Determination of prostate volume with transrectal US for cancer screening. Part I. Comparison with prostate-specific antigen assays.

To investigate whether radiologists can objectively define a high-risk group for prostate cancer, the researchers measured gland volume and compared it with results of a screening blood test, prostate-specific antigen (PSA) assay. A total of 768 men, aged 55-71 years, were self-referred to two prostate cancer screening programs using transrectal ultrasound (US) and digital rectal examination. In patients with no evidence of cancer, statistically significant increases in mean PSA values were noted with increasing gland volume ranges (P less than .05). PSA values in patients with cancer were more likely to exceed the volume-adjusted 95th percentile (mean + [1.65.standard deviation]) than those in patients with negative biopsy results (P less than .005). Patients with PSA values above the volume-adjusted 95th percentile have an estimated risk for prostate cancer up to nine times that of the general screening population. The researchers conclude that knowledge of transrectal US gland volume and prostate-specific antigen assay type are important objective variables for future prostate cancer screening programs. The volume-adjusted 95th percentiles presented may help guide cost-effective management of current early detection efforts

Development of ultrasound tomography for breast imaging: technical assessment

Ultrasound imaging is widely used in medicine because of its benign characteristics and real-time capabilities. Physics theory suggests that the application of tomographic techniques may allow ultrasound imaging to reach its full potential as a diagnostic tool allowing it to compete with other tomographic modalities such as X-ray CT and MRI. This paper describes the construction and use of a prototype tomographic scanner and reports on the feasibility of implementing tomographic theory in practice and the potential of US tomography in diagnostic imaging. Data were collected with the prototype by scanning two types of phantoms and a cadaveric breast. A specialized suite of algorithms was developed and utilized to construct images of reflectivity and sound speed from the phantom data. The basic results can be summarized as follows.(i) A fast, clinically relevant US tomography scanner can be built using existing technology, (ii) The spatial resolution, deduced from images of reflectivity, is 0.4 mm. The demonstrated 10 cm depth-of-field is superior to that of conventional ultrasound and the image contrast is improved through the reduction of speckle noise and overall lowering of the noise floor. (iii) Images of acoustic properties such as sound speed suggest that it is possible to measure variations in the sound speed of 5 m/s. An apparent correlation with X-ray attenuation suggests that the sound speed can be used to discriminate between various types of soft tissue. (iv) Ultrasound tomography has the potential to improve diagnostic imaging in relation to breast cancer detection