Mammographic determination of breast volume: comparing different methods.

OBJECTIVE: The purpose of this study was to compare the accuracy and reproducibility of different methods for calculating breast volume when using measurements made on mammograms. MATERIALS AND METHODS: The volumes of 32 breasts were determined by pathologic evaluation of mastectomy specimens. Two radiologists independently measured breast height and width on the preoperative craniocaudal mammograms and measured height, width, and width at half-height on mediolateral oblique mammograms. Compression thicknesses used on the craniocaudal and mediolateral oblique projections were recorded. Volume was then calculated using six different formulas. The accuracy of each method was determined and compared using bivariate and univariate linear regression analyses. Interobserver variability in measurement was also assessed. RESULTS: The most accurate method for calculating breast volume was the one that assumed a half-elliptic cylinder shape for the compressed breast in the craniocaudal projection. Measurements made on the craniocaudal view were more reproducible than those made on the mediolateral oblique view. CONCLUSION: Breast volume can be accurately and reproducibly determined on mammograms by making two measurements on the craniocaudal view and knowing the compression thickness. This information may be useful to plastic surgeons, investigators who study parenchymal patterns, and physicians who examine cancer patients being considered for breast conservation surgery.

X-ray imaging with amorphous selenium: optimal spectra for digital mammography.

The optimum x-ray spectra for acquisition of digital mammographic images using an amorphous selenium (a-Se) photoconductor are investigated. The recorded images consist of latent charge distributions on the surface of an a-Se plate, which are then read out using two methods, laser discharge, or flat panel recharge. The investigation is based on a model of the breast previously developed for a phosphor-based digital readout system, and has been extended to include the effects specific to the use of photoconductors. The effects of plate thickness, x-ray scatter, readout noise, dose, and the kind of breast tissue on the nature of the optimum spectrum are explored for the two readout methods. The results indicate that use of a kilovoltage setting in the current mammographic range, and a molybdenum target spectrum is appropriate for digital readout of a-Se detectors. This conclusion contrasts with the appreciably higher kilovoltages traditionally used with the xerographic (toner) readout of latent charge images on a-Se.

Parenchymal patterns of the breast defined by real time ultrasound.

The association of mammographic parenchymal patterns of the breast with breast cancer risk has been studied extensively but there is little information about the distribution of different patterns in populations at different risks for breast cancer. Such information could be obtained if a risk-free method of breast examination were available that could be applied to the general population. We have evaluated real time ultrasound for this application by comparing the parenchymal pattern as assessed by mammography with the extent of echogenicity in the breast on ultrasound examination in 102 subjects. Subjects were examined by both methods, the mammographic and ultrasound images independently classified, and the proportion of the breast occupied by radiological density or ductal prominence compared with the extent of echogenic areas on ultrasound. These two methods of classifying mammographic parenchymal patterns were found to be strongly correlated. Real time ultrasound may therefore be useful in the epidemiological study of mammographic pattern and breast cancer risk.

[ROC analysis of image quality in digital luminescence radiography in comparison with current film-screen systems in mammography]. / ROC-Analyse zur Bildqualität der digitalen Lumineszenzradiographie im Vergleich zu herkömmlichen Film-Folien-Systemen auf dem Gebiet der Mammographie.

AIM: To compare in mammography the image quality of digital luminescence radiography (DLR) to that of usual film screen mammography and xeromammography. MATERIALS AND METHODS: Three single emulsion film-screen combinations, one double coated high resolution film and xeroradiography, were tested for this purpose. In our phantom study the detectability of microcalcifications, fibrils and low contrast details were first of all studied separately. Image processing techniques were, for example, contrast variation by grey scale level windowing, "unsharp mask" filtering and regulatable edge enhancement. Phantom images were made and then the image quality was evaluated by observer performance study using a receiver operating characteristic (ROC analysis). RESULTS: Best results in respect of detection of microcalcifications and fibrils were found in xeroradiography, luminescent image plate and double-coated film-screen combination. These systems showed more favourable ROC curves than the single emulsion film-screen combinations. CONCLUSIONS: Our results indicate that image quality of digital images in the field of image processing is equal to that of conventional mammographic techniques and partially superior to detection of low contrast details.