Noninvasive pressue estimation using ultrasound methods: Preliminary in vitro results

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Citations (Scopus)

Abstract

Tumor interstitial pressure (TIP) inside a tumor is often high compared to normal tissues and can impede the delivery of chemotherapeutic drugs as well as decrease the effectiveness of radiation therapy. Recent efforts have focused on the development of a nanometer-sized phase-change contrast agent (PCCA) that can be activated from a liquid (nanodroplet) state using low energy ultrasound (US) pulses to form a larger highly echogenic microbubble (MB). Since PCCA activation is dependent on the hydrostatic pressure of the surrounding fluid, these same agents and custom US methods may permit TIP measurement in cancerous tissue, which is a new technology we have termed TIP estimation using US (TIPE-US). Lipid shelled decafluorobutane gas MBs were produced using mechanical agitation and then stable nanodroplets were produced by cooling and pressurizing the vial solutions. An US setup was used to deliver acoustic energy and activate nanodroplets from liquid to gaseous MB states. The effects of hydrostatic pressure on the US activation threshold of PCCA was studied by injecting PCCA into acoustically transparent sample holder preloaded with saline. Varying levels of hydrostatic pressure (0 to 39 mmHg) were applied by injecting air in the sample holders. Each sample was imaged using an US system while the acoustic pressure was progressively increased (0.3 to 3.6 MPa). From each image sequence, a modified contrast-to-tissue (CTR) metric was computed. The activation threshold required to convert PCCA from the liquid to gaseous state was taken as the US pressure needed to achieve a CTR at least two times that observed at baseline. PCCA sizes before and after US activation were measured using particle sizing systems. The greatest volume of liquid nanodroplets had a diameter of 150 nm whereas after activation into gaseous MBs the size of these same PCCA were considerably larger (majority of MBs > 1 μm) and suitable for US imaging. CTR values measured from US imaging studies of PCCA after exposure with varying levels of US energy clearly captured nanodroplet activation. Importantly, a strong correlation was found between the PCCA activation pressure and hydrostatic pressure on the nanodroplets (R2 = 0.99). This correlation could serve as a reference function for converting PCCA activation pressures to TIP estimates.

Original languageEnglish (US)
Title of host publication2016 IEEE International Ultrasonics Symposium, IUS 2016
PublisherIEEE Computer Society
Volume2016-November
ISBN (Electronic)9781467398978
DOIs
StatePublished - Nov 1 2016
Event2016 IEEE International Ultrasonics Symposium, IUS 2016 - Tours, France
Duration: Sep 18 2016Sep 21 2016

Other

Other2016 IEEE International Ultrasonics Symposium, IUS 2016
CountryFrance
CityTours
Period9/18/169/21/16

Fingerprint

activation
tumors
hydrostatic pressure
interstitials
liquids
holders
pressurizing
agitation
thresholds
acoustics
sizing
pressure measurement
lipids
energy
radiation therapy
delivery
drugs
cooling
fluids
air

Keywords

  • microbubbles
  • nanodroplets
  • phase-change contrast agents
  • pressure estimation
  • ultrasound

ASJC Scopus subject areas

  • Acoustics and Ultrasonics

Cite this

Hoyt, K., Sirsi, S., & Mattrey, R. (2016). Noninvasive pressue estimation using ultrasound methods: Preliminary in vitro results. In 2016 IEEE International Ultrasonics Symposium, IUS 2016 (Vol. 2016-November). [7728487] IEEE Computer Society. https://doi.org/10.1109/ULTSYM.2016.7728487

Noninvasive pressue estimation using ultrasound methods : Preliminary in vitro results. / Hoyt, Kenneth; Sirsi, Shashank; Mattrey, Robert.

2016 IEEE International Ultrasonics Symposium, IUS 2016. Vol. 2016-November IEEE Computer Society, 2016. 7728487.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Hoyt, K, Sirsi, S & Mattrey, R 2016, Noninvasive pressue estimation using ultrasound methods: Preliminary in vitro results. in 2016 IEEE International Ultrasonics Symposium, IUS 2016. vol. 2016-November, 7728487, IEEE Computer Society, 2016 IEEE International Ultrasonics Symposium, IUS 2016, Tours, France, 9/18/16. https://doi.org/10.1109/ULTSYM.2016.7728487
Hoyt K, Sirsi S, Mattrey R. Noninvasive pressue estimation using ultrasound methods: Preliminary in vitro results. In 2016 IEEE International Ultrasonics Symposium, IUS 2016. Vol. 2016-November. IEEE Computer Society. 2016. 7728487 https://doi.org/10.1109/ULTSYM.2016.7728487
Hoyt, Kenneth ; Sirsi, Shashank ; Mattrey, Robert. / Noninvasive pressue estimation using ultrasound methods : Preliminary in vitro results. 2016 IEEE International Ultrasonics Symposium, IUS 2016. Vol. 2016-November IEEE Computer Society, 2016.
@inproceedings{198f06853b0f4503afb0c82482e51060,
title = "Noninvasive pressue estimation using ultrasound methods: Preliminary in vitro results",
abstract = "Tumor interstitial pressure (TIP) inside a tumor is often high compared to normal tissues and can impede the delivery of chemotherapeutic drugs as well as decrease the effectiveness of radiation therapy. Recent efforts have focused on the development of a nanometer-sized phase-change contrast agent (PCCA) that can be activated from a liquid (nanodroplet) state using low energy ultrasound (US) pulses to form a larger highly echogenic microbubble (MB). Since PCCA activation is dependent on the hydrostatic pressure of the surrounding fluid, these same agents and custom US methods may permit TIP measurement in cancerous tissue, which is a new technology we have termed TIP estimation using US (TIPE-US). Lipid shelled decafluorobutane gas MBs were produced using mechanical agitation and then stable nanodroplets were produced by cooling and pressurizing the vial solutions. An US setup was used to deliver acoustic energy and activate nanodroplets from liquid to gaseous MB states. The effects of hydrostatic pressure on the US activation threshold of PCCA was studied by injecting PCCA into acoustically transparent sample holder preloaded with saline. Varying levels of hydrostatic pressure (0 to 39 mmHg) were applied by injecting air in the sample holders. Each sample was imaged using an US system while the acoustic pressure was progressively increased (0.3 to 3.6 MPa). From each image sequence, a modified contrast-to-tissue (CTR) metric was computed. The activation threshold required to convert PCCA from the liquid to gaseous state was taken as the US pressure needed to achieve a CTR at least two times that observed at baseline. PCCA sizes before and after US activation were measured using particle sizing systems. The greatest volume of liquid nanodroplets had a diameter of 150 nm whereas after activation into gaseous MBs the size of these same PCCA were considerably larger (majority of MBs > 1 μm) and suitable for US imaging. CTR values measured from US imaging studies of PCCA after exposure with varying levels of US energy clearly captured nanodroplet activation. Importantly, a strong correlation was found between the PCCA activation pressure and hydrostatic pressure on the nanodroplets (R2 = 0.99). This correlation could serve as a reference function for converting PCCA activation pressures to TIP estimates.",
keywords = "microbubbles, nanodroplets, phase-change contrast agents, pressure estimation, ultrasound",
author = "Kenneth Hoyt and Shashank Sirsi and Robert Mattrey",
year = "2016",
month = "11",
day = "1",
doi = "10.1109/ULTSYM.2016.7728487",
language = "English (US)",
volume = "2016-November",
booktitle = "2016 IEEE International Ultrasonics Symposium, IUS 2016",
publisher = "IEEE Computer Society",

}

TY - GEN

T1 - Noninvasive pressue estimation using ultrasound methods

T2 - Preliminary in vitro results

AU - Hoyt, Kenneth

AU - Sirsi, Shashank

AU - Mattrey, Robert

PY - 2016/11/1

Y1 - 2016/11/1

N2 - Tumor interstitial pressure (TIP) inside a tumor is often high compared to normal tissues and can impede the delivery of chemotherapeutic drugs as well as decrease the effectiveness of radiation therapy. Recent efforts have focused on the development of a nanometer-sized phase-change contrast agent (PCCA) that can be activated from a liquid (nanodroplet) state using low energy ultrasound (US) pulses to form a larger highly echogenic microbubble (MB). Since PCCA activation is dependent on the hydrostatic pressure of the surrounding fluid, these same agents and custom US methods may permit TIP measurement in cancerous tissue, which is a new technology we have termed TIP estimation using US (TIPE-US). Lipid shelled decafluorobutane gas MBs were produced using mechanical agitation and then stable nanodroplets were produced by cooling and pressurizing the vial solutions. An US setup was used to deliver acoustic energy and activate nanodroplets from liquid to gaseous MB states. The effects of hydrostatic pressure on the US activation threshold of PCCA was studied by injecting PCCA into acoustically transparent sample holder preloaded with saline. Varying levels of hydrostatic pressure (0 to 39 mmHg) were applied by injecting air in the sample holders. Each sample was imaged using an US system while the acoustic pressure was progressively increased (0.3 to 3.6 MPa). From each image sequence, a modified contrast-to-tissue (CTR) metric was computed. The activation threshold required to convert PCCA from the liquid to gaseous state was taken as the US pressure needed to achieve a CTR at least two times that observed at baseline. PCCA sizes before and after US activation were measured using particle sizing systems. The greatest volume of liquid nanodroplets had a diameter of 150 nm whereas after activation into gaseous MBs the size of these same PCCA were considerably larger (majority of MBs > 1 μm) and suitable for US imaging. CTR values measured from US imaging studies of PCCA after exposure with varying levels of US energy clearly captured nanodroplet activation. Importantly, a strong correlation was found between the PCCA activation pressure and hydrostatic pressure on the nanodroplets (R2 = 0.99). This correlation could serve as a reference function for converting PCCA activation pressures to TIP estimates.

AB - Tumor interstitial pressure (TIP) inside a tumor is often high compared to normal tissues and can impede the delivery of chemotherapeutic drugs as well as decrease the effectiveness of radiation therapy. Recent efforts have focused on the development of a nanometer-sized phase-change contrast agent (PCCA) that can be activated from a liquid (nanodroplet) state using low energy ultrasound (US) pulses to form a larger highly echogenic microbubble (MB). Since PCCA activation is dependent on the hydrostatic pressure of the surrounding fluid, these same agents and custom US methods may permit TIP measurement in cancerous tissue, which is a new technology we have termed TIP estimation using US (TIPE-US). Lipid shelled decafluorobutane gas MBs were produced using mechanical agitation and then stable nanodroplets were produced by cooling and pressurizing the vial solutions. An US setup was used to deliver acoustic energy and activate nanodroplets from liquid to gaseous MB states. The effects of hydrostatic pressure on the US activation threshold of PCCA was studied by injecting PCCA into acoustically transparent sample holder preloaded with saline. Varying levels of hydrostatic pressure (0 to 39 mmHg) were applied by injecting air in the sample holders. Each sample was imaged using an US system while the acoustic pressure was progressively increased (0.3 to 3.6 MPa). From each image sequence, a modified contrast-to-tissue (CTR) metric was computed. The activation threshold required to convert PCCA from the liquid to gaseous state was taken as the US pressure needed to achieve a CTR at least two times that observed at baseline. PCCA sizes before and after US activation were measured using particle sizing systems. The greatest volume of liquid nanodroplets had a diameter of 150 nm whereas after activation into gaseous MBs the size of these same PCCA were considerably larger (majority of MBs > 1 μm) and suitable for US imaging. CTR values measured from US imaging studies of PCCA after exposure with varying levels of US energy clearly captured nanodroplet activation. Importantly, a strong correlation was found between the PCCA activation pressure and hydrostatic pressure on the nanodroplets (R2 = 0.99). This correlation could serve as a reference function for converting PCCA activation pressures to TIP estimates.

KW - microbubbles

KW - nanodroplets

KW - phase-change contrast agents

KW - pressure estimation

KW - ultrasound

UR - http://www.scopus.com/inward/record.url?scp=84996558141&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84996558141&partnerID=8YFLogxK

U2 - 10.1109/ULTSYM.2016.7728487

DO - 10.1109/ULTSYM.2016.7728487

M3 - Conference contribution

AN - SCOPUS:84996558141

VL - 2016-November

BT - 2016 IEEE International Ultrasonics Symposium, IUS 2016

PB - IEEE Computer Society

ER -