Joe R. Suarez

A New, High-Performance Ultrasonic Camera

By virtue of their true-perspective presentation, focused and holographic methods of ultrasonic imaging hold great promise for soft tissue visualization. However, none of the numerous methods demonstrated to date combine the features required of a clinically useful instrument.

A real-time ultrasonic imaging system for carotid arteriography

Abstract A real-time ultrasonic imaging system for the noninvasive assessment of atherosclerotic vascular disease has been developed. This instrument displays cross-sectional images of the artery and surrounding tissues plus superimposed profiles of blood flow within the vessel. The anatomical structure is depicted by a 10-MHz B -scan subsystem operating at 15 frames/sec. An instantaneous profile of the blood flow velocity is produced by a 5-MHz pulsed Doppler subsystem that can display the velocity at up to 20 individual points along a line segment intersecting the artery. Cross-sectional high-resolution gray-scale images, both transverse and longitudinal, of the major vessels in the neck in the region of the carotid bifurcation are presented. These images also demonstrate the skin, subcutaneous fat, muscle, and thyroid gland. Estimates of severity of atherosclerotic disease measured as percentage of lumen diameter obstructed by each lesion, are essentially the same as subsequent estimates made using roentgen angiography. Pulsating blood flow profiles in the common carotid have been clearly displayed; however, clinical applicability of the Doppler subsystem is not yet demonstrated.

Biomedical Imaging with the SRI Ultrasonic Camera

Researchers at SRI have developed a real-time ultrasonic imaging system for the visualization of anatomical structures in an orthographic projection rather than the more common B-scan presentation. This system produces high resolution images of a 15-cm × 15-cm field by employing pulsed/range- gated operation and a 192-element linear array of piezoelectric detectors. The system’s high sensitivity (10−11W/cm2) permits imaging through the abdomen of adult humans with incident energies well below any known toxic level. Both transmission and reflection imaging are provided. Images are displayed on a television monitor and may be recorded on video tape.

A Real-Time High-Resolution Ultrasonic Arterial Imaging System

Atherosclerosis is one of the major diseases affecting the health of people throughout the world. Detection of atherosclerotic lesions by invasive techniques presents serious hazards to patients, while current noninvasive techniques often do not yield accurate diagnosis. There is an urgent need for instrumentation that will provide safe, noninvasive, and accurate diagnosis of this disease. Since July 1973, the Mayo Foundation and Stanford Research Institute have been involved in a joint effort to develop high-resolution ultrasonic imaging techniques for clinical application to the diagnosis of human cardiovascular diseases. A first generation, real-time ultrasonic arterial imaging system for the simultaneous visualization of vessel anatomy and blood flow in the carotid and femoral arteries has been developed at SRI for clinical evaluation at the Mayo Foundation. This instrument incorporates both B-scan and Doppler measurement modalities.

An Ultrasonic Camera System for Medical Diagnosis

An ultrasonic camera system for throughtransmission as well as reflection imaging has been developed for diagnostic use. The ultrasonic camera produces real-time focused, orthographic images of a 15- x-15 cm field. A specially designed linear array of 19 2 piezoelectric detectors provides both high resolution and high sensitivity. The camera incorporates a unique wavefield deflection system which scans the focused image past the transducer array, producing 15 image-fields per second on a television display. The principles of operation of this camera system are described and demonstrated.