IN AN A-mode ultrasound display, the amplitude of the echoes produced at acoustic interfaces by a single wave of ultrasound is presented. The B-scan ("Brightness" mode), which consists of a series of transverse and longitudinal scans made at 1- or 2-cm intervals, produces an accurate sonar "picture" of the region. The scan is displayed on an oscilloscope as a series of dots, each indicating the location of an echo. The brightness of each dot reflects the relative strength of its echo. All these points together provide a map of the acoustic representation of the organs and lesions, in essence an ultrasonic tomogram. A picture of the oscilloscopic image made with a Polaroid camera provides a permanent record. The B-scan is an ideal diagnostic tool in children, since ultrasound examination is quick, relatively simple to perform, very well tolerated by the patient, and has no known hazards.
Diagnosis of Abdominal Lesions