Ultra-Sonic Diagnosis Of Brain Disorders Studied

Press, Volume CIV, Issue 30911, 18 November 1965, Page 23

Ultra-Sonic Diagnosis Of Brain Disorders Studied

(N.Z.P.A.-Reuter) OTTAWA. Possible diagnosis of brain disorders by ultra-sonic means is being studied by the National Research Council in Ottawa. The high-frequency sound waves, inaudible but penetrating, could, it is believed, help to detect brain tumors, internal bleeding and the enlargement of ventricles (the cystic spaces within the brain) caused by an increase in the pressure of cerebral fluid.

Ultra-sonics may also be useful in diagnosing skull and brain injuries and for making possible a fast, convenient preliminary examination and for post-operative examinations.

Dr. David Makow who, with Mr R. R. Real, is carrying out the research, thinks ultra-sonics “may eventually replace other diagnostic means.”

Both men say the apparatus with which they are experimenting is not ready for commericail production. At present, two X-ray methods are used to show the inside of the brain. In ventriculography, the cerebral fluid is replaced by air and the head is then X-rayed. In angiography, the X-ray is made after an opaque substance has been injected into the blood. Both methods are fairly complicated Ultra-Sonic waves have Iready been used to outline tier internal parts of the *dy. They are directed into organ’ being investigated

and reflect back according to characteristics of the tissue they encounter. These reflected echo waves can be amplified, reproduced on an oscilloscope and photographed. The brain, however, presents unique problems. For instance, the skull causes a loss of energy in the ultrasonic waves, and because of its unequal thickness and composition, distorts the beam. Nevertheless, it has been shown that single echoes can be obtained from prominent structures in the centre of the brian, the midline. These echoes are displaced in one dimension when brain disorders are present. This suggests that a further extension of the technique would reveal not only the displacement but also the size and shape of internal structures. An improved instrument will require that echoes be obtained from sites around the head in such a way that results can be correlated to

obtain a two-dimensional picture.

The equipment now being developed comprises a rotating, water-filled tank, a scanning transducer which converts electrical energy into an ultra-sonic beam, a trans-mitter-receiver and a display screen.

The water provides a more efficient means of carrying utlra-sonic waves than air.

The patient lies on his back on a stretcher and bends the head downward into the water to the level of ears and eyes. Ultra-sonic pulses are beamed through the water at the head. After one tank revolution, the position of the echoes form a cross-sectional image of the structures inside the head. So far, it has been possible to receive reliable reflections only from tissues in the brain which lie in the midline plane separating the two hemispheres of the brain, but work is continuing with a view to extending the area which can be studied.