Characterization of solid breast masses: use of the sonographic breast imaging reporting and data system lexicon

Polyvinyl chloride plastisol breast phantoms for ultrasound imaging

Ultrasonic phantoms are objects that mimic some features of biological tissues, allowing the study of their interactions with ultrasound (US). In the diagnostic-imaging field, breast phantoms are an important tool for testing performance and optimizing US systems, as well as for training medical professionals. This paper describes the design and manufacture of breast lesions by using polyvinyl chloride plastisol (PVCP) as the base material. Among the materials available for this study, PVCP was shown to be stable, durable, and easy to handle. Furthermore, it is a nontoxic, nonpolluting, and low-cost material. The breast's glandular tissue (image background) was simulated by adding graphite powder with a concentration of 1% to the base material. Mixing PVCP and graphite powder in differing concentrations allows one to simulate lesions with different echogenicity patterns (anechoic, hypoechoic, and hyperechoic). From this mixture, phantom materials were obtained with speed of sound varying from 1379.3 to 1397.9ms(-1) and an attenuation coefficient having values between 0.29 and 0.94dBcm(-1) for a frequency of 1MHz at 24°C. A single layer of carnauba wax was added to the lesion surface in order to evaluate its applicability for imaging. The images of the phantoms were acquired using commercial ultrasound equipment; a specialist rated the images, elaborating diagnoses representative of both benign and malignant lesions. The results indicated that it was possible to easily create a phantom by using low-cost materials, readily available in the market and stable at room temperature, as the basis of ultrasonic phantoms that reproduce the image characteristics of fatty breast tissue and typical lesions of the breast.

Clinical Data as an Adjunct to Ultrasound Reduces the False-Negative Malignancy Rate in BI-RADS 3 Breast Lesions

PURPOSE

Ultrasound (US) is a well-established diagnostic procedure for breast examination. We investigated the malignancy rate in solid breast lesions according to their BI-RADS classification with a particular focus on false-negative BI-RADS 3 lesions. We examined whether patient history and clinical findings could provide additional information that would help determine further diagnostic steps in breast lesions.

MATERIALS AND METHODS

We conducted a retrospective study by exploring US BI-RADS in 1469 breast lesions of 1201 patients who underwent minimally invasive breast biopsy (MIBB) from January 2002 to December 2011.

RESULTS

The overall sensitivity and specificity of BI-RADS classification was 97.4% and 66.4%, respectively, with a positive (PPV) and negative predictive value (NPV) of 65% and 98%, respectively. In 506 BI-RADS 3 lesions, histology revealed 15 malignancies (2.4% malignancy rate), which corresponds to a false-negative rate (FNR) of 2.6%. Clinical evaluation and patient requests critically influenced the further diagnostic procedure, thereby prevailing over the recommendation given by the BI-RADS 3 classification.

CONCLUSION

Clinical criteria including age, family and personal history, clinical examination, mammography and patient choice ensure adequate diagnostic procedures such as short-term follow-up or MIBB in patients with lesions classified as US-BI-RADS 3.

Validation of the fifth edition BI-RADS ultrasound lexicon with comparison of fourth and fifth edition diagnostic performance using video clips

Purpose

The aim of this study was to evaluate the positive predictive value (PPV) and the diagnostic performance of the ultrasonographic descriptors in the fifth edition of BI-RADS, comparing with the fourth edition using video clips.

Methods

From September 2013 to July 2014, 80 breast masses in 74 women (mean age, 47.5±10.7 years) from five institutions of the Korean Society of Breast Imaging were included. Two radiologists individually reviewed the static and video images and analyzed the images according to the fourth and fifth edition of BI-RADS. The PPV of each descriptor was calculated and diagnostic performances between the fourth and fifth editions were compared.

Results

Of the 80 breast masses, 51 (63.8%) were benign and 29 (36.2%) were malignant. Suspicious ultrasonographic features such as irregular shape, non-parallel orientation, angular or spiculated margins, and combined posterior features showed higher PPV in both editions (all P<0.05). No significant differences were found in the diagnostic performances between the two editions (all P>0.05). The area under the receiver operating characteristics curve was higher in the fourth edition (0.708 to 0.690), without significance (P=0.416).

Conclusion

The fifth edition of the BI-RADS ultrasound lexicon showed comparable performance to the fourth edition and can be useful in the differential diagnosis of breast masses using ultrasonography.

Evaluation of Malignancy Grade of Breast Cancer Using Perflubutane-Enhanced Ultrasonography

Whether the contrast effects of perflubutane on contrast-enhanced ultrasonography can predict the malignancy grade of breast cancer is unknown. We analyzed associations between perfusion parameters created from time-intensity curves based on enhancement intensity and temporal changes in contrast-enhanced ultrasonography and clinicopathologic factors in 100 consecutive patients with invasive breast cancer. Values of perfusion parameters were significantly greater in estrogen receptor-negative than -positive tumors (peak intensity, p = 0.0002; ascending slope, p = 0.006; area under the curve, p = 0.0006). Variations in the peak intensity of Ki-67 were significantly correlated in all tumors (r = 0.54, p < 0.0001) and in luminal (r = 0.43, p = 0.0002), human epidermal growth factor receptor type 2-positive (r = 0.47, p = 0.047) and triple-negative (r = 0.55, p = 0.043) tumors. Perfusion parameters on contrast-enhanced ultrasonography can provide excellent predictive value for high-grade malignancy and might help to determine appropriate therapeutic strategies.

Computer-Aided Diagnosis for Breast Ultrasound Using Computerized BI-RADS Features and Machine Learning Methods

This work identifies effective computable features from the Breast Imaging Reporting and Data System (BI-RADS), to develop a computer-aided diagnosis (CAD) system for breast ultrasound. Computerized features corresponding to ultrasound BI-RADs categories were designed and tested using a database of 283 pathology-proven benign and malignant lesions. Features were selected based on classification performance using a "bottom-up" approach for different machine learning methods, including decision tree, artificial neural network, random forest and support vector machine. Using 10-fold cross-validation on the database of 283 cases, the highest area under the receiver operating characteristic (ROC) curve (AUC) was 0.84 from a support vector machine with 77.7% overall accuracy; the highest overall accuracy, 78.5%, was from a random forest with the AUC 0.83. Lesion margin and orientation were optimum features common to all of the different machine learning methods. These features can be used in CAD systems to help distinguish benign from worrisome lesions.

Nonpalpable BI-RADS 4 breast lesions: sonographic findings and pathology correlation

PURPOSE

We aimed to evaluate ultrasonography (US) findings for Breast Imaging Reporting and Data System (BI-RADS) category 4 lesions using BI-RADS US lexicon and determine the positive and negative predictive values (PPV and NPV) of US with respect to biopsy results.

METHODS

Sonograms of 186 BI-RADS 4 nonpalpable breast lesions with a known diagnosis were reviewed retrospectively. The morphologic features of all lesions were described using BI-RADS lexicon and the lesions were subcategorized into 4A, 4B, and 4C on the basis of the physician's level of suspicion. Lesion descriptors and biopsy results were correlated. Pathologic results were compared with US features. PPVs of BI-RADS subcategories 4A, 4B, and 4C were calculated.

RESULTS

Of 186 lesions, 38.7% were malignant and 61.2% were benign. PPVs according to subcategories 4A, 4B, and 4C were 19.5%, 41.5%, and 74.3%, respectively. Microlobulated, indistinct, and angular margins, posterior acoustic features, and echo pattern were nonspecific signs for nonpalpable BI-RADS 4 lesions. Typical signs of malignancy were irregular shape (PPV, 66%), spiculated margin (PPV, 80%) and nonparallel orientation (PPV, 58.9%). Typical signs of benign lesions were oval shape (NPV, 77.1%), circumscribed margin (NPV, 67.5%), parallel orientation (NPV, 70%), and abrupt interface (NPV, 67.6%).

CONCLUSION

BI-RADS criteria are not sufficient for discriminating between malignant and benign lesions, and biopsy is required. Subcategories 4A, 4B, and 4C are useful in predicting the likelihood of malignancy. However, objective and clear subclassification rules are needed.

Variability in Observer Performance Between Faculty Members and Residents Using Breast Imaging Reporting and Data System (BI-RADS)-Ultrasound, Fifth Edition (2013)

Background

Ultrasonography (US) is a useful tool for breast imaging, yet is highly operator-dependent.

Objectives

We evaluated inter-observer variability and performance discrepancies between faculty members and radiology residents when describing breast lesions, by the fifth edition of breast imaging reporting and data system (BI-RADS)-US lexicon, and then attempted to identify whether inter-observer variability could be improved after one education session.

Patients and Methods

In total, 50 malignant lesions and 70 benign lesions were considered in our retrospective study. Two faculty members, two senior residents, and two junior residents separately assessed the US images. After the first assessment, the readers received one education session, and then reassessed the images in a random order. Inter-observer variability was measured using the kappa coefficient (κ). Performance discrepancy was evaluated by receiver operating characteristic (ROC) curves.

Results

For the faculty members, fair-to-good agreement was obtained in all descriptors and final assessment, while for residents, poor-to-moderate agreement was obtained. The areas under the ROC curves were 0.78 for the faculty members, 0.59 for the senior residents, and 0.52 for the junior residents, respectively. Diagnostic performance was significantly higher in the faculty members than the senior and junior residents (P = 0.0001 and < 0.0001, respectively). After one education session, the agreement in the final assessment was one level higher in the faculty members and senior residents, yet in the senior residents, the degree of agreement was still only fair. Moreover, in the junior residents, there was no improvement.

Conclusion

Investigative assessment of breast US by residents is inadvisable. We recommend continued professional resident training to improve the degree of agreement and performance.

Application of wavelet techniques for cancer diagnosis using ultrasound images: A Review

Ultrasound is an important and low cost imaging modality used to study the internal organs of human body and blood flow through blood vessels. It uses high frequency sound waves to acquire images of internal organs. It is used to screen normal, benign and malignant tissues of various organs. Healthy and malignant tissues generate different echoes for ultrasound. Hence, it provides useful information about the potential tumor tissues that can be analyzed for diagnostic purposes before therapeutic procedures. Ultrasound images are affected with speckle noise due to an air gap between the transducer probe and the body. The challenge is to design and develop robust image preprocessing, segmentation and feature extraction algorithms to locate the tumor region and to extract subtle information from isolated tumor region for diagnosis. This information can be revealed using a scale space technique such as the Discrete Wavelet Transform (DWT). It decomposes an image into images at different scales using low pass and high pass filters. These filters help to identify the detail or sudden changes in intensity in the image. These changes are reflected in the wavelet coefficients. Various texture, statistical and image based features can be extracted from these coefficients. The extracted features are subjected to statistical analysis to identify the significant features to discriminate normal and malignant ultrasound images using supervised classifiers. This paper presents a review of wavelet techniques used for preprocessing, segmentation and feature extraction of breast, thyroid, ovarian and prostate cancer using ultrasound images.

Combined Use of Ultrasound Elastography and B-Mode Sonography for Differentiation of Benign and Malignant Circumscribed Breast Masses

OBJECTIVES

To evaluate the diagnostic performance of combined B-mode sonography and ultrasound elastography for differentiation between benign and malignant breast masses with circumscribed margins.

METHODS

We analyzed 109 pathologically proven circumscribed breast masses. Two radiologists retrospectively reviewed B-mode sonograms and elastograms in consensus. Based on the American College of Radiology Breast Imaging Reporting and Data System, we determined categories of the masses on B-mode sonography. Elastographic scores were assessed by a 3-point scale (negative, 0; equivocal, 1; and positive, 2). When the elastographic score for a lesion was 0 or 2, we downgraded or upgraded the B-mode category, respectively; thus, the reclassified Breast Imaging Reporting and Data System category was defined as the "reclassification category." Mean category values for benign and malignant lesions were compared by a Student t test. The diagnostic performance of B-mode, elastographic, and reclassification assessments was compared by receiver operating characteristic curve analysis.

RESULTS

The mean B-mode category (2.5 versus 1.7), elastographic score (1.7 versus 0.8), and reclassification category (3.2 versus 1.6) were significantly higher in malignant than benign lesions (P < .001). The area under the curve for reclassification assessment was significantly higher than that for B-mode sonography (0.916 versus 0.795; P < .05). With a cutoff value between 1 and 2, the specificity was increased from 26.5% to 42.9% after reclassification.

CONCLUSIONS

For differentiation between benign and malignant circumscribed breast masses, combined use of B-mode sonography and elastography could provide a better diagnostic performance than B-mode sonography alone.

Undiagnosed Breast Cancer: Features at Supplemental Screening US

PURPOSE

To retrospectively investigate the reasons for and features of undiagnosed cancers at previous supplemental screening ultrasonography (US) in women who subsequently received a diagnosis of breast cancer.

MATERIALS AND METHODS

The institutional review board approved this retrospective study and waived the requirement to obtain informed patient consent. The study consisted of 230 women (median age, 49 years; age range, 29-81 years) with 230 pairs of US examinations (prior and subsequent examinations) performed between December 2003 and August 2013 who were found to have cancer (median interval, 12 months; range, 2-24 months). The authors compared the clinical-pathologic features of patients with negative findings on prior images with those of patients with visible findings on prior images. Findings visible at prior US were classified as actionable or underthreshold by means of a blinded review by five radiologists. Lesions classified as Breast Imaging Reporting and Data System category 4 or 5 by fewer than three readers were determined to be underthreshold. Reasons for undiagnosed cancers and their imaging features were analyzed.

RESULTS

Among the 230 prior US examinations, 72 (31.3%) showed visible findings and 158 (68.7%) showed negative findings. High-nuclear-grade cancers and triple-negative cancers were more common in patients with negative findings than in those with visible findings (P = .023 and P = .006, respectively). Blinded review revealed that 57 of the 72 visible findings (79%) were actionable. Misinterpretation (39% [28 of 72 lesions]) and multiple distracting lesions (17% [12 of 72 lesions]) were the two most common reasons for missing these actionable findings, which showed more noncircumscribed margins than did underthreshold findings (P = .028).

CONCLUSION

At supplemental screening breast US, close attention should be paid to the presence of a margin that is not circumscribed, and multiple lesions should be separately assessed to reduce the number of missed breast cancers.

A multi-centre randomised trial comparing ultrasound vs mammography for screening breast cancer in high-risk Chinese women

Background:

Chinese women tend to have small and dense breasts and ultrasound is a common method for breast cancer screening in China. However, its efficacy and cost comparing with mammography has not been evaluated in randomised trials.

Methods:

At 14 breast centres across China during 2008–2010, 13 339 high-risk women aged 30–65 years were randomised to be screened by mammography alone, ultrasound alone, or by both methods at enrolment and 1-year follow-up.

Results:

A total of 12 519 and 8692 women underwent the initial and second screenings, respectively. Among the 30 cancers (of which 15 were stage 0/I) detected, 5 (0.72/1000) were in the mammography group, 11 (1.51/1000) in the ultrasound group, and 14 (2.02/1000) in the combined group (P=0.12). In the combined group, ultrasound detected all the 14 cancers, whereas mammography detected 8, making ultrasound more sensitive (100 vs 57.1%, P=0.04) with a better diagnostic accuracy (0.999 vs 0.766, P=0.01). There was no difference between mammography and ultrasound in specificity (100 vs 99.9%, P=0.51) and positive predictive value (72.7 vs 70.0% P=0.87). To detect one cancer, the costs of ultrasound, mammography, and combined modality were $7876, $45 253, and $21 599, respectively.

Conclusions:

Ultrasound is superior to mammography for breast cancer screening in high-risk Chinese women.

Elastography ultrasound for breast lesions: fat-to-lesion strain ratio vs gland-to-lesion strain ratio

OBJECTIVE

To compare the diagnostic performance of the fat-to-lesion strain ratio (FLR) and gland-to-lesion strain ratio (GLR) in the diagnosis of breast lesions.

METHODS

This was an institutional ethics committee approved prospective study. One hundred and ninety-three breast lesions in 193 women (mean age, 46.03 ± 13.60 years, range 18-82 years) were examined with conventional and elastographic US. Both the FLR and GLR of the lesions were calculated. The elasticity scores of the lesions were also evaluated using the five-point elasticity scoring system. For diagnostic performance, the sensitivity, specificity and receiver operating characteristic (ROC) analysis were obtained.

RESULTS

Seventy lesions were malignant and 123 were benign. Both the FLR and GLR of the lesions were significantly higher in malignant cases than in benign ones (P < 0.001 for both). The Az values for the FLR (0.847) and the elasticity score (0.829) were significantly higher than that for the GLR (0.752) (P = 0.009, P = 0.029, respectively). However, there was no significant difference in the Az value between the FLR and the elasticity score (P = 0.443).

CONCLUSION

The FLR yielded better diagnostic performance than GLR in breast lesions; the fatty tissue was better than glandular tissue as the reference normal tissue for calculating strain ratio in breast elastography.

KEY POINTS

FLR was higher than GLR in both malignant and benign breast lesions. Both FLR and GLR were higher in malignant than in benign breast lesions. FLR yielded better diagnostic performance than GLR in breast lesions.

Sonographic Confirmation of Bilateral Invasive Ductal Carcinoma Undetected on Mammogram

Invasive ductal carcinoma of the breast is cancer that originates in the ducts and subsequently invades the fatty tissue of the breast outside the duct. It is the most common form of breast cancer, representing 80% of all breast cancers. Invasive ductal carcinoma has the potential to metastasize via the bloodstream and lymph nodes, making early diagnosis critical. In the case presented, a rare instance of bilateral primary invasive ductal carcinoma is discussed: It was identified by magnetic resonance imaging, and it was visualized, confirmed, and located by sonography; yet, it was undetected by mammography.

Breast carcinomas: variations in sonoelastographic appearance

Background

This study assessed factors influencing the sonoelastographic presentation of breast carcinoma.

Methods

A prospective collaborative study was conducted by the Santa Casa de São Paulo and CTC-Center, on 540 breast lesions in women referred for percutaneous breast biopsy. Eighty-four carcinomas showing lesions on ultrasonography were included. These lesions were classified into four sonoelastographic scores, where scores of 1, 2, and 3 were considered false-negative, and a score of 4 was considered true-positive. Scores were compared against histopathologic results, which were divided into two groups, ie, soft lesions (group 1) and hard lesions (group 2). False-negative and true-positive results were also assessed for variation according to patient age and mean lesion diameter.

Results

Of the 84 lesions studied, nine yielded false-negative results on sonoelastography and 75 yielded true-positive results. In terms of histopathologic classification, eight were assigned to group 1 and 76 to group 2. The chi-squared test showed a correlation between sonoelastographic scores and histopathologic lesion type. No statistically significant differences were observed according to patient age or largest lesion diameter.

Conclusion

Our results revealed an association between sonoelastographic presentation of breast lesions and histology. False-negative results on sonoelastography were influenced by histologic type of lesion and not by lesion size or patient age.

Elastic free energy drives the shape of prevascular solid tumors

It is well established that the mechanical environment influences cell functions in health and disease. Here, we address how the mechanical environment influences tumor growth, in particular, the shape of solid tumors. In an in vitro tumor model, which isolates mechanical interactions between cancer tumor cells and a hydrogel, we find that tumors grow as ellipsoids, resembling the same, oft-reported observation of in vivo tumors. Specifically, an oblate ellipsoidal tumor shape robustly occurs when the tumors grow in hydrogels that are stiffer than the tumors, but when they grow in more compliant hydrogels they remain closer to spherical in shape. Using large scale, nonlinear elasticity computations we show that the oblate ellipsoidal shape minimizes the elastic free energy of the tumor-hydrogel system. Having eliminated a number of other candidate explanations, we hypothesize that minimization of the elastic free energy is the reason for predominance of the experimentally observed ellipsoidal shape. This result may hold significance for explaining the shape progression of early solid tumors in vivo and is an important step in understanding the processes underlying solid tumor growth.

Benign core biopsy of probably benign breast lesions 2 cm or larger: correlation with excisional biopsy and long-term follow-up

Purpose:

To evaluate the accuracy of benign core biopsy of probably benign breast lesions (category 3) 2 cm or larger on the basis of excisional biopsy and long-term follow-up.

Methods:

We retrospectively reviewed 146 category 3 lesions in 146 patients 2 cm or larger which were diagnosed as benign by ultrasound (US)-guided core biopsy. Patients were initially diagnosed as benign at core needle biopsy and then followed up with excisional biopsy (surgical excision, n=91; US-guided vacuum assisted excision, n=35) or breast ultrasonography (n=20).

Results:

Of the 126 patients who underwent surgical excision or US-guided vacuum-assisted excision, 114 patients were diagnosed with benign lesions, 10 patients with borderline lesions (benign phyllodes tumor), and two patients with malignant phyllodes tumors. The probabilities of lesions being benign, borderline and malignant were 91.8% (134/146), 6.8% (10/146), and 1.4% (2/146), respectively. Of 13 patients who had growing masses on follow-up ultrasonography, three (23.1%) were non-benign (two benign phyllodes tumors and one malignant phyllodes tumor).

Conclusion:

US-guided core needle biopsy of probably benign breast mass 2 cm or larger was accurate (98.6%) enough to rule out malignancy. But, it was difficult to rule out borderline lesions even when they were diagnosed as benign.

Probably benign lesions at screening breast US in a population with elevated risk: prevalence and rate of malignancy in the ACRIN 6666 trial

PURPOSE

To prospectively validate predefined breast ultrasonographic (US) Breast Imaging Reporting and Data System (BI-RADS) category 3 criteria in a multicenter setting in an elevated-risk population.

MATERIALS AND METHODS

The American College of Radiology Imaging Network 6666 database was reviewed for prospectively defined BI-RADS category 3 lesions. Patient characteristics, lesion US features at initial detection, and work-up recommendations were analyzed with descriptive statistics. Exact 95% confidence intervals (CIs) were given, where appropriate. Lesion reference standard was biopsy or a minimum of 1-year follow-up. In addition, malignancy rate for lesions that had at least 2 years of follow-up data or that had biopsy data was calculated.

RESULTS

Of 2662 participants, 519 (19.5%) had 745 BI-RADS category 3 lesions (25.5% of 2916 US lesions other than simple cysts), with a median size of 7 mm (range, 2-135 mm). The number of new BI-RADS category 3 lesions decreased with year 2-3 screening, but the percentage of new BI-RADS category 3 lesions was stable at 26.4% (506 of 1920 lesions), 23.6% (142 of 601 lesions), and 24.6% (97 of 395 lesions), respectively. Of 745 BI-RADS category 3 lesions, 124 (16.6%) were ultimately sampled for biopsy. Six malignancies (0.8% of BI-RADS category 3 lesions; 95% confidence interval [CI]: 0.3%, 1.7%) occurred in five (1.0%) of 519 participants: Five malignancies were invasive (median size, 10 mm; size range, 2-18 mm), and one was node positive. When the analysis is limited to lesions with at least 2-year follow-up or biopsy, the malignancy rate among BI-RADS category 3 lesions is 0.9% (95% CI: 0.3%, 2.0%). Three malignant BI-RADS category 3 lesions were sampled for biopsy because of a suspicious change at follow-up (two N0 lesions, one each at 6- and 12-month follow-up; one N1 lesion at 24-month follow-up), one was sampled for biopsy because of an upgrade after additional mammography (NX), one was found at mastectomy for another cancer (N0), and one was found at prophylactic contralateral mastectomy in the same patient (NX).

CONCLUSION

As BI-RADS category 3 lesions have a low malignancy rate (0.8%; 95% CI: 0.3%, 1.7%) and only 0.1% of the cancers had suspicious changes at 6-month follow-up and only one (17%; 95% CI: 0.4%, 64%) of six malignancies were node positive at detection (24-month follow-up), a recommendation of 1-year diagnostic follow-up may be appropriate for BI-RADS category 3 lesions detected at screening US. Online supplemental material is available for this article.

Anthropomorphic ultrasound elastography phantoms - characterization of silicone materials to build breast elastography phantoms

In this paper a mechanical characterization of low cost and simply available materials to build efficient anthropomorphic ultrasound elastography phantoms is described. The class of silicone materials was selected because of their deformability, durability and the possibility of reproducing specific tissue properties and shapes. Innovative formulations of silicone mixtures with echogenic and/or softening additives were tested. The proposed models have good acoustic properties and tactile feedback; moreover they are durable and do not require special storage since they do not dehydrate or decompose over time.

Interobserver and Intraobserver Agreement of Sonographic BIRADS Lexicon in the Assessment of Breast Masses

BACKGROUND

BI-RADS was first developed in 1993 for mammography and in 2003 it was redesigned for ultrasonography (US). If the observer agreement is high, the method used in the classification of lesion would be reproducible.

OBJECTIVES

The aim of this study is to evaluate the inter- and intraobserver agreement of sonographic BI-RADS lexicon in the categorization and feature characterization of nonpalpable breast lesions.

PATIENTS AND METHODS

We included 223 patients with 245 nonpalpable breast lesions who underwent ultrasound-guided wire needle localization. Two radiologists retrospectively described each lesion using sonographic BI-RADS descriptors and final assessment. The observers were blinded to mammographic images, medical history and pathologic results. Inter- and intraobserver agreement was assessed using Kappa (κ) agreement coefficient.

RESULTS

The interobserver agreement for sonographic descriptors changed between fair and substantial. The highest agreement was detected for mass orientation (κ=0.66). The lowest agreement was found in the margin (κ=0.33). The interobserver agreement for BI-RADS final category was found as fair (κ=0.35). The intraobserver agreement for sonographic descriptors changed between substantial and almost perfect. The intraobserver agreement of BI-RADS result category was found as substantial for observer 1 (κ=0.64) and excellent for observer 2 (κ=0.83).

CONCLUSION

Our results demonstrated that each observer was self-consistent in interpreting US BI-RADS classification, while interobserver agreement was relatively poor. Although it has been ten years since the description of sonographic BI-RADS lexicon, further training and periodic performance evaluations would probably help to achieve better agreement among radiologists.

Correlation of sonographic features of invasive ductal mammary carcinoma with age, tumor grade, and hormone-receptor status

PURPOSE

To determine whether presenting sonographic features of invasive ductal carcinomas (IDC) are associated with patient age, tumor histologic grade, and hormonal receptor status.

METHODS

Sonographic features of 101 consecutive cases of IDC seen at ultrasound were retrospectively assessed based on the BI-RADS criteria of posterior acoustic appearance, tumor margins, and echogenicity. Associations between sonographic features and tumor characteristics were statistically evaluated with attention to patient age.

RESULTS

IDC with shadowing compared with unchanged posterior acoustic appearance were significantly more likely to be of low histologic grade (Odds Ratio [OR] = 5.00; p < 0.05) and estrogen receptor (ER) -positive (OR = 10.00; p < 0.05). Conversely, posterior enhancement was associated with ER-negative status (OR = 4.45; p < 0.01), particularly among patients younger than 60 years of age (OR = 5.36, p < 0.05). Circumscribed tumors were more often high grade, particularly among older women (p < 0.01), and hormone receptor--negative regardless of age group. Among older women, tumors with mixed echogenicity tended to be high grade and progesterone receptor--negative (p values < 0.05). Noncircumscribed borders were observed for all tumors with posterior shadowing, and 97% of such tumors were also ER positive.

CONCLUSIONS

Sonographic features were significantly associated with tumor grade and hormone receptor status, with some differences based on patient age. Specifically, the presence of posterior shadowing was associated with lower histologic grade and ER-positive status, especially in older patients. In contrast, we found that posterior acoustic enhancement was more commonly associated with ER-negative status, especially in younger patients.

Cost minimization analysis of ultrasound-guided diagnostic evaluation of probably benign breast lesions

The objective of this study was to compare direct health care costs for two competing diagnostic strategies for probably benign breast lesions detected by ultrasound in young women. We developed a decision analytic model and performed a cost minimization analysis comparing ultrasound-guided vacuum-assisted core biopsy and conservative short-term diagnostic ultrasound follow-up. Relative probabilities for diagnostic outcomes were derived from pooled analysis of the medical literature. Direct health care costs were estimated using United States national average figures from calendar year 2010. Deterministic sensitivity analyses were conducted, as well as a first-order Monte Carlo simulation to confirm cost differences between the two strategies. The conservative short-term imaging follow-up strategy ($639.55 average cost per patient) was the most economical strategy compared to immediate vacuum-assisted core biopsy ($879.55 average cost per patient). Sensitivity analyses demonstrated that the preferred strategy is most dependent on the probabilities of detecting change in appearance on follow-up ultrasound, having a benign finding on immediate core biopsy, and finding cancer on a biopsy triggered by an interval change in ultrasound appearance. The model was also sensitive to the costs of vacuum-assisted core biopsy and diagnostic ultrasound. Conservative imaging follow-up of BIRADS 3 breast masses by ultrasound is cost saving compared to immediate vacuum-assisted core biopsy, with a potential of saving more than one-third of overall costs associated with the diagnostic work-up of such lesions. Watchful waiting with short-term interval follow-up ultrasounds will spare women from unnecessary procedures and spare the United States health care system from unnecessary direct health care costs.

Combination of elastography and tissue quantification using the acoustic radiation force impulse (ARFI) technology for differential diagnosis of breast masses

PURPOSE

We evaluated the diagnostic performance of elastography and tissue quantification using acoustic radiation force impulse (ARFI) technology for differential diagnosis of breast masses.

MATERIALS AND METHODS

There were 161 mass lesions. First, lesion correspondence on ARFI elastographic images to those on the B-mode images was evaluated: no findings on ARFI images (pattern 1), lesions that were bright inside (pattern 2), lesions that were dark inside (pattern 4), lesions that contained both bright and dark areas (pattern 3). In addition, pattern 4 was subdivided into 4a (dark area same as B-mode lesion) and 4b (dark area larger than lesion). Next, shear wave velocity (SWV) was measured using virtual touch tissue quantification.

RESULTS

There were 13 pattern 1 lesions and five pattern 2 lesions; all of these lesions were benign, whereas all pattern 4b lesions (n = 43) were malignant. When the value of 3.59 m/s was chosen as the cutoff value, the combination of elastography and tissue quantification showed 91 % (83-91) sensitivity, 93 % (65-70) specificity, and 92 % (148-161) accuracy.

CONCLUSION

The combination of elastography and tissue quantification is thought to be a promising ultrasound technique for differential diagnosis of breast-mass lesions.

Complex breast masses: assessment of malignant potential based on cyst diameter

OBJECTIVES

The purpose of this study was to assess whether cyst diameter might contribute to the prediction of malignancy in complex breast masses.

METHODS

In this cross-sectional study, we identified 48 breast masses that had sonographic features suggestive of benign breast lesions (oval shape, circumscribed margins, parallel axis, and abrupt limits). However, these masses were classified as Breast Imaging Reporting and Data System (BI-RADS) category 4 because of the presence of at least 1 cyst (complex echogenicity). All breast masses were biopsied (25 core needle and 23 core needle and excision). Subsequent histologic analysis was performed, and 12 malignancies (25%) were identified. Mammographic features were reviewed. Different sonographic measurements (largest diameters of the mass and cyst and vascular pattern) were assessed for the detection of malignancy.

RESULTS

Among the sonographic features, the vascular pattern, ie, the detection of blood flow (present in the lesion [P >.99] or present immediately adjacent to the lesion [P = .46]), was not associated with malignancy, whereas the largest mass and cyst dimensions had significantly positive correlations (P = .02; P < .001, respectively) with tumor malignancy. In receiver operating characteristic curve analysis, the point with the highest sum of sensitivity and specificity corresponded to a maximum cyst diameter of 8 mm (sensitivity, 67%; specificity, 86%). The positive and negative predictive values at that cutoff point were 61% and 86%, respectively. The area under the curve was 0.772. In this study, all masses with cysts smaller than 3 mm in diameter (7 cases) were benign, and all masses with cysts larger than 13 mm in diameter (4 cases) were malignant.

CONCLUSIONS

Cyst diameter is a good predictor of malignancy in complex breast masses, which, except for the presence of internal cysts, would be otherwise classified as BI-RADS category 3.

Virtual touch tissue quantification using acoustic radiation force impulse technology: initial clinical experience with solid breast masses

OBJECTIVES

The purpose of this study was to investigate the clinical usage of Virtual Touch tissue quantification (VTQ; Siemens Medical Solutions, Mountain View, CA) implementing sonographic acoustic radiation force impulse technology for differentiation between benign and malignant solid breast masses.

METHODS

A total of 143 solid breast masses were examined with VTQ, and their shear wave velocities (SWVs) were measured. From all of the masses, 30 were examined by two independent operators to evaluate the reproducibility of the results of VTQ measurement. All masses were later surgically resected, and the histologic results were correlated with the SWV results. A receiver operating characteristic curve was calculated to assess the diagnostic performance of VTQ.

RESULTS

A total of 102 benign lesions and 41 carcinomas were diagnosed on the basis of histologic examination. The VTQ measurements performed by the two independent operators yielded a correlation coefficient of 0.885. Applying a cutoff point of 3.065 m/s, a significant difference (P < .001) was found between the SWVs of the benign (mean ± SD, 2.25 ± 0.59 m/s) and malignant (5.96 ± 2.96 m/s) masses. The sensitivity, specificity, and area under the receiver operating characteristic curve for the differentiation were 75.6%, 95.1%, and 85.6%, respectively. When the repeated non-numeric result X.XX of the SWV measurements was designated as an indicator of malignancy, the sensitivity, specificity, and accuracy were 63.4%, 100%, and 89.5%.

CONCLUSIONS

Virtual Touch tissue quantification can yield reproducible and quantitative diagnostic information on solid breast masses and serve as an effective diagnostic tool for differentiation between benign and malignant solid masses.

Category assessment based on 3D volume data acquired by automated breast ultrasonography

PURPOSE

To assess the validity of categorization of ultrasonographic findings using automated breast ultrasonography (US).

MATERIALS AND METHODS

Bilateral whole-breast US was performed using an automated breast volume scanner (ABVS) in 400 women. The 3D data were evaluated using the ABVS workstation, and final assessment categories were recorded based on the following criteria. Irregular-shaped masses with a spiculated margin or echogenic halo were defined as category 5. Solid masses with one of the three suspicious findings (no circumscribed margin, no parallel orientation, and microcalcifications) were defined as category 4a, and masses with two or more suspicious findings were defined as category 4b. For non-mass lesions, localized hypoechoic areas with one of the three suspicious findings (segmental distribution, ductal change, and microcalcifications) were defined as category 4a. Localized hypoechoic areas with two or three suspicious findings were defined as category 4b or 5, respectively.

RESULTS

Malignancy was confirmed histologically in 57 women (invasive, n = 38; in situ, n = 19). The rate of malignant findings was 0.6% (1/168) in category 3, 12% (15/129) in category 4a, 53% (31/59) in category 4b and 100% (10/10) in category 5.

CONCLUSION

Categorization of ultrasonographic findings using automated breast US are useful for predicting the likelihood of malignancy.

Pattern classification of ShearWave™ Elastography images for differential diagnosis between benign and malignant solid breast masses

BACKGROUND

ShearWave™ Elastography (SWE) provides a quantitative measurement of tissue stiffness and may improve characterization of breast masses. However, the significance of Young's modulus measurements and appropriate SWE evaluation criteria has not been established yet.

PURPOSE

To assess the usefulness of the pattern classification and Young's modulus measurements in the differential diagnosis between benign and malignant solid breast masses.

MATERIAL AND METHODS

Ninety-six patients (age range 18-84 years, mean 54 years) with 100 solid breast masses who underwent tissue sampling after a US examination were analyzed. We tried to create a visual pattern classification based on the SWE images. After classifying the visual patterns, the Young's modulus of the lesions was measured in every case.

RESULTS

It was possible to classify the images into four patterns by the visual evaluation: no findings (coded blue homogeneously; Pattern 1), vertical stripe pattern artifacts (Pattern 2), a localized colored area at the margin of the lesion (Pattern 3), and heterogeneously colored areas in the interior of the lesion (Pattern 4). There were 17 Pattern 1 lesions, 14 Pattern 2 lesions, 20 Pattern 3 lesions, and 49 Pattern 4 lesions. When Patterns 1 and 2 were assumed to be benign, and Patterns 3 and 4 were assumed to be malignant, the sensitivity and specificity were 91.3% (63/69) and 80.6% (25/31), respectively. The mean Young's modulus measurements of the benign and the malignant lesions were 42 kPa and 146 kPa, respectively (P < 0.0001). No significant differences were found between benign and malignant lesions in Pattern 3. In Pattern 4, however, the Young's modulus of the benign lesions (50 kPa) was lower than the smallest Young's modulus of malignant lesions (61 kPa).

CONCLUSION

The visual pattern classification and adding Young's modulus measurements may improve characterization of solid breast masses.

Quantification of the UK 5-point breast imaging classification and mapping to BI-RADS to facilitate comparison with international literature

OBJECTIVE

The UK 5-point breast imaging scoring system, recently formalised by the Royal College of Radiologists Breast Group, does not specify the likelihood of malignancy in each category. The breast imaging and reporting data system (BI-RADS) is widely used throughout North America and much of Europe. The main purpose of this study is to quantify the cancer likelihood of each of the UK 5-point categories and map them to comparable BI-RADS categories to facilitate comparison with North American and European literature and publication of UK research abroad.

METHODS

During the 8 year study period, mammogram and ultrasound results were UK scored and the percentage of cancer outcomes within each group calculated. These were then compared with the percentage incidence of the BI-RADS categories.

RESULTS

Of 23 741 separate assessment episodes, 15 288 mammograms and 10 642 ultrasound examinations were evaluated. There was a direct correlation between UK scoring and BI-RADS for categories 1 and 5. UK Score 2 lipomas and simple cysts correlated with BI-RADS 2, with the remaining UK Score 2 lesions (mostly fibroadenomas) assigned to BI-RADS 3. BI-RADS 4 incorporates a wide range of cancer risk (2-95%) with subdivisions a, b and c indicating increasing, but unspecified, likelihood of malignancy. UK Score 3 correlated with BI-RADS 4 a/b and UK Score 4 corresponded with BI-RADS 4c.

CONCLUSION

This study quantifies the cancer likelihood of the UK scoring and maps them to parallel BI-RADS categories, with equivalent cancer risks. This facilitates the ability to share UK research data and clinical practice on an international scale.

Does power Doppler ultrasonography improve the BI-RADS category assessment and diagnostic accuracy of solid breast lesions?

BACKGROUND

Power Doppler ultrasonography (US) is used in addition to B-mode US as a tool for the differential diagnosis between benign and malignant lesions. However, there are few data showing how useful power Doppler US is for BI-RADS category assessment.

PURPOSE

To assess how much power Doppler US contributed to increasing the category diagnosis from Breast Imaging Reporting and Data System (ACR BI-RADS(®)-US) category 3 to category 4.

MATERIAL AND METHODS

A total of 2426 patients (age range 16-91 years, mean 52 years) who underwent B-mode and power Doppler breast US using a linear 10-MHz transducer were analyzed. We devised integrated US category classification (BI-RADS-Integral) based on BI-RADS descriptors and vascularity. Masses with a circumscribed margin, parallel orientation, and negative vascularity on power Doppler US were defined as category 3. Irregular-shaped masses with a spiculated margin or echogenic halo were defined as category 5. Masses with one of the four suspicious findings (no circumscribed margin, no parallel orientation, microcalcifications, and positive vascularity) were defined as category 4a, and masses with two or more suspicious findings were defined as category 4b.

RESULTS

There were 98 breast cancer cases, and the average sizes of invasive and non-invasive cancers were 15 mm and 18 mm, respectively. The frequency of breast cancer according to category was: 0.4% (3/714) of the category 3 cases, 2.7% (7/256) in category 4a, 64% (47/73) in category 4b, and 100% (41/41) in category 5. Among the cases with a category 4a mass lesion, there were 183 lesions whose category diagnosis had been raised from category 3 to category 4a based on the Doppler blood flow findings alone, and 3 (1.6%) of those lesions were breast cancer. All three of them were ductal carcinoma in situ (DCIS) cases. When the cut-off point was placed between category 3 and category 4, BI-RADS-Integral and BI-RADS-US without power Doppler had a sensitivity of 96.9% and 93.9%, respectively, specificity of 72.1% and 90.4%, respectively, and accuracy of 74.4% and 90.7%, respectively.

CONCLUSION

The presence of Doppler blood flow increases the malignancy pick-up rate, but at the expense of a significant decrease in specificity and diagnostic accuracy and an increase in biopsy rate.

Subcategorization of ultrasonographic BI-RADS category 4: positive predictive value and clinical factors affecting it

The objective of this study was to evaluate the positive predictive value (PPV) in ultrasonographically (US)-detected breast lesions of BI-RADS category 4a, 4b and 4c and to find how various clinical factors influenced the PPV of category 4. A total of 2142 women with 2430 breast lesions diagnosed on US as BI-RADS category 4 and underwent biopsy were included. Among them, 452 (18.6%) were pathologically confirmed as malignancy. PPV of each US BI-RADS subcategory was 7.6% (149/1963) for category 4a, 37.8% (68/180) for category 4b and 81.9% (235/287) for category 4c. Several clinical factors were more significantly seen in malignancy of category 4a and 4b, whereas none of the factors showed significance in category 4c. Subcategorization of category 4 is a feasible method in predicting malignancy in which patients' age, lack of multiplicity and symptoms affected the PPV of category 4 lesions.

Role of elastography in the assessment of breast lesions: preliminary results

OBJECTIVES

The purposes of this study were to evaluate the diagnostic utility of elastography in differentiating benign from malignant breast lesions and compare it with conventional sonography.

METHODS

A total of 124 breast lesions (59 malignant and 65 benign) were examined with B-mode sonography and subsequently with elastography. Conventional sonographic findings were classified according to the American College of Radiology Breast Imaging Reporting and Data System for sonography, and elastographic images were assigned an elasticity score of 1 to 5 (1-3, benign; 4 and 5, malignant) according to the Ueno classification. Cytologic diagnoses obtained from fine-needle aspiration and histopathologic results from a core-needle biopsy or surgical biopsy were used as reference standards. Statistical analysis included sensitivity, specificity, and positive and negative predictive values for both elastography and conventional sonography.

RESULTS

B-mode sonography had sensitivity of 96.6% (95% confidence interval, 93.3%-99.9%), specificity of 76.9% (69.2%-84.6%), a positive predictive value of 79.2% (72.1%-86.2%), and a negative predictive value of 96.2% (92.4%-99.9%), compared with sensitivity of 69.5% (60.5%-78.5%), specificity of 83.1% (76.3%-89.8%), a positive predictive value of 78.9% (70.6%-87.1%), and a negative predictive value of 75.0% (67.4%-82.6%) for elastography. Elastography showed less sensitivity but higher specificity than conventional sonography.

CONCLUSIONS

Our results show that elastography may be useful as a complementary technique in addition to conventional sonography in the characterization of breast lesions because it increases the diagnostic specificity, thus reducing the false-positive rate.

Breast ultrasonography in young Asian women: analyses of BI-RADS final assessment category according to symptoms

BACKGROUND

Breast ultrasound is the major imaging modality in young women because it incurs no radiation exposure and dense breast tissue, which is common in young women, yields a high rate of false-negative results on mammography.

PURPOSE

To investigate the cancer rates of the sonographic BI-RADS categorization and histopathologic results according to the presence of symptoms in young Asian women.

MATERIAL AND METHODS

We included 811 young women under 30 years of age who underwent a breast ultrasound during the study period. The mean age of all subjects was 24.5 years (range 11-29 years). Histopathologic results were compared with the results after application of the BI-RADS categorization.

RESULTS

Sonographic findings were classified as category 1 (n=192), category 2 (n=81), category 3 (n=399), category 4 (n=134), and category 5 (n=5). The cancer rates for category 1, 2, 3, 4, and 5 were 0, 0, 0.3, 6.3, and 100% in the symptomatic group, respectively. For the asymptomatic group, the cancer rates were 0, 0, 0, 8.7, and 100%, respectively. More cancers were found in high-risk women (22.2%, 4/18) than in non-high-risk women (1.4%, 11/793).

CONCLUSION

BI-RADS categorization was helpful for predicting the probability of malignancy in young Asian women.

Performance of hand-held whole-breast ultrasound based on BI-RADS in women with mammographically negative dense breast

OBJECTIVE

To assess the performance of breast ultrasound based on BI-RADS final assessment categories in women with mammographically negative dense breast.

METHODS

Of 3,820 cases with mammographically negative dense breast and subsequent hand-held bilateral whole-breast ultrasound, a total of 1,507 cases in 1,046 women who had biopsy or at least 2-year follow-up ultrasound constituted the basis of this retrospective study. Cancer rate of each sonographic BI-RADS category was determined and medical audit was performed separately in screening-general, screening-treated, and diagnostic group.

RESULTS

A total of 43 cases (2.9%) were confirmed as malignancy. Cancer rate among BI-RADS categories was significantly different (p < 0.0001). Among three groups, the cancer rate was significantly different (p < 0.0001) and the highest in diagnostic group (15.8%, 22 of 139). Abnormal interpretation rate, PPV of biopsy performed, cancer detection rate, and rate of early stage cancer, and the size of invasive cancer were significantly different among three groups and the highest in diagnostic group. Regarding cancer characteristics, the proportion of advanced cancer was the highest in diagnostic group.

CONCLUSION

Breast ultrasound based on BI-RADS as an adjunctive to negative mammography can be useful for predicting malignancy in women with dense breast.

Malignant lesions initially categorized as probably benign breast lesions: retrospective review of ultrasonographic, clinical and pathologic characteristics

The primary objective of this study was to review the ultrasonographic features of BI-RADS category 3 ("probably benign") lesions that eventually proved to be malignant. A second objective was to investigate their clinical and pathologic features according to their palpability and time of biopsy. Thirty-two (0.8%) of 4000 women with lesions that were initially classified as "probably benign" proved to be malignant and formed the study group. The most common reason for a false negative assessment on ultrasound was a failure to recognize suspicious margin characteristics (28 of 32 malignancies, 87.5%). Malignancy was more frequent in palpable (2.4%, 21 of 859) than nonpalpable lesions (0.4%, 11 of 3141, p < 0.001). There was no statistical difference in the mean age, mean size of lesions, or tumor stage between patients who underwent early biopsy (n = 19) or biopsy after 6 months (n = 13). Twenty-nine of the lesions (90.6%) were retrospectively recategorized as BI-RADS 4, which calls for early biopsy. BI-RADS 3 lesions require especially careful assessment.

Effect of clinical information on diagnostic performance in breast sonography

OBJECTIVE

The purpose of this study was to assess whether the clinical information (CI) of patients affects the degree of suspicion for malignancy by radiologists performing breast sonography.

METHODS

We included 150 breast lesions in 144 patients who underwent breast sonography and sonographically guided core needle biopsy. A pathologic diagnosis was available for all 150 breast lesions: 78 (52%) were malignant, and 72 (48%) were benign. Three radiologists retrospectively reviewed the sonograms of all lesions twice at 8-week intervals first without any CI for the patients (first review) and then with CI such as patient age, palpability, and personal history of risk factors for breast cancer (second review). The reviewers categorized the final assessment according to the American College of Radiology Breast Imaging Reporting and Data System. We compared diagnostic performance such as sensitivity and specificity and the degree of suspicion for malignancy between the image reviews with and without CI.

RESULTS

In the second review, sensitivity was improved in all 3 reviewers (94.0 to 99.2%; P < .05), and specificity was decreased (39.8 to 30.8%; P = .04). There was a significant increase of suspicion for malignancy with the patients' CI (P < .05).

CONCLUSIONS

Clinical information about a patient's breast cancer history and clinical presentation with a palpable mass can increase the suspicion for malignancy on sonography and the sensitivity of sonographic interpretation.

Acurácia dos achados ultrassonográficos do câncer de mama: correlação da classificação BI-RADS® e achados histológicos

OBJETIVO: O objetivo geral do estudo é avaliar a acurácia da ultrassonografia (BI-RADS) no diagnóstico do câncer de mama, e os objetivos específicos, descrever a frequência de apresentação dos diferentes achados ultrassonográficos e a avaliação da concordância entre observadores. MATERIAIS E MÉTODOS: Exames de 110 pacientes encaminhados para biópsia, com diagnóstico prévio de nódulos, foram reanalisados independentemente por dois médicos especialistas utilizando a nomenclatura do BI-RADS. Os achados histológicos foram utilizados como padrão-ouro. A acurácia dos achados foi determinada. As diferenças nos grupos de comparação foram analisadas com teste qui-quadrado para variáveis categóricas e a concordância entre os médicos foi calculada por meio da estatística kappa (κ). RESULTADOS: Cento e dez massas mamárias foram avaliadas pelo ultrassom, sendo que 76 (69%) foram benignas e 34 (30,9%), malignas. Foram observados, entre os radiologistas, sensibilidade variando entre 70,5% e 82,3%, valor preditivo negativo entre 81,1% e 87,5%, valor preditivo positivo entre 42,1% e 45,1%, especificidade entre 56,58% e 55,2% e acurácia entre 60,9% e 63,6%. Na avaliação entre observadores foi obtida concordância global considerada moderada (κ= 0,50). CONCLUSÃO: O BI-RADS 4ª edição é um acurado sistema para auxiliar os médicos na descrição das lesões mamárias e na tomada de condutas.

[Diagnostic accuracy and interobserver variability in the BI-RADS ultrasound system]

OBJECTIVES

To determine the predictive values and the interobserver variability of the descriptors and diagnostic categories of the BI-RADS- Ultrasound system and its usefulness for predicting malignancy in solid breast nodules.

MATERIAL AND METHODS

We evaluated 601 consecutive solid nodules in 554 patients studied with ultrasound. All ultrasound examinations were performed by one of the three radiologists that participated in the study and the static images were reviewed by all three radiologists independently; radiologists were blind to the clinical history and to the findings at mammography and at histological study.

RESULTS

The descriptors that best predicted benignity were circumscribed margins and oval shape (NPV, > 96%), parallel orientation (NPV, 84%-91%), and abrupt interface (NPV, 81%-90%). The descriptors that best predicted malignancy were spiculated margins (PPV, 77%-85%), echogenic halo (PPV, 61%-71%), and nonparallel orientation (PPV, 53%-54%). Interobserver concordance was good for lesion shape (kappa=0.61), circumscribed margins (kappa=0.65), and calcifications (kappa=0.63). The descriptors that presented the highest prognostic values for malignancy were spiculated margins (OR=14.68-10.45) and nonparallel orientation (OR=3.95-6.17). Final assessment category 3 yielded an excellent NPV for all three radiologists (99%-100%). The interobserver concordance was good for category 5 (kappa=0.77) and for category 3 (kappa=0.68); it was moderate for category 4 (kappa=0.59).

CONCLUSIONS

The BI-RADS- Ultrasound system helps differentiate benign breast lesions from malignant ones and has a good or moderate interobserver concordance. Final assessment category 3 yielded an excellent negative predictive value, making it possible to avoid biopsies in lesions in this category.

Appearance of breast masses on sonoelastography with special focus on the diagnosis of fibroadenomas

The aim of this study was to show and correlate the imaging features of breast masses, especially fibroadenomas, using sonoelastography. Two hundred thirty-five patients with 302 breast lesions referred for core needle biopsy participated in the study. All lesions appearing as solid masses on conventional US were included. Out of the included lesions (270), 115 (42.6%) corresponded to histologically confirmed fibroadenomas and 155 (57.4%) to lesions with histologically confirmed diagnoses other than fibroadenomas. These were further subdivided into fibrocystic changes, lesions with low malignancy potential, and malignant lesions. Fibroadenomas were also divided according to histological presentation into three subgroups to allow comparative study based on elastographic scores. All lesions were classified using a four-point scoring system based on ultrasound elastography imaging characteristics. Different presentations were observed for elastographic scores according to histological presentation of fibroadenomas, whereby fibroadenomas with benign characteristics tended to have elastographic classification similar to fibrocystic changes, and complex and hypercellular fibroadenomas had classifications similar to harder lesions. Fibroadenomas are generally classified as category 3 in the BI-RADS lexicon and are the most commonly found lesions in breast biopsies. Sonoelastography can provide additional information to conventional studies and be used as an auxiliary tool in assessing these masses in clinical practice.