			Home About us Contact

Navigation Technology (navigation + technology)

Distribution by Scientific Domains

Medical Sciences	80%

Selected Abstracts

Steerable Sheath Catheter Navigation for Ablation of Atrial Fibrillation: A Case-Control Study

PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 7 2008
CHRISTOPHER PIORKOWSKI M.D.
Background: Lack of stable access to all desired ablation target sites is one of the limitations for efficacious circumferential left atrial (LA) pulmonary vein (PV) ablation. Targeting that, new catheter navigation technologies have been developed. The aim of this study was to describe atrial fibrillation (AF) mapping and ablation using manually controlled steerable sheath catheter navigation and to compare it against an ablation approach with a nonsteerable sheath. Methods and Results: In this case-control-analysis 245 consecutive patients (controls) treated with circumferential left atrial PV ablation were matched with 105 subsequently consecutive patients (cases) ablated with a similar line concept but mapping and ablation performed with a manually controlled steerable sheath. One hundred sixty-six patients were selected to be included into 83 matched patient pairs. Ablation success was measured with serial 7-day Holter electrocardiograms. Patients ablated with the steerable sheath showed an increase in the success rate (freedom from AF) from 56% to 77% (P = 0.009) after a single procedure and 6 months of follow-up. With respect to procedural data no difference could be found for procedure time, fluoroscopy time, irradiation dose, and radiofrequency (RF) burning time. With the steerable sheath mean procedural RF power (33 ± 9 vs 41 ± 4 W; P < 0.0005) and total RF energy delivery (97,498 vs 111,864 J; P < 0.005) were significantly lower and the rate of complete PV isolation significantly increased from 10% to 52% (P < 0.0005). The complication rate was the same in both groups. Among different arrhythmia, procedure, and patient characteristics, the lack of early postinterventional arrhythmia recurrences was the only but powerful predictor for long-term ablation success. Conclusions: An AF mapping and ablation approach solely using a manually controlled steerable sheath for catheter navigation improved the outcome of circumferential left atrial PV ablation at similar intervention times and similar complication rates. The 6-month success rate after a single LA intervention increased from 56% to 77%. [source]

Semantic visual features in content-based video retrieval

PROCEEDINGS OF THE AMERICAN SOCIETY FOR INFORMATION SCIENCE & TECHNOLOGY (ELECTRONIC), Issue 1 2006
Xiangming Mu
A new semantic visual features (e.g., car, mountain, and fire) navigation technology is proposed to improve the effectiveness of video retrieval. Traditional temporal neighbor browsing technology allows users to navigate temporal neighbors of a selected sample frame to find additional matches, while semantic visual feature browsing enables users to navigate keyframes that have similar features to the selected sample frame. A pilot evaluation was conducted to compare the effectiveness of three video retrieval designs that support 1) temporal neighbor browsing; 2) semantic visual feature browsing; and 3) fused browsing which is a combination of both temporal neighbor and semantic visual feature browsing. Two types of searching tasks: visual centric and non-visual centric tasks were applied. Initial results indicated that the semantic visual feature browsing system was more efficient for non-visual centric tasks. [source]

Target registration and target positioning errors in computer-assisted neurosurgery: proposal for a standardized reporting of error assessment

THE INTERNATIONAL JOURNAL OF MEDICAL ROBOTICS AND COMPUTER ASSISTED SURGERY, Issue 4 2009
Gerlig Widmann
Abstract Background Assessment of errors is essential in development, testing and clinical application of computer-assisted neurosurgery. Our aim was to provide a comprehensive overview of the different methods to assess target registration error (TRE) and target positioning error (TPE) and to develop a proposal for a standardized reporting of error assessment. Methods A PubMed research on phantom, cadaver or clinical studies on TRE and TPE has been perfomed. Reporting standards have been defined according to (a) study design and evaluation methods and (b) specifications of the navigation technology. Results The proposed standardized reporting includes (a) study design (controlled, non-controlled), study type (non-anthropomorphic phantom, anthropomorphic phantom, cadaver, patient), target design, error type and subtypes, space of TPE measurement, statistics, and (b) image modality, scan parameters, tracking technology, registration procedure and targeting technique. Conclusions Adoption of the proposed standardized reporting may help in the understanding and comparability of different accuracy reports. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Image-guided surgery of liver metastases by three-dimensional ultrasound-based optoelectronic navigation

BRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 7 2007
S. Beller
Background: Vessel-oriented surgery and tumour-free resection margins are essential for resection of liver metastases to preserve liver parenchyma and improve oncological outcome. Preoperative three-dimensional models reconstructed from imaging data could facilitate surgical planning with the use of navigation technology. Methods: Thirty-three patients with central and/or impalpable liver metastases were scheduled for navigated hepatic resection. Intraoperative three-dimensional ultrasonography and an infrared-based optical tracking system were used for data registration and image-guided surgery. Postoperative three-dimensional data were compared with the preoperative virtual surgical plan to assess the accuracy of navigation, and clinical results were compared with those of a matched control group of 32 patients. Results: Navigation was successful in 32 of 33 patients. Realization of the preoperative plan and R0 resection was achieved in 30 of these 32 patients. The median discrepancy between the planned and actual vascular dissection level was 6 (range 0,11) mm. There was a reduced rate of R1 resection in the navigated group compared with the control group (two versus four patients), and more parenchyma was preserved. Conclusion: Three-dimensional ultrasound-based optoelectronic navigation technology improves intraoperative orientation and enables parenchyma-preserving surgery with high precision. Copyright © 2007 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd. [source]