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Poster — Thur Eve — 05: Semi-Automated Segmentation of Lung Tumours on CT Scans Using Level Set Sparse Field Active Model

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Medical Physics 2010年第7PART2期37卷 3887-3887页

作者： J Awad L Wilson G Parraga A Fenster Imaging Research Laboratories Robarts Research Institute London ON Department of Medical Biophysics The University of Western Ontario London ON Department of Medical Imaging The University of Western Ontario London ON Graduate Program in Biomedical Engineering The University of Western Ontario London ON

We present a semi-automated algorithm for segmenting lung tumours on chest computed tomography (CT) images to be utilized for monitoring tumour response or progression. Seven lung tumours were evaluated; each tumour was radially sliced into 10 slices for a total of 70 radial slices, and manually segmented. The manual segmentations were used as the ground truth for evaluating the proposed algorithm. The tumour image on each radial slice was classified into two categories: (1) well-defined boundaries, located centrally in the lung parenchyma without significant vasculature; and (2) vascularized or juxtapleural (VJ). To segment the well-defined boundaries, a shape constrained multi-thresholding technique with one user-defined seed point on the tumour is applied. For vascularized and juxtapleural tumours, this multi-thresholding technique provided an initial contour that was deformed by a level set sparse field active model to produce the final segmentation for these tumours. The dice index (DI) measure was adopted to evaluate the segmentation results. The average and standard deviation values of the DI for the well-defined and VJ images were 96.32 ± 1.12% and 95.19 ± 1.58%, respectively. The DI overall average and standard deviation of the 70 slices was 95.50 ± 1.55%. The preliminary results show that using the proposed algorithm produced accurate results.

关键词： Cancer Lungs Medical imaging Computed tomography Medical image segmentation

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Registration of finger vein image using skin surface information for authentication

Registration of finger vein image using skin surface informa...

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Image Processing: Machine Vision Applications II

作者： Noh, SeungWoo Kong, Hyoun-Joong Park, SangYun Kim, JiMan Lee, Seung-Rae Kim, Taejeong Kim, Hee Chan Interdisciplinary Program Bioengineering Major Graduate School Seoul National University Seoul Korea Republic of Interdisciplinary Program Biomedical Engineering Major Graduate School Seoul National University Seoul Korea Republic of Institute of Medical and Biological Engineering Medical Research Center Seoul National University Seoul Korea Republic of Department of Electrical Engineering and Computer Sciences Seoul National University Seoul Korea Republic of Department of Biomedical Engineering College of Medicine Seoul National University Seoul Korea Republic of

ISBN: (纸本)9780819475015

The finger vein image acquired with an acquisition system should be properly aligned to proceed with comparing algorithm. However it is not easy to find control the points since the images are naturally blurred with an inherent scattering property. To overcome this problem, we propose a novel finger vein registration method utilizing skin surface information (i.e. wrinkles and outlines). We assumed that finger crooking was insignificant. Images were sampled with intended translation and rotation. Each time, two images were acquired successively by switching the light source;one with infrared light and the other with white light. Degree of rotation and translation of sampled image were calculated using outline features in the white light image and then the infrared image was transformed according to the calculated data. To validate our method, correlation values were computed between identical subjects and different subjects. High correlation values were shown between identical subjects whereas low values were shown between different subjects. © 2009 SPIE.

关键词： Authentication

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In vitro cardiac catheter navigation via augmented reality surgical guidance

In vitro cardiac catheter navigation via augmented reality s...

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Medical Imaging 2009: Visualization, Image-Guided Procedures, and Modeling

作者： Linte, Cristian A. Moore, John Wiles, Andrew Lo, Jennifer Wedlakea, Chris Peters, Terry M. Imaging Research Laboratories Robarts Research Institute Canada Biomedical Engineering Graduate Program University of Western Ontario Canada Department of Medical Biophysics University of Western Ontario London Ontario ON Canada

ISBN: (纸本)9780819475121

Catheter-driven cardiac interventions have emerged in response to the need of reducing invasiveness associated with the traditional cut-and-sew techniques. Catheter manipulation is traditionally performed under real-time fluoroscopy imaging, resulting in an overall trade-off of procedure invasiveness for radiation exposure of both the patient and clinical staff. Our approach to reducing and potentially eliminating the use of fluoroscopy in the operating room entails the use of multi-modality imaging and magnetic tracking technologies, wrapped together into an augmented reality environment for enhanced intra-procedure visualization and guidance. Here we performed an in vitro study in which a catheter was guided to specific targets located on the endocardial atrial surface of a beating heart phantom. "Therapy delivery" was modeled in the context of a blinded procedure, mimicking a beating heart, intracardiac intervention. The users navigated the tip of a magnetically tracked Freezor 5 CRYOCATH catheter to the specified targets. Procedure accuracy was determined as the distance between the tracked catheter tip and the tracked surgical target at the time of contact, and it was assessed under three different guidance modalities: endoscopic, augmented reality, and ultrasound image guidance. The overall RMS targeting accuracy achieved under augmented reality guidance averaged to 1.1 mm. This guidance modality shows significant improvements in both procedure accuracy and duration over ultrasound image guidance alone, while maintianing an overall targeting accuracy comparable to that achieved under endoscopic guidance. © 2009 SPIE.

关键词： Catheters

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Indirect ophthalmoscopic stereo video system using three-dimensional LCD

Indirect ophthalmoscopic stereo video system using three-dim...

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Stereoscopic Displays and Applications XX

作者： Kong, Hyoun-Joong Seo, Jong Mo Hwang, Jeong Min Kim, Hee Chan Interdisciplinary Program Biomedical Engineering Major Graduate School Seoul National University Seoul Korea Republic of Department of Electrical Engineering and Computer Sciences Seoul National University Seoul Korea Republic of Department Ophthalmology College of Medicine Seoul National University Seoul Korea Republic of Department of Biomedical Engineering College of Medicine Seoul National University Seoul Korea Republic of

Binocular indirect ophthalmoscope (BIO) provides a wider view of fundus with stereopsis contrary to the direct one. Proposed system is composed of portable BIO and 3D viewing unit. The illumination unit of BIO utilized high flux LED as a light source, LED condensing lens cap for beam focusing, color filters and small lithium ion battery. In optics unit of BIO, beam splitter was used to distribute an examinee's fundus image both to examiner's eye and to CMOS camera module attached to device. Captured retinal video stream data from stereo camera modules were sent to PC through USB 2.0 connectivity. For 3D viewing, two video streams having parallax between them were aligned vertically and horizontally and made into side-by-side video stream for cross-eyed stereoscopy. And the data were converted into autostereoscopic video stream using vertical interlacing for stereoscopic LCD which has glass 3D filter attached to the front side of it. Our newly devised system presented the real-time 3-D view of fundus to assistants with less dizziness than cross-eyed stereoscopy. And the BIO showed good performance compared to conventional portable BIO (Spectra Plus, Keeler Limited, Windsor, UK). © 2009 SPIE-IS&T.

关键词： Stereo image processing

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Analytical solutions to axisymmetric plane strain porous media-transport models in large arteries

Analytical solutions to axisymmetric plane strain porous med...

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10th ASME Summer Bioengineering Conference, SBC2008

作者： Vande Geest, Jonathan P. Simon, Bruce R. Aerospace and Mechanical Engineering University of Arizona Tucson AZ United States Graduate Interdisciplinary Program in Biomedical Engineering University of Arizona Tucson AZ United States Bio5 Institute for Collaborative Research University of Arizona Tucson AZ United States

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Digital ionic circuits on a microfluidic chip

Digital ionic circuits on a microfluidic chip

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13th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2009

作者： Han, Ji-Hyung Kim, Kwang Bok Kim, Hee Chan Chung, Taek Dong Department of Chemistry Seoul National University Korea Republic of Interdisciplinary Program Bioengineering Major Graduate School Seoul National University Korea Republic of Department of Biomedical Engineering College of Medicine Seoul National University Korea Republic of

ISBN: (纸本)9780979806421

A sophisticatedly designed polyelectrolyte diode was fabricated on a microchip and exhibited well-defined nonlinear rectifying behavior. Multiple polyelectrolyte diodes were integrated on a microchip to produce a variety of logic gates based on ionic circuits. By employing a fluorescent dye, the polyelectrolyte micro plugs also acted as optical indicators displaying the input signals applied to individual diodes in the ionic circuit on a microchip. Also, this system visualized the dynamic distribution of ions in a charged polymer phase under an electric field on a real time basis through fluorescence images. © 2009 CBMS.

关键词： Polyelectrolytes

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SERS decoding using functionalized micro gold balls flowing in a microfluidic channel

SERS decoding using functionalized micro gold balls flowing ...

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13th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2009

作者： Lee, Sa Ram Kim, Hee Chan Chung, Taek Dong Interdisciplinary Program Graduate School Seoul National University Seoul Korea Republic of Department of Biomedical Engineering College of Medicine Seoul National University Seoul Korea Republic of Department of Chemistry Seoul National University Seoul Korea Republic of

ISBN: (纸本)9780979806421

This paper reports the decoding strategy of surface-enhanced Raman scattering (SERS) signals from microspheres with Au shell structures, or gold balls, with Raman-tags in a microfluidic channel. On the surface of the gold balls, Raman tags were functionalized. We measured SERS signals from functionalized gold balls on a glass plate and in a fluidic channel at static and flowing conditions, respectively. © 2009 CBMS.

关键词： Microfluidics

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Janus micro gold shells fabricated by wireless electrochemistry

Janus micro gold shells fabricated by wireless electrochemis...

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13th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2009

作者： Jo, Ji-Hum Noh, Jongmin Kim, Hee Chan Chung, Taek Dong Department of Chemistry Seoul National University Seoul Korea Republic of Interdisciplinary Program Graduate School Seoul National University Seoul Korea Republic of Department of Biomedical Engineering College of Medicine Seoul National University Seoul Korea Republic of

ISBN: (纸本)9780979806421

This work reports a new method to partially coat a film of our interest on a microbead with a thin gold shell, briefly 'gold ball', using wireless electrochemistry. The key point of this method is to control the potential of the external electrodes, which will drive an electrochemical reaction on the gold ball in a microchannel without any electric contact. This method allows partial modification of a variety of organic or inorganic compounds that can electrochemical reaction. © 2009 CBMS.

关键词： Surface treatment

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Attenuation artifacts and time-of-flight PET

Attenuation artifacts and time-of-flight PET

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IEEE Symposium on Nuclear Science (NSS/MIC)

作者： Timothy G. Turkington Joshua M. Wilson Departments of Radiology and Biomedical Engineering and the Graduate Program in Medical Physic Duke university Durham NC USA Graduate Program in Medical Physics Duke university Durham NC USA

Attenuation artifacts in PET are seen when attenuation correction (AC) is not performed and when AC is performed but is based on an incorrect attenuation map. PET attenuation artifacts are generally more profound than the straightforward differences in photon attenuation through surrounding tissue from one source location to another. Effects such as the apparent radioactivity in gas pockets in the body or concave contours of the body surface, distortions, and a pronounced body contour are all in addition to the expected nonuniformities due to depth in the body. We have investigated the effects of time-of-flight (TOF) reconstruction on PET artifacts. Uniformity without AC (NAC) was investigated in a large tapering F-18-fillled phantom that increases from a small end to the size of a large patient. Throughout the length of the phantom, the NAC images with TOF were more uniform that the non-TOF images. A whole-body phantom with oval cross section was imaged with uniform F-18 background and a 5.5 cm air-filled sphere at one section, and a 5.5 cm hot (8? background) sphere at another section. In NAC images, the air-filled lesion was artificially hotter than background with non-TOF, but comparable to background with TOF. When this section was corrected with a uniform AC (as if the gas pocket had moved before transmission scan), the non-TOF image showed the sphere to be artificially hot (hotter than background) whereas the TOF images reduced the artifact. In the section with the hot sphere, the NAC distortions typical near the bladder (higher counts anterior and posterior to bladder; depleted areas lateral to bladder) were greatly diminished with TOF images. While AC is necessary for quantitation in PET, the use of TOF and NAC may be useful in providing more interpretable images in some situations were an attenuation map is impossible to obtain, or introduces errors of its own. TOF may also lessen some artifacts in corrected images.

关键词： Attenuation Positron emission tomography Imaging phantoms Image reconstruction Bladder Filling biomedical imaging Physics Telephony Electronic mail

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Understanding quantification of microvascularity with high-frequency power Doppler ultrasound

Understanding quantification of microvascularity with high-f...

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Medical Imaging 2009: Ultrasonic Imaging and Signal Processing

作者： Pinter, Stephen Z. Lacefield, James C. Biomedical Engineering Graduate Program Departments of Electrical University of Western Ontario London ON Canada Department of Electrical and Computer Engineering University of Western Ontario London ON Canada Department of Medical Biophysics University of Western Ontario London ON Canada Robarts Research Institute University of Western Ontario London ON Canada

ISBN: (纸本)9780819475169

High-frequency power Doppler imaging of angiogenesis can be challenging given the presence of small blood vessels and slow flow velocities. In the presence of substantial Doppler artifacts such as false-positive color pixels or undetected vessels, color pixel density (CPD) and related vascularity metrics do not provide accurate estimates of vascular volume fraction. As a step towards improved microvascular quantification, flow-phantom experiments were performed to establish relationships between CPD and wall filter cut-off velocity for various combinations of vessel size (160, 200, 250, 300, and 360 μm), flow velocity (4, 3, 2, 1, and 0.5 mm/s), and transducer frequency (30 and 40 MHz). Three distinct regions were observed in plots of CPD versus wall filter cut-off velocity: overestimation of CPD at low cut-offs, underestimation of CPD at high cut-offs, and a plateau at intermediate cut-offs. The CPD at the plateau closely matched the phantom's actual vascular volume fraction. The length of the plateau corresponded with the flow-detection performance of the Doppler system, which was assessed using receiver operating characteristic analysis. Color pixel density versus wall filter cut-off curves from analogous in vivo experiments exhibited the same shape, including a distinct CPD plateau. The similar shape of the flow-phantom and in vivo curves suggests that the presence of a plateau can be used to identify the best-estimate CPD value in an in vivo experiment. The ability to identify the best CPD estimate is expected to improve quantification of angiogenesis and anti-angiogenic treatment responses with power Doppler. © 2009 SPIE.

关键词： Flow velocity

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