Background parenchymal enhancement on breast MRI: A comprehensive review.

The degree of normal fibroglandular tissue that enhances on breast MRI, known as background parenchymal enhancement (BPE), was initially described as an incidental finding that could affect interpretation performance. While BPE is now established to be a physiologic phenomenon that is affected by both endogenous and exogenous hormone levels, evidence supporting the notion that BPE frequently masks breast cancers is limited. However, compelling data have emerged to suggest BPE is an independent marker of breast cancer risk and breast cancer treatment outcomes. Specifically, multiple studies have shown that elevated BPE levels, measured qualitatively or quantitatively, are associated with a greater risk of developing breast cancer. Evidence also suggests that BPE could be a predictor of neoadjuvant breast cancer treatment response and overall breast cancer treatment outcomes. These discoveries come at a time when breast cancer screening and treatment have moved toward an increased emphasis on targeted and individualized approaches, of which the identification of imaging features that can predict cancer diagnosis and treatment response is an increasingly recognized component. Historically, researchers have primarily studied quantitative tumor imaging features in pursuit of clinically useful biomarkers. However, the need to segment less well-defined areas of normal tissue for quantitative BPE measurements presents its own unique challenges. Furthermore, there is no consensus on the optimal timing on dynamic contrast-enhanced MRI for BPE quantitation. This article comprehensively reviews BPE with a particular focus on its potential to increase precision approaches to breast cancer risk assessment, diagnosis, and treatment. It also describes areas of needed future research, such as the applicability of BPE to women at average risk, the biological underpinnings of BPE, and the standardization of BPE characterization. Level of Evidence: 3 Technical Efficacy Stage: 5 J. Magn. Reson. Imaging 2020;51:43-61.

The impact of preoperative magnetic resonance imaging and lumpectomy cavity shavings on re-excision rate in pure ductal carcinoma in situ-A single institution's experience.

BACKGROUND AND OBJECTIVES: The impact of preoperative magnetic resonance imaging (pMRI) and cavity shave margins (CSM) on re-excision rate (RR) in DCIS is unclear. We investigated whether either modality was associated with RR in DCIS. METHODS: This is a single-institution retrospective study of 295 women undergoing breast conservation surgery for pure DCIS (2010-2013). CSM were the systematic resection of 4-6 margins during lumpectomy whereas selective shave margins (SSM) were the selective resection of 1-3 margins. Patient demographics and clinical characteristics were abstracted. RR was analyzed according to the use of pMRI, SSM, or CSM with respect to three high-volume breast surgeons at our institution. RESULTS: RR was not associated with the use of pMRI (P = 0.87). Any shave margins (P = 0.05), DCIS size (P < 0.001), and DCIS grade (P = 0.14) associated with a lower RR. Of our high-volume surgeons, RR was lower for Surgeon A (P = 0.02). Multivariate analyses showed larger DCIS (OR 1.35, P = 0.005) and practices specific to surgeons B (OR 3.23, P = 0.04) and C (OR 3.57, P = 0.04) increased re-excision odds. CONCLUSIONS: SSM/CSM and pMRI use varied among surgeons. Our results suggested the routine use of CSM, not pMRI, could lower re-excision rate, which highlighted a quality improvement opportunity at our institution.

The Impact of Imaging Informatics Fellowships.

Imaging informatics (II) is an area within clinical informatics that is particularly important in the field of radiology. Provider groups have begun employing dedicated radiologist-informaticists to bridge medical, information technology and administrative functions, and academic institutions are meeting this demand through formal II fellowships. However, little is known about how these programs influence graduates' careers and perceptions about professional development. We electronically surveyed 26 graduates from US II fellowships and consensus leaders in the II community-many of whom were subspecialty diagnostic radiologists (68%) employed within academic institutions (48%)-about the perceived impact of II fellowships on career development and advancement. All graduates felt that II fellowship made them more valuable to employers, with the majority of reporting ongoing II roles (78%) and continued used of competencies (61%) and skills (56%) gained during fellowship in their current jobs. Other key benefits included access to mentors, protected time for academic work, networking opportunities, and positive impacts of annual compensation. Of respondents without II fellowship training, all would recommend fellowships to current trainees given the ability to gain a "still rare" but "essential skill set" that is "critical for future leaders in radiology" and "better job opportunities." While some respondents felt that II fellowships needed further formalization and standardization, most (85%) disagreed with requiring a 2-year II fellowship in order to qualify for board certification in clinical informatics. Instead, most believed that fellowships should be integrated with clinical residency or fellowship training while preserving formal didactics and unstructured project time. More work is needed to understand existing variations in II fellowship training structure and identify the optimal format for programs targeted at radiologists.

Radiologist Preferences for Artificial Intelligence-Based Decision Support During Screening Mammography Interpretation.

BACKGROUND: Artificial intelligence (AI) may improve cancer detection and risk prediction during mammography screening, but radiologists' preferences regarding its characteristics and implementation are unknown. PURPOSE: To quantify how different attributes of AI-based cancer detection and risk prediction tools affect radiologists' intentions to use AI during screening mammography interpretation. MATERIALS AND METHODS: Through qualitative interviews with radiologists, we identified five primary attributes for AI-based breast cancer detection and four for breast cancer risk prediction. We developed a discrete choice experiment based on these attributes and invited 150 US-based radiologists to participate. Each respondent made eight choices for each tool between three alternatives: two hypothetical AI-based tools versus screening without AI. We analyzed samplewide preferences using random parameters logit models and identified subgroups with latent class models. RESULTS: Respondents (n = 66; 44% response rate) were from six diverse practice settings across eight states. Radiologists were more interested in AI for cancer detection when sensitivity and specificity were balanced (94% sensitivity with <25% of examinations marked) and AI markup appeared at the end of the hanging protocol after radiologists complete their independent review. For AI-based risk prediction, radiologists preferred AI models using both mammography images and clinical data. Overall, 46% to 60% intended to adopt any of the AI tools presented in the study; 26% to 33% approached AI enthusiastically but were deterred if the features did not align with their preferences. CONCLUSION: Although most radiologists want to use AI-based decision support, short-term uptake may be maximized by implementing tools that meet the preferences of dissuadable users.

The voice of the radiologist: Enabling patients to speak directly to radiologists.

Patients and patient advocates express a desire to speak directly with radiologists, who are ideally suited to answer imaging-related questions and recommend for further imaging or testing. While web-based patient portals have improved patient access to reports of radiology examinations, they do little to help patients understand the report, and rarely facilitate contact with their radiologists. We implemented an alias phone number that forwarded to the smartphone of each participating radiologist and embedded it in 3896 reports over 8 months. It was embedded as an invitation to the individual viewing the report to call with questions. For each call received, we logged parameters such as call duration, call reason, and required radiologist time/resources. Finally, the call was documented in the electronic medical record. Radiologists received 27 calls exclusively about cross-sectional exams: 22 from patients or caregivers, and 5 from physicians. The reasons for the calls included term definitions, correction of dictation errors, findings not specifically mentioned, and clinical impact of findings. Time spent on the phone with patients averaged 8.6 min. When including the time spent reviewing the images, patient chart, and/or literature; the total radiologist time per call was approximately 13.9 min. Averaged over all of the exams in the study, this service added 5 s to each exam. While the total call rate was low, implementation of this program required minimal effort. The aliased phone number masked the radiologist's phone number and allowed scheduled consultation hours. Even when called, the time to address questions appears to be minimal.

Physician Ordering of Screening Ultrasound: National Rates and Association With State-Level Breast Density Reporting Laws.

PURPOSE: To describe factors associated with screening ultrasound ordering and determine whether adoption of state-level breast density reporting laws was associated with changes in ordering rates. MATERIALS AND METHODS: We performed a cohort study using National Ambulatory Medical Care Survey data for 2007 to 2015. We included preventive office visits for women aged 40 to 74 years without breast symptoms and signs or additional reasons requiring ultrasound ordering. Multivariate logistic regression was used to identify changes in ultrasound ordering rates pre- versus post-state-level density reporting laws, accounting for patient-, physician-, and practice-level characteristics. Analyses were weighted to account for the multistage probability sampling design of National Ambulatory Medical Care Survey. RESULTS: Our sample included 12,787 visits over the 9-year study period. Overall, 28.9% (3,370 of 12,787) of women underwent a breast examination and 22.1% (2,442 of 12,787) had a screening mammogram ordered. Only 3.3% (379 of 12,787) had screening ultrasound ordered. Screening ultrasounds were ordered more frequently for younger women (rate ratio [RR] 0.8 per 10-year increase in age, 95% confidence interval [CI]: 0.6-0.9, P = .003) and at urban practices (RR 2.3, 95% CI: 1.1-5.0, P = .028), and less frequently in practices with computer reminders for ordering screening tests (RR 0.6, 95% CI: 0.3-0.9, P = .024). In multivariate analyses, the rate of ultrasound ordering did not change after adoption of density notification laws (RR 0.7, 95% CI: 0.3-2.0, P = .57). CONCLUSION: The rate of screening ultrasound ordering remains low over time. There was no observed association between adoption of state-level density reporting laws and overall changes in ultrasound ordering.

Location, Location, Location: The Association Between Imaging Setting and Follow-Up of Findings of Indeterminate Malignant Potential.

PURPOSE: To evaluate the relationship between patient location at time of imaging and completion of relevant imaging follow-up for findings with indeterminate malignant potential. METHODS: We used a mandatory hospital-wide standardized assessment categorization system to analyze all ultrasound, CT, and MRI examinations performed over a 7-month period. Multivariate logistic regression, adjusted for imaging modality, characteristics of patients, ordering clinicians, and interpreting radiologists, was used to evaluate the relationship between patient location (outpatient, inpatient, or emergency department) at the time of index examination and completion of relevant outpatient imaging follow-up. RESULTS: Relevant follow-up occurred in 49% of index examinations, with a greater percentage among those performed in the outpatient setting compared with those performed in the inpatient or emergency department settings (62% versus 18% versus 17%, respectively). Compared with examinations obtained in the outpatient setting, examinations performed in the emergency department (adjusted odds ratio [aOR] 0.07; 95% confidence interval [CI], 0.03-0.19) and inpatient (aOR 0.14; 95% CI, 0.09-0.23) settings were less likely to be followed up. Black patients and those residing in lower-income neighborhoods were also less likely to receive relevant follow-up. Few lesions progressed to more suspicious lesions (4.6%). CONCLUSIONS: Patient location at time of imaging is associated with the likelihood of completing relevant follow-up imaging for lesions with indeterminate malignant potential. Future work should evaluate health system-level care processes related to care setting, as well as their effects on appropriate follow-up imaging. Doing so would support efforts to improve appropriate follow-up imaging and reduce health care disparities.

Double reading of automated breast ultrasound with digital mammography or digital breast tomosynthesis for breast cancer screening.

PURPOSE: To evaluate the impact of double reading automated breast ultrasound (ABUS) when added to full field digital mammography (FFDM) or digital breast tomosynthesis (DBT) for breast cancer screening. METHODS: From April 2014 to June 2015, 124 women with dense breasts and intermediate to high breast cancer risk were recruited for screening with FFDM, DBT, and ABUS. Readers used FFDM and DBT in clinical practice and received ABUS training prior to study initiation. FFDM or DBT were first interpreted alone by two independent readers and then with ABUS. All recalled women underwent diagnostic workup with at least one year of follow-up. Recall rates were compared using the sign test; differences in outcomes were evaluated using Fisher's exact test. RESULTS: Of 121 women with complete follow-up, all had family (35.5%) or personal (20.7%) history of breast cancer, or both (43.8%). Twenty-four women (19.8%) were recalled by at least one modality. Recalls increased from 5.0% to 13.2% (p = 0.002) when ABUS was added to FFDM and from 3.3% to 10.7% (p = 0.004) when ABUS was added to DBT. Findings recalled by both readers were more likely to result in a recommendation for short term follow-up imaging or tissue biopsy compared to findings recalled by only one reader (100% vs. 42.1%, p = 0.041). The cancer detection rate was 8.3 per 1000 screens (1/121); mode of detection: FFDM and DBT. CONCLUSIONS: Adding ABUS significantly increased the recall rate of both FFDM and DBT screening. Double reading of ABUS during early phase adoption may reduce false positive recalls.

Viewing the Value of Radiology Through Patient Web Portals.

With widespread adoption of web portals and unfettered patient access to online radiology reports, these previous end products are quickly becoming springboards for direct radiologist-patient interactions, further increasing the value proposition for radiologists in an era of patient-centered care. Here, we provide a real-world scenario demonstrating a teachable moment on how imaging examination reporting in the digital era is expanding the radiologist's role in patient consultation.

Geographic Patterns of Radiology Referrals in the United States: A Descriptive Network Analysis.

PURPOSE: To provide a nationwide description of radiology referral patterns for Medicare beneficiaries and network-based measures that can describe and monitor shifts in referral patterns. METHODS: We linked publicly available Medicare data with the National Plan and Provider Enumeration System data set to analyze 3,925,366 encounters representing referrals from nonradiology referrers to diagnostic radiology providers in 2015. We assessed per-state referral volume as well as in-state and in-region referrals and the correlation between state referral volume and in-state referrals. Additionally, we applied the conceptual framework of networks to create two measures to evaluate referrer-radiologist connections within each state: number of referrer relationships and referral density index (RDI). RESULTS: In 2015, there was considerable variation in in-state referrals across states, and the correlation between state referral volume and in-state referrals was low (0.18). Across census regions, in-region referrals were high (84.3% in the South to 89.2% in the Midwest). Across states, the mean number of referrer relationships ranged from 7.0 in Utah to 25.0 in California, and the number of referrer relationships varied significantly within states. Radiology provider RDI also varied both within and across states, with mean radiology provider RDI spanning from 0.05 in Kansas to 0.25 in Hawaii. CONCLUSIONS: In a nationwide description of geographic patterns in radiology referrals among Medicare beneficiaries, we demonstrate wide variation in radiology referral patterns and utilized network methods to develop two measures that can be used in the future to monitor shifts in referral patterns.

Time to Talk: Can Radiologists Improve Follow-Up of Abdominal Imaging Findings Indeterminate for Malignancy by Initiating Verbal Communication?

PURPOSE: The aims of this study were to examine the association between radiologist-initiated verbal communication for abdominal imaging findings indeterminate for malignancy and receipt of relevant outpatient follow-up imaging and to evaluate the proportion of findings that progress from indeterminate to suspicious for malignancy. METHODS: Using a mandatory standardized assessment coding system, 727 eligible outpatient abdominal CT, MRI, and ultrasound studies performed between July 1, 2013, and January 31, 2014, were identified. Multivariate logistic regression was used to evaluate the association between radiologist-initiated verbal communication and receipt of relevant outpatient imaging follow-up, adjusted for patient, ordering physician, interpreting radiologist, and imaging variables. RESULTS: Sixty-two percent of patients (451 of 727) with imaging findings indeterminate for malignancy received relevant outpatient imaging follow-up. Radiologist-initiated verbal communication occurred in 4.8% of cases (35 of 727). Radiologist-initiated verbal communication (odds ratio [OR], 2.45; 95% confidence interval [CI], 1.02-5.87) and existing cancer diagnosis (OR, 3.00; 95% CI, 2.11-4.26) were associated with a higher likelihood of receiving relevant imaging follow-up. Compared with those whose imaging studies were ordered by clinicians in a medical specialty, patients with studies ordered by clinicians in surgical (OR, 0.70; 95% CI, 0.49-0.99) or other (OR, 0.44; 95% CI, 20.24-0.83) specialties were less likely to receive relevant imaging follow-up. Progression of findings from indeterminate to suspicious for malignancy occurred in 5.4% of cases and was not associated with radiologist-initiated verbal communication. CONCLUSIONS: Radiologist-initiated verbal communication increases the likelihood that patients receive outpatient imaging follow-up for abdominal findings indeterminate for malignancy. Progression of these findings is relatively infrequent.

18F-Fluoroestradiol PET: Current Status and Potential Future Clinical Applications.

Estrogen receptor (ER) expression in breast cancer is associated with a more favorable prognosis and is necessary for a response to endocrine therapies. Traditionally, ER expression is assessed by in vitro assays on biopsied tumor tissue. However, recent advances have allowed in vivo evaluation of ER expression with (18)F-fluoroestradiol ((18)F-FES) PET. Clinical studies have demonstrated the use of (18)F-FES PET as a method for quantifying in vivo ER expression and have explored its potential as a predictive assay and method of assessing in vivo pharmacodynamic response to endocrine therapy. This review outlines the biology and pharmacokinetics of (18)F-FES, highlights the current experience with (18)F-FES in patient studies on breast cancer and other diseases, and discusses potential clinical applications and the possible future clinical use of (18)F-FES PET.