Initialization of fitting parameters for perfusion assessment based on bolus administration

A data-processing method for analyzing a body-part perfused with an ultrasound contrast agent, the ultrasound contrast agent being pre-administered as a bolus to circulate through the body-part with a first passage and with at least one second passage during an analysis interval, wherein the method includes the steps of:

• displaying one or more video images of the body-part on a monitor of a data-processing system,
• storing a representation of at least one input signal indicative of a response to an ultrasound interrogation signal of a corresponding location of the body-part during the analysis interval in a memory of the data-processing system,
• fitting, by the data-processing system accordingly configured, each input signal over the analysis interval by an instance of a combined bolus function of time based on a combination of a first bolus function of time modeling the first passage of the contrast agent and at least one second bolus function of time each one modeling a corresponding second passage of the ultrasound contrast agent, the combined bolus function being defined by the values of a set of first fitting parameters of the first bolus function, a set of second fitting parameters of each second bolus function and a delay parameter of each second bolus function with respect to the first bolus function, and
• displaying information based on each combined bolus function of time on the monitor of the data-processing system for use in analyzing the body-part, said displaying information comprising:
• a) generating at least one parametric image of the body-part based on the combined bolus function of time for each location, and
• a1) superimposing the parametric image on a selected video image on the monitor of the data-processing system, or
• a2) displaying the parametric image on the monitor of the data-processing system;
• or
• b) calculating a parametric value based on the combined bolus function for a location corresponding to a region of interest of the body-part, and
• c) displaying the parametric value on the monitor of the data-processing system,
• wherein the step of fitting each input signal includes:
• estimating a peak instant of the input signal when the corresponding response reaches an absolute peak,
• setting a truncation interval within the analysis interval according to the peak instant,
• fitting a truncated signal defined by the input signal over the truncation interval by an instance of a truncated bolus function of time modeling a single passage of the contrast agent during the truncation interval, the truncated bolus function being defined by the values of a set of truncated fitting parameters, and
• initializing the first fitting parameters of the first bolus function, the second fitting parameters of each second bolus function and the delay parameter of each second bolus function according to the values of the truncated fitting parameters.

A data-processing system including an electronic circuit configured to perform the steps of a data processing method for analyzing a body part perfused with an ultrasound contrast agent, the ultrasound contrast agent being pre-administered as a bolus to circulate through the body-part with a first passage and with at least one second passage during an analysis interval, wherein the data processing method includes the steps of:

• displaying one or more video images of the body-part on a monitor of the data-processing system,
• storing a representation of at least one input signal indicative of a response to an ultrasound interrogation signal of a corresponding location of the body-part during the analysis interval in a memory of the data-processing system,
• fitting, by the data-processing system, each input signal over the analysis interval by an instance of a combined bolus function of time based on a combination of a first bolus function of time modeling the first passage of the ultrasound contrast agent and at least one second bolus function of time each one modeling a corresponding second passage of the ultrasound contrast agent, the combined bolus function being defined by the values of a set of first fitting parameters of the first bolus function, a set of second fitting parameters of each second bolus function and a delay parameter of each second bolus function with respect to the first bolus function, and
• displaying information based on each combined bolus function of time on the monitor of the data-processing system for use in analyzing the body-part, said displaying information comprising:
• a) generating at least one parametric image based on the combined bolus function of time for each location, and
• a1) superimposing the parametric image on a selected video image of the body-part on the monitor of the data-processing system, or
• a2) displaying the parametric image on the monitor of the data-processing system;
• orb) calculating a parametric value based on the combined bolus function for a location corresponding to a region of interest of the body-part, and
• b) displaying the parametric value on the monitor of the data-processing system, wherein the step of fitting each input signal includes:
• estimating a peak instant of the input signal when the corresponding response reaches an absolute peak,
• setting a truncation interval within the analysis interval according to the peak instant,
• fitting a truncated signal defined by the input signal over the truncation interval by an instance of a truncated bolus function of time modeling a single passage of the ultrasound contrast agent during the truncation interval, the truncated bolus function being defined by the values of a set of truncated fitting parameters, and
• initializing the first fitting parameters of the first bolus function, the second fitting parameters of each second bolus function and the delay parameter of each second bolus function according to the values of the truncated fitting parameters.

A non-transitory computer readable medium storing program instructions that are directly loadable into a working memory of a data-processing system, and that, when executed by the data-processing system, cause the data-processing system to perform a data-processing method for analyzing a body-part perfused with an ultrasound contrast agent, the ultrasound contrast agent being pre-administered as a bolus to circulate through the body-part with a first passage and with at least one second passage during an analysis interval, wherein the data processing method includes the steps of:

• displaying one or more video images of the body-part on a monitor of the data-processing system,
• storing a representation of at least one input signal indicative of a response to an ultrasound interrogation signal of a corresponding location of the body-part during the analysis interval in a memory of the data-processing system,
• fitting, by the data-processing system, each input signal over the analysis interval by an instance of a combined bolus function of time based on a combination of a first bolus function of time modeling the first passage of the ultrasound contrast agent and at least one second bolus function of time each one modeling a corresponding second passage of the ultrasound contrast agent, the combined bolus function being defined by the values of a set of first fitting parameters of the first bolus function, a set of second fitting parameters of each second bolus function and a delay parameter of each second bolus function with respect to the first bolus function,
• displaying information based on each combined bolus function of time on the monitor of the data-processing system for use in analyzing the body-part, said displaying information comprising:
• a1) generating at least one parametric image based on the combined bolus function of time for each location, and
• a2) superimposing the parametric image on a selected video image of the body-part on the monitor of the data-processing system, or
• b) displaying the parametric image on the monitor of the data-processing system;
• or
• c) calculating a parametric value based on the combined bolus function for a location corresponding to a region of interest of the body-part, and
• displaying the parametric value on the monitor of the data-processing system,
• wherein the step of fitting each input signal including:
• estimating a peak instant of the input signal when the corresponding response reaches an absolute peak,
• setting a truncation interval within the analysis interval according to the peak instant,
• fitting a truncated signal defined by the input signal over the truncation interval by an instance of a truncated bolus function of time modeling a single passage of the contrast agent during the truncation interval, the truncated bolus function being defined by the values of a set of truncated fitting parameters, and
• initializing the first fitting parameters of the first bolus function, the second fitting parameters of each second bolus function and the delay parameter of each second bolus function for the fitting of the input signal by the combined bolus function according to the values of the truncated fitting parameters.

A diagnostic method for analyzing a body-part, the diagnostic method including the steps of:

• administering an ultrasound contrast agent to the body-part to cause the body-part to be perfused with the ultrasound contrast agent, the ultrasound contrast agent being administered as a bolus to circulate through the body-part with a first passage and with at least one second passage during an analysis interval,
• applying an ultrasound interrogation signal to the body-part during the analysis interval,
• acquiring at least one input signal indicative of a response to the ultrasound interrogation signal of a corresponding location of the body-part during the analysis interval, each input signal being processed according to the data-processing method of claim 1 to obtain the corresponding combined bolus function, and
• assessing a perfusion of each location of the body-part according to the corresponding combined bolus function.