Radiology, Vol 146, 91-95, Copyright © 1983 by Radiological Society of North America
Detectability of depth information by use of magnification stereoscopic technique in cerebral angiography
K Doi and EE Duda
Two types of stereoscopic phantoms were constructed to determine the
sensitivity of observers in detecting depth information obtained by means
of the magnification stereoscopic technique. One of these, a "plus"
phantom, contained perpendicular aluminum wires at the top and bottom of
steps of various thicknesses; the observer was asked to identify whether
one of the wires was on the top, the bottom, or uncertain in location. The
fraction of correct responses versus the height of the step was plotted,
indicating the detectability of depth. Fourteen of 20 unselected observers
(70%) responded consistently and were considered "good" observers. In
general, the greater the stereo shift, the greater the fraction of correct
responses. A second phantom, a mesh phantom, contained standard and
randomly positioned test wires. The observer was asked to identify the
depth position of a test wire with respect to the standard wire if they
were in the same plane. It was found that observers can discriminate depth
differences of one to two millimeters in magnification stereoscopy, and
similar performance for magnification stereoscopic cerebral angiograms is
expected.
