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Sekins KM, Barnes SR, Fan L, Hopple JD, Hsu SJ, Kook J, Lee CY, Maleke C, Ramachandran AR, Zeng XJ, Moreau-Gobard R, Ahiekpor-Dravi A, Funka-Lea G, Mitchell SB, Dunmire B, Kucewicz JC, Eaton J, Wong K, Keneman S, Crum LA. Deep bleeder acoustic coagulation (DBAC)-Part I: development and in vitro testing of a research prototype cuff system. J Ther Ultrasound 2015; 3:16. [PMID: 26388994 PMCID: PMC4575471 DOI: 10.1186/s40349-015-0037-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 09/02/2015] [Indexed: 12/03/2022] Open
Abstract
Background Bleeding from limb injuries is a leading cause of death on the battlefield, with deep wounds being least accessible. High-intensity focused ultrasound (HIFU) has been shown capable of coagulation of bleeding (cautery). This paper describes the development and refereed in vitro evaluation of an ultrasound (US) research prototype deep bleeder acoustic coagulation (DBAC) cuff system for evaluating the potential of DBAC in the battlefield. The device had to meet quantitative performance metrics on automated operation, therapeutic heating, bleeder detection, targeting accuracy, operational time limits, and cuff weight over a range of limb sizes and bleeder depths. These metrics drove innovative approaches in image segmentation, bleeder detection, therapy transducers, beam targeting, and dose monitoring. A companion (Part II) paper discusses the in vivo performance testing of an animal-specific DBAC system. Materials and methods The cuff system employed 3D US imaging probes (“Ix”) for detection and localization (D&L) and targeting, with the bleeders being identified by automated spectral Doppler analysis of flow waveforms. Unique high-element-count therapeutic arrays (“Tx”) were developed, with the final cuff prototype having 21 Tx’s and 6 Ix’s. Spatial registration of Ix’s and Tx’s was done with a combination of image-registration, acoustic time-of-flight measurement, and tracking of the cuff shape via a fiber optic sensor. Acoustic radiation force impulse (ARFI) imaging or thermal strain imaging (TSI) at low-power doses were used to track the HIFU foci in closed-loop targeting. Recurrent neural network (RNN) acoustic thermometry guided closed-loop dosing. The cuff was tested on three phantom “limb” sizes: diameters = 25, 15, and 7.5 cm, with bleeder depths from 3.75 to 12.5 cm. “Integrated Phantoms” (IntP) were used for assessing D&L, closed-loop targeting, and closed-loop dosing. IntPs had surrogate arteries and bleeders, with blood-mimicking fluids moved by a pulsatile pump, and thermocouples (TCs) on the bleeders. Acoustic dosing was developed and tested using “HIFU Phantoms” having precisely located TCs, with end-of-dose target ∆T = 33–58 °C, and skin temperature ∆T ≤ 20 °C, being required. Results Most DBAC cuff performance requirements were met, including cuff weight, power delivery, targeting accuracy, skin temperature limit, and autonomous operation. The automated D&L completed in 9 of 15 tests (65 %), detecting the smallest (0.6 mm) bleeders, but it had difficulty with the lowest flow (3 cm/sec) bleeders, and in localizing bleeders in the smallest (7.5 cm) phantoms. D&L did not complete within the 9-min limit (results ranged 10–21 min). Closed-loop targeting converged in 20 of 31 tests (71 %), and closed-loop dosing power shut-off at preset ∆Ts was operational. Summary and conclusion The main performance objectives of the prototype DBAC cuff were met, however the designs required a number of challenging new technology developments. The novel Tx arrays exhibited high power with significant beam steering and focusing flexibility, while their integrated electronics enabled the required compact, lightweight configurability and simplified driving controls and cable/connector architecture. The compounded 3D imaging, combined with sophisticated software algorithms, enabled automated D&L and initial targeting and closed-loop targeting feedback via TSI. The development of RNN acoustic thermometry made possible feedback-controlled dosing. The lightweight architecture required significant design and fabrication effort to meet mechanical functionalities. Although not all target specifications were met, future engineering solutions addressing these performance deficiencies are proposed. Lastly, the program required very complex limb test phantoms and, while very challenging to develop, they performed well.
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Affiliation(s)
- K Michael Sekins
- Siemens Ultrasound Business Unit, 22010 S.E. 51st Street, Issaquah, WA 98029-1271 USA ; Medical Device and Technology Development and Commercialization (concultancy) , 8808 Points Dr. N.E, Yarrow Point, WA 98004 USA
| | - Stephen R Barnes
- Siemens Ultrasound Business Unit, 22010 S.E. 51st Street, Issaquah, WA 98029-1271 USA
| | - Liexiang Fan
- Siemens Ultrasound Business Unit, 22010 S.E. 51st Street, Issaquah, WA 98029-1271 USA
| | - Jerry D Hopple
- Siemens Ultrasound Business Unit, 22010 S.E. 51st Street, Issaquah, WA 98029-1271 USA
| | - Stephen J Hsu
- Siemens Ultrasound Business Unit, 22010 S.E. 51st Street, Issaquah, WA 98029-1271 USA
| | - John Kook
- Siemens Ultrasound Business Unit, 22010 S.E. 51st Street, Issaquah, WA 98029-1271 USA
| | - Chi-Yin Lee
- Siemens Ultrasound Business Unit, 22010 S.E. 51st Street, Issaquah, WA 98029-1271 USA
| | - Caroline Maleke
- Siemens Ultrasound Business Unit, 22010 S.E. 51st Street, Issaquah, WA 98029-1271 USA
| | - A R Ramachandran
- Siemens Ultrasound Business Unit, 22010 S.E. 51st Street, Issaquah, WA 98029-1271 USA
| | - Xiaozheng Jenny Zeng
- Siemens Ultrasound Business Unit, 22010 S.E. 51st Street, Issaquah, WA 98029-1271 USA
| | - Romain Moreau-Gobard
- Siemens Corporate Research and Technology, 755 College Road East, Princeton, NJ 08540 USA
| | - Alexis Ahiekpor-Dravi
- Siemens Corporate Research and Technology, 755 College Road East, Princeton, NJ 08540 USA
| | - Gareth Funka-Lea
- Siemens Corporate Research and Technology, 755 College Road East, Princeton, NJ 08540 USA
| | - Stuart B Mitchell
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, 1013 NE 40th Street, Seattle, WA 98105-6698 USA
| | - Barbrina Dunmire
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, 1013 NE 40th Street, Seattle, WA 98105-6698 USA
| | - John C Kucewicz
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, 1013 NE 40th Street, Seattle, WA 98105-6698 USA
| | - John Eaton
- ETN LLC, 1150 Guinda St., Palo Alto, CA 94301 USA
| | - Keith Wong
- ETN LLC, 1150 Guinda St., Palo Alto, CA 94301 USA
| | - Scott Keneman
- Siemens Corporate Research and Technology, 755 College Road East, Princeton, NJ 08540 USA
| | - Lawrence A Crum
- Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, 1013 NE 40th Street, Seattle, WA 98105-6698 USA
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