Mass detection in automated three dimensional breast ultrasound using cascaded convolutional neural networks.

PURPOSE: Early detection of breast cancer has a significant effect on reducing its mortality rate. For this purpose, automated three-dimensional breast ultrasound (3-D ABUS) has been recently used alongside mammography. The 3-D volume produced in this imaging system includes many slices. The radiologist must review all the slices to find the mass, a time-consuming task with a high probability of mistakes. Therefore, many computer-aided detection (CADe) systems have been developed to assist radiologists in this task. In this paper, we propose a novel CADe system for mass detection in 3-D ABUS images. METHODS: The proposed system includes two cascaded convolutional neural networks. The goal of the first network is to achieve the highest possible sensitivity, and the second network's goal is to reduce false positives while maintaining high sensitivity. In both networks, an improved version of 3-D U-Net architecture is utilized in which two types of modified Inception modules are used in the encoder section. In the second network, new attention units are also added to the skip connections that receive the results of the first network as saliency maps. RESULTS: The system was evaluated on a dataset containing 60 3-D ABUS volumes from 43 patients and 55 masses. A sensitivity of 91.48% and a mean false positive of 8.85 per patient were achieved. CONCLUSIONS: The suggested mass detection system is fully automatic without any user interaction. The results indicate that the sensitivity and the mean FP per patient of the CADe system outperform competing techniques.

Comparison of Curative Complications between Mammotome-Assisted Minimally Invasive Resection and Conventional Open Resection for Breast Neoplasm: A Retrospective Clinical Study.

BACKGROUND: To know the clinical value of mammotome-assisted minimally invasive resection (MAMIR) in the treatment of patients with breast neoplasm, we performed a retrospective clinical study for the patients treated with the MAMIR and conventional open resection (COR). METHODS: Postoperative complications were compared between 40 patients treated with the MAMIR and 40 patients treated with the COR. The postoperative complications mainly included intraoperative blood loss, hospitalization days, operative time, surgical scar, and incidence of postoperative complications. RESULTS: We found that the amount of intraoperative blood loss, hospitalization days, operative time, surgical scar, and incidence of postoperative complications in the MAMIR group were significantly lower than those of patients in the COR group. CONCLUSION: Our results indicated that patients with breast neoplasm treated with the MAMIR had better outcomes, which reinforced the advantage of this approach.

Agreement in breast lesion assessment and final BI-RADS classification between radial and meander-like breast ultrasound.

BACKGROUND: This study prospectively investigates the agreement between radial (r-US) and meander-like (m-US) breast ultrasound with regard to lesion location, lesion size, morphological characteristics and final BI-RADS classification of individual breast lesions. METHODS: Each patient of a consecutive, unselected, mixed collective received a dual ultrasound examination. RESULTS: The agreement between r-US and m-US for lesion location ranged from good (lesion to mammilla distance ICC 0.64; lesion to skin distance ICC 0.72) to substantial (clock-face localization κ 0.70). For lesion size the agreement was good (diameter ICC 0.72; volume ICC 0.69), for lesion margin and architectural distortion it was substantial (κ 0.68 and 0.70, respectively). Most importantly, there was a substantial agreement (κ 0.76) in the final BI-RADS classification between r-US and m-US. CONCLUSIONS: Our recent comparison of radial and meander-like breast US revealed that the diagnostic accuracy of the two scanning methods was comparable. In this study, we observe a high degree of agreement between m-US and r-US for the lesion description (location, size, morphology) and final BI-RADS classification. These findings corroborate that r-US is a suitable alternative to m-US in daily clinical practice. Trial registration NCT02358837. Registered January 2015, retrospectively registered https://clinicaltrials.gov/ct2/results?cond=&term=NCT02358837&cntry=&state=&city=&dist =.

The concordance in lesion detection and characteristics between the Anatomical Intelligence and conventional breast ultrasound Scan method.

BACKGROUND: The aim of this study was to investigate the concordance in lesion detection, between conventional Handhold Ultrasound (HHUS) and The Anatomical Intelligence for Breast ultrasound scan method. RESULT: The AI-breast showed the absolute agreement between the resident and an experienced breast radiologist. The ICC for the scan time, number, clockface location, distance to the nipple, largest diameter and mean diameter of the lesion obtained by a resident and an experienced breast radiologist were 0.7642, 0.7692, 0.8651, 0.8436, 0.7502, 0.8885, respectively. The ICC of the both practitioners of AI-breast were 0.7971, 0.7843, 0.9283, 0.8748, 0.7248, 0.8163, respectively. The k value of Anatomical Intelligence breast between experienced breast radiologist and resident in these image characteristics of boundary, morphology, aspect ratio, internal echo, and BI-RADS assessment were 0.7424, 0.7217, 0.6741, 0.6419, 0.6241, respectively. The k value of the two readers of AI-breast were 0.6531, 0.6762, 0.6439, 0.6137, 0.5981, respectively. CONCLUSION: The anatomical intelligent breast US scanning method has excellent reproducibility in recording the lesion location and the distance from the nipple, which may be utilized in the lesions surveillance in the future.

First proof-of-concept evaluation of the FUSION-X-US-II prototype for the performance of automated breast ultrasound in healthy volunteers.

PURPOSE: The FUSION-X-US-II prototype was developed to combine 3D-automated breast ultrasound (ABUS) and digital breast tomosynthesis in a single device without decompressing the breast. We evaluated the technical function, feasibility of the examination workflow, image quality, breast tissue coverage and patient comfort of the ABUS device of the new prototype. METHODS: In this prospective feasibility study, the FUSION-X-US-II prototype was used to perform ABUS in 30 healthy volunteers without history of breast cancer. The ABUS images of the prototype were interpreted by a physician with specialization in breast diagnostics. Any detected lesions were measured and classified using BI-RADS® scores. Image quality was rated subjectively by the physician and coverage of the breast was measured. Patient comfort was evaluated by a questionnaire after the examination. RESULTS: One hundred and six scans were performed (61 × CC, 23 × ML, 22 × MLO) in 60 breasts. Image acquisition and processing by the prototype was fast and accurate. Breast coverage by ABUS was approximately 90.8%. Sixteen breast lesions (all benign, classified as BIRADS® 2) were identified. The examination was tolerated by all patients. CONCLUSION: The FUSION-X-US-II prototype allows a rapid ABUS scan with mostly high patient comfort. Technical developments resulted in an improvement of quality and coverage compared to previous prototype versions. The results are encouraging for a test of the prototype in a clinical setting in combination with tomosynthesis.

Comparison of Automated Breast Ultrasound and Hand-Held Breast Ultrasound in the Screening of Dense Breasts.

OBJECTIVE: To compare hand-held breast ultrasound (HHBUS) and automated breast ultrasound (ABUS) as screening tool for cancer. METHODS: A cross-sectional study in patients with mammographically dense breasts was conducted, and both HHBUS and ABUS were performed. Hand-held breast ultrasound was acquired by radiologists and ABUS by mammography technicians and analyzed by breast radiologists. We evaluated the Breast Imaging Reporting and Data System (BI-RADS) classification of the exam and of the lesion, as well as the amount of time required to perform and read each exam. The statistical analysis employed was measures of central tendency and dispersion, frequencies, Student t test, and a univariate logistic regression, through the odds ratio and its respective 95% confidence interval, and with p < 0.05 considered of statistical significance. RESULTS: A total of 440 patients were evaluated. Regarding lesions, HHBUS detected 15 (7.7%) BI-RADS 2, 175 (89.3%) BI-RADS 3, and 6 (3%) BI-RADS 4, with 3 being confirmed by biopsy as invasive ductal carcinomas (IDCs), and 3 false-positives. Automated breast ultrasound identified 12 (12.9%) BI-RADS 2, 75 (80.7%) BI-RADS 3, and 6 (6.4%) BI-RADS 4, including 3 lesions detected by HHBUS and confirmed as IDCs, in addition to 1 invasive lobular carcinoma and 2 high-risk lesions not detected by HHBUS. The amount of time required for the radiologist to read the ABUS was statistically inferior compared with the time required to read the HHBUS (p < 0.001). The overall concordance was 80.9%. A total of 219 lesions were detected, from those 70 lesions by both methods, 126 only by HHBUS (84.9% not suspicious by ABUS) and 23 only by ABUS. CONCLUSION: Compared with HHBUS, ABUS allowed adequate sonographic study in supplemental screening for breast cancer in heterogeneously dense and extremely dense breasts.

OBJETIVO: Comparar a ultrassonografia convencional das mamas (US) com a ultrassonografia automatizada das mamas (ABUS) no rastreio do câncer. MéTODOS: Realizamos um estudo transversal com pacientes com mamas mamograficamente densas, sendo avaliadas pela US e pela ABUS. A US foi realizada por radiologistas e a ABUS por técnicos de mamografia e analisada por radiologistas especializados em mama. A classificação Breast Imaging Reporting and Data System (BIRADS) do exame e das lesões o tempo de leitura e de aquisição foram avaliados. A análise estatística foi realizada através de medidas de tendência central, dispersão e frequências, teste t de Student e regressão logística univariada, através do odds ratio, com intervalo de confiança de 95%, e com p < 0,05 sendo considerado estatisticamente significante. RESULTADOS: Foram avaliadas 440 pacientes. Em relação às lesões, a US detectou 15 (7,7%) BI-RADS 2, 175 (89,3%) BI-RADS 3 e 6 (3%) BI-RADS 4, das quais 3 foram confirmadas, por biópsia, como carcinomas ductais invasivos e 3 falso-positivos. A ABUS identificou 12 (12,9%) BI-RADS 2, 75 (80,7%) BI-RADS 3 e 6 (6,4%) BI-RADS 4, incluindo 3 lesões detectadas pela US e confirmadas como carcinomas ductais invasivos, além de 1 carcinoma lobular invasivo e 2 lesões de alto risco não detectadas pela US. O tempo de leitura dos exames da ABUS foi estatisticamente inferior ao tempo do radiologista para realizar a US (p < 0,001). A concordância foi de 80,9%. Um total de 219 lesões foram detectadas, das quais 70 por ambos os métodos, 126 observadas apenas pela US (84,9% não eram lesões suspeitas no ABUS) e 23 apenas pela ABUS. CONCLUSãO: Comparado à US, a ABUS permitiu adequado estudo complementar no rastreio do câncer de mamas heterogeneamente densas e extremamente densas.

Comparison of automated breast ultrasound and hand-held breast ultrasound in the screening of dense breasts / Comparação entre a ultrassonografia automatizada e a ultrassonografia convencional no rastreio de mamas densas

Abstract Objective To compare hand-held breast ultrasound (HHBUS) and automated breast ultrasound (ABUS) as screening tool for cancer. Methods A cross-sectional study in patients with mammographically dense breasts was conducted, and both HHBUS and ABUS were performed. Hand-held breast ultrasound was acquired by radiologists and ABUS by mammography technicians and analyzed by breast radiologists. We evaluated the Breast Imaging Reporting and Data System (BI-RADS) classification of the exam and of the lesion, as well as the amount of time required to perform and read each exam. The statistical analysis employed was measures of central tendency and dispersion, frequencies, Student t test, and a univariate logistic regression, through the odds ratio and its respective 95% confidence interval, and with p<0.05 considered of statistical significance. Results Atotal of 440 patientswere evaluated. Regarding lesions,HHBUS detected 15 (7.7%) BI-RADS 2, 175 (89.3%) BI-RADS 3, and 6 (3%) BI-RADS 4, with 3 being confirmed by biopsy as invasive ductal carcinomas (IDCs), and 3 false-positives. Automated breast ultrasound identified 12 (12.9%) BI-RADS 2, 75 (80.7%) BI-RADS 3, and 6 (6.4%) BI-RADS 4, including 3 lesions detected by HHBUS and confirmed as IDCs, in addition to 1 invasive lobular carcinoma and 2 high-risk lesions not detected by HHBUS. The amount of time required for the radiologist to read the ABUS was statistically inferior compared with the time required to read the HHBUS (p<0.001). The overall concordance was 80.9%. A total of 219 lesions were detected, from those 70 lesions by both methods, 126 only by HHBUS (84.9% not suspicious by ABUS) and 23 only by ABUS. Conclusion Compared with HHBUS, ABUS allowed adequate sonographic study in supplemental screening for breast cancer in heterogeneously dense and extremely dense breasts.

Resumo Objetivo Comparar a ultrassonografia convencional das mamas (US) com a ultrassonografia automatizada das mamas (ABUS) no rastreio do câncer. Métodos Realizamos um estudo transversal com pacientes com mamas mamograficamente densas, sendo avaliadas pela US e pela ABUS. A US foi realizada por radiologistas e a ABUS por técnicos de mamografia e analisada por radiologistas especializados em mama. A classificação Breast Imaging Reporting and Data System (BIRADS) do exame e das lesões o tempo de leitura e de aquisição foram avaliados. A análise estatística foi realizada através de medidas de tendência central, dispersão e frequências, teste t de Student e regressão logística univariada, através do odds ratio, com intervalo de confiança de 95%, e com p<0,05 sendo considerado estatisticamente significante. Resultados Foram avaliadas 440 pacientes. Em relação às lesões, a US detectou 15 (7,7%) BI-RADS 2, 175 (89,3%) BI-RADS 3 e 6 (3%) BI-RADS 4, das quais 3 foram confirmadas, por biópsia, como carcinomas ductais invasivos e 3 falso-positivos. A ABUS identificou 12 (12,9%) BI-RADS 2, 75 (80,7%) BI-RADS 3 e 6 (6,4%) BI-RADS 4, incluindo 3 lesões detectadas pela US e confirmadas como carcinomas ductais invasivos, além de 1 carcinoma lobular invasivo e 2 lesões de alto risco não detectadas pela US. O tempo de leitura dos exames da ABUS foi estatisticamente inferior ao tempo do radiologista para realizar a US (p<0,001). A concordância foi de 80,9%. Um total de 219 lesões foram detectadas, das quais 70 por ambos os métodos, 126 observadas apenas pela US (84,9% não eram lesões suspeitas no ABUS) e 23 apenas pela ABUS. Conclusão Comparado à US, a ABUS permitiu adequado estudo complementar no rastreio do câncer de mamas heterogeneamente densas e extremamente densas.

The Ability to Look: Management of Breast Disease in the Democratic Republic of the Congo Using Smart Ultrasound Technology.

BACKGROUND: The vast majority of women with breast cancer in sub-Saharan Africa present with advanced stage disease, due primarily to the lack of opportunities for early detection and treatment. As part of a larger effort to increase access to diagnostic and therapeutic services for women's cancers in the Democratic Republic of Congo (DRC), we implemented a curriculum to train the local workforce and a program to build the supportive infrastructure for the diagnosis and treatment of breast cancer at a private sector health facility (Biamba Marie Mutombo Hospital) in Kinshasa. STUDY DESIGN: After onsite trainings in the DRC by a US breast surgeon (RT), Congolese surgeons, general physicians, physician assistants, and nurses used the Phillips Lumify smart-phone ultrasound device to perform and interpret the results of whole breast ultrasound on symptomatic women. Surgeons were trained to perform ultrasound-guided core needle biopsy on those who met the criteria for tissue diagnosis, after which they trained nurses to do the same. RESULTS: Over 3 years, 5,211 patients were identified as having a breast abnormality on clinical breast examination. Ultrasound abnormalities were noted in 1,493 (27%) patients, of which 632 (42%) met the criteria for ultrasound-guided core needle biopsy or fine needle aspiration. Pathology reports were available on 368 (58%) patients who underwent biopsy, of which 164 were malignant and 204 benign. CONCLUSIONS: We demonstrated how the "ability to look" using smart technology can be successfully used to augment clinical breast exam and triage patients for biopsy in a resource-constrained African setting.

Fundamentals of High-Resolution Ultrasound in Breast Implant Screening for Plastic Surgeons.

This article introduces the plastic surgeon to the basics of high-resolution ultrasound (HRUS) for screening breast implants. It describes how HRUS has become an accepted alternative to MRI for screening and diagnosis, and how plastic surgeons should use this new technology for the benefit of their patients and their practices. Basic principles, technology, and nomenclature are presented. Key steps to obtaining diagnostic images of breast implants are reviewed, including typical artifacts and sources of error. Imaging examples are presented. The article ends with a review and a step-by-step guide for plastic surgeons looking to use the technology.

Optimization of Wire-guided Technique With Bracketing Reduces Resection Volumes in Breast-conserving Surgery for Early Breast Cancer.

BACKGROUND: Wire-guided localization (WGL) of early breast cancer can be facilitated using multiple wires, which is called bracketing wire-guided localization (BWL). The primary aim of this study is to compare BWL and conventional WGL regarding minimization of resection volumes without compromising margin status. Secondly, BWL is evaluated as an alternative method for intraoperative ultrasound (US) guidance in poorly definable breast tumors on US. PATIENTS AND METHODS: In this retrospective cohort study, patients with preoperatively diagnosed breast cancer undergoing wide local excision between January 2016 and December 2018 were analyzed. Patients with multifocal disease or neoadjuvant treatment were excluded from this study. Optimal resection with minimal healthy breast tissue removal was assessed using the calculated resection ratio (CRR). RESULTS: BWL was performed in 17 (9%) patients, WGL in 44 (22%), and US in 139 (70%). The rate of negative margins was comparable in all 3 groups. The CRR was significantly smaller for BWL (0.6) than WGL (1.3) in tumors larger than 1.5 cm. Additionally, BWL (0.8) led to smaller CRRs than US (1.7). This could be explained by the high number of small tumors (≤ 1.5 cm) in the US group for which greater CRRs are obtained than for large tumors (> 1.5 cm) (1.9 vs. 1.4; P = .005). CONCLUSION: For breast tumors larger than 1.5 cm, BWL achieves more optimal resection volumes without compromising margin status compared with WGL. Moreover, BWL seems a suitable alternative to US in patients with poorly ultrasound-visible breast tumors and patients with a small tumor in a (large) breast.

Flexible ultrasonic array for breast-cancer diagnosis based on a self-shape-estimation algorithm.

Breast cancer is a very common malignant tumour that typically occurs in women aged 35-70 years (accounting for 85% of patients). Recently, it has been appearing in younger women as well. Traditional ultrasonic transducers usually use a fixed array, which avoids the radiation from mammography, has a low cost, and can be used for repeated testing. This substantially benefits the clinical diagnosis of breast cancer. However, the fixed transducer-array diagnosis process exerts considerable pressure on the human body, which can easily cause mass displacement or unnecessary pain. Therefore, ultrasound breast cancer diagnosis without compression has attracted attention. In this study, we used a flexible ultrasonic array to record the ultrasound information of the mass, and proposed a mathematical model suitable for breast-cancer diagnosis. Then, we used a self-shape-estimation algorithm to obtain a two-dimensional (2D) ultrasound image of the breast cancer. The algorithm was tested with simulated and experimental array data, and its performance was evaluated according to the tumour location. The surface-shape error obtained through the numerical simulation was less than 0.8 mm, and the deviation in the estimated mass position was less than 1.24 mm. The tumour location was also obtained experimentally in a breast-cancer model. Therefore, the method proposed in this paper can realize ultrasound diagnoses and represents a new diagnostic tool for breast cancer.

Comparison of automated versus hand-held breast US in supplemental screening in asymptomatic women with dense breasts: is there a difference regarding woman preference, lesion detection and lesion characterization?

PURPOSE: To compare automated breast volumetric scanning (ABVS) with hand-held bilateral whole breast ultrasound (HHUS) prospectively in regards to patient workflow, woman preference, efficacy in lesion detection, and characterization. MATERIALS AND METHODS: Supplemental screening was performed with both ABVS and HHUS to 345 women with dense breasts and negative mammograms. Acquisition and evaluation times were recorded. Lesions were classified according to BIRADS US criteria and compared one to one. Women were recalled for a secondary HHUS examination if ABVS showed any additional lesions. Findings were compared based on biopsy results and/or 36-48 months of follow-up. RESULTS: Findings could be compared for 340 women. There were two carcinomas which were detected by both methods, with no interval cancers in the follow-up period. Recall rate was 46/340 (13.05%) for ABVS and 4/340 (1.18%) for HHUS. ABVS recalls decreased with experience. HHUS had more true negative (BIRADS 1-2) results, while ABVS had more false positive ones (p < 0.001). Positive predictive value was 4.17% for ABVS and 50% for HHUS. ABVS overdiagnosed shadowings (p < 0.01), distortions (p < 0.034), and irregular nodules (p < 0.001) in comparison to HHUS. At ABVS, 10.6% of women experienced severe pain. 59.7% stated that they would choose HHUS if they had the chance. CONCLUSION: ABVS is as good as HHUS in lesion detection. However, the recall rate is higher and positive predictive value is lower with ABVS, which could result in more follow-ups, and more anxiety for the women. More than 50% women stated they would prefer HHUS if they were given the chance.

Quantitative Ultrasound Monitoring of Breast Tumour Response to Neoadjuvant Chemotherapy: Comparison of Results Among Clinical Scanners.

Quantitative ultrasound (QUS) techniques have been demonstrated to detect cell death in vitro and in vivo. Recently, multi-feature classification models have been incorporated into QUS texture-feature analysis methods to increase further the sensitivity and specificity of detecting treatment response in locally advanced breast cancer patients. To effectively incorporate these analytic methods into clinical applications, QUS and texture-feature estimations should be independent of data acquisition systems. The study here investigated the consistencies of QUS and texture-feature estimation techniques relative to several factors. These included the ultrasound system properties, the effects of tissue heterogeneity and the effects of these factors on the monitoring of response to neoadjuvant chemotherapy. Specifically, tumour-response-detection performance based on QUS and texture parameters using two clinical ultrasound systems was compared. Observed variations in data between the systems were small and the results exhibited good agreement in tumour response predictions obtained from both ultrasound systems. The results obtained in this study suggest that tissue heterogeneity was a dominant feature in the parameters measured with the two different ultrasound systems; whereas differences in ultrasound system beam properties only exhibited a minor impact on texture features. The McNemar statistical test performed on tumour response prediction results from the two systems did not reveal significant differences. Overall, the results in this study demonstrate the potential to achieve reliable and consistent QUS and texture-based analyses across different ultrasound imaging platforms.

Value of Hand-held Ultrasound in the Differential Diagnosis and Accurate Breast Imaging Reporting and Data System Subclassification of Complex Cystic and Solid Breast Lesions.

To explore the value of hand-held ultrasound (HHUS) for diagnosing complex cystic and solid breast lesions, 472 pathologically proven lesions were analyzed. The lesions were divided into four types based on ultrasound features. Positive predictive values (PPVs) for lesion types and risk factor performances were assessed. Furthermore, HHUS and mammography (MAM) performances were compared: 27 lesions missed in MAM were detected in HHUS. Ultrasound feature analysis revealed higher PPVs for type III and IV lesions than for type I and II lesions. In patients older than 51 y, a type III or IV lesion with a diameter greater than 18 mm, an irregular shape, a non-parallel orientation, an uncircumscribed margin, calcification, vascularity and abnormal axillary lymph nodes were suggestive of malignancy; the area under the curve reached 0.869. Thus, ultrasound is useful in diagnosing complex cystic and solid breast lesions, which should be categorized as Breast Imaging Reporting and Data System (BI-RADS) 4B or 4C.

Breast ultrasound: automated or hand-held? Exploring patients' experience and preference.

BACKGROUND: Our aim was to compare women's experience with automated breast ultrasound (ABUS) versus breast hand-held ultrasound (HHUS) and to evaluate their acceptance rate. METHODS: After ethical approval, from October 2017 to March 2018, 79 consecutive patients were enrolled in this prospective study. On the same day, patients underwent HHUS followed by ABUS. Each patient's experience was assessed using the modified testing morbidities index (TMI) (the lower the score, the better is the experience). Nine items were assessed for both techniques: seven directly related to the examination technique (pain or discomfort immediately before (preparation), during and after testing, fear or anxiety immediately before (preparation) and during testing, physical and mental function after testing) and two indirectly related to the examination technique (embarrassment during testing and overall satisfaction). Finally, we asked patients to choose between the two techniques for a potential next breast examination. Wilcoxon signed ranks test was used. RESULTS: The median TMI score for the seven items was found to be significantly better for HHUS (8, interquartile range [IQR] 7-11) compared to ABUS (9, IQR 8-12) (p = 0.003). The item 'pain/discomfort during the test' (p < 0.001) was significantly higher for ABUS compared to HHUS. Instead, the item 'fear/anxiety before the test' was higher for HHUS (p = 0.001). Overall, 40.5% of the patients chose HHUS, 29.1% chose ABUS, and 30.4% were unable to choose. CONCLUSIONS: ABUS and HHUS exams were well tolerated and accepted. However, HHUS was perceived to be less painful than ABUS.

Design of an end-effector for robot-assisted ultrasound-guided breast biopsies.

PURPOSE: The biopsy procedure is an important phase in breast cancer diagnosis. Accurate breast imaging and precise needle placement are crucial in lesion targeting. This paper presents an end-effector (EE) for robotic 3D ultrasound (US) breast acquisitions and US-guided breast biopsies. The EE mechanically guides the needle to a specified target within the US plane. The needle is controlled in all degrees of freedom (DOFs) except for the direction of insertion, which is controlled by the radiologist. It determines the correct needle depth and stops the needle accordingly. METHOD: In the envisioned procedure, a robotic arm performs localization of the breast, 3D US volume acquisition and reconstruction, target identification and needle guidance. Therefore, the EE is equipped with a stereo camera setup, a picobeamer, US probe holder, a three-DOF needle guide and a needle stop. The design was realized by prototyping techniques. Experiments were performed to determine needle placement accuracy in-air. The EE was placed on a seven-DOF robotic manipulator to determine the biopsy accuracy on a cuboid phantom. RESULTS: Needle placement accuracy was 0.3 ± 1.5 mm in and 0.1 ± 0.36 mm out of the US plane. Needle depth was regulated with an accuracy of 100 µm (maximum error 0.89 mm). The maximum holding force of the stop was approximately 6 N. The system reached a Euclidean distance error of 3.21 mm between the needle tip and the target and a normal distance of 3.03 mm between the needle trajectory and the target. CONCLUSION: An all in one solution was presented which, attached to a robotic arm, assists the radiologist in breast cancer imaging and biopsy. It has a high needle placement accuracy, yet the radiologist is in control like in the conventional procedure.

The Wire and Beyond: Recent Advances in Breast Imaging Preoperative Needle Localization.

Many patients with breast cancer are candidates for breast conservation therapy. This group includes individuals with small nonpalpable tumors detected at screening mammography and those with sufficient tumor shrinkage after neoadjuvant chemotherapy. Breast conservation surgery often requires the use of an imaging-guided preoperative localization procedure, during which a device is placed within or adjacent to the target lesion to guide the surgeon intraoperatively. For decades, wire localization has been the standard for preoperative localization in breast imaging. With this method, a wire is placed in the breast percutaneously, with the distal wire segment positioned adjacent to the abnormality and the proximal wire segment remaining outside the breast. Because of the external component of the wire, the patient must be compliant, and care must be taken to not disturb the wire's position before surgery. Scheduling flexibility is also limited because the wire localization must be performed on the same day as the subsequent surgery. More recently, the available options for performing preoperative localization have expanded greatly and now include the use of nonwire devices such as radioactive and magnetic seeds, radar reflectors, and radiofrequency identification tags. Nonwire localization devices can be placed days in advance of the surgery, at the patient's convenience, to avoid wire-related challenges and complications. They are placed percutaneously within or adjacent to the target breast lesion and detected intraoperatively by using a probe outside the breast.©RSNA, 2019.

Oil Gel-Based Phantom for Evaluating Quantitative Accuracy of Speed of Sound Measured in Ultrasound Computed Tomography.

To evaluate the quantitative accuracy of the measured speed of sound in ultrasound computed tomography for breast imaging, it is necessary to use a phantom with inclusions whose speed of sound is known. Accordingly, a phantom with known-speed-of-sound inclusions (e.g., containing water and saltwater solution) under the control of temperature was developed. In addition, an oil gel was used as the phantom material for mimicking wave refraction from fatty breast tissue to dense breast tissue. The oil gel was generated by adding SEBS (styrene-ethylene/butylene-styrene, 10% w/w) to paraffin oil. The oil gel-based phantom has a cylindrical shape and contains rod-shaped inclusions that can be filled with water or saltwater solution (3.5% w/w sodium chloride in water). When temperature increases, the speed of sound in the water increases, while that in the oil gel decreases; in particular, the speed of sound in the oil gel was higher than that in the water at temperatures <20.6°C, while the speed of sound in the oil gel was lower than that in the water at temperatures >20.6°C. It has been reported that the speed of sound in dense breast tissue is higher than that in water, while that in fatty breast tissue is lower than that in water. Ultrasound is refracted owing to the difference between the speed of sound in the breast tissue and that in the background water. By controlling the temperatures of the oil gel and water, the oil gel-based phantom simulates the refraction of an ultrasound wave from fatty breast tissue to dense breast tissue. For 43 d, the variation ranges of the speed of sound and attenuation in the oil gel in the reconstructed images were 0.7 m/s and 0.03 dB/MHz/cm, respectively. The concentration of the saltwater solution in the polyacrylamide gel-based phantom decreased from 1% (w/w) to 0.48% (w/w) after 24 h, while that in the oil-gel-based phantom was constant. In addition, magnetic resonance imaging of the oil gel-based phantom revealed that NiSO4 solution was stably contained in the phantom for 42 d. It is therefore concluded that the liquid cannot penetrate the oil gel. This oil gel-based phantom with such high temporal stability is suitable for multicenter distribution and may be used for standardization of data acquisition and image reconstruction across centers.

Automatic Breast Volume Scanner versus Handheld Ultrasound in Differentiation of Benign and Malignant Breast Lesions: A Systematic Review and Meta-analysis.

The goal of the study described here was to compare the automatic breast volume scanner (ABVS) and handheld ultrasound (HHUS) with respect to diagnostic performance in the differential diagnosis of benign and malignant breast lesions. A literature search of the PubMed, EMBASE and Cochrane Library databases through 30 June 2018 was conducted. Pooled sensitivity, specificity, positive and negative likelihood ratios and diagnostic odds ratios of the ABVS and HHUS were calculated, and summary receiver operating characteristic (SROC) curves were drawn. A total of nine studies, including 1985 lesions (628 malignant and 1357 benign) from 1774 patients, were analyzed. The pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio and diagnostic odds ratio for ABVS were 90.8% (95% confidence interval: 88.3%-93.0%), 82.2% (80.0%-84.2%), 5.39 (4.26-6.80), 0.10 (0.06-0.15) and 61.68 (32.31-117.76); those for HHUS were 90.6% (88.1%-92.8%), 81.0% (78.8%-83.0%), 5.22 (3.14-8.67), 0.11 (0.08-0.17) and 52.60 (32.06-86.35), respectively. The areas under the SROC curves in the differentiation of benign and malignant breast lesions were 0.93 and 0.94 for ABVS and HHUS, respectively, which were not significantly different (p = 0.853). In conclusion, based on available evidence in the literature, ABVS the diagnostic performance of the ABVS is similar to that of HHUS in the differentiation of benign and malignant breast lesions.