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Proceedings Paper

Multiple capture locations for 3D ultrasound-guided robotic retrieval of moving bodies from a beating heart
Author(s): Paul Thienphrapa; Bharat Ramachandran; Haytham Elhawary; Russell H. Taylor; Aleksandra Popovic
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Paper Abstract

Free moving bodies in the heart pose a serious health risk as they may be released in the arteries causing blood flow disruption. These bodies may be the result of various medical conditions and trauma. The conventional approach to removing these objects involves open surgery with sternotomy, the use of cardiopulmonary bypass, and a wide resection of the heart muscle. We advocate a minimally invasive surgical approach using a flexible robotic end effector guided by 3D transesophageal echocardiography. In a phantom study, we track a moving body in a beating heart using a modified normalized cross-correlation method, with mean RMS errors of 2.3 mm. We previously found the foreign body motion to be fast and abrupt, rendering infeasible a retrieval method based on direct tracking. We proposed a strategy based on guiding a robot to the most spatially probable location of the fragment and securing it upon its reentry to said location. To improve efficacy in the context of a robotic retrieval system, we extend this approach by exploring multiple candidate capture locations. Salient locations are identified based on spatial probability, dwell time, and visit frequency; secondary locations are also examined. Aggregate results indicate that the location of highest spatial probability (50% occupancy) is distinct from the longest-dwelled location (0.84 seconds). Such metrics are vital in informing the design of a retrieval system and capture strategies, and they can be computed intraoperatively to select the best capture location based on constraints such as workspace, time, and device manipulability. Given the complex nature of fragment motion, the ability to analyze multiple capture locations is a desirable capability in an interventional system.

Paper Details

Date Published: 17 February 2012
PDF: 9 pages
Proc. SPIE 8316, Medical Imaging 2012: Image-Guided Procedures, Robotic Interventions, and Modeling, 831619 (17 February 2012); doi: 10.1117/12.911732
Show Author Affiliations
Paul Thienphrapa, Philips Research North America (United States)
The Johns Hopkins Univ. (United States)
Bharat Ramachandran, Philips Research North America (United States)
Haytham Elhawary, Philips Research North America (United States)
Russell H. Taylor, The Johns Hopkins Univ. (United States)
Aleksandra Popovic, Philips Research North America (United States)

Published in SPIE Proceedings Vol. 8316:
Medical Imaging 2012: Image-Guided Procedures, Robotic Interventions, and Modeling
David R. Holmes III; Kenneth H. Wong, Editor(s)

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