Patent ID: 7682310

Claim:
A method of using an ultrasound contrast agent to measure pressure in an intracranial area filled with micro-bubbles formed by the injected contrast agent, the method comprising: (a) emitting an ultrasound signal having a bandwidth to the intracranial area; (b) receiving an echoed signal from a micro-bubble; (c) performing a spectral analysis on the echoed signal and extracting a low-frequency response, the low-frequency response formed by exciting a difference between two frequencies of a dual-frequency acoustic signal when the micro-bubbles are excited by the dual-frequency acoustic signal with the two frequencies, the difference being close to a DC component of a frequency spectrum, and the bandwidth of the low-frequency response being similar to the bandwidth of the ultrasound signal; (d) calculating a resonant frequency of the micro-bubble according to the low-frequency response; and (e) calculating a size of the micro-bubble and a pressure of the intracranial area according to the resonant frequency and a property of the contrast agent.