The role of ultrasonography as an adjunct to mammography in the detection of breast cancer. a systematic review

Evaluating clinical efficacy of hospital-based surveillance with mammography and ultrasonography for breast cancer

Periodic mammography and/or sonography examinations are conducted across numerous hospitals nationalwidely, especially for antedees with a positive mammography screening. Despite the regular practice, clinical efficacy of hospital-based breast cancer surveillance remains unclear. Specifically, the impact of surveillance interval upon survival and prognostic surrogates stratified by menopausal status, as well as malignant transition rate should be deciphered. We retrieved cancer registry to ascertain 841 breast cancers with surveillance history through administration data. Healthy controls underwent breast surveillance and were concurrently free of cancer. More benign diseases rather than cancers were identified from premenopausal women (age ≤50 years) with sonography alone within one year, as well as older women (age >50) with both mammography and sonography one to two years before a cancer or benign diagnosis. Among breast cancers, mammography alone during the antecedent one to two years had a protective effect for diagnosing carcinoma in situ rather than invasive cancer (age-adjusted odds ratio: 0.048, P = 0.016). Three-state time homogeneous Markov model showed that hospital-based breast surveillance within 2 years of disease onset reduced the malignant transition rate by 65.16% (59.79-76.74%). The clinical efficacy of breast cancer surveillance was evidenced.

Quantitative Indicators of Retraction Phenomenon on an Automated Breast Volume Scanner: Initial Study in the Diagnosis and Prognostic Prediction of Breast Tumors

Retraction phenomenon is a unique sign on an automated breast volume scanner coronal plane image and has high specificity in differentiating benign lesions from malignant breast cancer. The purpose of this study was to quantify the retraction phenomenon by setting different rules to describe connected regions from different dimensions. In total, six quantitative indicators (F_Ω1,F_Γ,F_S,F_Ω2,F_Ω3and F_L) were obtained. F_Ω1, F_Ω2 and F_Ω3 represent the relative areas of the connected region under different rules. F_ΓandF_S represent the number ratio and absolute area of the connected region, respectively. F_L represents the ratio of edge numbers. Two hundred fourteen patients with 214 lesions (90 benign and 124 malignant) were enrolled in this study. All quantitative indicators in the malignant group were significantly higher than those in the benign group (all p values <0.001). The indicator F_Γ achieved the highest area under the receiver operating characteristic curve (AUC) (0.701, 95% confidence interval: 0.631-0.771). Both F_Γ and F_S had significant associations with axillary lymph node metastasis (p = 0.023 and 0.049). Compared with the classic texture feature gray-level co-occurrence matrix, retraction phenomenon quantization improved the AUC by 8.3%. The results indicate that retraction phenomenon quantitative indicators have certain value in distinguishing benign and malignant breast lesions and seem to be associated with axillary lymph node metastasis.

Breast cancer screening and early diagnosis in Chinese women

Breast cancer is the most common malignant tumor in Chinese women, and its incidence is increasing. Regular screening is an effective method for early tumor detection and improving patient prognosis. In this review, we analyze the epidemiological changes and risk factors associated with breast cancer in China and describe the establishment of a screening strategy suitable for Chinese women. Chinese patients with breast cancer tend to be younger than Western patients and to have denser breasts. Therefore, the age of initial screening in Chinese women should be earlier, and the importance of screening with a combination of ultrasound and mammography is stressed. Moreover, Chinese patients with breast cancers have several ancestry-specific genetic features, and aiding in the determination of genetic screening strategies for identifying high-risk populations. On the basis of current studies, we summarize the development of risk-stratified breast cancer screening guidelines for Chinese women and describe the significant improvement in the prognosis of patients with breast cancer in China.

A Prospective Pilot Study on Use of Liquid Crystal Thermography to Detect Early Breast Cancer

Background: Breast cancer is the most common cancer in women. While mammography is the standard for early detection in women older than 50 years of age, there is no standard for younger women. The aim of this prospective pilot study was to assess liquid crystal contact thermography, using the Braster device, as a means for the early detection of breast cancer. The device is intended to be used as a complementary tool to standard of care (sonography, mammography, etc). Patients and Methods: A total of 274 consecutive women presenting at Polish breast centers for prophylactic breast examination were enrolled to receive thermography; 19 were excluded for errors in thermographic image acquisition. The women were divided according to age (n = 135, <50 years; n = 120, ≥50 years). A control population was included (n = 40, <50 years; n = 23, ≥50 years). The primary endpoint, stratified by age group, was the C-statistic for discrimination between breast cancer and noncancer. Results: In women with abnormal breast ultrasound (n = 95, <50 years; n = 87, ≥50 years), the C-statistic was 0.85 and 0.75, respectively (P = .20), for discrimination between breast cancer and noncancer. Sensitivity did not differ (P = .79) between the younger (82%) and older women (78%), while specificity was lower in the older women (60% vs 87%, P = .025). The false-positive rate was similar in women with normal and abnormal breast ultrasound. Positive thermographic result in women with Breast Imaging Reporting and Data System (BIRADS) 4A on ultrasound increased the probability of breast cancer by over 2-fold. Conversely, a negative thermographic result decreased the probability of cancer more than 3-fold. Breast size and structure did not affect the thermography performance. No adverse events were observed. Conclusions: Thermography performed well in women <50 years of age, while its specificity in women ≥50 years was inadequate. These promising findings suggest that the Braster device deserves further investigation as a supporting tool for the early detection of breast cancer in women younger than 50 years of age.

Silicone-based composite materials simulate breast tissue to be used as ultrasonography training phantoms

A silicone-based composite breast phantom is fabricated to be used as an education model in ultrasonography training. A matrix of silicone formulations is tracked to mimic the ultrasonography and tactile response of human breast tissue. The performance of two different additives: (i) silicone oil and (ii) vinyl-terminated poly (dimethylsiloxane) (PDMS) are monitored by a home-made acoustic setup. Through the use of 75 wt% vinyl-terminated PDMS in two-component silicone elastomer mixture, a sound velocity of 1.29 ± 0.09 × 10³ m/s and an attenuation coefficient of 12.99 ± 0.08 dB/cm-values those match closely to the human breast tissue-are measured with 5 MHz probe. This model can also be used for needle biopsy as well as for self-exam trainings. Herein, we highlight the fabrication of a realistic, durable, accessible, and cost-effective training platform that contains skin layer, inner breast tissue, and tumor masses.

Can mechanical imaging increase the specificity of mammography screening?

Objectives

This study aimed to investigate the effects of adding adjunct mechanical imaging to mammography breast screening. We hypothesized that mechanical imaging could detect increased local pressure caused by both malignant and benign breast lesions and that a pressure threshold for malignancy could be established. The impact of this on breast screening was investigated with regard to reductions in recall and biopsy rates.

Methods

155 women recalled from breast screening were included in the study, which was approved by the regional ethical review board (dnr 2013/620). Mechanical imaging readings were acquired of the symptomatic breast. The relative mean pressure on the suspicious area (RMPA) was defined and a threshold for malignancy was established.

Results

Biopsy-proven invasive cancers had a median RMPA of 3.0 (interquartile range (IQR) = 3.7), significantly different from biopsy-proven benign at 1.3 (IQR = 1.0) and non-biopsied cases at 1.0 (IQR = 1.3) (P < 0.001). The lowest RMPA for invasive cancer was 1.4, with 23 biopsy-proven benign and 33 non-biopsied cases being below this limit. Had these women not been recalled, recall rates would have been reduced by 36% and biopsy rates by 32%.

Conclusions

If implemented in a screening situation, this may substantially lower the number of false positives.

Key Points

• Mechanical imaging is used as an adjunct to mammography in breast screening.

• A threshold pressure can be established for malignant breast cancer.

• Recalls and biopsies can be substantially reduced.

Feasibility Testing: Three-dimensional Tumor Mapping in Different Orientations of Automated Breast Ultrasound

A tumor-mapping algorithm was proposed to identify the same regions in different passes of automated breast ultrasound (ABUS). A total of 53 abnormal passes with 41 biopsy-proven tumors and 13 normal passes were collected. After computer-aided tumor detection, a mapping pair was composed of a detected region in one pass and another region in another pass. Location criteria, including the radial position as on a clock, the relative distance and the distance to the nipple, were used to extract mapping pairs with close regions. Quantitative intensity, morphology, texture and location features were then combined in a classifier for further classification. The performance of the classifier achieved a mapping rate of 80.39% (41/51), with an error rate of 5.97% (4/67). The trade-offs between the mapping and error rates were evaluated, and Az = 0.9094 was obtained. The proposed tumor-mapping algorithm was capable of automatically providing location correspondence information that would be helpful in reviews of ABUS examinations.

Comparison of automated breast ultrasonography to handheld ultrasonography in detecting and diagnosing breast lesions

BACKGROUND

Automated breast ultrasonography (ABUS) is increasingly used as a screening tool. Several studies have demonstrated a similar diagnostic performance for ABUS compared with handheld ultrasonography (HHUS), but the overall results have been controversial.

PURPOSE

To compare the clinical utility of ABUS and HHUS for detection and diagnosis of breast lesions.

MATERIAL AND METHODS

ABUS and HHUS images of suspicious breast lesions were obtained for 173 consecutive women scheduled to undergo ultrasonography (US)-guided or stereotactic biopsy. There were a total of 206 lesions, 46 of which were malignant and 160 benign. Three breast radiologists took part in this study: two reviewed the ABUS images, and the third reviewed all of the images, ABUS and HHUS, as well as the patients' medical records. The biopsied-lesion-detection rates were obtained. Using the Breast Imaging Reporting and Data System (BI-RADS), the images of the biopsied lesions were evaluated. Factors affecting ABUS detectability were analyzed.

RESULTS

The overall detection rates were 83.0% for ABUS and 94.2% for HHUS. Ten lesions were not detected on either HHUS or ABUS and these were microcalcifications (one malignancy and nine benign lesions). Of the 194 HHUS-detected lesions, 169 were detected by ABUS and 25 benign were not. ABUS less frequently detected lesions of smaller size as well as those of benign appearance and lower final-assessment category (P = 0.011 and P < 0.0001, respectively).

CONCLUSION

ABUS detected all of the malignant lesions that were detected on HHUS. ABUS missed several smaller benign lesions.

Comparison of mammography in combination with breast ultrasonography versus mammography alone for breast cancer screening in asymptomatic women

AIM

To compare the agreement of screening breast mammography plus ultrasound and reviewed mammography alone in asymptomatic women.

MATERIALS AND METHODS

All breast imaging data were obtained for women who presented for routine medical checkup at National Cancer Institute (NCI), Thailand from January 2010 to June 2013. A radiologist performed masked interpretations of selected mammographic images retrieved from the computer imaging database. Previous mammography, ultrasound reports and clinical data were blinded before film re-interpretation. Kappa values were calculated to assess the agreement between BIRADS assessment category and BIRADS classification of density obtained from the mammography with ultrasound in imaging database and reviewed mammography alone.

RESULTS

Regarding BIRADS assessment category, concordance between the two interpretations were good. Observed agreement was 96.1%. There was moderate agreement in which the Kappa value was 0.58% (95%CI; 0.45, 0.87). The agreement of BI-RADS classification of density was substantial, with a Kappa value of 0.60 (95%CI; 0.54, 0.66). Different results were obtained when a subgroup of patients aged ≥60 years were analyzed. In women in this group, observed agreement was 97.6%. There was also substantial agreement in which the Kappa value was 0.74% (95%CI; 0.49, 0.98).

CONCLUSIONS

The present study revealed that concordance between mammography plus ultrasound and reviewed mammography alone in asymptomatic women is good. However, there is just moderate agreement which can be enhanced if age- targeted breast imaging is performed. Substantial agreement can be achieved in women aged ≥60. Adjunctive breast ultrasound is less important in women in this group.

Multi-dimensional tumor detection in automated whole breast ultrasound using topographic watershed

Automated whole breast ultrasound (ABUS) is becoming a popular screening modality for whole breast examination. Compared to conventional handheld ultrasound, ABUS achieves operator-independent and is feasible for mass screening. However, reviewing hundreds of slices in an ABUS image volume is time-consuming. A computer-aided detection (CADe) system based on watershed transform was proposed in this study to accelerate the reviewing. The watershed transform was applied to gather similar tissues around local minima to be homogeneous regions. The likelihoods of being tumors of the regions were estimated using the quantitative morphology, intensity, and texture features in the 2-D/3-D false positive reduction (FPR). The collected database comprised 68 benign and 65 malignant tumors. As a result, the proposed system achieved sensitivities of 100% (133/133), 90% (121/133), and 80% (107/133) with FPs/pass of 9.44, 5.42, and 3.33, respectively. The figure of merit of the combination of three feature sets is 0.46 which is significantly better than that of other feature sets ( [Formula: see text]). In summary, the proposed CADe system based on the multi-dimensional FPR using the integrated feature set is promising in detecting tumors in ABUS images.

Quantification of acoustic radiation force impulse in differentiating between malignant and benign breast lesions

The aim of this study was to evaluate the use of gray-level quantification (GLQ) in virtual touch tissue imaging (VTI) in the differential diagnosis of breast lesions. GLQ values of 153 lesions (101 benign, 52 malignant) were analyzed with matrix laboratory software (MATLAB, The MathWorks, Natick, MA, USA), with gray levels ranging from 0 (pure black) to 255 (pure white). The diagnostic performance of GLQ was also evaluated using receiver operating characteristic curve analysis. The mean GLQ value for benign lesions (103.27 ± 39.44) differed significantly from that for malignant lesions (44.57 ± 13.61) (p < 0.001). At a cutoff value of 52.31, the sensitivity, specificity, accuracy, positive predictive value and negative predictive value were 86.5%, 93.1%, 90.8%, 86.5% and 93.1%, respectively. In conclusion, we have proposed a method for quantification of gray levels in VTI for the differential diagnosis of breast lesions. Our results indicate that this method has the potential to aid in the classification of benign and malignant breast masses.

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.

Detection of Breast Lesions using an Automated Breast Volume Scanner System

OBJECTIVE: This study investigated the clinical utility of an automated breast volume scanner (ABVS) system for the detection of breast lesions. METHODS: The breasts of 81 patients referred for ultrasonographic examination were scanned using the ABVS system and handheld ultrasonography independently by two experienced examiners. The ABVS was used to perform scans of the breast in three directions (anteroposterior, lateral and medial), with the addition of further inferior and superior scans if necessary. The scanning data were then stored and automatically reconstructed. For hand-held ultrasonography the whole breast was scanned radially from the outside to the centre of the nipple. RESULTS: The numbers of lesions reported by the two examiners were 89 and 99, respectively, using the ABVS (not statistically significant), compared with 60 and 85, respectively, using handheld ultrasonography (statistically significant). CONCLUSIONS: The ABVS system is an operator-independent method for automated breast scanning. It detected more breast lesions and provided additional information for the diagnosis of intraductal and malignant lesions compared with hand-held ultrasonography.

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.

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.

Detectability of breast lesions under the nipple using an automated breast volume scanner: comparison with handheld ultrasonography

PURPOSE

The aims of this study were to investigate the visualization rate for the mammary gland under the nipple with automated breast ultrasonography (US) and to compare the detectability of breast lesions under the nipple with automated breast imaging and handheld US imaging.

MATERIALS AND METHODS

A total of 60 patients underwent automated breast US (ABVS; Siemens Medical Solutions, Mountain View, CA, USA) and handheld US. The scans of the four segments of the breast included sequential scans in the upper-outer (C), lower-outer (D), lower-inner (B), and upper-inner (A) regions.

RESULTS

The visualization rates for the mammary gland under the nipple were 72% (86/120 breasts) in A-scanning, 84% (101/120) in B-scanning, 78% (93/120) in C-scanning, and 80% (96/120) in D-scanning. Interscanning mode differences were statistically significant only for A-scanning and B-scanning (P = 0.02). Eventually, 98% (117/120 breasts) of the breasts examined were rated as "visualized." In 14 of the 15 patients with breast lesions under the nipple, the lesions were detectable with handheld US and the ABVS. In the other patient, the lesion was not detectable on handheld US but was detected on ABVS imaging.

CONCLUSION

ABVS imaging is by no means inferior to handheld US for detecting breast lesions under the nipple.

Time for a re-evaluation of mammography in the young? Results of an audit of mammography in women younger than 40 in a resource restricted environment

Mammography in younger women is considered to be of limited value. In a resource restricted environment without access to magnetic resonance imaging (MRI) and with a high incidence of breast cancer in the young, mammography remains an important diagnostic tool. Recent technical advances and better regulation of mammography make a reassessment of its value in these conditions necessary. Data of all the mammograms performed at a tertiary hospital and private breast clinic between January 2003 and July 2009 in women less than 40 years of age were collected. Indications were the presence of a mass, follow-up after primary cancer therapy, and screening for patients perceived at high risk due to a family history or the presence of atypical hyperplasia. Data acquired were as follows: Demographics, prior breast surgery, indication for mammography, outcome of mammography, diagnostic procedures, and their results. Of 2,167 mammograms, 393 were performed for a palpable mass, diagnostic mammography. In these, the overall cancer detection rate was 40%. If the mammography was reported as breast imaging reporting and data system (BIRADS(®)) 5 versus BIRADS(®) 3 and 4 versus BIRADS(®) 1 and 2, a final diagnosis of malignancy was established in 96, 48, and 5%, respectively. Of 367 mammograms done for the follow-up after primary treatment of breast cancer, seven cancers were diagnosed for a detection rate of 1.9%. Of 1,312 mammograms performed for screening, the recall rate was 4%; the biopsy rate 2%, and the cancer diagnosis rate 3/1,000 examinations. In contrast to past series, this series has shown that recent advances in mammography have made it a useful tool in the management of breast problems in young women, notably in a resource-restricted environment. Women for screening should be selected carefully.

Measuring the accuracy of diagnostic imaging in symptomatic breast patients: team and individual performance

OBJECTIVE

The combination of mammography and/or ultrasound remains the mainstay in current breast cancer diagnosis. The aims of this study were to evaluate the reliability of standard breast imaging and individual radiologist performance and to explore ways that this can be improved.

METHODS

A total of 16,603 separate assessment episodes were undertaken on 13,958 patients referred to a specialist symptomatic breast clinic over a 6 year period. Each mammogram and ultrasound was reported prospectively using a five-point reporting scale and compared with final outcome.

RESULTS

Mammographic sensitivity, specificity and receiver operating curve (ROC) area were 66.6%, 99.7% and 0.83, respectively. The sensitivity of mammography improved dramatically from 47.6 to 86.7% with increasing age. Overall ultrasound sensitivity, specificity and ROC area was 82.0%, 99.3% and 0.91, respectively. The sensitivity of ultrasound also improved dramatically with increasing age from 66.7 to 97.1%. Breast density also had a profound effect on imaging performance, with mammographic sensitivity falling from 90.1 to 45.9% and ultrasound sensitivity reducing from 95.2 to 72.0% with increasing breast density.

CONCLUSION

The sensitivity ranges widely between radiologists (53.1-74.1% for mammography and 67.1-87.0% for ultrasound). Reporting sensitivity was strongly correlated with radiologist experience. Those radiologists with less experience (and lower sensitivity) were relatively more likely to report a cancer as indeterminate/uncertain. To improve radiology reporting performance, the sensitivity of cancer reporting should be closely monitored; there should be regular feedback from needle biopsy results and discussion of reporting classification with colleagues.

Diagnostic performance of breast technologists in reading mammograms in a clinical patient population

PURPOSE

In the setting of an increasing workload for radiologists, this study focuses on the feasibility of skill mixing in breast imaging in a hospital radiology department.

METHODS

Two radiological technologists with more than 10 years of experience in performing mammograms were trained in prereading mammograms to select the cases that require further evaluation by a radiologist. Mammograms of consecutive patients were independently evaluated by the technologists, next to the standard clinical interpretation by the radiologist on duty. Mammographic findings were recorded and a BI-RADS classification was assigned for each breast. Different prereading scenarios were analysed using clinical decision rules. Two different cut-off points of BI-RADS classifications were applied to the data. Analysis was performed for the overall clinical patient population as well as for a subgroup of patients with no immediate indication for further work-up.

RESULTS

Mammograms of 1994 patients were evaluated. In total, 93 breast cancers were found in 91 patients (prevalence 4.6%). Sensitivity and specificity in selecting mammographic findings (cut-off point between BI-RADS 1 and BI-RADS 0, 2-5 and the radiologist's diagnosis as reference standard) was 98% and 74% for technologist 1 and 98% and 78% for technologist 2. In distinguishing normal and benign mammograms from those with abnormalities that are probably benign, suspicious or highly suggestive for malignancy (cut-off point BI-RADS 1-2 and BI-RADS 0, 3-5 and pathology results as reference standard), sensitivity decreased to 89% and 91% respectively. Specificity increased to 82% for both technologists. In a subgroup of 1389 patients with no immediate indication for additional imaging with the involvement of a radiologist, technologists obtained a mean sensitivity and specificity of 98% and 77% in detecting mammographic findings, and a mean sensitivity and specificity of 78% and 88% in detecting suspicious abnormalities.

CONCLUSIONS

The employment of technologists in prereading mammograms seems to be an effective working strategy in daily clinical practice. However, its position in clinical practice remains indistinct as a continuous availability of radiologists still needs to be guaranteed. Nevertheless, as a substantial proportion of mammograms could be evaluated without the attention of a radiologist, the employment of technologists in prereading mammograms seems a promising new working strategy.

Clinical application of the BI-RADS final assessment to breast sonography in conjunction with mammography

OBJECTIVE

The objective of our study was to report the results of classification of sonographic findings according to BI-RADS and to calculate the positive predictive value (PPV) for each BI-RADS assessment category.

SUBJECTS AND METHODS

We prospectively classified 4,668 breast sonograms according to BI-RADS final assessment category. Suspicious sonographic findings were divided into major and minor suspicious findings. Category 1 was normal and category 2 was a benign finding such as cyst or nodule with uniform and intense hyperechogenicity. A nodule neither category 2 nor category 4 or 5 was defined as category 3. A nodule with one or more suspicious findings, not category 5, was defined as category 4. A nodule with two or more major suspicious findings was defined as category 5.

RESULTS

Of the 4,668 cases, 321 cases failed to undergo follow-up of at least 1 year. The PPV was 0.1% in category 1 (3/2,191), 0% in category 2 (0/773), 0.8% in category 3 (6/737), 31.1% in category 4 (161/519), and 96.9% in category 5 (123/127). In palpable lesions (n = 751), the PPV was 2.2% in category 1 (2/93), 0.9% in category 3 (2/217), 54% in category 4 (107/198), and 98% in category 5 (98/100). In nonpalpable lesions (n = 3,596), the PPV was 0.05% in category 1 (1/2,098), 0.8% in category 3 (4/520), 16.8% in category 4 (54/321), and 92.6% in category 5 (25/27).

CONCLUSION

As with mammography, placing sonographic lesions into BI-RADS categories is useful for predicting the presence of malignancy.

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.

Diagnostic utility of combined ultrasonography and mammography in the evaluation of women with mammographically dense breasts

PURPOSE

To assess the diagnostic utility and additional cost of combined breast ultrasonography and mammography in the evaluation of asymptomatic women with mammographically dense breasts.

MATERIALS AND METHODS

Of 5108 asymptomatic women, who underwent mammography, 1754 had dense breasts (BI-RADS 3 or 4) and negative mammographic outcome. They were divided in 4 subgroups according to their age (<40 yrs; 40-49 yrs; 50-59 yrs; >59 yrs). Breast ultrasonography was performed immediately after mammography. Lesions detected at ultrasonography were examined cytologically/histologically. Mammograms from women, who were diagnosed carcinoma at ultrasonography, were reviewed by an external radiologist. Costs per diagnosed carcinoma and per examined woman were calculated on the basis of current regional charges.

RESULTS

Mammographies (5108) were performed, 67 cancers were detected (cancer detection rate 13.1‰): mammography identified 55 carcinomas and ultrasonography performed in women with dense breasts identified 12 cancers (17.9% of all cancers detected, overall cancer detection rate 6.8‰). Ultrasonography identified a benign condition in 1567 out of 1754 women (89.3%) (in 925 absence of focal lesions; 438 simple cysts; 56 ductal ectasia; 148 benign solid lesions); 97 complex cysts, 52 lesions that could not be differentiated as liquid or solid lesions, and 38 solid lesions suspicious for malignancy in the remaining 187 out of 1754 patients (10.7%). Cytology/histology confirmed carcinoma in 12 women (overall biopsy rate 26.2‰, benign biopsy rate 19.4‰). The additional costs were: € 6,123.45 per detected cancer, € 41.89 per examined woman.

CONCLUSION

Breast ultrasonography immediately after mammography in women with dense breasts is useful to avoid diagnostic delays and inconvenient medico-legal implications even though this procedure involves increased costs.

Performance of radiographers in mammogram interpretation: a systematic review

Radiologists may be relieved from work that could be performed by radiographers. This systematic literature review focuses on the performance of radiographers (also referring to technologists and physician assistants) compared with radiologists in the interpretation of mammograms; the effect of training; and the question whether there are any studies evaluating the effects of involving radiographers in the interpretation of diagnostic mammograms in daily clinical practice on the sensitivity and specificity of cancer detection in breast imaging. Six studies met the inclusion criteria (primary aim of the study has to be the evaluation of the performance of radiographers, sensitivity and specificity have to be reported or calculable and there has to be a sufficient gold standard). The results showed that, in a screening setting, radiographers scored higher false positive rates with a similar sensitivity in the detection of malignancies, compared with radiologists. Furthermore, results suggested that training could improve their performance. No studies were reported assessing the performance of radiographers interpreting diagnostic mammograms in a consecutive patient population in a daily clinical setting. This indicates a need for a well-designed diagnostic study using an adequate gold standard, in order to evaluate the feasibility of deploying radiographers in the interpretation of diagnostic mammograms in a clinical setting.

Increasing the diagnosis of multifocal primary breast cancer by the use of bilateral whole-breast ultrasound

AIM

The aim of this study was to evaluate the contribution of bilateral whole-breast ultrasound (BBUS) to the diagnosis and management of women with newly diagnosed breast cancer.

METHODS

Over a period of 6 months, 102 women presenting with breast cancer underwent BBUS. Data were collected on clinical findings, radiology, histology and surgical outcome. These women were compared with a control group of 124 women presenting over a similar 6-month period 1 year previously, who had undergone targeted breast ultrasound.

RESULTS

Multicentric/multifocal tumours were demonstrated in 35 (34%) of the 102 participants and in 18 (15%) of the 124 controls, a statistically significant difference (Fisher's exact test, p = 0.001). Multiple tumours were diagnosed preoperatively in 18% of the study population compared with 8% of the controls, and BBUS identified invasive multifocal/multicentric tumours in significantly more women in the study population (11 versus 1 control) (Fisher's exact test, p = 0.019). Contralateral cancer was diagnosed in 4 women in the study population and none in the control population (Fisher's exact test, p = 0.040). Surgical review showed that the surgical management changed significantly in 8% (95% confidence interval 4 to 14%) of cases in the study population following BBUS. The increase in the number of women undergoing benign biopsies in the study population (10 versus 5 controls) was not statistically significant (Fisher's exact test, p = 0.11).

CONCLUSION

BBUS increased the preoperative diagnosis of multiple tumours in women presenting with primary breast cancer, resulting in a management change in 8% of cases.