A method (A1-A18) for analyzing a body-part of a patient, the body-part having been perfused before performing the method with an ultrasound contrast agent capable of circulating within the patient and of being substantially immobilized on a biological target, wherein the method comprises: providing (A1-A2) at least one filtered ultrasound comprising a plurality of filtered values for corresponding locations of the body-part, each filtered value comprising an indication of the immobilized contrast agent at the corresponding location with a contribution of the circulating contrast agent being substantially reduced, generating a thresholded image comprising a plurality of thresholded values corresponding to the filtered values, the thresholded image being generated by setting each thresholded value to the corresponding filtered value or to a reset value according to a comparison of the filtered value with an amplitude threshold, wherein providing (A3-A7) a plurality of candidate thresholds defined by corresponding candidate values of the amplitude threshold, generating a plurality of candidate images corresponding to the candidate thresholds each one comprising a plurality of candidate values corresponding to the filtered values, each candidate image being generated by setting each candidate value to the corresponding filtered value or to the reset value according to said comparison of the filtered value with the candidate threshold, calculating (A9-A14) a plurality of comparison values corresponding to the candidate images, the comparison value of each candidate image being calculated according to a further comparison between the candidate values in an immobilization region corresponding to a group of locations containing a significant amount of the immobilized contrast agent and the candidate values in a circulation region corresponding to at least part of the locations excluding the immobilization region, determining a peak of the comparison values, and setting the amplitude threshold according to the peak of the comparison values. providing (A1-A2) at least one filtered ultrasound comprising a plurality of filtered values for corresponding locations of the body-part, each filtered value comprising an indication of the immobilized contrast agent at the corresponding location with a contribution of the circulating contrast agent being substantially reduced, generating a thresholded image comprising a plurality of thresholded values corresponding to the filtered values, the thresholded image being generated by setting each thresholded value to the corresponding filtered value or to a reset value according to a comparison of the filtered value with an amplitude threshold, wherein providing (A3-A7) a plurality of candidate thresholds defined by corresponding candidate values of the amplitude threshold, generating a plurality of candidate images corresponding to the candidate thresholds each one comprising a plurality of candidate values corresponding to the filtered values, each candidate image being generated by setting each candidate value to the corresponding filtered value or to the reset value according to said comparison of the filtered value with the candidate threshold, calculating (A9-A14) a plurality of comparison values corresponding to the candidate images, the comparison value of each candidate image being calculated according to a further comparison between the candidate values in an immobilization region corresponding to a group of locations containing a significant amount of the immobilized contrast agent and the candidate values in a circulation region corresponding to at least part of the locations excluding the immobilization region, determining a peak of the comparison values, and setting the amplitude threshold according to the peak of the comparison values.