Method to measure ambient fluid pressure
First Claim
1. A method for measuring ambient pressure at a region of interest in a fluid-filled body cavity or vessel comprising the steps of:
- (a) introducing into said cavity or vessel a composition of gas-containing microbubbles, said microbubbles having a predetermined fragility threshold, said fragility threshold correlating the disintegration response of said microbubbles to a combination of fluid and applied acoustic pressure, said acoustic pressure being applied from an ultrasonic energy producing source and said composition having predetermined acoustic response properties correlating to ambient pressure of a surrounding fluid;
(b) applying an ultrasonic signal at said region of interest within said cavity or vessel at a power level sufficient to cause acoustic pressure to disintegrate a microbubble population, said power level being above or equal to said predetermined fragility threshold;
(c) detecting the returned acoustic signals backscattered from the population of disintegrating and intact microbubbles remaining at said region of interest;
(d) correlating said returned acoustic signals to said predetermined acoustic response properties of said composition to determine said ambient pressure at said region of interest;
(e) repeating steps (a)-(b).
5 Assignments
0 Petitions
Accused Products
Abstract
A method is provided for measuring real time ambient pressure at a region of interest in a fluid-filled body cavity by introducing into the cavity a composition of gas-containing microbubbles having a predetermined fragility threshold correlating to the rupture response of their capsules to the ambient fluid pressure and/or applied acoustic pressure. An ultrasonic signal is applied at the region of interest at a power level sufficient to destroy the microbubble population having a fragility threshold below the applied power level. The ultrasound backscatter response is detected from the population of intact and disintegrating microbubbles remaining at the region of interest and this backscatter signal is correlated to predetermined acoustic response properties to determine the ambient pressure at the region of interest.
32 Citations
43 Claims
-
1. A method for measuring ambient pressure at a region of interest in a fluid-filled body cavity or vessel comprising the steps of:
-
(a) introducing into said cavity or vessel a composition of gas-containing microbubbles, said microbubbles having a predetermined fragility threshold, said fragility threshold correlating the disintegration response of said microbubbles to a combination of fluid and applied acoustic pressure, said acoustic pressure being applied from an ultrasonic energy producing source and said composition having predetermined acoustic response properties correlating to ambient pressure of a surrounding fluid;
(b) applying an ultrasonic signal at said region of interest within said cavity or vessel at a power level sufficient to cause acoustic pressure to disintegrate a microbubble population, said power level being above or equal to said predetermined fragility threshold;
(c) detecting the returned acoustic signals backscattered from the population of disintegrating and intact microbubbles remaining at said region of interest;
(d) correlating said returned acoustic signals to said predetermined acoustic response properties of said composition to determine said ambient pressure at said region of interest;
(e) repeating steps (a)-(b). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
-
-
35. A method of determining the fragility thresholds of a plurality of populations of microbubbles and correlating said thresholds to ambient pressures at rupture surrounding said microbubbles comprising the steps of:
-
a) determining the fragility slope of each said population from respective curves, said curves determined by measuring acoustic density as each of said population as it is acoustically interrogated along a channel versus distance along said channel;
b) determining fragility curves by plotting each of said fragility slopes versus mechanical index, a measure of the acoustic power used to interrogate each said population;
c) identifying the intercept of substantially linear portions of each of said fragility curves at zero fragility slope as the mechanical index at the threshold fragility for each said population;
d) correlating each of said mechanical indices at the threshold fragility to an ambient pressure from a predetermined mechanical index-to-pressure relationship. - View Dependent Claims (36, 37, 38, 39, 40, 41, 42, 43)
-
Specification