Takako Morita

Development of a fully automatic scheme for detection of masses in whole breast ultrasound images.

Ultrasonography has been used for breast cancer screening in Japan. Screening using a conventional hand-held probe is operator dependent and thus it is possible that some areas of the breast may not be scanned. To overcome such problems, a mechanical whole breast ultrasound (US) scanner has been proposed and developed for screening purposes. However, another issue is that radiologists might tire while interpreting all images in a large-volume screening; this increases the likelihood that masses may remain undetected. Therefore, the aim of this study is to develop a fully automatic scheme for the detection of masses in whole breast US images in order to assist the interpretations of radiologists and potentially improve the screening accuracy. The authors database comprised 109 whole breast US imagoes, which include 36 masses (16 malignant masses, 5 fibroadenomas, and 15 cysts). A whole breast US image with 84 slice images (interval between two slice images: 2 mm) was obtained by the ASU-1004 US scanner (ALOKA Co., Ltd., Japan). The feature based on the edge directions in each slice and a method for subtracting between the slice images were used for the detection of masses in the authors proposed scheme. The Canny edge detector was applied to detect edges in US images; these edges were classified as near-vertical edges or near-horizontal edges using a morphological method. The positions of mass candidates were located using the near-vertical edges as a cue. Then, the located positions were segmented by the watershed algorithm and mass candidate regions were detected using the segmented regions and the low-density regions extracted by the slice subtraction method. For the removal of false positives (FPs), rule-based schemes and a quadratic discriminant analysis were applied for the distribution between masses and FPs. As a result, the sensitivity of the authors scheme for the detection of masses was 80.6% (29/36) with 3.8 FPs per whole breast image. The authors scheme for a computer-aided detection may be useful in improving the screening performance and efficiency.

Suppressive effect of iodine on DMBA-induced breast tumor growth in the rat

Concerning the suppressive effect of inorganic iodine on the growth of 7,12‐dimethyl‐benz(a)anthracene (DMBA)‐induced breast tumor in female Sprague‐Dawley (SD) rats, we previously reported that although iodine itself had a suppressive effect on the tumor growth, its effect was not as strong as that of MPA (medroxy‐progesterone acetate). However, the combined medication of iodine at a low concentration + MPA showed a stronger effect than MPA alone. The purpose of the present study is to elucidate this mechanism of action by determining the uptake of the administered iodine into breast tumor tissue. Breast tumors were induced with DMBA in female SD rats, and these animals were treated with MPA + inorganic iodine at various concentrations for 4 weeks to determine tumor growth and tumor iodine content. In the comparison of tissue iodine content in growth‐suppressive tumors with that in nonsuppressive tumors, the former showed a much higher iodine content. This suggests that direct uptake of inorganic iodine by breast tumors led to the suppression of tumor growth.

Intracytoplasmic lipid accumulation in apocrine carcinoma of the breast evaluated with adipophilin immunoreactivity: a possible link between apocrine carcinoma and lipid-rich carcinoma.

Although apocrine carcinoma is a distinct histologic entity, there is no immunohistochemical marker to confirm apocrine differentiation with high sensitivity and specificity, and its differential cytologic characteristics are still not fully clarified. Despite the foamy cytoplasm of some apocrine carcinomas and the existence of lipid in the normal apocrine gland, intracytoplasmic lipid in apocrine carcinomas has not been fully explored. By using immunohistochemistry for adipophilin, which is a specific marker of lipid accumulation that can be applied to paraffin sections, we examined intracytoplasmic lipid in apocrine carcinomas. Twenty-four of 26 (92%) apocrine carcinomas and 38 of 116 (33%) nonapocrine carcinomas contained intracytoplasmic lipid. The frequency of adipophilin-positive cases was significantly higher in apocrine carcinomas compared with nonapocrine carcinomas (P<0.01). The positive cell rate per tumor ranged from 10% to 70% (mean, 29%) for apocrine carcinomas. The staining density was heterogeneous from cell to cell. There was no difference in the staining pattern of adipophilin between apocrine ductal carcinoma in situ and invasive apocrine carcinoma or between eosinophilic cells and foamy cells. Sporadic or mosaic distribution of adipophilin-positive cells throughout the tumor and microvesicular or fine granular cytoplasmic staining with heterogeneous density were characteristic features of apocrine carcinoma. Although intracytoplasmic lipid was identified in most apocrine carcinomas, none of the apocrine carcinomas contained prominent intracytoplasmic lipid in >90% of the tumor cells; thus, the criteria for lipid-rich carcinoma was not fulfilled. However, the immunohistochemical study suggests that lipid-rich carcinomas are closely related to apocrine carcinomas.

A Comparison between Film-Screen Mammography and Full-Field Digital Mammography Utilizing Phase Contrast Technology in Breast Cancer Screening Programs

A digital phase contrast mammography (PCM) system was introduced into a hospitals screening programs with the expectation of improved clinical image quality. A total of 3835 examinations with the PCM system and 4338 examinations with a film-screen (FS) system were performed. The screening performance measures of the two systems were compared. Both in recall rates and in cancer detection rates, the performances of PCM and FS exhibited no statistically significant difference. For microcalcifications and masses, recall rates were lower with PCM than with FS despite the fact that more findings were reported with PCM. It would appear that PCMs superior depiction of abnormalities helped radiologists improve the accuracy of categorization. PCM is considered a beneficial imaging modality in breast cancer screening programs.

Computerized mass detection in whole breast ultrasound images: Reduction of false positives using bilateral subtraction technique

The comparison of left and right mammograms is a common technique used by radiologists for the detection and diagnosis of masses. In mammography, computer-aided detection (CAD) schemes using bilateral subtraction technique have been reported. However, in breast ultrasonography, there are no reports on CAD schemes using comparison of left and right breasts. In this study, we propose a scheme of false positive reduction based on bilateral subtraction technique in whole breast ultrasound images. Mass candidate regions are detected by using the information of edge directions. Bilateral breast images are registered with reference to the nipple positions and skin lines. A false positive region is detected based on a comparison of the average gray values of a mass candidate region and a region with the same position and same size as the candidate region in the contralateral breast. In evaluating the effectiveness of the false positive reduction method, three normal and three abnormal bilateral pairs of whole breast images were employed. These abnormal breasts included six masses larger than 5 mm in diameter. The sensitivity was 83% (5/6) with 13.8 (165/12) false positives per breast before applying the proposed reduction method. By applying the method, false positives were reduced to 4.5 (54/12) per breast without removing a true positive region. This preliminary study indicates that the bilateral subtraction technique is effective for improving the performance of a CAD scheme in whole breast ultrasound images.

Topographical, morphological and immunohistochemical characteristics of carcinoma in situ of the breast involving sclerosing adenosis. Two distinct topographical patterns and histological types of carcinoma in situ.

Moritani S, Ichihara S, Hasegawa M, Endo T, Oiwa M, Shiraiwa M, Nishida C, Morita T, Sato Y, Hayashi T, Kato A, Aoyama H & Yoshikawa K
(2011) Histopathology 58, 835–846
Topographical, morphological and immunohistochemical characteristics of carcinoma in situ of the breast involving sclerosing adenosis. Two distinct topographical patterns and histological types of carcinoma in situ

Automated analysis of breast parenchymal patterns in whole breast ultrasound images: preliminary experience

PurposeA computerized classification scheme to recognize breast parenchymal patterns in whole breast ultrasound (US) images was developed. A preliminary evaluation of the system performance was performed.MethodsBreast parenchymal patterns were classified into three categories: mottled pattern (MP), intermediate pattern (IP), and atrophic pattern (AP). Each classification was defined as proposed by an experienced physician. A total of 281 image features were extracted from a volume of interest which was automatically segmented. Canonical discriminant analysis with stepwise feature selection was employed for the classification of the parenchymal patterns.ResultsThe classification scheme accuracy was computed to be 83.3% (10/12 cases) in MP cases, 91.7% (22/24 cases) in IP cases, 92.9% (13/14 cases) in AP cases, and 90.0% (45/50 cases) in all the cases.ConclusionsThe feasibility of an automated ultrasonography classifier for parenchymal patterns was demonstrated with promising results in whole breast US images.

Uniqueness of ductal carcinoma in situ of the breast concurrent with papilloma: implications from a detailed topographical and histopathological study of 50 cases treated by mastectomy and wide local excision

To clarify the diagnostic clues of ductal carcinomas in situ (DCIS) associated with papilloma and optimal clinical management of papilloma diagnosed on core needle biopsy (CNB).

Classification of Benign and Malignant Masses in Ultrasound Breast Image Based on Geometric and Echo Features

The aim of this paper is to study the use of geometric and echo features in classifying masses in ultrasound images as benign or malignant. While mammography is very effective in detecting masses and other lesions, breast ultrasound is a valuable adjunct in distinguishing solid and fluid-filled masses where the former is mostly malignant and the latter benign. Six features including two geometric features and four echo features derived from the segmented mass and its neighboring regions are employed in this study. They are the compactness and orientation of the mass, two intensity ratios of the mass and its neighboring regions, homogeneity, and depth-to-width ratio of the mass. Linear discriminant analysis and receiver operating characteristic (ROC) analysis are employed for classification and performance evaluation. The area under the ROC curve (AUC) has a value of 0.940 using all breast masses for training and testing and 0.923 using the leave-one-mass-out cross-validation method. Clinically significance of the results will be evaluated using a larger dataset.

Genetic regulation of slowly progressing mild muscle atrophy in fast-twitch muscles of BUF/Mna rats

BUF/Mna strain rats spontaneously develop slowly progressing mild‐moderate muscle atrophy of extensor digitorum longus, tibialis, and extraocular muscles, which consist mainly of fast‐twitch type fibers, at nearly 100% incidence. They have lighter extensor digitorum longus muscles than soleus muscles, when alive for more than 6 weeks. Genetic segregation of the development of the muscle atrophy was studied by crossing the BUF/Mna strain with three other strains, ACI/NMs, WKY/NCrj, and BDIX, which were free of muscle atrophy. Two autosomal dominant susceptible genes, Mas‐1 and Mas‐2, determine the development of the muscle atrophy in these combinations of crosses.