Patent ID: 7734330

Claim:
A method of detecting vulnerable plaques engrained or embedded in otherwise normal tissue in a wall of a patient's blood vessel containing blood whose temperature corresponds to that of said normal tissue, said method comprising the steps of forming an intravascular catheter containing a first microwave antenna tuned to a first frequency enabling it to detect temperature at depth in said wall and produce a corresponding first frequency signal, and a second antenna designed to pick up thermal emissions from said blood to sense the temperature thereof and produce a corresponding reference signal; applying said signals by way of a diplexer separately to a differential radiometer to produce an output signal therefrom which reflects said temperature at depth relative to the blood temperature, and moving the catheter along said vessel so that at each point along the vessel said output signal indicates the presence or absence of vulnerable plaques in said vessel wall due to the higher emissivity thereof as compared to that of the normal tissue.