Patent ID: 8323620

Claim:
An ultrasound contrast agent in the form of particles, comprising: a perfluoropentane as a low-boiling point water-insoluble substance; and a perfluoroheptane as a high-boiling point water-insoluble substance; wherein a relative concentration of the perfluoropentane to the total amount of the perfluoropentane and the perfluoroheptane is lower than 0.7, and the ultrasound contrast agent is a liquid at the time of administration into a living body, and wherein the low-boiling point water-insoluble substance is directly vaporized by an application of pulsed ultrasound with a pulse length of 1 ms to 20 ms, and the high-boiling point water-insoluble substance is indirectly vaporized by the ultrasound by being vaporized by the low-boiling point water-insoluble vapor, so that vaporization of the low-boiling point water-insoluble substance and the high-boiling point water-insoluble substance is used to give an image.