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Breast microcalcifications are small crystals of calcium phosphates which are important diagnostic indicators under mammography. Despite continuing advances in the resolution and sensitivity of modern scanners, the role of ultrasound in the breast clinic is limited by the inability of current ultrasound practice to visualize microcalcifications reliably. While mammography is currently the gold standard for their detection, approximately 70% of breast biopsies prompted by the presentation of microcalcifications result in negative biopsy. The improved visualization of microcalcifications under ultrasound could provide additional diagnostic information in these cases, potentially reducing the number of negative biopsies. A review is presented of the theoretical and empirical results to date of this group’s studies of the acoustic properties of microcalcifications as characterized through the application of classical theoretical models, including the Faran model, and through clinical studies of suspected in vivo microcalcifications and breast tissue backscatter. The similarities found between theoretical and clinical results strongly suggest that microcalcifications have elastic scattering properties. The findings are presented in an analysis of the relative impact of phase aberration, spatial resolution, and tissue backscatter on the visualization of microcalcifications with ultrasound. [Work supported by NIH Grant No. RO1‐CA43334.]

The sonographic appearances of ten breast carcinomas associated with microcalcifications were reviewed. None of the clusters of microcalcifications were visualized sonographically. All of the tumors were seen on sonomammography as either solid mass lesions or areas of acoustical shadowing.

Summary A hundred cases of fibroadenomas and 300 cases of benign breast diseases were studied without previous roentgenographic examination of the specimens. Microcalcifications were found in 19% of the fibroadenomas, in 26% of the cases of “fibrous disease” and in 57% of the cases of fibrocystic disease. Benign microcalcifications were not found in normal mammary tissue. They were steadily associated with metaplastic epithelial cells and with their abnormal secretions. Two basic types of microcalcifications were encountered: The granular microcalcifications with a predominately intracellular location and the homogeneous (with or without concentric rings) mainly associated with secreted materials. Microcalcifications were associated with metaplastic epithelial cells of the small eosinophilic variety and with their secretions, with the foam cells and with materials secreted by the apocrine cells. A common histochemical feature in cells or matrixes containing microcalcifications was the presence of compound lipids. The possible relationship of benign breast microcalcifications to the calcifications of other tissues, in connection with their association with lipids is discussed.

Objective To assess the diagnostic value of high-frequency (MicroPure) ultrasound in evaluating suspicious microcalcifications and to determine its capability in biopsy guidance. Subjects and methods Sixty-two cases with suspicious microcalcifications detected on mammographic examination had been re-evaluated by MicroPure US. The studied cases underwent true cut tissue/surgical excision biopsy. Histopathology revealed 25 benign and 37 malignant lesions and was considered the gold standard of reference. Results Malignant microcalcifications were easier to be visible at MicroPure US, as they were detected in 86.5% ( n = 32/39) compared to only 68% ( n = 17/25) of the benign lesions. US depicted more breast masses associated with malignant microcalcifications in 78% ( n = 29/37) than those associated with benign ones seen in 36% ( n = 9/25). Visibility of suspicious microcalcifications at US was aided by preliminary mammogram. Given known mammography location of these microcalcifications had made their visualization accessible by MicroPure US in 79% ( n = 49) of the cases. Conclusion MicroPure ultrasound cannot discriminate benign from malignant breast microcalcifications. MicroPure can be useful in detecting clustered microcalcifications that are not accessible by B-mode ultrasound; provided knowledge of their mammographic location and thus can provide better guidance for pre-surgical wire localization and ultrasound-guided biopsies.

Microcalcifications are actually indirect signs of pathological processes, and only a few of these processes may be correctly correlated to the morphologic pattern of calcifications. This is true of the microcalcifications typically classified as benign by the 4th edition of the BI-RADS Atlas, except for round and punctuate microcalcifications. This is also the case of polymorphous fine and linear fine microcalcifications most often, but not exclusively, associated with DCIS with necrosis. For other types of microcalcifications, other parameters are analyzed in a more global approach: the associated clinical or mammographical signs; the context, especially genetic; the spatial distribution; the number; the evolution over time. The radiologist should compare the images with the anatomy of the terminal ductal-lobular unit, from where most cancers arise, and estimates the risk by taking into account the clinical context and the antecedents.

This prospective study evaluates the ability of a single microfocal spot magnification (1.5X) mammogram to aid in the diagnosis of isolated clustered breast microcalcifications. Of the 429 patients studied, there were 117 pathologically proved cases for which concurrent convential contact (1X) mammography resulted in an equivocal interpretation. The superior image quality of the additional magnification mammogram resulted in an equivocal interpretation. The superior image quality of the additional magnification mammogram resulted in improved visualization of microcalcifications in every instance, permitting a definitive and correct radiographic interpretation (benign or malignant) in over 70% of the cases. Microfocal spot magnification mammography as an adjunct to the conventional mammography examination can greatly improve diagnostic accuracy in the evaluation of isolated clustered microcalcifications, and should permit a substantial reduction in the number of biopsies for benign breast lesions.

A commercial mammography image-enhancement system manufactured by Damon Corporation (Needham, MA) is evaluated. Using a dedicated computer, the system implements a real-time video local adaptive image processing algorithm based on the Wallis equation. Radiographs of a mammographic QA phantom (Nuclear Associates Model 76-001-4) containing five groups of simulated breast microcalcifications ranging in diameter from 0.12 to 0.35 mm were viewed by four investigators under three viewing conditions: on a light box with the unaided eye, on the image enhancer in magnified “bypass” (unenhanced) mode, and on the enhancer using all features for optimum enhancement. A mammogram was then overlaid on the radiographs, and the composite images were viewed under the same three conditions. Using the enhancer, as compared to using a light box alone, average increases of 1.4 and 1.1 microcalcifications per radiograph were observed for the phantom and phantom-with-mammogram radiographs, respectively. High-contrast resolution and spatial distortion were also measured.

Small amounts of milk of calcium settling to the bottom of multiple tiny benign breast cysts produce the mammographic picture of clustered linear and curvilinear calcifications when imaged in lateral projection with a horizontal x-ray beam. These calcifications, although benign, may be confused with the microcalcifications of carcinoma. Milk of calcium is found much more frequently in small breast cysts than anywhere else in the body. It is not at all uncommon, occurring in more than 4% of women undergoing diagnostic mammography. Fortunately, the overall mammographic appearance of milk of calcium cysts is quite characteristic, permitting them to be a differentiated from malignant breast microcalcifications with a high level of confidence.

Controlled in vitro studies of breast microcalcification detectability were done comparing a wide variety of standard and state-of-the-art mammography techniques (conventional and microfocal spot x-ray tubes, screen-film and xeroradiographic recording systems, contact and magnification techniques). Results confirmed previous observations that geometric unsharpness is the limiting factor in microcalcification detectability for most conventional mammography systems. Results also indicated superior microcalcification detection for: xeroradiographic over screen-film recording systems, positive-mode over negative-mode xeroradiography, microfocal spot contact over conventional contact techniques, and microfocal spot magnification over all contact techniques. No differences were found between a standard screen-film technique and a screen-film technique requiring about one-half the radiation exposure. On the other hand, although there was no differences between standard xeroradiography and a modest-added-filtration (reduced-dose) xeroradiographic technique, standard xeroradiography demonstrated superior microcalcification detection over a reduced-dose technique that used large amounts of added beam filtration. The clinical applicability of these findings is discussed.

Although the presence of microcalcifications in a breast cancer mass seen on mammography was first reported by Salomon (1913), Leborgne (1949) was the first to recognize that microcalcifications can represent the only mammographie manifestation of carcinoma. Since then, it has become apparent that 29%–48% of nonpalpable carcinomas are visible on the basis of microcalcifications alone (Table 1).

The early diagnosis of breast cancer is based upon the radiographic visualization of microstructures on the mammogram. Extremely small fibrotic structures and microcalcifications are each of fundamental importance in this process. Almost half (43%-49%) of clinically occult breast carcinomas are detected from the presence of microcalcifications, 21% of which are less than 0.25 mm in size; many are no larger than 0.1 mm (FRIEDRICH 1983; FRISCHBIER and LOHBECK 1977; LANYI 1977b). But accurate diagnosis hinges not just on the perception of these fine calcium particles, but also on their correct interpretation. Only by a meticulous analysis of the shapes of individual calcifications and their clusters is it possible to differentiate definitely benign clusters from those that are definitely malignant or suspicious. Thus, optimum image quality is a critical factor in both the diagnosis and differential diagnosis of breast microcalcifications.

Background: Detection of microcalcifications on mammograms indicates the presence of breast lesion, and the shapes of the microcalcifications as seen by conventional mammography correlates with the probability of malignancy. This preliminary study evaluated the 3D shape of breast microcalcifications using micro-computed tomography (micro-CT) and compared the findings with those obtained using anatomopathological analysis. Methods: The study analyzed breast biopsy samples from 11 women with findings of suspicious microcalcifications on routine mammograms. The samples were imaged using a micro-CT (SkyScan 1076) at a resolution of 35 mu m. Images were reconstructed using filtered back-projection and analyzed in 3D using surface rendering. The samples were subsequently analyzed by the pathology service. Reconstructed 3D images were compared with the corresponding histological slices. Results: Anatomopathological analysis showed that 5 of 11 patients had ductal breast carcinoma in situ. One patient was diagnosed with invasive ductal carcinoma. Individual object analysis was performed on 597 microcalcifications. Malignant microcalcifications tended to be thinner and to have a smaller volume and surface area, while their surface area-to-volume ratio was greater than that of benign microcalcifications. The structure model index values were the same for malignant and benign microcalcifications. Conclusions: This is the first study to use micro-CT for quantitative 3D analysis of microcalcifications. This high-resolution imaging technique will be valuable for gaining a greater understanding of the morphologic characteristics of malignant and benign microcalcifications. The presence of many small microcalcifications can be an indication of malignancy. For the larger microcalcifications, 3D parameters confirmed the more irregular shape of malignant microcalcifications.

Our goal was to evaluate dynamic contrast-enhanced subtraction MRI in the diagnosis of isolated clustered calcifications of the breast. One hundred seventy-two patients underwent surgical biopsy for isolated clustered breast calcifications. Their mammograms showed round (n = 88) or linear/irregular (n = 84) microcalcifications. All patients had a preoperative Gd-DOTA-enhanced subtraction dynamic study. Any early contrast enhancement in the breast parenchyma concomitant with early enhancement of normal vessels was considered positive. Fifty-eight in situ carcinomas, 22 invasive carcinomas, and 92 benign lesions were found at histological analysis. Dynamic MR sequences showed early contrast enhancement in 76 of 80 malignant lesions (sensitivity 95%) and in 45 of 92 benign lesions (specificity 51%). Two invasive and two intraductal carcinomas did not show early contrast enhancement. Three independent observers agreed in rating early contrast enhancement in 143 of 172 lesions. Poor specificity limits the diagnostic accuracy of dynamic contrast-enhanced subtraction MRI in distinguishing benign from malignant microcalcifications on mammography. 8 refs., 2 figs., 2 tabs.

Aims To evaluate the reliability of magnetic resonance imaging (MRI) performed with three-dimensional (3D) sequences in mammographically detected breast microcalcifications. Methods During an 8-month period, a group of 28 patients with mammographically detected microcalcifications suspicious for malignancy underwent MRI. Their ages ranged from 33 to 65 years. Examinations were performed with a 1.5 Tesla MR unit and a 3D T1 weighted sequence. Images were interpreted on the basis of morphologic parameters and dynamic behavior in the uptake of contrast medium (Gd-DTPA). Histologic findings were considered as the gold reference. Results Histologic analysis revealed invasive carcinoma in 7 patients, 3 of which were associated with foci of lobular carcinoma in situ. Intraductal carcinoma was diagnosed in 8 patients, 1 of which was associated with a tubular carcinoma. Benign lesions accounted for 13 patients. All the neoplastic conditions showed enhancement on MR images (sensitivity, 100%), whereas early and intense enhancement was noted in 5 of 13 benign lesions (specificity, 61%). The positive predictive value was 75% and negative predictive value, 100%. Conclusions Although an overlap in the enhancement behavior of malignant and some benign lesions is clearly evident, a careful interpretation of MR images is helpful in detecting and mainly ruling out breast cancer combined with mammographically suspicious microcalcifications.