Breast Imaging System Research Articles

Added Value of a Previous Exam Comparison in the Final Breast Imaging and Reporting Data System (BI-RADS®) Assessment in Screening Mammography

Added Value of a Previous Exam Comparison in the Final Breast Imaging and Reporting Data System (BI-RADS®) Assessment in Screening Mammography

Estimation of the absorbed dose in simultaneous digital breast tomosynthesis and mechanical imaging.

Use of mechanical imaging (MI) as complementary to digital mammography (DM), or in simultaneous digital breast tomosynthesis (DBT) and MI - DBTMI, has demonstrated the potential to increase the specificity of breast cancer screening and reduce unnecessary biopsies compared with DM. The aim of this study is to investigate the increase in the radiation dose due to the presence of an MI sensor during simultaneous image acquisition when automatic exposure control is used. A radiation dose study was conducted on clinically available breast imaging systems with and without an MI sensor present. Our estimations were based on three approaches. In the first approach, exposure values were compared in paired clinical DBT and DBTMI acquisitions in 97 women. In the second approach polymethyl methacrylate (PMMA) phantoms of various thicknesses were used, and the average glandular dose (AGD) values were compared. Finally, a rectangular PMMA phantom with a 45mm thickness was used, and the AGD values were estimated based on air kerma measurements with an electronic dosemeter. The relative increase in exposure estimated from digital imaging and communications in medicine headers when using an MI sensor in clinical DBTMI was . For the phantom measurements of various thicknesses of PMMA, the relative increases in the AGD for DM and DBT measurements were, on average, and , respectively. The relative increase in the AGD using the electronic dosemeter was in DM and in DBT. The average difference in dose between the methods was . Our measurements suggest that the use of simultaneous breast radiography and MI increases the AGD by an average of . The increase in dose is within the acceptable values for mammography screening recommended by European guidelines.

Spatial N-glycomics of the normal breast microenvironment reveals fucosylated and high-mannose N-glycan signatures related to BI-RADS density and ancestry.

Higher breast cancer mortality rates continue to disproportionally affect black women (BW) compared to white women (WW). This disparity is largely due to differences in tumor aggressiveness that can be related to distinct ancestry-associated breast tumor microenvironments (TMEs). Yet, characterization of the normal microenvironment (NME) in breast tissue and how they associate with breast cancer risk factors remains unknown. N-glycans, a glucose metabolism-linked post-translational modification, has not been characterized in normal breast tissue. We hypothesized that normal female breast tissue with distinct Breast Imaging and Reporting Data Systems (BI-RADS) categories have unique microenvironments based on N-glycan signatures that varies with genetic ancestries. Profiles of N-glycans were characterized in normal breast tissue from BW (n=20) and WW (n=20) at risk for breast cancer using matrix assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI). A total of 176 N-glycans (32 core-fucosylated and 144 noncore-fucosylated) were identified in the NME. We found that certain core-fucosylated, outer-arm fucosylated and high-mannose N-glycan structures had specific intensity patterns and histological distributions in the breast NME dependent on BI-RADS densities and ancestry. Normal breast tissue from BW, and not WW, with heterogeneously dense breast densities followed high-mannose patterns as seen in invasive ductal and lobular carcinomas. Lastly, lifestyles factors (e.g. age, menopausal status, Gail score, BMI, BI-RADS) differentially associated with fucosylated and high-mannose N-glycans based on ancestry. This study aims to decipher the molecular signatures in the breast NME from distinct ancestries towards improving the overall disparities in breast cancer burden.

Results for the London investigation into dielectric scanning of lesions study of the MARIA® M6 breast imaging system.

Determine the proportion of breast cancers for which MARIA® findings correspond to the cancer, with stratification by breast density and histological type. Investigate performance in symptomatic lesions. Gain patient feedback on experience with MARIA®. MARIA® uses a radio frequency antennae array to measure signal attenuation and back scatter to build up a 3D map of tissue dielectric values. The study was a prospective, single-centre, interventional, post-approval device study. Patients were eligible if they were attending symptomatic breast clinic or had confirmed or suspected breast cancer from any referral source. Recruitment between May 2018 and March 2020. Regions of higher signal compared to background or distinct by shape were considered candidates for lesion correspondence. Up to 4 candidate regions per breast were annotated in likelihood order for representing a true lesion. 389 patients were recruited, and 6 excluded. 114 patients recruited with breast cancers (2 bilateral, 5 multicentric). 57 (47%) malignant lesions showed correspondence between the MARIA® signal and the cancer. Higher correspondence was seen in invasive (50%) than in situ (29%) disease. There was no reduction in correspondence at higher breast density. Reduced signal correspondence in the central scan volume and for small lesions. MARIA® scanning was well tolerated. We believe that MARIA® signal corresponds to a malignant lesion in 47% of breast cancers examined. Our study, the largest to date for this type of technology, demonstrates successes and limitations of this MARIA® M6 version.

A 7-year experience in core needle biopsy of breast lesions: Correlation between imaging and hematoxylin and eosin-stained sections

Screening mammography is an imaging procedure which allows breast cancer detection in its early stage. The Breast Imaging and Reporting Data System (BI-RADS) determined six radiological categories for describing lesions. The core needle biopsy (CNB) is minimally invasive procedure that provides pathohistological samples. Via microscopic analysis, samples are categorized into five groups according to the B system for pathohistological report. The aim of the study was to follow the spectrum of pathohistological diagnoses; to define which BI-RADS and core categories are most commonly expressed in certain age groups; and to determine the incidence of histological diagnoses in different BI-RADS categories. The study included 631 patients and data was analysed in order to localise the lesion, BI-RADS and core category and pathohistological diagnosis. Within 631 biopsies, 33 diagnoses were given. In each age group, the findings indicating a high risk for malignancy were the most common (>2 %). The highest percentage of malignant categories was found in patients over the age of 61. Final diagnoses showed a deviation compared to the radiological categories, especially in BI-RADS4 category. Pathohistological diagnosis is always a definite confirmation of a breast lesion type and it has significant contribution to the evaluation of CNB quality.

Abstract C118: Racial disparities in insurance coverage for supplemental breast cancer screening

Abstract Introduction and Purpose: Women with dense breasts have increased risk both for developing breast cancer and false-negative mammograms. Supplemental screening with breast MRI has been shown to shown to significantly increase cancer detection among women with dense breasts. In May 2023, Pennsylvania (PA) mandated insurance coverage of one supplemental screening study (breast MRI or ultrasound ) annually for women with dense breasts. Prior research suggests that Black women have lower breast density on average than white women based on subjective grading from the American College of Radiology Breast Imaging and Reporting Data System (BI-RADS), partially due to larger average breast size and higher body mass index (BMI) than white women. The purpose of this study was to estimate the potential impact of this supplemental screening law on different patient populations in a large health system. Methods: Women without prior breast cancer or known BRCA1/2 mutations who underwent mammographic screening at a large PA health system from April 2015-December 2017and completed a risk factor questionnaire were included (N=83,579). Under PA law, women must have either heterogeneously dense breasts plus >20% lifetime risk of breast cancer or extremely dense breasts to be eligible for insurance coverage for supplemental screening, both of which involve subjectively graded breast measurements. Breast cancer risk for each patient was estimated using the Gail model. The cancer detection rate (CDR) for mammographic screening was calculated as the number of cancers diagnosed within one year of a positive mammographic screen; the interval cancer rate was calculated as the number of cancers diagnosed within one year of a non-actionable screening mammogram per 1000 women. Logistic regression was used to calculate the odds of eligibility adjusted for age and BMI. Results: Black women were less likely to have extremely or heterogeneously dense breasts than white women (23.7% vs. 45.0%, p<0.001). Under PA law, 2.5% of Black women and 9.9% of white women would qualify for insurance coverage for supplemental screening (p<0.001). Only 0.2% of Black women and 2.3% of white women had heterogeneously dense breasts and >20% lifetime risk. Black women were more likely to have triple-negative breast cancer (TNBC) than white women (p<0.001). After adjusting for age and BMI, Black women remained 54% less likely to be eligible for supplemental screening than white women (OR=0.46, 95% 0.42-0.51, p<0.001).Conclusions: Black women are less likely to qualify for insurance coverage for supplemental breast cancer screening than white women under PA law. Given that Black women have lower prevalence of subjectively graded dense breasts and higher prevalence of TNBC, the new supplemental screening law is unlikely to meaningfully reduce racial disparities in breast cancer mortality. Methods to better assess breast cancer risk among Black women, particularly the risk of TNBC, are urgently needed to identify Black women that may benefit from supplemental screening. Citation Format: Mattia A. Mahmoud, Sarah Ehsan, Oluwadamilola M. Fayanju, Susan M. Domchek, Katherine L. Nathanson, Despina Kontos, Emily F. Conant, Anne Marie McCarthy. Racial disparities in insurance coverage for supplemental breast cancer screening [abstract]. In: Proceedings of the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2023 Sep 29-Oct 2;Orlando, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2023;32(12 Suppl):Abstract nr C118.

The role of ultrasonographic findings for PIK3CA-mutated, hormone receptor-positive, human epidermal growth factor receptor-2-negative breast cancer.

To determine whether ultrasound (US) features of breast cancer are associated with Breast Imaging and Reporting Data System molecular subtype, histologic grade, and hormone receptor status as well as to assess the predictive value of these features. Retrospective analysis of the medical records of 220 consecutive patients with invasive breast cancer was reviewed according to the PIK3CA-mutated molecular tumor subtype. US findings of all patients were analyzed. Breast tumors harboring a PIK3CA-mutation were large and exhibited liquefied necrosis and posterior echo attenuation in the nodule. Moreover, such tumors were lobulated and calcified. The aspect ratio of the PIK3CA-mutant was more likely >1. The average nodule elasticity (7.479 ± 0.993 m/s) was measured using US shear wave elastography. Microcalcification was easier to detect inside the nodule using a fluorescence technique. Measurement of the nodule blood flow spectrum showed that the internal blood flow resistance index of nodules was lower than that of other types of breast cancer. The sonographic features of PIK3CA-mutated breast cancers were strongly associated with extensive and liquefied necrosis. The ability to predict molecular subtypes, particularly using US to detect the triple-negative subtype, may play an important role in early management and treatment.

Distance compensation-based dual adaptive artifact removal algorithm in microwave breast tumor imaging system

Microwave imaging techniques have been rapidly developed in the medical field due to its non-invasive and non-radiological advantages. Pre-artifact removal is a critical procedure for desirable imaging quality produced by microwave breast imaging systems. However, current methods do not sufficiently remove pre-artifact to allow accurate localization of multiple tumors from the retrieved images. This paper presents a dual adaptive artifact removal method based on distance compensation to address issues of improving imaging quality. The method compensates for the attenuation effects due to magnetic wave propagation and adaptively selects the time entropy window threshold for grouped signals. The signals are then fed into an adaptive filter with variable filter parameters to minimize pre-artifact before imaging. Comparative tests are conducted to evaluate the merits of pre-artifact removal. The proposed method effectively reduces the pre-artifact for improving the overall quality of imaging and greatly enhances the accuracy of localizing multiple tumors.

Breast silicone implants' pericapsular impairment: current underdiagnosed status.

Many complications related to silicone implants have been reported recently, from clinical symptoms manifestations to association with some specific types of cancer. During the early 2010s, it was believed that implants were biocompatible and inert to the human body and that gel bleeding/leakage events were rare and without repercussions for the human body. However, at the end of 2010s, several studies pointed out that gel bleeding was more frequent than previously believed, and the pathogenic potential of free silicone should not be ignored. The Food and Drug Administration recommends performing magnetic resonance imaging in asymptomatic patients 5-6 years after implant placement. The descriptors in the Breast Imaging and Reporting Data System lexicon seem outdated for classifying the new generations of implants with cohesive gel, which hinders the diagnosis of device complications. In this review, supported by our research data publications related to silicone implants for 6 years on a prospective study protocol, most of them being original articles, we summarized the main complications observed in clinical practice and discuss the impact of these changes on patients' outcomes focusing on the pericapsular space.

Do We Need Breast Magnetic Resonance Imaging or Biopsy for Breast Imaging and Reporting Data System Category 3 Lesions on Ultrasound?

Do We Need Breast Magnetic Resonance Imaging or Biopsy for Breast Imaging and Reporting Data System Category 3 Lesions on Ultrasound?

The effects of breast reduction with superomedial and inferior pedicle techniques on radiological breast imaging

Several breast reduction techniques have been introduced, and the reliability of these techniques has been demonstrated in clinical practice. However, it is still controversial how patients should be evaluated radiologically both preoperative and postoperative. This study aims to compare the radiological findings seen following reduction mammoplasty with two different techniques (inferior pedicle and superomedial pedicle), in connection with the surgical steps. Medical records of 141 patients and a total of 278 breasts who underwent breast reduction with the diagnosis of macromastia were retrospectively analyzed. Demographic and operative data such as age, type of pedicle, preoperative and postoperative nipple-areola complex (NAC) position, and NAC transfer distance were recorded. Radiological evaluation was performed by two radiologists experienced in breast imaging by reinterpreting preoperative and postoperative mammography images. The rate of postoperative structural distortion (p<0.001), thickened areola (p=0.011), and retroareolar fibrotic band (p<0.001) were observed to be significantly higher in the superomedial group. The risk of fat necrosis increases as the NAC transfer distance increases and a value of >9.5cm in the NAC transfer distance can be considered as the cutoff value in terms of fat necrosis development, especially in those using superomedial pedicle technique. Surgical technique-specific benign radiological changes occur following reduction mammoplasty. However, these changes do not significantly affect the Breast imaging, reporting, and data system category. The localization of fat necrosis differs depending on the surgical technique, and the risk of fat necrosis increases as the NAC transfer distance increases, especially in those who have undergone superomedial pedicle breast reduction surgery.

Mitigating Under-Sampling Artifacts in 3D Photoacoustic Imaging Using Res-UNet Based on Digital Breast Phantom.

In recent years, photoacoustic (PA) imaging has rapidly grown as a non-invasive screening technique for breast cancer detection using three-dimensional (3D) hemispherical arrays due to their large field of view. However, the development of breast imaging systems is hindered by a lack of patients and ground truth samples, as well as under-sampling problems caused by high costs. Most research related to solving these problems in the PA field were based on 2D transducer arrays or simple regular shape phantoms for 3D transducer arrays or images from other modalities. Therefore, we demonstrate an effective method for removing under-sampling artifacts based on deep neural network (DNN) to reconstruct high-quality PA images using numerical digital breast simulations. We constructed 3D digital breast phantoms based on human anatomical structures and physical properties, which were then subjected to 3D Monte-Carlo and K-wave acoustic simulations to mimic acoustic propagation for hemispherical transducer arrays. Finally, we applied a 3D delay-and-sum reconstruction algorithm and a Res-UNet network to achieve higher resolution on sparsely-sampled data. Our results indicate that when using a 757 nm laser with uniform intensity distribution illuminated on a numerical digital breast, the imaging depth can reach 3 cm with 0.25 mm spatial resolution. In addition, the proposed DNN can significantly enhance image quality by up to 78.4%, as measured by MS-SSIM, and reduce background artifacts by up to 19.0%, as measured by PSNR, even at an under-sampling ratio of 10%. The post-processing time for these improvements is only 0.6 s. This paper suggests a new 3D real time DNN method addressing the sparse sampling problem based on numerical digital breast simulations, this approach can also be applied to clinical data and accelerate the development of 3D photoacoustic hemispherical transducer arrays for early breast cancer diagnosis.

Inclusion of a GaAs detector model in the Photon Counting Toolkit software for the study of breast imaging systems.

We present an upgraded version of the Photon Counting Toolkit (PcTK), a freely available by request MATLAB tool for the simulation of semiconductor-based photon counting detectors (PCD), which has been extended and validated to account for gallium arsenide (GaAs)-based PCD(s). The modified PcTK version was validated by performing simulations and acquiring experimental data for three different cases. The LAMBDA 60 K module planar detector (X-Spectrum GmbH, Germany) based on the Medipix3 ASIC technology was used in all cases. This detector has a 500-μm thick GaAs sensor and a 256 × 256-pixel array with 55 μm pixel size. The first validation was a comparison between simulated and measured spectra from a 109Cd radionuclide source. In the second validation study, experimental measurements and simulations of mammography spectra were generated to observe the performance of the GaAs version of the PcTK with polychromatic radiation used in conventional x-ray imaging systems. The third validation study used single event analysis to validate the spatio-energetic model of the extended PcTK version. Overall, the software provided a good agreement between simulated and experimental data, validating the accuracy of the GaAs model. The software could be an attractive tool for accurate simulation of breast imaging modalities relying on photon counting detectors and therefore could assist in their characterization and optimization.

Malignant Detection of Breast Nodules On BIRADS-Based Ultrasound Images Margin, Orientation, And Posterior

Breast cancer has the largest prevalence in the world in 2020, with 2,261,419 cases or 11.7%. It is also the leading cause of cancer death, accounting for 6.9% of all cancer deaths. Asia and Indonesia have the greatest prevalence and mortality rates. This is an urgent issue that must be addressed. Ultrasonography (USG) is advised for assessing the features of breast nodules. Breast nodules on ultrasound pictures are interpreted using the Breast Imaging, Reporting, and Data System (BIRADS) category, which has five features. Yet, the probability of a False Positive Result (FPR) on ultrasound imaging is relatively high. Computer Aided Diagnosis (CAD) was created to reduce FPR. However, CAD research based on many BIRADS traits is currently margined. As a result, based on three BIRADS characteristics, namely the margin, posterior, and orientation aspects, this study aims to proposed the methode for diagnosing breast nodule malignancy. The proposed method consists of 4 stages, namely, pre-processing, automatic segmentation, features extraction, and classification. Pre-processing adaptive median filter maximum window size is 11 pixels, linear histogram normalizing, and Reduction Anisotropic Diffusion (SRAD) filter were used to construct the method. The neutrosophic watershed method was used in the suggested automatic segmentation. Based on the nodule's margin, orientation, and posterior, 10 features were proposed: nodule width, gradient, slenderness, margin sharpness, shadow indicators, skewness, energy, entropy, dispersion, and solidity. MLP is a classification approach. The test used 94 nodule pictures and yielded an accuracy of 88.30%, a sensitivity of 82.35%, a specificity of 91.67%, a Kappa of 0.7449, and an AUC of 0.865. As a result, it is feasible to conclude that the proposed method is capable of detecting malignancy in breast nodules in ultrasound images. To make the proposed method more reliable in the future, automatic RoI can be developed.

Artificial Lossy Backgrounds to Improve Linear Electromagnetic Imaging Inside PEC Enclosures

Herein, we propose the use of artificial (or numerical) backgrounds for electromagnetic inversion inside conducting enclosures. Such enclosed imaging systems are used both due to external constraints (e.g., grain bin imaging), or in order to provide external shielding and easy-to-model boundary conditions (e.g., in stroke or breast imaging systems). We use the orthogonality sampling method (OSM), although the use of such artificial backgrounds is independent of the imaging method. Using a set of 2-D simulated examples, we show that the performance of the OSM is generally poor inside such perfect electric conductor (PEC) enclosures if the background material surrounding the target is lossless. However, we show that the performance of the OSM can be greatly improved through the use of artificial lossy backgrounds. With such artificial backgrounds, the imaging experiment can take place in a lossless PEC enclosure, but one can compute the scattered fields relative to an arbitrary lossy background, then perform the OSM inside that artificial lossy enclosure. The introduction of loss in the background problem can improve the performance of OSM when the average target permittivity is approximately known.

Artificial Intelligence for Neuroimaging and Musculoskeletal Radiology: Overview of Current Commercial Algorithms

To assess differences in the mammographic and sonographic appearance of breast cancer in African American (AA) and Non-Latina White (NLW) women.We identified AA and NLW women with biopsy proven ductal carcinoma in situ or invasive breast cancer between June 1, 2015 and May 31, 2018. Racial differences in Breast Imaging and Reporting Data System (BI-RADS) imaging features were analyzed by imaging cohorts, i.e. screen detected vs. clinical presentation, using logistic regression adjusted for histology and molecular subtypes.We analyzed 270 AA women with 278 cancers (166 screen detected, 112 clinical) and 586 NLW women with 599 cancers (397 screen detected, 202 clinical). Compared with NLW women, AA women had higher rates of non-dense breast composition (almost entirely fatty 12.0% vs. 4.6%, scattered fibroglandular 50.9% vs. 45.2%; overall P < 0001) in both cohorts and were less likely to have screen detected architectural distortion, (odds ratio (OR) = 0.38, 95% CI 0.18–0.80). AA women were less likely than NLW women to have screen detected irregular than oval/round masses (mammography: OR = 0.36, 95% CI 0.19–0.68; sonography: OR = 0.48, 95% CI 0.24–0.94), and more likely to present clinically with high density masses (OR = 3.03, 95% CI 1.12–8.20) demonstrating posterior enhancement (OR = 3.02, 95% CI 1.11–8.27).There are racial differences in the mammographic and sonographic appearance of breast cancer even after accounting for higher rates of triple negative breast cancer in AA women. Understanding these differences may provide breast imagers with a framework to approach breast cancer diagnosis in the AA population in clinical practice.

Design of a Low-Dose, Stationary, Tomographic Molecular Breast Imaging System Using 3-D Position Sensitive CZT Detectors

Molecular breast imaging (MBI) has been shown to have high sensitivity for lesion detection, particularly in patients with dense breasts where conventional mammography is limited. However, relatively high radiation dose and long imaging time are limiting factors. Most current MBI systems are based on planar imaging. Improved performance can be achieved using tomographic techniques, which normally involve detector motion. Our goal is to develop a low-dose stationary tomographic MBI system with similar or better performance in terms of lesion detection compared to planar MBI. The proposed system utilizes two opposing cadmium zinc telluride detectors with high intrinsic resolution and depth of interaction (DOI) capability, combined with densely packed multipinhole collimators. This leads to improved efficiency and adequate angular sampling, but also to significant multiplexing (MX), which can result in artefacts. We have developed de-MX algorithms that take advantage of the DOI information. We have performed both analytic and Monte Carlo simulations to demonstrate the feasibility, optimize the design and investigate the expected performance of the proposed system. Lesion detectability was preserved with reduction of acquisition time (or radiation dose) by a factor of 2 compared to planar images at the lowest reported dose. The first prototype is under evaluation at Kromek.

Textile monopole sensors for breast cancer detection

This paper presents two flexible monopole antennas implemented on cotton substrate as sensors designed for radar-based microwave imaging and particularly breast imaging systems. The flexible antennas are basic building block of a radar-based microwave imaging system that could be integrated in clothes. Thus, these low-cost textile sensors could be used by women for self-monitoring and early breast cancer detection at an affordable price. The ultra-wideband fully textile sensors are designed as rectangular and circular monopole antennas. Both sensors have an impedance bandwidth le − 10 dB from 2.2 to 8 GHz with an overall footprint of 50 × 50 mm2. Simulations for antenna in proximity to breast model with and without tumor as well as bending capacity are performed. The simulations are complemented with fabrication of a breast phantom and a tumor sample with parameters that mimic these of the human breast’s healthy and malignant tissue. Measurements are compared to simulation results as well as the performance of antenna before and after subjected to washing. Finally, the specific absorption rate is also calculated and measured to ensure safety for on-body deployment. The proposed work demonstrates the potential to develop wearable microwave imaging system using fully textile antennas.

Interpretacija mamografije po BI-RADS klasifikaciji

Interpretation of mammograms is done according to the BIRADS (Breast Imaging and Reporting Data System) classification, which was introduced by the American Association of Radiologists as a unique and standard terminology in the radiological diagnosis of breast diseases. In use are: BI-RADS 0, BIRADS 1, BI-RADS 2, BI-RADS 3, BI-RADS 4, BI-RADS 5 and BI-RADS 6. Within the framework of organized breast cancer screening in Serbia, in use is BI-RADS 1, BI-RADS 2, BI-RADS 4, and BI-RADS 5, while categories BI-RADS 0, BI-RADS 3 and BI-RADS 6 are not in use. The goal of the work is the interpretation of mammograms according to the BI-RADS classification, while the material of the work consists of literal reports and over 500,000 mammograms performed from 1995 to 2022. in the Radiology Center of the University Clinical Center in Niš. The authors conclude that BI-RADS represents a modern dictionary of mammography in the form of a numerically coded conclusion with the level of suspicion of breast cancer

Pathway to Demonstrating Clinical Efficacy of Microwave Breast Imaging: Qualitative and Quantitative Performance Assessment

In the last five years alone, there has been an increasing number of operational microwave breast imaging systems used in clinical trials, with increasingly large and diverse patient populations. However, despite this increased activity and volume of clinical evidence motivating research in the modality, large differences exist in how studies evaluate and report their findings. In this work, the qualitative and quantitative metrics used to measure both image quality and clinical effectiveness and efficacy are reviewed in detail. Image quality, effectiveness and efficacy do not have precise or agreed definitions and the differences between these definitions are discussed in detail. Finally, based on these understandings, the current evidence for clinical acceptance of microwave breast imaging is reviewed, with an emphasis on gaps in the trial populations to date.