imaging part of the ossicular chain and wall of the middle ear cavity of a normal mouse. During the experiment, we electronically moved the plane of best focus from the incudo-stapedial joint to the stapedial artery. Repositioning the object plane allowed us to image anatomical details of the middle ear beyond the depth of field of a static optical system. We also demonstrated for the first time to our best knowledge, that an optical system with an electrowetted, tunable lens may be successfully employed to measure sound-induced vibrations within the auditory system by measuring the vibratory amplitude of the tympanic membrane in a normal mouse in response to pure tone stimuli.

18.
Proc Natl Acad Sci U S A ; 112(10): 3128-33, 2015 Mar 10.
Article in English | MEDLINE | ID: mdl-25737536

ABSTRACT

Sound is encoded within the auditory portion of the inner ear, the cochlea, after propagating down its length as a traveling wave. For over half a century, vibratory measurements to study cochlear traveling waves have been made using invasive approaches such as laser Doppler vibrometry. Although these studies have provided critical information regarding the nonlinear processes within the living cochlea that increase the amplitude of vibration and sharpen frequency tuning, the data have typically been limited to point measurements of basilar membrane vibration. In addition, opening the cochlea may alter its function and affect the findings. Here we describe volumetric optical coherence tomography vibrometry, a technique that overcomes these limitations by providing depth-resolved displacement measurements at 200 kHz inside a 3D volume of tissue with picometer sensitivity. We studied the mouse cochlea by imaging noninvasively through the surrounding bone to measure sound-induced vibrations of the sensory structures in vivo, and report, to our knowledge, the first measures of tectorial membrane vibration within the unopened cochlea. We found that the tectorial membrane sustains traveling wave propagation. Compared with basilar membrane traveling waves, tectorial membrane traveling waves have larger dynamic ranges, sharper frequency tuning, and apically shifted positions of peak vibration. These findings explain discrepancies between previously published basilar membrane vibration and auditory nerve single unit data. Because the tectorial membrane directly overlies the inner hair cell stereociliary bundles, these data provide the most accurate characterization of the stimulus shaping the afferent auditory response available to date.


Subject(s)
Basilar Membrane/physiology , Cochlea/physiology , Tectorial Membrane/physiology , Animals , Mice , Tomography, Optical Coherence
19.
Eur Heart J Cardiovasc Imaging ; 16(8): 910-8, 2015 Aug.
Article in English | MEDLINE | ID: mdl-25722204

ABSTRACT

AIMS: The aim of this study was to validate novel imaging technology for simultaneous morphological and biochemical endogenous optical imaging of coronary atherosclerotic plaque. METHODS AND RESULTS: Optical coherence tomography (OCT) generates high-resolution 3D images of plaque morphology and endogenous fluorescence lifetime imaging microscopy (FLIM) characterizes biochemical composition. Both imaging modalities rely on plaque's intrinsic optical characteristics, making contrast agents unnecessary. A multimodal OCT/FLIM system was utilized to generate luminal biochemical maps superimposed on high-resolution (7 µm axial and 13 µm lateral) structural volumetric images. Forty-seven fresh postmortem human coronary segments were imaged: pathological intimal thickening (PIT, n = 26), fibroatheroma (FA, n = 12), thin-cap FA (TCFA, n = 2), and fibrocalcific plaque (CA, n = 7), determined by histopathology. Multimodal images were evaluated, and each plaque identified as PIT, FA, TCFA, or CA based on expert OCT readers, and as having high-lipid (HL), high-collagen (HC), or low-collagen/low-lipid (LCL) luminal composition based on linear discriminant analysis of FLIM. Of 47 plaques, 89.4% (42/47) of the plaques were correctly identified based on OCT/FLIM evaluation using tissue histopathology and immunohistochemistry as the gold standard. Four of the misclassifications corresponded to confusing PIT with HL luminal composition for FA with HL cap. The other corresponded to confusing FA with a HC cap for FA with an LCL cap. CONCLUSION: We have demonstrated the feasibility of accurate simultaneous OCT/FLIM morphological and biochemical characterization of coronary plaques at spatial resolutions and acquisition speeds compatible with catheter-based intravascular imaging. The success of this pilot study sets up future development of a multimodal intravascular imaging system that will enable studies that could help improve our understanding of plaque pathogenesis.


Subject(s)
Coronary Artery Disease/diagnosis , Microscopy, Fluorescence , Multimodal Imaging , Tomography, Optical Coherence , Coronary Artery Disease/pathology , Coronary Vessels/pathology , Feasibility Studies , Humans , Image Interpretation, Computer-Assisted , Imaging, Three-Dimensional , In Vitro Techniques , Pilot Projects
20.
Opt Lett ; 39(21): 6233-6, 2014 Nov 01.
Article in English | MEDLINE | ID: mdl-25361322

ABSTRACT

Phase-sensitive optical coherence tomography (PhOCT) offers exquisite sensitivity to mechanical vibration in biological tissues. There is growing interest in using PhOCT for imaging the nanometer scale vibrations of the ear in animal models of hearing disorders. Swept-source-based systems offer fast acquisition speeds, suppression of common mode noise via balanced detection, and good signal roll-off. However, achieving high phase stability is difficult due to nonlinear laser sweeps and trigger jitter in a typical swept laser source. Here, we report on the initial application of a Vernier-tuned distributed Bragg reflector (VT-DBR) swept laser as the source for a fiber-based PhOCT system. The VT-DBR swept laser is electronically tuned and precisely controls sweeps without mechanical movement, resulting in highly linear sweeps with high wavelength stability and repeatability. We experimentally measured a phase sensitivity of 0.4 pm standard deviation, within a factor of less than 2 of the computed shot-noise limit. We further demonstrated the system by making ex vivo measurements of the vibrations of the mouse middle ear structures.


Subject(s)
Ear, Middle/anatomy & histology , Lasers , Tomography, Optical Coherence/instrumentation , Animals , Mice , Vibration
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