{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,29]],"date-time":"2026-03-29T00:30:51Z","timestamp":1774744251700,"version":"3.50.1"},"reference-count":44,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2018,11,22]],"date-time":"2018-11-22T00:00:00Z","timestamp":1542844800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/2.zoppoz.workers.dev:443\/https\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["11774369, 81530056, 81530056, 11534013, 81527901, 81671698, 81571689"],"award-info":[{"award-number":["11774369, 81530056, 81530056, 11534013, 81527901, 81671698, 81571689"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100012571","name":"Key Laboratory for Magnetic Resonance and Multimodality Imaging of Guangdong Province","doi-asserted-by":"publisher","award":["2014B030301013"],"award-info":[{"award-number":["2014B030301013"]}],"id":[{"id":"10.13039\/501100012571","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Shenzhen Basic Research Program","award":["JCYJ20170413100222613, JCYJ20170307165254568"],"award-info":[{"award-number":["JCYJ20170413100222613, JCYJ20170307165254568"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Microbubbles are considered a promising tool for noninvasive estimation of local blood pressure. It is reported that the subharmonic scattering amplitude of microbubbles decreases by 9 to 12 dB when immersed in the media under an ambient pressure variation from 0 to 180 mmHg. However, the pressure sensitivity still needs to be improved to satisfy clinical diagnostic requirements. Here, we investigated the effects of acoustic parameters on the pressure sensitivity of microbubbles through measuring the acoustic attenuation and scattering properties of commercially available SonoVue microbubbles. Our results showed that the first harmonic, subharmonic, and ultraharmonic amplitudes of microbubbles were reduced by 6.6 dB, 10.9 dB, and 9.3 dB at 0.225 mechanical index (MI), 4.6 dB, 19.8 dB, and 12.3 dB at 0.25 MI, and 18.5 dB, 17.6 dB, and 12.6 dB at 0.3 MI, respectively, when the ambient pressure increased from 0 to 180 mmHg. Our finding revealed that a moderate MI (0.25\u20130.4) exciting microbubbles could significantly improve their sensitivities to detect ambient pressure.<\/jats:p>","DOI":"10.3390\/s18124083","type":"journal-article","created":{"date-parts":[[2018,11,22]],"date-time":"2018-11-22T09:18:25Z","timestamp":1542878305000},"page":"4083","update-policy":"https:\/\/2.zoppoz.workers.dev:443\/https\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":26,"title":["Improvement of Detection Sensitivity of Microbubbles as Sensors to Detect Ambient Pressure"],"prefix":"10.3390","volume":"18","author":[{"given":"Fei","family":"Li","sequence":"first","affiliation":[{"name":"Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China"},{"name":"Shenzhen Key Laboratory of Ultrasound Imaging and Therapy, Shenzhen 518055, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Deyu","family":"Li","sequence":"additional","affiliation":[{"name":"School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Fei","family":"Yan","sequence":"additional","affiliation":[{"name":"Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China"},{"name":"Shenzhen Key Laboratory of Ultrasound Imaging and Therapy, Shenzhen 518055, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2018,11,22]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"275","DOI":"10.1016\/S0301-5629(98)00163-X","article-title":"Pressure dependence of subharmonic signals from contrast microbubbles","volume":"25","author":"Shi","year":"1999","journal-title":"Ultrasound Med. Biol."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"2718","DOI":"10.1016\/j.ultrasmedbio.2017.07.009","article-title":"Non-invasive intra-cardiac pressure measurements using subharmonic-aided pressure estimation: Proof of concept in humans","volume":"43","author":"Dave","year":"2017","journal-title":"Ultrasound Med. 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