Method and apparatus for intravascular ultrasonography

Claim 1

A catheter system for obtaining an image of a vessel in a vascular system comprising: an elongate flexible element adapted to enter the vessel, a flexible rotatable elongate element disposed in the elongate flexible element, an ultrasonic transducer carried by the flexible rotatable elongate element and being rotatable therewith for scanning the vessel, motor means for rotating the flexible rotatable elongate element, the flexible rotatable elongate element and the transducer carried thereby being movable longitudinally with respect to the elongate flexible element, transmitter means coupled to the ultrasonic transducer and producing electrical signals and supplying the same to the ultrasonic transducer to cause ultrasonic waves to be emitted therefrom and to be shifted longitudinally as the rotatable element is moved longitudinally and rotated as the flexible rotatable elongate element is rotated, receiver means coupled to the ultrasonic transducer, the ultrasonic transducer being capable of receiving reflected ultrasonic waves and supplying electrical signals to the receiver means, timing control means for causing operation of the transmitter means, the receiver means and the motor means and means connected to the receiver means for creating a visual display of the vessel being scanned by the ultrasonic transducer, said flexible elongate element further comprising at least one inflatable balloon disposed at the distal extremity thereof, at least one said balloon covering at least a part of the longitudinal section in which the ultrasonic transducer is moved during imaging without substantially attenuating the ultrasonic waves emitted from the transducer.

Claim 10

A method for imaging the interior wall of a blood vessel using a flexible elongate element having at least one inflatable balloon disposed on a distal extremity thereof, said method comprising: generating an ultrasonic signal using a transducer located within the blood vessel; sweeping the signal continuously in a predetermined patterned about the interior wall of the blood vessel, wherein said sweeping is accomplished by rotating the transducer or a reflective surface which deflects the signal from the transducer within the flexible elongate element which remains substantially stationary while the signal is being swept, and wherein at least one said balloon covers at least a part of the longitudinal section through which the ultrasonic transducer is swept during imaging without substantially attenuating the ultrasonic waves emitted from the transducer; receiving the ultrasonic signal reflected from the interior wall of the blood vessel; and producing an image from the reflected signal.

Claim 11

A method for imaging the interior wall of a blood vessel using a flexible elongate element having at least one inflatable balloon disposed on a distal extremity thereof, said method comprising: generating an ultrasonic signal using a transducer located within the blood vessel; sweeping the signal continuously in a predetermined patterned about the interior wall of the blood vessel, wherein said sweeping is accomplished by rotating the transducer or a reflective surface which deflects the signal from the transducer within the flexible elongate element which remains substantially stationary while the signal is being swept, and wherein at least one said balloon covers at least a part of the longitudinal section through which the ultrasonic transducer is swept during imaging without substantially attenuating the ultrasonic waves emitted from the transducer; receiving the ultrasonic signal reflected from the interior wall of the blood vessel; and producing an image from the reflected signal.