Ultrasound (US) diagnosis of nonpalpable breast cancer

The Japan Society of Ultrasonics in Medicine guidelines on non-mass abnormalities of the breast

It is possible to appropriately diagnose non-mass abnormalities by elucidating ultrasound non-mass abnormality findings and sharing the concept. If non-mass abnormalities can be diagnosed early, the number of curable cases could increase, leading to fewer breast cancer deaths. The Japan Society of Ultrasonics in Medicine (JSUM) Terminology/Diagnostic Criteria Committee has classified non-mass abnormalities into five subtypes: hypoechoic area in the mammary gland, abnormalities of the ducts, architectural distortion, multiple small cysts, and echogenic foci without a hypoechoic area. We herein define the findings for each of these subtypes and present a summary of the JSUM guidelines on non-mass abnormalities of the breast generated based on those findings.

Application and Analysis of Biomedical Imaging Technology in Early Diagnosis of Breast Cancer

Breast cancer is the primary malignant tumor that endangers women's health. The incidence of breast cancer is increasing rapidly in recent years. Accurate disease evaluation before treatment is the key to the selection of treatment options. Biomedical imaging technology plays an irreplaceable role in the diagnosis and staging of tumors. Various imaging methods can provide excellent temporal and spatial resolution from multiple levels and perspectives and have become one of the most commonly used means of breast cancer early detection. With the development of radiomics, it has been found that early imaging diagnosis of breast cancer plays an important guiding role in clinical decision-making. The purpose of this study is to explore the characteristics of various breast cancer imaging technologies, promote the development of individualized accurate diagnosis and treatment of imaging, and improve the clinical application value of radiomics in the early diagnosis of breast cancer.

Non-mass-like lesions on breast ultrasound: classification and correlation with histology

PURPOSE

Owing to advances in ultrasound (US) technology, optimal US techniques with a high-frequency transducer can identify more and more breast lesions. However, some lesions show up as non-mass-like lesions, which are difficult to be correctly identified and often result in missed diagnosis and misdiagnosis. The purpose of the present study was to develop a classification of the US features of non-mass-like breast lesions correlated with pathology, so as to improve the diagnostic accuracy of US in non-mass-like breast lesions.

MATERIALS AND METHODS

A total of 854 breast lesions in 836 consecutive women scheduled for US-guided core-needle biopsy or US-guided vacuum-assisted biopsy between May 2008 and October 2011 were initially included in this study. Finally, 80 breast lesions in 78 women were classified as non-mass-like lesion and included in this study. The US features of the 80 non-mass-like breast lesions were classified and their correlation with pathology was analysed.

RESULTS

Of the 80 non-mass-like breast lesions, 43 cases (53.8 %) were malignant and 37 cases (46.2 %) were benign. Fifty-two cases (73.7 %) appeared as a hypoechoic area, 22 cases (21.1 %) appeared as a hypoechoic area with sporadic or clustered microcalcification, four cases appeared as architectural distortion, and two cases appeared as solid echogenicity within a duct. The diagnostic accuracy, sensitivity, specificity, positive predictive value and negative predictive value of US for non-mass-like breast lesions were 71.25, 95.35, 43.24, 66.13 and 88.89 %, respectively. The finding of a hypoechoic area with microcalcification showed a statistically significant association with malignant lesions and its positive predictive value for carcinoma was 78.26 %.

CONCLUSION

Non-mass-like breast lesions usually appeared as a hypoechoic area or a hypoechoic area with microcalcification. The finding of a hypoechoic area with microcalcification had a close correlation with malignant lesions. US had a high sensitivity but a low specificity in the diagnosis of non-mass-like breast lesions and a definitive diagnosis requires a US-guided biopsy.

Non-mass-like breast lesions at ultrasonography: feature analysis and BI-RADS assessment

OBJECTIVE

To analyze the features of non-mass-like (NML) breast lesions on ultrasound (US) and determine their corresponding malignancy rate and to stratify these lesion patterns according to US BI-RADS categories.

MATERIALS AND METHODS

One hundred sixty-four consecutive lesions were retrospectively classified into four types according to the US features, the corresponding positive predictive values (PPVs) were obtained. Clinical, imaging, and histopathological findings were reviewed.

RESULTS

Among the 164 lesions, 39 (24%) were classified as type Ia, 14 (8%) as type Ib, 39 (24%) as type IIa, 19 (12%) as type IIb, 19 (12%) as type III, and 34 (21%) as type IV. The PPVs for malignancy were 21% for type Ia, 79% for type Ib, 10% for type IIa, 58% for type IIb, 16% for type III, and 21% for type IV. All NML lesions were classified as BI-RADS category 4a (type IIa), 4b (type Ia, III and IV) and 4c (type Ib and IIb) according to their PPVs. There was a significantly higher frequency of malignancy among lesions of type Ib and type IIb compared with the other types (P<0.01 for each). Lesions with associated calcifications, presence of abnormal axillary nodes, or a mammographic finding of suspected malignancy had a higher probability of malignancy (P<0.05 for each).

CONCLUSION

US is useful in clarifying the indication for biopsy of NML lesions. The types of US classifications used in our study establish reliable references for the NML patterns when stratified according to the BI-RADS categories.

Nonmasslike lesions on breast sonography: comparison between benign and malignant lesions

OBJECTIVES

To compare the imaging and clinical features of benign and malignant nonmasslike lesions in the breast.

METHODS

During a 2-year period at a single institution, 186 nonmasslike lesions in 158 women were pathologically confirmed through surgery or sonographically guided biopsy. The sonographic patterns (mottled, geographic, and indistinct) and distributions (focal and regional) were compared between benign and malignant lesions. The presence of sonographically visible calcifications, amount of color Doppler signals, presence of positive findings on mammography, and presence of symptoms were also compared between the two groups.

RESULTS

A total of 156 lesions (84%) were confirmed as benign and 30 (16%) as malignant. On sonography, malignant nonmasslike lesions more frequently had mottled and geographic patterns and regional distribution than benign lesions (P < .0001). Malignant lesions also more frequently had sonographically visible calcifications (40% versus 0%; P < 0.0001) and a greater amount of color Doppler signals than benign lesions (P < .0001). On mammography, malignant lesions more frequently had densities and calcifications than benign lesions (30.4% versus 7.1%; P = 0.0052; 73.9% versus 6.1%; P < .0001, respectively). Clinically, malignant lesions were more frequently palpable and accompanied by localized pain than benign lesions (50% versus 2.6%; P< .0001; 13.3% versus 0.6%; P = .0025).

CONCLUSIONS

The imaging and clinical features of malignant nonmasslike lesions differed significantly from those of benign nonmasslike lesions.

Non-mass-like lesions on breast ultrasonography: a systematic review

This article reviews various non-mass-like ultrasonography (US) findings of the breast and the sonographic-pathologic correlation with Doppler techniques, elastography, and MRI. High-resolution US allows for identification of small, clinically occult non-mass-like US findings. Ductal carcinoma in situ and invasive lobular carcinoma usually manifest as a non-mass-like lesion on US. It is useful to classify non-mass-like lesions on US in a similar manner to the classification of non-mass-like enhancement on MRI.

Imaging studies for the early detection of breast cancer

INTRODUCTION

The effectiveness of mammographic screening has been proven at evidence level 1A. Mammography offers the best ratio of benefits to side effects of any screening method tested to date. In this literature review, we ask whether early detection might be improved still further by combining mammography with other imaging modalities.

METHODS

The authors performed a selective literature search for combined key words in the Medline and Cochrane Library databases from 1/2000 to 11/2007, screened all titles, and evaluated the full text of all original articles. We selected articles for further analysis according to systematic criteria (minimum numbers, avoidance of overlap) and also considered published guidelines.

RESULTS

No screening studies of comparable size to those for mammography are available for ultrasound or MRI. Smaller studies have indicated that the use of these two modalities might lead to the detection of additional cancers in selected subgroups. For mass screening an increase in the detection rate of 10% to 15% might become possible. This increase would probably be associated with a tripling of the breast biopsy rate, compared to mammography alone. The number of indeterminate cases in which short-term follow-up (i.e., at 6 months) would be recommended would increase roughly tenfold with MRI, and to an unknown extent with ultrasound. The related quality-assurance issues remain to be addressed.

DISCUSSION

Randomized controlled studies are needed for a realistic assessment of the achievable benefits and unavoidable side effects of combined screening. For women whose risk of breast cancer is not elevated, mammography remains the standard screening method.

Computed tomography for imaging the breast

Despite the success of screening mammography contributing to the reduction of cancer mortality, a number of other imaging techniques are being studied for breast cancer screening. In our laboratory, a dedicated breast computed tomography (CT) system has been developed and is currently undergoing patient testing. The breast CT system is capable of scanning the breast with the woman lying prone on a tabletop, with the breast in the pendant position. A 360 degrees scan currently requires 16.6 s, and a second scanner with a 9-second scan time is nearly operational. Extensive effort was placed on computing the radiation dose to the breast under CT geometry, and the scan parameters are selected to utilize the same radiation dose levels as two-view mammography. A total of 55 women have been scanned, ten healthy volunteers in a Phase I trial, and 45 women with a high likelihood of having breast cancer in a Phase II trial. The breast CT process leads to the production of approximately three hundred 512 x 512 images for each breast. Subjective evaluation of the breast CT images reveals excellent anatomical detail, good depiction of microcalcifications, and exquisite visualization of the soft tissue components of the tumor when contrasted against adipose tissues. The use of iodine contrast injection dramatically enhances the visualization of tumors. While a thorough scientific investigation based upon observer performance studies is in progress, initial breast CT images do appear promising and it is likely that breast CT will play some role in breast cancer imaging.