LIVIVO - The Search Portal for Life Sciences

zur deutschen Oberfläche wechseln
Back to previous search Search history
Advanced search

Your last searches

  1. AU="Mewes, PW"
  2. AU="Perera, Sudheesha"

Search results

Result 1 - 7 of total 7

Search options

  1. Article ; Online: Cryo-Balloon Catheter Localization Based on a Support-Vector-Machine Approach.

    Kurzendorfer, Tanja / Mewes, Philip W / Maier, Andreas / Strobel, Norbert / Brost, Alexander

    IEEE transactions on medical imaging

    2016  Volume 35, Issue 8, Page(s) 1892–1902

    Abstract: Cryo-balloon catheters have attracted an increasing amount of interest in the medical community as they can reduce patient risk during left atrial pulmonary vein ablation procedures. As cryo-balloon catheters are not equipped with electrodes, they cannot ...

    Abstract Cryo-balloon catheters have attracted an increasing amount of interest in the medical community as they can reduce patient risk during left atrial pulmonary vein ablation procedures. As cryo-balloon catheters are not equipped with electrodes, they cannot be localized automatically by electro-anatomical mapping systems. As a consequence, X-ray fluoroscopy has remained an important means for guidance during the procedure. Most recently, image guidance methods for fluoroscopy-based procedures have been proposed, but they provide only limited support for cryo-balloon catheters and require significant user interaction. To improve this situation, we propose a novel method for automatic cryo-balloon catheter detection in fluoroscopic images by detecting the cryo-balloon catheter's built-in X-ray marker. Our approach is based on a blob detection algorithm to find possible X-ray marker candidates. Several of these candidates are then excluded using prior knowledge. For the remaining candidates, several catheter specific features are introduced. They are processed using a machine learning approach to arrive at the final X-ray marker position. Our method was evaluated on 75 biplane fluoroscopy images from 40 patients, from two sites, acquired with a biplane angiography system. The method yielded a success rate of 99.0% in plane A and 90.6% in plane B, respectively. The detection achieved an accuracy of 1.00 mm±0.82 mm in plane A and 1.13 mm±0.24 mm in plane B. The localization in 3-D was associated with an average error of 0.36 mm±0.86 mm.
    Language English
    Publishing date 2016-08
    Publishing country United States
    Document type Journal Article
    ZDB-ID 622531-7
    ISSN 1558-254X ; 0278-0062
    ISSN (online) 1558-254X
    ISSN 0278-0062
    DOI 10.1109/TMI.2016.2537052
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

    In stock of ZB MED Cologne/Königswinter

    Zs.A 2546: Show issues Location:
    Je nach Verfügbarkeit (siehe Angabe bei Bestand)
    bis Jg. 1994: Bestellungen von Artikeln über das Online-Bestellformular
    Jg. 1995 - 2021: Lesesall (2.OG)
    ab Jg. 2022: Lesesaal (EG)

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

  2. Article: An augmented reality framework for soft tissue surgery.

    Mountney, Peter / Fallert, Johannes / Nicolau, Stephane / Soler, Luc / Mewes, Philip W

    Medical image computing and computer-assisted intervention : MICCAI ... International Conference on Medical Image Computing and Computer-Assisted Intervention

    2014  Volume 17, Issue Pt 1, Page(s) 423–431

    Abstract: Augmented reality for soft tissue laparoscopic surgery is a growing topic of interest in the medical community and has potential application in intra-operative planning and image guidance. Delivery of such systems to the operating room remains complex ... ...

    Abstract Augmented reality for soft tissue laparoscopic surgery is a growing topic of interest in the medical community and has potential application in intra-operative planning and image guidance. Delivery of such systems to the operating room remains complex with theoretical challenges related to tissue deformation and the practical limitations of imaging equipment. Current research in this area generally only solves part of the registration pipeline or relies on fiducials, manual model alignment or assumes that tissue is static. This paper proposes a novel augmented reality framework for intra-operative planning: the approach co-registers pre-operative CT with stereo laparoscopic images using cone beam CT and fluoroscopy as bridging modalities. It does not require fiducials or manual alignment and compensates for tissue deformation from insufflation and respiration while allowing the laparoscope to be navigated. The paper's theoretical and practical contributions are validated using simulated, phantom, ex vivo, in vivo and non medical data.
    MeSH term(s) Algorithms ; Computer Graphics ; Computer Simulation ; Humans ; Image Enhancement/methods ; Image Interpretation, Computer-Assisted/methods ; Imaging, Three-Dimensional/methods ; Laparoscopy/methods ; Models, Biological ; Preoperative Care/methods ; Robotics/methods ; Surgery, Computer-Assisted/methods ; Tomography, X-Ray Computed/methods ; User-Computer Interface
    Language English
    Publishing date 2014-10-15
    Publishing country Germany
    Document type Journal Article
    DOI 10.1007/978-3-319-10404-1_53
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

  3. Article ; Conference proceedings: Chromoendoskopie zur besseren Erkennung von Frühkarzinomen bei magnetisch gesteuerter Kapselendoskopie: Eine Machbarkeitsstudie

    Foertsch, S / Mewes, PW / Angeolopoulou, E / Guldi, D / Messmann, H

    Endoskopie heute

    2012  

    Abstract: Beide Autoren haben den gleichen Anteil an der Arbeit.: Einleitung: Das Magenkarzinom ist weltweit der Krebs mit der zweihöchsten Sterblichkeitsrate unter den im Verdauungstrakt vorkommenden Krebserkrankungen. Gewebeveränderungen, so genannte ... ...

    Event/congress 42. Kongress der Deutschen Gesellschaft für Endoskopie und Bildgebende Verfahren e.V., München, 2012
    Abstract *Beide Autoren haben den gleichen Anteil an der Arbeit.
    Einleitung: Das Magenkarzinom ist weltweit der Krebs mit der zweihöchsten Sterblichkeitsrate unter den im Verdauungstrakt vorkommenden Krebserkrankungen. Gewebeveränderungen, so genannte Metaplasien und Polypen können Anzeichen von Magenkarzinomen sein. Bei der Diagnose und Klassifizierung des entarteten Gewebes durch die klassische gastrointestinale Endoskopie werden absorbierende und kontrastverstärkende Farbstoffe eingesetzt, um die oft sehr schwer zu sehenden Veränderungen in der Gewebestruktur besser sichtbar und abgrenzbar machen zu können. 2010 wurde die Magnetisch gesteuerte Kapselendoskopie vorgestellt. Bei diesem Verfahren schluckt ein Patient eine endoskopische Kapsel, die durch externe magnetische Felder in einem mit Wasser gefüllten Magen gesteuert wird. Im Vergleich zur konventionelle Endoskopie benötigt dieses nicht-invasive Verfahren keine Sedierung und weist einen höheren Patientenkomfort auf Zwei klinisches Studien zeigen einen gute Genauigkeit des Verfahrens im Vergleich zu konventionellen Gastroskopie. (Klinische Studie: Rey et al., 2010). Bekannte Schwierigkeiten bei der Diagnose von Metaplasien bei konventioneller Endoskopie finden sich aber auch in der magnetischen Kapselendoskopie.
    Ziel: Es soll die Machbarkeit eines Einfärbeverfahrens ähnlich der klassischen Chromoendoskopie bei einer MGCE-Untersuchung im Magenphantom gezeigt werden.
    Material und Methoden: Es wurden kommerziell verfügbare Endoskopkapseln und Schweinemägen mit Ösophagus genutzt. Die Krankheitsbilder wurden durch Verätzung mit Säure und durch Einnähen von Polypen simuliert. Um einen Färbeprozess realistisch zu simulieren wurden die Schweinemägen durch den Ösophagus mit 100ml Methylenblaulösung (Konzentration 1,00g/L) eingefärbt. Nach 5 Minuten Einwirkzeit wurde der Magen dreimal mit je 500 mL handwarmem Wasser gespült und anschließend mit 2 Litern Wasser gefüllt. Nach Zugabe der Endoskopiekapsel über den Ösophagus wurden Bilder von allen anatomischen Abschnitten aufgenommen. Die Kapsel wurde durch einem Plastikschlauch im Magen bewegt um die magnetische Steuerbarkeit zu simulieren. Zur besseren Sichtbarkeit der Schleimhautstrukturen wurden die Kapselbilder nachbearbeitet, um den Kontrast weiter zu verbessern.
    Ergebnis: Ähnlich der konventionellen Chromoendoskopie, wird bei der neu eingeführten Methode die Sichtbarkeit der Schleimhautstrukturen gegenüber klassischen Kapselbildern verbessert. Sie erscheint detailreicher. Wir konnten feststellen, dass sich das Wasser nicht färbt und somit auch die Sicht nicht getrübt oder eingefärbt ist. Die relevanten Stellen der gefärbten Mukosa, werden unter verschiedenen Kapselpositionen und dadurch resultierenden Lichtbedingungen aufgenommen und ausgewertet.
    Schlussfolgerung: Die Resultate zeigen, dass die angewandte Färbeprozedur bei Schweinemägen nutzbar ist und die Schleimhaut im Vergleich zur nicht gefärbten Mucosa detailreicher erscheint. Zusätzlich können Bildbearbeitungsalgorythmen die Bildqualität weiter verbessern. Doch auch wenn die Sichtbarkeit von Metaplasien und Dysplasien gesteigert wird, können andere Pathologien durch die Blaufärbung verdeckt werden. Dieser Sachverhalt ist für Untersuchungen mit Fokus auf die Feststellung von Schleimhautunregelmäßigkeiten akzeptabel.
    Language German
    Publishing date 2012-03-02
    Publishing place Stuttgart ; New York
    Document type Article ; Conference proceedings
    ZDB-ID 2082669-2
    ISSN 1439-2577 ; 0933-811X
    ISSN (online) 1439-2577
    ISSN 0933-811X
    DOI 10.1055/s-0032-1308793
    Database Thieme publisher's database

    More links

    Kategorien

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

  4. Article: Automatic region-of-interest segmentation and pathology detection in magnetically guided capsule endoscopy.

    Mewes, Philip W / Neumann, Dominik / Licegevic, Oleg / Simon, Johannes / Juloski, Aleksandar L / Angelopoulou, Elli

    Medical image computing and computer-assisted intervention : MICCAI ... International Conference on Medical Image Computing and Computer-Assisted Intervention

    2011  Volume 14, Issue Pt 3, Page(s) 141–148

    Abstract: Magnetically-guided capsule endoscopy (MGCE) was introduced in 2010 as a procedure where a capsule in the stomach is navigated via an external magnetic field. The quality of the examination depends on the operator's ability to detect aspects of interest ... ...

    Abstract Magnetically-guided capsule endoscopy (MGCE) was introduced in 2010 as a procedure where a capsule in the stomach is navigated via an external magnetic field. The quality of the examination depends on the operator's ability to detect aspects of interest in real time. We present a novel two step computer-assisted diagnostic-procedure (CADP) algorithm for indicating gastritis and gastrointestinal bleedings in the stomach during the examination. First, we identify and exclude subregions of bubbles which can interfere with further processing. Then we address the challenge of lesion localization in an environment with changing contrast and lighting conditions. After a contrast-normalized filtering, feature extraction is performed. The proposed algorithm was tested on 300 images of different patients with uniformly distributed occurrences of the target pathologies. We correctly segmented 84.72% of bubble areas. A mean detection rate of 86% for the target pathologies was achieved during a 5-fold leave-one-out cross-validation.
    MeSH term(s) Algorithms ; Automation ; Capsule Endoscopy/methods ; Contrast Media/pharmacology ; Endoscopy/methods ; Endoscopy, Gastrointestinal/methods ; Humans ; Image Processing, Computer-Assisted/methods ; Magnetics ; Models, Statistical ; Models, Theoretical ; Reproducibility of Results ; Stomach/pathology
    Chemical Substances Contrast Media
    Language English
    Publishing date 2011-10-15
    Publishing country Germany
    Document type Journal Article
    DOI 10.1007/978-3-642-23626-6_18
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

  5. Article ; Online: Chromoendoscopy in magnetically guided capsule endoscopy.

    Mewes, Philip W / Foertsch, Stefan / Juloski, Aleksandar Lj / Angelopoulou, Elli / Goelder, Stefan K / Guldi, Dirk / Hornegger, Joachim / Messmann, Helmut

    Biomedical engineering online

    2013  Volume 12, Page(s) 52

    Abstract: Background: Diagnosis of intestinal metaplasia and dysplasia via conventional endoscopy is characterized by low interobserver agreement and poor correlation with histopathologic findings. Chromoendoscopy significantly enhances the visibility of mucosa ... ...

    Abstract Background: Diagnosis of intestinal metaplasia and dysplasia via conventional endoscopy is characterized by low interobserver agreement and poor correlation with histopathologic findings. Chromoendoscopy significantly enhances the visibility of mucosa irregularities, like metaplasia and dysplasia mucosa. Magnetically guided capsule endoscopy (MGCE) offers an alternative technology for upper GI examination. We expect the difficulties of diagnosis of neoplasm in conventional endoscopy to transfer to MGCE. Thus, we aim to chart a path for the application of chromoendoscopy on MGCE via an ex-vivo animal study.
    Methods: We propose a modified preparation protocol which adds a staining step to the existing MGCE preparation protocol. An optimal staining concentration is quantitatively determined for different stain types and pathologies. To that end 190 pig stomach tissue samples with and without lesion imitations were stained with different dye concentrations. Quantitative visual criteria are introduced to measure the quality of the staining with respect to mucosa and lesion visibility. Thusly determined optimal concentrations are tested in an ex-vivo pig stomach experiment under magnetic guidance of an endoscopic capsule with the modified protocol.
    Results: We found that the proposed protocol modification does not impact the visibility in the stomach or steerability of the endoscopy capsule. An average optimal staining concentration for the proposed protocol was found at 0.4% for Methylene blue and Indigo carmine. The lesion visibility is improved using the previously obtained optimal dye concentration.
    Conclusions: We conclude that chromoendoscopy may be applied in MGCE and improves mucosa and lesion visibility. Systematic evaluation provides important information on appropriate staining concentration. However, further animal and human in-vivo studies are necessary.
    MeSH term(s) Animals ; Capsule Endoscopy/methods ; Coloring Agents/metabolism ; Gastric Mucosa/metabolism ; Magnetic Phenomena ; Staining and Labeling ; Stomach/surgery ; Swine
    Chemical Substances Coloring Agents
    Language English
    Publishing date 2013-06-11
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ISSN 1475-925X
    ISSN (online) 1475-925X
    DOI 10.1186/1475-925X-12-52
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

  6. Article: Pneumatically Operated MRI-Compatible Needle Placement Robot for Prostate Interventions.

    Fischer, Gregory S / Iordachita, Iulian / Csoma, Csaba / Tokuda, Junichi / Mewes, Philip W / Tempany, Clare M / Hata, Nobuhiko / Fichtinger, Gabor

    IEEE International Conference on Robotics and Automation : ICRA : [proceedings]. IEEE International Conference on Robotics and Automation

    2011  Volume 2008, Page(s) 2489–2495

    Abstract: Magnetic Resonance Imaging (MRI) has potential to be a superior medical imaging modality for guiding and monitoring prostatic interventions. The strong magnetic field prevents the use of conventional mechatronics and the confined physical space makes it ... ...

    Abstract Magnetic Resonance Imaging (MRI) has potential to be a superior medical imaging modality for guiding and monitoring prostatic interventions. The strong magnetic field prevents the use of conventional mechatronics and the confined physical space makes it extremely challenging to access the patient. We have designed a robotic assistant system that overcomes these difficulties and promises safe and reliable intra-prostatic needle placement inside closed high-field MRI scanners. The robot performs needle insertion under real-time 3T MR image guidance; workspace requirements, MR compatibility, and workflow have been evaluated on phantoms. The paper explains the robot mechanism and controller design and presents results of preliminary evaluation of the system.
    Language English
    Publishing date 2011-06-20
    Publishing country United States
    Document type Journal Article
    ISSN 2152-4092
    ISSN 2152-4092
    DOI 10.1109/ROBOT.2008.4543587
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

  7. Article ; Online: Integrated navigation and control software system for MRI-guided robotic prostate interventions.

    Tokuda, Junichi / Fischer, Gregory S / DiMaio, Simon P / Gobbi, David G / Csoma, Csaba / Mewes, Philip W / Fichtinger, Gabor / Tempany, Clare M / Hata, Nobuhiko

    Computerized medical imaging and graphics : the official journal of the Computerized Medical Imaging Society

    2009  Volume 34, Issue 1, Page(s) 3–8

    Abstract: A software system to provide intuitive navigation for MRI-guided robotic transperineal prostate therapy is presented. In the system, the robot control unit, the MRI scanner, and the open-source navigation software are connected together via Ethernet to ... ...

    Abstract A software system to provide intuitive navigation for MRI-guided robotic transperineal prostate therapy is presented. In the system, the robot control unit, the MRI scanner, and the open-source navigation software are connected together via Ethernet to exchange commands, coordinates, and images using an open network communication protocol, OpenIGTLink. The system has six states called "workphases" that provide the necessary synchronization of all components during each stage of the clinical workflow, and the user interface guides the operator linearly through these workphases. On top of this framework, the software provides the following features for needle guidance: interactive target planning; 3D image visualization with current needle position; treatment monitoring through real-time MR images of needle trajectories in the prostate. These features are supported by calibration of robot and image coordinates by fiducial-based registration. Performance tests show that the registration error of the system was 2.6mm within the prostate volume. Registered real-time 2D images were displayed 1.97 s after the image location is specified.
    MeSH term(s) Algorithms ; Biopsy, Needle/methods ; Computer Communication Networks ; Feedback ; Magnetic Resonance Imaging/methods ; Prostatectomy/methods ; Robotics/methods ; Software ; Software Design ; Surgery, Computer-Assisted/methods ; Systems Integration
    Language English
    Publishing date 2009-08-20
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 639451-6
    ISSN 1879-0771 ; 0895-6111
    ISSN (online) 1879-0771
    ISSN 0895-6111
    DOI 10.1016/j.compmedimag.2009.07.004
    Database MEDical Literature Analysis and Retrieval System OnLINE

    Full text online

    More links

    Kategorien

    In stock of ZB MED Cologne/Königswinter

    Zs.A 1323: Show issues Location:
    Je nach Verfügbarkeit (siehe Angabe bei Bestand)
    bis Jg. 1994: Bestellungen von Artikeln über das Online-Bestellformular
    Jg. 1995 - 2021: Lesesall (1.OG)
    ab Jg. 2022: Lesesaal (EG)

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

To top