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A preliminary clinical study of ultrasound transmission computed tomography of the breast (UTCTB) was undertaken to evaluate its capacity in the detection of breast abnormalities and to establish criteria for distinguishing benign from malignant lesions. Only patients with palpable and/or mammographically evident lesions were selected for study; complete analysis was accomplished in 78 cases. Visual and computer interpretations of reconstructed UTCTB scans were based on changes in speed of sound wave transmission and attenuation between the suspicious area and the surrounding tissue. In the computer-aided classification, discriminant functions were derived to predict the presence or absence of carcinoma. Visual analysis was subject to a low sensitivity. The presence of high speed transmission within a lesion usually indicated malignancy, although the converse was not true. Computer-aided preliminary screening of UTCTB scans by a trained technician may have the potential of contributing to interpretation accuracy; however, this finding must be highly qualified, given the methodologic constraints of the study.

Vibro-acoustography is a recently developed imaging method based on the dynamic response of to low-frequency vibration produced by of ultrasound radiation force. The main differentiating feature of this method is that the image includes information about the dynamic properties of the object at the frequency of the vibration, which is normally much lower than the ultrasound frequency. Such information is not available from conventional ultrasound imaging. The purpose of this study is to evaluate the performance of vibro-acoustography in imaging mass lesions in soft tissue. Such lesions normally have elastic properties that are different from the surrounding tissue. Here, we first present a brief formulation of image formation in vibro-acoustography. Then we study vibro-acoustography of solid masses through computer simulation and in vitro experiments. Experiments are conducted on excised fixed liver tissues. Resulting images show lesions with enhanced boundary and often with distinctive textures relative to their background. The results suggest that vibro-acoustography maybe a clinically useful imaging modality for detection of mass lesions.

Shear wave propagation techniques have been introduced for measuring the viscoelastic material properties of tissue, but assessing the accuracy of these measurements is difficult for in vivo measurements in tissue. We propose using the Kramers-Kronig relationships to assess the consistency and quality of the measurements of shear wave attenuation and phase velocity. In ex vivo skeletal muscle we measured the wave attenuation at different frequencies, and then applied finite bandwidth Kramers-Kronig equations to predict the phase velocities. We compared these predictions with the measured phase velocities and assessed the mean square error (MSE) as a quality factor. An algorithm was derived for computing a quality factor using the Kramers-Kronig relationships.

The APS Journal Legacy Content is the corpus of 100 years of historical scientific research from the American Physiological Society research journals. This package goes back to the first issue of each of the APS journals including the American Journal of Physiology, first published in 1898. The full text scanned images of the printed pages are easily searchable. Downloads quickly in PDF format.