Radiology, Vol 156, 773-775, Copyright © 1985 by Radiological Society of North America
Breast mass detection by US: a phantom study
WJ Davros, EL Madsen and JA Zagzebski
Phantoms were used to compare imaging of various masses in the glandular
region for two types of breasts. In one type, normal glandular tissue
contains no fat clumps; in the other type, randomly distributed spherical
fat clumps exist. The size distribution and number of fat clumps per unit
volume in the phantoms represented those found in actual normal glandular
tissue. For a 5-cm path length between the scanning window of the phantom
and the centers of the masses, the presence of the fat clumps caused
distortions and deviations of the beam, resulting in image distortion. This
degradation was reduced when successive slabs of the material containing
the fat clumps were removed. Image degradation appeared to be less severe
when a 2.25 (rather than a 3.5) MHz transducer was used. The results show
that the thickness of tissue containing fat clumps between the scanning
transducer and a mass plays a role in the detectability of masses and
diagnostic usefulness of the image of a breast. This suggests that imaging
of the breast in the compressed configuration should be performed
regardless of whether the freely suspended breast is imaged. Also,
transducers of lower nominal frequency may have an important role in breast
imaging.
