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A conformable phased-array ultrasound patch for bladder volume monitoring

Nature Electronics volume 7, pages 77–90 (2024)Cite this article

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A Publisher Correction to this article was published on 27 November 2023

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Abstract

Ultrasound can be used to image soft tissues in vivo for the early diagnosis and monitoring of disease progression. However, conventional ultrasound probes are rigid, have a narrow field of view and are operator dependent. Conformable transducers have been proposed, but they lack efficient element localization and effective spatial resolution during mechanical deformations. Here we report a conformable ultrasound bladder patch that is based on multiple phased arrays embedded in a stretchable substrate and can provide mechanically robust, conformable and in vivo volumetric organ monitoring. The phased arrays use Sm/La-doped Pb(Mg1/3Nb2/3)O3–PbTiO3 ceramics as the piezoelectric material, which offers superior properties (d33 = 1,000 pC N−1, εr = 7,500 and k33 = 0.77) than conventional piezoelectric ceramics. We use the conformable ultrasound patch in a pilot clinical study of bladder monitoring. Bladder volume estimation with the patch is comparable (relative errors of 3.2 ± 6.4% and 10.8 ± 8.2% with and without ultrasound gel, respectively) to that obtained using standard clinical ultrasound equipment, and not requiring manual translation or rotation by an operator.

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Fig. 1: Overview of the phased array and cUSB-Patch.
Fig. 2: Characterization of morphological, piezoelectric and dielectric properties of Sm/La-PMN-xPT ceramics.
Fig. 3: Piezoelectric and acoustic performances of phased-array transducers.
Fig. 4: Real-time ultrasound imaging by the C5-2v commercial probe and the cUSB-Patch on the oval phantom.
Fig. 5: Real-time ultrasound imaging on the bladders of different subjects.
Fig. 6: Summary and comparison of the calculated bladder volumes of four subjects.

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Data availability

The raw data from human trials are available from the corresponding author, subject to approval from The Mass General Brigham IRB (#2021P001706). All other data that support the findings of this study are available from the corresponding author upon reasonable request.

Code availability

The codes based on Python used for the synthetic array beamforming, simulation and image analysis are available from the corresponding author on reasonable request.

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Acknowledgements

C.D. thanks C. Dagdeviren and H. E. Dagdeviren for fruitful discussions throughout this project. This work was supported by the National Science Foundation CAREER: Conformable Piezoelectrics for Soft Tissue Imaging (grant no. 2044688), 3M Non-Tenured Faculty Award, Sagol Weizmann-MIT Bridge Program, Texas Instruments Inc. and MIT Media Lab Consortium funding. W.D. was supported by the National Science Foundation Graduate Research Fellowship Program (grant no. 2141064). Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. T.T.P. was supported by the 2020 ARRS Scholar Award. This work was performed in part at the Harvard University Center for Nanoscale Systems (CNS)—a member of the National Nanotechnology Coordinated Infrastructure Network (NNCI), which is supported by the National Science Foundation under NSF award no. ECCS-2025158. We thank P. Cao and C. Peng for technical discussions; H. Park and J. Tresback for assistance on microfabrication; O. Drori, A. Mamistvalov, K. Brahma and A. Benjamin for imaging discussion; E. Suh for patch design discussion; and M.-C. O’Connell, M. Martin, E. Sands and Y. Gu for assisting on the clinical study.

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Author notes

  1. These authors contributed equally: Lin Zhang, Colin Marcus, Dabin Lin.

Authors and Affiliations

  1. Media Lab, Massachusetts Institute of Technology, Cambridge, MA, USA

    Lin Zhang, Colin Marcus, David Mejorado, Sara V. Fernandez, Ikra Iftekhar Shuvo, David Sadat, Wenya Du & Canan Dagdeviren

  2. Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA

    Colin Marcus & Anantha P. Chandrakasan

  3. School of Opto-electronical Engineering, Xi’an Technological University, Xi’an, China

    Dabin Lin & Weiguo Liu

  4. Center for Ultrasound Research & Translation, Department of Radiology, Massachusetts General Hospital, Boston, MA, USA

    Scott Joseph Schoen Jr, Theodore T. Pierce, Viksit Kumar, David Hunt, Qian Li, Hannah Edenbaum & Anthony E. Samir

  5. Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA

    Sara V. Fernandez

  6. Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education, School of Electronic Science and Engineering, Xi’an Jiaotong University, Xi’an, China

    Li Jin & Fei Li

  7. Faculty of Math and Computer Science, Weizmann Institute of Science, Rehovot, Israel

    Yonina C. Eldar

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Contributions

C.D. conceived the research idea, designed the research direction and directed all the research activities. A.E.S. directed the proposed implementation of the technology and supervised the clinical study. A.P.C. contributed to the overall system architecture. L.Z. and C.D. conceived the research methodology and aims. L.Z., C.M. and C.D. designed the experiments. D.L. processed and characterized the piezoelectric ceramics. W.L. supervised the materials investigation. D.L. and L.J. studied the structure and morphology of ceramics. D.L., L.Z. and F.L. analysed the performance of the ceramics. C.D., L.Z. and D.M. designed the patch for the bladder. L.Z. designed and fabricated the ultrasound arrays. D.M. and L.Z. characterized the array and fabricated the patch. C.M. and D.M. designed the electronic circuits for data acquisition. S.J.S., assisted by V.K., conducted the coding and ultrasound signal processing for image generation by the Verasonics Vantage 256 system. L.Z., C.M., S.J.S. and D.M. conducted the in vitro ultrasound imaging. I.I.S., W.D. and S.V.F. assisted with the device characterization. V.K. coordinated the in vitro study at Mass General Hospital, and T.T.P. coordinated the in vivo study, including overseeing recruitment and scheduling (with H.E.), obtaining subject informed consent and monitoring subject safety. H.E. recruited the subjects and assisted in the clinical study. L.Z., D.M., S.J.S. and V.K. conducted the safety testing and prepared the related IRB document filings. D.H., T.T.P., L.Z. and C.M. designed the clinical-trial imaging protocols. D.H. and Q.L. performed the image acquisition of the human subject. C.M., S.J.S., T.T.P., H.E., V.K., D.H. and Q.L. executed the in vivo study and analysed the data. Y.C.E. assisted in the imaging process. W.D. and D.S. composed the layout of Supplementary Videos 1–8 and formed the videos. All authors contributed to the manuscript writing.

Corresponding author

Correspondence to Canan Dagdeviren.

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Competing interests

A.P.C. is on the Board of Analog Devices. The other authors declare no competing interests.

Peer review

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Nature Electronics thanks Yangzhi Zhu, Qifa Zhou and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Supplementary information

Supplementary Information

Supplementary Notes 1–8, Tables 1–12, Figs. 1–64, captions for Videos 1–8 and references.

Reporting Summary

Supplementary Video 1

Patch bending, stretching and twisting.

Supplementary Video 2

Patch attaching and detaching on belly, and then cleaning.

Supplementary Video 3

Comparison of phased array with C5-2v on planar phantom without pressure.

Supplementary Video 4

Three-dimensional image reconstruction on US-18 phantom.

Supplementary Video 5

Ultrasound image of five arrays on subject A (case I with gel).

Supplementary Video 6

Ultrasound image of five arrays on subject A (case I without gel).

Supplementary Video 7

Ultrasound image of five arrays on subject A (case II with gel).

Supplementary Video 8

Ultrasound image of five arrays on subject A (case II without gel).

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Zhang, L., Marcus, C., Lin, D. et al. A conformable phased-array ultrasound patch for bladder volume monitoring. Nat Electron 7, 77–90 (2024). https://doi.org/10.1038/s41928-023-01068-x

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