Methods and apparatus for using ultrasound with contrast agent

A method for producing an ultrasound image of a contrast agent infused target, the method comprising the steps of:

• subjecting the target to an ultrasound flash capable of producing a plurality of first and second target zones, the first and second target zones being stripes, the first target zones having a higher concentration of contrast agent than the second target zones;
• forming an ultrasound image of the target, wherein the first target zones appear substantially brighter than the second target zones in the ultrasound image;
• comparing, over time, a brightness of at least one of the second target zones with a brightness of at least one neighboring first target zone;
• and
• measuring an amount of time that elapses from the step of subjecting the target to an ultrasound flash to a time when a ratio between the brightness of the at least one of the second target zones and the brightness of the at least one neighboring first target zone reaches a pre-determined value.

An ultrasound imaging system for calculating blood perfusion in tissue, the system including:

• a keyboard for selecting first and second energies used to radiate contrast agent infused tissue for a first predetermined amount of time and for selecting a third energy used to radiate the tissue for a second predetermined amount of time, said first and third energies destroying a relatively small amount of contrast agent and said second energy destroying a relatively large amount of contrast agent;
• a front-end controller (FEC) controlling a transducer to radiate, within said first period of time, a plurality of first beam positions forming first transmission regions at said first energy and a plurality of second beam positions forming second transmission regions at said second energy, said FEC radiating the tissue with said third energy for said second predetermined amount of time;
• and
• a display for displaying the tissue while the FEC is radiating the tissue with the third energy, said keyboard selecting first and second points within the first and second transmission regions, respectively, said first and second points being used to calculate brightness values for each of said first and second transmission regions, said brightness values representing a perfusion rate of the tissue.

A method for determining a perfusion rate of contrast agent infused tissue, the method comprising:

• subjecting contrast agent infused tissue to an ultrasound flash capable of producing a plurality of first and second target zones, said ultrasound flash destroying a first percentage of contrast agent in said first target zones and a second percentage of contrast agent in said second target zones, said second percentage being greater than said first percentage;
• acquiring consecutive image frames comprising said first and second target zones, at least one second target zone being substantially brighter than at least one first target zone;
• measuring a brightness of said at least one first target zone for each image frame;
• measuring a brightness of said at least one second target zone for said each image frame;
• comparing, over time, a brightness of said at least one second target zone with a brightness of at least one first target zone to determine a rate of perfusion of said at least one second target zone;
• and
• determining a perfusion rate for the tissue based on a ratio of said brightnesses for said each image frame.

A method for estimating blood perfusion of tissue, the method comprising:

• transmitting first and second ultrasound transmissions within one frame, said first ultrasound transmission being transmitted in at least one first region of tissue and said second ultrasound transmission being transmitted in at least one second region of tissue, said at least one first and second regions of tissue being continuously infused with a contrast agent, said first ultrasound transmission destroying a first percentage of the contrast agent in said at least one first region, said second ultrasound transmission destroying a second percentage of the contrast agent in said at least one second region, said first percentage being greater than said second percentage;
• acquiring consecutive image frames comprising said first and second regions of tissue, said first and second regions displaying different ultrasonic responses;
• measuring said ultrasound response of said first regions of tissue for each, image frame;
• measuring said ultrasound response of said second regions of tissue for said each image frame;
• measuring an amount of time that elapses from the transmitting step to a time when an ultrasound response of said second regions is substantially the same as an ultrasound response of said first regions;
• and
• determining a perfusion rate for the tissue based on a ratio of said ultrasound responses for said each image frame.

A method for identifying an interface between tissue and blood within a contrast agent infused target, the method comprising the steps of:

• subjecting a target comprising tissue and blood to an ultrasound flash capable of forming a pattern of acoustic markers, said pattern comprising a plurality of first and second target zones with substantially different brightness levels, said ultrasound flash destroying a first percentage of contrast agent in said first target zones and a second percentage of contrast agent in said second target zones, the first and second percentages being substantially different to produce said first and second target zones;
• forming an ultrasound image of the target;
• and
• identifying an interface between the tissue and blood based on said pattern of acoustic markers, said pattern of acoustic markers being absent from target zones being produced in areas of the target comprising blood, said pattern of acoustic markers being present in target zones being produced in areas of the target comprising tissue.

An ultrasound imaging system for detecting motion in tissue, the system including:

• a keyboard for selecting first and second energies used to radiate contrast agent infused tissue for a first predetermined amount of time and for selecting a third energy used to radiate the tissue for a second predetermined amount of time, said first and third energies destroying a relatively small amount of contrast agent and said second energy destroying a relatively large amount of contrast agent;
• a front-end controller (FEC) controlling a transducer to radiate, within said first period of time, a plurality of first beam positions forming first transmission regions at said first energy and a plurality of beam positions forming second transmission regions at said second energy, said FEC radiating said first and second transmission regions with said third energy for said second predetermined amount of time;
• and
• a display for displaying said first and second transmission regions while the FEC is radiating said first and second transmission regions with the third energy, said keyboard measuring a width of at least one second transmission region over time to detect movement of the tissue.