Ultrasonic imaging catheter having rotational image correlation

An ultrasonic imaging catheter comprising:

• a catheter body having a proximal end and a distal end;
• means within the distal end of the catheter body for producing an ultrasonic cross-sectional image in an image plane generally normal to the longitudinal axis of the catheter body;
• an ultrasonically opaque element fixed relative to the catheter body and passing through the image plane;
• a fluoroscopically opaque marker formed on the catheter body and spaced longitudinally apart from the ultrasonic imaging means, wherein said marker when viewed in a direction normal to the longitudinal axis of the catheter body produces a pattern which is uniquely characteristic of a particular rotational orientation of the catheter body.

A method for producing a cross-sectional image of the interior of a blood vessel, said marker comprising:

• introducing the distal end of a catheter to a desired region within the blood vessel;
• mechanically rotating an ultrasonic signal about an image plane which is normal to the distal end of the catheter;
• receiving reflected ultrasonic signal from the interior of the blood vessel and producing an ultrasonic cross-sectional image therefrom;
• producing a marker in the ultrasonic cross-sectional image which is aligned with a fixed radial direction in the image plane;
• fluoroscopically imaging the distal end of the catheter in a plane generally normal to the image plane;
• and
• producing a marker in the fluoroscopic image which corresponds to the rotational alignment of the catheter in the blood vessel, whereby the rotational orientation of the catheter can be correlated with the rotational orientation of the ultrasonic image.