Two-dimensional echo-encephalography. 1. Acoustic properties of some tissues and the characteristics of echo patterns obtained using equipment especially adapted for detection of these tissues.

In this paper the results of measurements of ultrasound velocity in, and density of, a number of normal and pathological tissues are given. From the results it can be concluded that intracranial pathological regions will often be detectable with ultrasound techniques, but is is not possible with any degree of certainty to localise precisely the morphological boundaries of these abnormal regions. Because, in the large majority of cases, the echoes from intracranial pathological structural changes are of weak intensity, a simple electronic device is described which, in conjunction with standard echo equipment, has been shown to be of use for better detection of these weak signals.