Contrast-enhanced spectral mammography (CESM)-guided breast biopsy as an alternative to MRI-guided biopsy

A deep learning approach for virtual contrast enhancement in Contrast Enhanced Spectral Mammography

Contrast Enhanced Spectral Mammography (CESM) is a dual-energy mammographic imaging technique that first requires intravenously administering an iodinated contrast medium. Then, it collects both a low-energy image, comparable to standard mammography, and a high-energy image. The two scans are combined to get a recombined image showing contrast enhancement. Despite CESM diagnostic advantages for breast cancer diagnosis, the use of contrast medium can cause side effects, and CESM also beams patients with a higher radiation dose compared to standard mammography. To address these limitations, this work proposes using deep generative models for virtual contrast enhancement on CESM, aiming to make CESM contrast-free and reduce the radiation dose. Our deep networks, consisting of an autoencoder and two Generative Adversarial Networks, the Pix2Pix, and the CycleGAN, generate synthetic recombined images solely from low-energy images. We perform an extensive quantitative and qualitative analysis of the model's performance, also exploiting radiologists' assessments, on a novel CESM dataset that includes 1138 images. As a further contribution to this work, we make the dataset publicly available. The results show that CycleGAN is the most promising deep network to generate synthetic recombined images, highlighting the potential of artificial intelligence techniques for virtual contrast enhancement in this field.

Breast radiation dose with contrast-enhanced mammography-guided biopsy: a retrospective comparison with stereotactic and tomosynthesis guidance

OBJECTIVES

This retrospective study aimed to compare the average glandular dose (AGD) per acquisition in breast biopsies guided by contrast-enhanced mammography (CEM), conventional stereotactic breast biopsy (SBB), and digital breast tomosynthesis (DBT). The study also investigated the influence of compressed breast thickness (CBT) and density on AGD. Furthermore, the study aimed to estimate the AGD per procedure for each guidance modality.

METHODS

The study included 163 female patients (mean age 57 ± 10 years) who underwent mammography-guided biopsies using SBB (9%), DBT (65%), or CEM (26%) guidance. AGD and CBT data were extracted from DICOM headers, and breast density was visually assessed. Statistical analyses included two-sample t-tests and descriptive statistics.

RESULTS

Mean AGD per acquisition varied slightly among CEM (1.48 ± 0.22 mGy), SBB (1.49 ± 0.40 mGy), and DBT (1.55 ± 0.47 mGy), with CEM presenting higher AGD at lower CBTs and less dose escalation at higher CBTs. For CBT > 55 mm, CEM showed reduced AGD compared to SBB and DBT (p < 0.001). Breast density had minimal impact on AGD, except for category A. The estimated AGD per procedure was approximately 11.84 mGy for CEM, 11.92 mGy for SBB, and 6.2 mGy for DBT.

CONCLUSION

The study found mean AGD per acquisition to be similar for CEM and SBB, with DBT slightly higher. CEM demonstrated higher AGD at lower CBT but lower AGD at higher CBT, indicating reduced dose escalation with increasing thickness. While breast density had minimal overall impact, variations were noted in category A. DBT was more dose-efficient per procedure due to fewer acquisitions required.

CLINICAL RELEVANCE STATEMENT

CEM guidance provides effective lesion visualization within safe radiation limits, improving the precision of percutaneous image-guided breast interventions and supporting its potential consideration in a wider range of breast diagnostic procedures.

KEY POINTS

Limited data exist on the AGD using CEM guidance for breast biopsies. CEM and SBB exhibit similar AGD per acquisition; DBT demonstrated the lowest AGD per procedure. Radiation from CEM guidance fits within safe limits for percutaneous image-guided breast interventions.

Stereotactic biopsy with contrast-enhanced mammography: the initial Australian experience

INTRODUCTION

Contrast-enhanced mammography (CEM) and MRI detect 'contrast-only' lesions (COLs) occult on standard breast imaging (ultrasound and conventional mammography). Until recently, MRI was the only reliable method of biopsy. This study presents the first Australian experience with CEM-guided biopsy (CEMBx) and the lessons learnt.

METHODS

A prospective audit of the first 15 consecutive patients who underwent CEMBx for COLs was performed. Indications for contrast imaging, patient and lesion characteristics, procedural details, radiation dose and pathology data were collected.

RESULTS

The 15 women were aged 37-81 years (mean 59 years). Indications for contrast imaging were problem solving (n = 3), moderate risk screening (n = 2), cancer staging (n = 9) and symptoms (n = 1). The COLs were non-mass (n = 14), mass (n = 1) and an enhancing asymmetry (n = 1). For one patient, two lesions were sampled during the same event. All lesions enhanced and were successfully sampled followed by marker clip insertion. Most biopsies (87.5%) were performed with the breast in cranio-caudal compression using a horizontal approach. Procedural duration ranged from 13 to 33 min (mean 22 min). Radiation dose was similar to standard stereotactic biopsy. Post-biopsy hematomas occurred in three patients, none required intervention. Clip displacement occurred in three cases. Core biopsy histopathology results were benign (n = 8), malignant (n = 7) and a borderline breast lesion (BBL) (n = 1). Patient satisfaction rates were high. Imaging follow-up is ongoing.

CONCLUSIONS

CEMBx is a quick, safe and reliable alternative to MRIBx to sample COLs.

Contrast-Enhanced Mammography-Guided Biopsy: Preliminary Results of a Single-Center Retrospective Experience

Background: CEM-guided breast biopsy is an advanced diagnostic procedure that takes advantage of the ability of CEM to enhance suspicious breast lesions. The aim pf this paper is to describe a single-center retrospective experience on CEM-guided breast biopsy in terms of procedural features and histological outcomes. Methods: 69 patients underwent the procedure. Patient age, breast density, presentation, dimensions, and lesion target enhancement were recorded. All the biopsy procedures were performed using a 7- or 10-gauge (G) vacuum-assisted biopsy needle. The procedural approach (horizontal or vertical) and the decubitus of the patient (lateral or in a sitting position) were noted. Results: A total of 69 patients underwent a CEM-guided biopsy. Suspicious lesions presented as mass enhancement in 35% of cases and non-mass enhancement in 65% of cases. The median size of the target lesions was 20 mm. The median procedural time for each biopsy was 10 ± 4 min. The patients were placed in a lateral decubitus position in 52% of cases and seated in 48% of cases. The most common approach was horizontal (57%). The mean AGD was 14.8 mGy. At histology, cancer detection rate was 28% (20/71). Conclusions: CEM-guided biopsy was feasible, with high procedure success rates and high tolerance by the patients.

Short-term follow-up of contrast-enhanced mammography lesions after negative breast MRI in women with elevated breast cancer risk

PURPOSE

To determine the outcome of enhancing lesions detected on contrast-enhanced mammography (CEM) that had no correlate on magnetic resonance imaging (MRI) and underwent short-term follow-up CEM.

METHODS

In this retrospective single-center study, we identified patients with elevated breast cancer risk who had a CEM between 2014 and 2021 showing indeterminate enhancement on recombined images (BI-RADS 0, 3, 4) that had no correlate on subsequent MRI (performed within one month), and therefore underwent short-term follow-up CEM (performed within eight months). Medical records and imaging studies were reviewed to collect data on patient and lesion characteristics, and outcomes. Cancer incidence with 95% confidence interval (CI) was calculated.

RESULTS

This study included 71 women (median age 49 years) with 81 enhancing CEM lesions who underwent short-term follow-up CEM (median 6.2 months) after MRI reported no correlate. Of 81 lesions (median size = 0.7 cm), 73 (90%) were non-mass enhancement and 8 (10%) were enhancing masses. No sonographic correlate was identified for 75 lesions that had a same-day targeted ultrasound. Two cancers (2.5%, 95% CI 0.3-8.6) were diagnosed during the short-term follow-up period, one at 6-months (invasive ductal carcinoma) and one at 12-months (ductal carcinoma in situ). The remaining 79 lesions were benign at 6-month follow-up CEM and at one-year mammographic follow-up.

CONCLUSIONS

Follow-up CEM of MRI-occult lesions is prudent and may be reasonable to perform at one-year given the low incidence of cancer detected at six-months (one of 81) in our small study sample.

Contrast-enhanced ultrasound-guided biopsy of suspicious breast lesions on contrast-enhanced mammography and contrast-enhanced MRI: a case series

PURPOSE

To assess the effectiveness of contrast-enhanced ultrasound (CEUS) in guiding biopsies of breast lesions that were detected on contrast-enhanced mammography (CEM) or contrast-enhanced breast MRI (CE-MRI) but were not clearly visible on B-mode ultrasound (B-US).

METHODS

In this study, 23 lesions in 16 patients were selected for CEUS-guided biopsy due to poor visualization on B-US despite being detected on CEM (n = 20) or CE-MRI (n = 3). B-US, color Doppler ultrasound (CDUS), and CEUS were used to visualize the suspicious lesions, followed by a CEUS-guided core needle biopsy using Sonazoid as the contrast agent. The accuracy of the biopsy was assessed based on pathology-radiology concordance and 12-month imaging follow-up. The conspicuity scores for lesion visualization were evaluated using a 5-point conspicuity scale agreed upon by two breast radiologists.

RESULTS

The enhancing lesions detected on CEM/CE-MRI had an average size of 1.6 ± 1.3 cm and appeared as mass-enhancing (61%) or non-mass-enhancing (39%). The lesions had mean conspicuity scores of 2.30 on B-US, 2.78 on CDUS, and 4.61 on CEUS, with 96% of the lesions showing contrast enhancement on CEUS. CEUS-guided biopsy showed increased visibility in 96% and 91% of the lesions compared to B-US and CDUS, respectively. The overall accuracy of CEUS-guided biopsy was 100% based on concordance with histology and 12-month follow-up.

CONCLUSIONS

CEUS enhances the visibility of suspicious CEM/CE-MRI lesions that are poorly visible on B-US during biopsy procedures.

Iopromide for Contrast-Enhanced Mammography: A Systemic Review and Meta-Analysis of Pertinent Literature

Background

Contrast-enhanced mammography (CEM) is an emerging breast imaging modality. Clinical data is scarce.

Objectives

To summarize clinical evidence on the use of iopromide in CEM for the detection or by systematically analyzing the available literature on efficacy and safety.

Design

Systematic review and meta-analysis.

Data sources and methods

Iopromide-specific publications reporting its use in CEM were identified by a systematic search within Bayer's Product Literature Information (PLI) database and by levering a recent review publication. The literature search in PLI was performed up to January 2023. The confirmatory-supporting review publication was based on a MEDLINE/EMBASE + full text search for publications issued between September 2003 and January 2019. Relevant literature was selected based on pre-defined criteria by 2 reviewers. The comparison of CEM vs traditional mammography (XRM) was performed on published results of sensitivity and specificity. Differences in diagnostic parameters were assessed within a meta-analysis.

Results

Literature search: A total of 31 studies were identified reporting data on 5194 patients. Thereof, 19 studies on efficacy and 3 studies on safety. Efficacy: in 11 studies comparing iopromide CEM vs XRM, sensitivity was up to 43% higher (range 1%-43%) for CEM. Differences in specificity were found to be in a range of -4% to 46% for CEM compared with XRM. The overall gain in sensitivity for CEM vs XRM was 7% (95% CI [4%, 11%]) with no statistically significant loss in specificity in any study assessed. In most studies, accuracy, positive predictive value, and negative predictive value were found to be in favor of CEM. In 2 studies comparing CEM with breast magnetic resonance imaging (bMRI), both imaging modalities performed either equally well or CEM tended to show better results with respect to sensitivity and specificity. Safety: eight cases of iopromide-related adverse drug reactions were reported in 1022 patients (0.8%).

Conclusions

Pertinent literature provides evidence for clinical utility of iopromide in CEM for the detection or confirmation of breast cancer. The overall gain in sensitivity for iopromide CEM vs XRM was 7% with no statistically significant loss in specificity.

Contrast-enhanced mammography-guided biopsy: technique and initial outcomes

Contrast-enhanced mammography-guided biopsy (CEM-Bx), a novel technique for diagnosing suspicious enhanced lesions, was commercialized for clinical application in 2021; however, there are only a few publications documenting this technique in the existing literature. The aim of this study was to evaluate the procedural performance and preliminary outcomes of CEM-Bx performed in our hospital between from September 2021 to June 2022. We reviewed data of 12 women who underwent CEM-Bx during the study period, including their demographic and procedural characteristics, biopsy success rate, histopathological diagnosis, and average glandular dose (AGD). All women (mean age ± standard deviation: 54±6 years) showed enhanced breast lesions on CEM and underwent CEM-Bx within one week. The success rate of CEM-Bx was 100%. The vertical needle approach was used in a decubitus position (N=7, 58%), while the horizontal needle approach was used in an upright sitting position (N=5, 42%). The mean procedure time for the CEM-Bx was 17±6.3 min. The mean AGD was 14.3±12.3 mGy. Histopathologic examination revealed a malignancy rate of 66.7%. In summary, CEM-Bx is a feasible technique, with a high success rate of diagnosing contract-enhanced lesions.

Barriers to Implementation of Contrast-Enhanced Mammography in Clinical Practice: AJR Expert Panel Narrative Review

Accumulating evidence shows that contrast-enhanced mammography (CEM) has higher diagnostic performance than digital mammography and ultrasound and comparable diagnostic performance to MRI for various indications. CEM also offers certain practical advantages for patients. Nevertheless, the clinical implementation of CEM has been limited because of a range of factors. This AJR Expert Panel Narrative Review explores such factors hindering CEM implementation. These factors include the following: the risks of iodinated contrast media, increased radiation exposure, indications for which CEM is not the preferred test or for which further evidence is needed, workflow adjustments needed when performing CEM examinations, incomplete availability of CEM-guided biopsy systems, and reimbursement challenges. Considerations that currently mitigate or are expected to mitigate these factors are also highlighted.

Contrast-enhanced Mammography-guided Biopsy: Initial Trial and Experience

OBJECTIVE

Evaluate lesion visibility and radiologist confidence during contrast-enhanced mammography (CEM)-guided biopsy.

METHODS

Women with BI-RADS ≥4A enhancing breast lesions were prospectively recruited for 9-g vacuum-assisted CEM-guided biopsy. Breast density, background parenchymal enhancement (BPE), lesion characteristics (enhancement and conspicuity), radiologist confidence (scale 1-5), and acquisition times were collected. Signal intensities in specimens were analyzed. Patient surveys were collected.

RESULTS

A cohort of 28 women aged 40-81 years (average 57) had 28 enhancing lesions (7/28, 25% malignant). Breast tissue was scattered (10/28, 36%) or heterogeneously dense (18/28, 64%) with minimal (12/28, 43%), mild (7/28, 25%), or moderate (9/28, 32%) BPE on CEM. Twelve non-mass enhancements, 11 masses, 3 architectural distortions, and 2 calcification groups demonstrated weak (12/28, 43%), moderate (14/28, 50%), or strong (2/28, 7%) enhancement. Specimen radiography demonstrated lesion enhancement in 27/28 (96%). Radiologists reported complete lesion removal on specimen radiography in 8/28 (29%). Average time from contrast injection to specimen radiography was 18 minutes (SD = 5) and, to post-procedure mammogram (PPM), 34 minutes (SD = 10). Contrast-enhanced mammography PPM was performed in 27/28 cases; 13/19 (68%) of incompletely removed lesions on specimen radiography showed residual enhancement; 6/19 (32%) did not. Across all time points, average confidence was 2.2 (SD = 1.2). Signal intensities of enhancing lesions were similar to iodine. Patients had an overall positive assessment.

CONCLUSION

Lesion enhancement persisted through PPM and was visible on low energy specimen radiography, with an average "confident" score. Contrast-enhanced mammography-guided breast biopsy is easily implemented clinically. Its availability will encourage adoption of CEM.

Invasive Lobular Carcinoma: A Review of Imaging Modalities with Special Focus on Pathology Concordance

Invasive lobular cancer (ILC) is the second most common type of breast cancer. It is characterized by a unique growth pattern making it difficult to detect on conventional breast imaging. ILC can be multicentric, multifocal, and bilateral, with a high likelihood of incomplete excision after breast-conserving surgery. We reviewed the conventional as well as newly emerging imaging modalities for detecting and determining the extent of ILC- and compared the main advantages of MRI vs. contrast-enhanced mammogram (CEM). Our review of the literature finds that MRI and CEM clearly surpass conventional breast imaging in terms of sensitivity, specificity, ipsilateral and contralateral cancer detection, concordance, and estimation of tumor size for ILC. Both MRI and CEM have each been shown to enhance surgical outcomes in patients with newly diagnosed ILC that had one of these imaging modalities added to their preoperative workup.

Contrast-enhanced mammography in breast cancer screening

Contrast-enhanced mammography (CEM) is a promising vascular-based breast imaging technique with high diagnostic performance in detecting breast cancer. Dual-energy acquisition using low and high energy x-ray spectra following intravenous iodinated contrast injection provides both anatomic and functional information in the same examination. The low-energy images are equivalent to standard digital mammography and the post-processed recombined images depict enhancement analogous to contrast-enhanced breast magnetic resonance imaging (MRI). Thus, CEM has the potential to detect abnormal morphologic features as well as neovascularity associated with breast cancer. Since its emergence in 2011, CEM has consistently demonstrated superior performance compared with standard mammography and mammography plus ultrasound, particularly in women with dense breasts, with high sensitivity approaching that of MRI, supporting its use as a cost-effective diagnostic and screening tool. CEM has been primarily used in the diagnostic setting to evaluate patients with screening abnormalities or with symptomatic breasts, to perform preoperative staging of newly diagnosed breast cancer, and to evaluate response to neoadjuvant chemotherapy. More recently, CEM has been performed to screen women who have an intermediate to high lifetime risk of developing breast cancer. In addition to its high diagnostic performance, CEM is less expensive and more accessible than MRI and potentially better tolerated by patients. Minor drawbacks to CEM include a slightly increased radiation dose compared with standard mammography and a low risk for contrast allergy reaction. The aim of this study is to review the background, current literature, and future applications of CEM in breast cancer screening.