Journal of Ultrasound in Medicine, Vol 7, Issue 9 487-498, Copyright © 1988 by American Institute of Ultrasound in Medicine
Slice thickness measurements
A. Goldstein
Department of Obstetrics/Gynecology, Wayne State University School of Medicine, Detroit, Michigan.
A new slice thickness test object is discussed, with results of feasibility
tests using 13 transducers from six different commercial scanners
presented. Both inplane beamwidth and slice thickness measurements could be
easily performed and interpreted. For proper equipment gain settings the
slice thickness measurement results were found to be independent of
receiver gain with a tissue-mimicking (TM) fill in the test object. This is
explained by a simple model in which test object low-amplitude internal
fill echoes effectively act as an invariant measurement reference level
with respect to the slice thickness profile echoes. This model also
predicts that in clinical images the inplane lateral resolution (and slice
thickness) will be governed by the local image contrast between adjacent
tissues as well as the beam profile. Slice thickness measurement results
from various types of real-time transducers demonstrate their inherent
slice thickness focal characteristics.
