ABSTRACT
Measurements have a significant role in many areas of ultrasound practice. Some of the earliest ultrasound measurements were made in the field of obstetrics, originally in A-mode. A small range of measurements was quickly established in regular practice, and this range has been considerably developed over the years. Measurement systems have the sophistication and flexibility provided by digital electronics and software control. In the early days of ultrasound, particularly before the advent of digital scan converters, only simple axial measurements were possible on scanners. These were made on the A-mode display by aligning the ultrasound beam with the targets to be measured, and identifying and placing markers on the appropriate signals on the display. Measurements made using ultrasound callipers range from simple linear distance measurements to more complex volume measurements. Scanners will often be able to perform calculations using measurements. Non-linear distances, including irregular circumferences, may be calculated from a tracing.
