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Biomedical subjects

D B Kopans

Publications and source records attributed to D B Kopans.

At least 91 records · Page 5Linked to original sources
PubMed1993

Breast cancer detection in an institution. Is mammography detrimental?

The poor results of the National Breast Screening Study of Canada regarding the screening of women aged 40-49 have been interpreted to suggest that mammography might be detrimental. Our comparison of women who had mammography and had their cancers detected by mammography with women who did not have mammography and had palpable cancers suggest that this is not the case. There is no detrimental effect; rather, the use of mammography results in an improvement in survival. The poor results of the National Breast Screening Study likely are due to the unbalanced allocation of women with advanced cancers to the screened group, the poor quality of the mammography in the trial, and an insufficient sample size.

Adult↗
PubMed1993

Mammography.

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Adult↗
PubMed1993

Breast imaging and breast cancer prevention.

Earlier detection of breast cancer through periodic screening is the only currently available intervention likely to reduce breast cancer-related mortality in the near term; prevention would be preferable. The alteration of proliferative changes and the assessment of intermediate endpoints may establish some interventions as more likely than others to interrupt the progression to lethal cancer. However, since not all breast cancers are fatal, the endpoint that will ultimately be accepted as proof of prevention success will be a reduction in breast cancer mortality. Methods of detection and monitoring must be carefully tailored so that the influences of the detection techniques do not alter the prevention results.

Breast Neoplasms↗
PubMed1993

Echo-planar chemical shift imaging of silicone gel prostheses.

We have developed an echo-planar (EP) proton chemical shift imaging (CSI) MR technique that allow us to discriminate the polydimethylsiloxane (PDMS, silicone) proton MR signal from that of the fat and water protons found in tissues, in order to map the distribution of PDMA in humans who have silicone gel prostheses. Silicone gel-filled prosthetic implants induce histologic changes in the surrounding tissue which are attributed to the leakage of free PDMS from the prosthesis. The T2 relaxation measurements of three silicone gels show that there are two components in them, each with a different degree of molecular mobility. The presence of free silicone is confirmed by chloroform extraction, which removed 14-28% of the material. This free polymer present in the gel can pass through the intact or ruptured membrane of the implant into the surrounding tissue. Our preliminary imaging results indicate that EP-CSI MR might be useful as a diagnostic technique for implant malfunction.

Breast↗
PubMed1993

Mammographically detected breast cancer: location in women under 50 years old.

The mammograms of 86 women under the age of 50 years with mammographically detected cancers were reviewed. Sixty-three of these cancers (73%) were found at the periphery of the breast as defined by a zone 1 cm wide beneath the subcutaneous fat or anterior to the retromammary fat. This finding is likely due to the geometric configuration of the breast. If the breast is hemispheric, then more than 50% of the volume of breast tissue lies within this zone in a large percentage of women. Furthermore, the contrasting adjacent fat likely improves the ability to perceive an abnormality. Interaction of the terminal ducts with chemicals contained within or produced by the fat is a much less likely reason for the high percentage of cancers in this zone. Radiologists should be aware of this phenomenon and pay particular attention to this zone.

Adipose Tissue↗
PubMed1993

Imaging of the radiographically dense breast.

Despite recent improvements in mammography equipment and technique, the radiographically dense breast remains difficult to image. The problems in imaging the dense breast account for a large percentage of the cases of mammographically "missed" carcinomas. Other imaging modalities--such as ultrasonography, transillumination, thermography, computed tomography, magnetic resonance imaging, and radionuclide imaging--have been investigated for use in breast cancer detection. This overview discusses the current problems associated with imaging of the radiographically dense breast and suggests some avenues for investigation to develop solutions to these problems.

Breast↗