ACR Appropriateness Criteria® Imaging of Invasive Breast Cancer.

As the proportion of women diagnosed with invasive breast cancer increases, the role of imaging for staging and surveillance purposes should be determined based on evidence-based guidelines. It is important to understand the indications for extent of disease evaluation and staging, as unnecessary imaging can delay care and even result in adverse outcomes. In asymptomatic patients that received treatment for curative intent, there is no role for imaging to screen for distant recurrence. Routine surveillance with an annual 2-D mammogram and/or tomosynthesis is recommended to detect an in-breast recurrence or a new primary breast cancer in women with a history of breast cancer, and MRI is increasingly used as an additional screening tool in this population, especially in women with dense breasts. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Breast Cancer Method of Detection: 5-Year Outcomes Across a Multisite Health Care Enterprise.

PURPOSE: To investigate the feasibility and accuracy of radiologists categorizing the method of detection (MOD) when performing image-guided breast biopsies. METHODS: This retrospective, observational study was conducted across a health care enterprise that provides breast imaging services at 18 imaging sites across four US states. Radiologists used standardized templates to categorize the MOD, defined as the first test, sign, or symptom that triggered the subsequent workup and recommendation for biopsy. All image-guided breast biopsies since the implementation of the MOD-inclusive standardized template-from October 31, 2017 to July 6, 2023-were extracted. A random sample of biopsy reports was manually reviewed to evaluate the accuracy of MOD categorization. RESULTS: A total of 29,999 biopsies were analyzed. MOD was reported in 29,423 biopsies (98.1%) at a sustained rate that improved over time. The 10 MOD categories in this study included the following: 15,184 mammograms (51.6%); 4,561 MRIs (15.5%); 3,473 ultrasounds (11.8%); 2,382 self-examinations (8.1%); 2,073 tomosynthesis studies (7.0%); 432 clinical examinations (1.5%); 421 molecular breast imaging studies (1.4%); 357 other studies (1.2%); 338 contrast-enhanced digital mammograms (1.1%); and 202 PET studies (0.7%). Original assignments of the MOD agreed with author assignments in 87% of manually reviewed biopsies (n = 100, 95% confidence interval: [80.4%, 93.6%]). CONCLUSIONS: This study demonstrates that US radiologists can consistently and accurately categorize the MOD over an extended time across a health care enterprise.

Including the method of detection for breast cancer in the Surveillance, Epidemiology, and End Results database is long overdue.

Debates about breast cancer screening have continued in part because the Surveillance, Epidemiology, and End Results database, which began in 1974, has never included the method of detection so that it has been impossible to determine the role that early detection has played in the major decline in deaths from breast cancer that we have seen in the US since 1990. Method of detection should be added to the Surveillance, Epidemiology, and End Results database as soon as possible.

False-Positive and False-Negative Contrast-enhanced Mammograms: Pitfalls and Strategies to Improve Cancer Detection.

Contrast-enhanced mammography (CEM) is a relatively new breast imaging modality that uses intravenous contrast material to increase detection of breast cancer. CEM combines the structural information of conventional mammography with the functional information of tumor neovascularity. Initial studies have demonstrated that CEM and MRI perform with similar accuracies, with CEM having a slightly higher specificity (fewer false positives), although larger studies are needed. There are various reasons for false positives and false negatives at CEM. False positives at CEM can be caused by benign lesions with vascularity, including benign tumors, infection or inflammation, benign lesions in the skin, and imaging artifacts. False negatives at CEM can be attributed to incomplete or inadequate visualization of lesions, marked background parenchymal enhancement (BPE) obscuring cancer, lack of lesion contrast enhancement due to technical issues or less-vascular cancers, artifacts, and errors of lesion perception or characterization. When possible, real-time interpretation of CEM studies is ideal. If additional views are necessary, they may be obtained while contrast material is still in the breast parenchyma. Until recently, a limitation of CEM was the lack of CEM-guided biopsy capability. However, in 2020, the U.S. Food and Drug Administration cleared two devices to support CEM-guided biopsy using a stereotactic biopsy technique. The authors review various causes of false-positive and false-negative contrast-enhanced mammograms and discuss strategies to reduce these diagnostic errors to improve cancer detection while mitigating unnecessary additional imaging and procedures. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

Imaging Characteristics of and Multidisciplinary Management Considerations for Atypical Ductal Hyperplasia and Flat Epithelial Atypia: Review of Current Literature.

High-risk lesions of the breast are frequently encountered in percutaneous biopsy specimens. While benign, these lesions have historically undergone surgical excision due to their potential to be upgraded to malignancy. However, there is emerging evidence that a tailored management approach should be considered to reduce overtreatment of these lesions. Flat epithelial atypia (FEA) and atypical ductal hyperplasia (ADH) are two of the most commonly encountered high-risk lesions. FEA has been shown to have a relatively low rate of progression to malignancy, and some guidelines are now recommending observation over routine excision in select cases. Selective observation may be reasonable in cases where the target lesion is small and completely removed at biopsy and when there are no underlying risk factors, such as a history of breast cancer or genetic mutation or concurrent ADH. ADH has the highest potential upgrade rate to malignancy of all the high-risk lesions. Most society guidelines continue to recommend surgical excision of this lesion. More recently, some literature suggests that ADH lesions that appear completely removed at biopsy, involve limited foci (less than two or three) with no necrosis or significant atypia, manifest as a small group of mammographic calcifications, or demonstrate no enhancement at MRI may be reasonable for observation. Ultimately, management of all high-risk lesions must be based on a multidisciplinary approach that considers all patient, radiologic, clinical, and histopathologic factors. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

ACR Appropriateness Criteria® Monitoring Response to Neoadjuvant Systemic Therapy for Breast Cancer: 2022 Update.

Imaging plays a vital role in managing patients undergoing neoadjuvant chemotherapy, as treatment decisions rely heavily on accurate assessment of response to therapy. This document provides evidence-based guidelines for imaging breast cancer before, during, and after initiation of neoadjuvant chemotherapy. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

ACR Appropriateness Criteria® Evaluation of Nipple Discharge: 2022 Update.

The type of nipple discharge dictates the appropriate imaging study. Physiologic nipple discharge is common and does not require diagnostic imaging. Pathologic nipple discharge in women, men, and transgender patients necessitates breast imaging. Evidence-based guidelines were used to evaluate breast imaging modalities for appropriateness based on patient age and gender. For an adult female or male 40 years of age or greater, mammography or digital breast tomosynthesis (DBT) is performed initially. Breast ultrasound is usually performed at the same time with rare exception. For males or females 30 to 39 years of age, mammography/DBT or breast ultrasound is performed based on institutional preference and individual patient considerations. For young women less than 30 years of age, ultrasound is performed first with mammography/DBT added if there are suspicious findings or if the patient is at elevated lifetime risk for developing breast cancer. There is a high incidence of breast cancer in males with pathologic discharge. Men 25 years and older should be evaluated using mammography/DBT and ultrasound added when indicted. In transfeminine (male-to-female) patients, mammography/DBT and ultrasound are useful due to the increased incidence of breast cancer. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer-reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances in which peer-reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

ACR Appropriateness Criteria® Imaging of the Axilla.

This publication reviews the current evidence supporting the imaging approach of the axilla in various scenarios with broad differential diagnosis ranging from inflammatory to malignant etiologies. Controversies on the management of axillary adenopathy results in disagreement on the appropriate axillary imaging tests. Ultrasound is often the appropriate initial imaging test in several clinical scenarios. Clinical information (such as age, physical examinations, risk factors) and concurrent complete breast evaluation with mammogram, tomosynthesis, or MRI impact the type of initial imaging test for the axilla. Several impactful clinical trials demonstrated that selected patient's population can received sentinel lymph node biopsy instead of axillary lymph node dissection with similar overall survival, and axillary lymph node dissection is a safe alternative as the nodal staging procedure for clinically node negative patients or even for some node positive patients with limited nodal tumor burden. This approach is not universally accepted, which adversely affect the type of imaging tests considered appropriate for axilla. This document is focused on the initial imaging of the axilla in various scenarios, with the understanding that concurrent or subsequent additional tests may also be performed for the breast. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Women's Experience With Screening Mammography During the COVID-19 Pandemic: A Multi-Institutional Prospective Survey Study.

OBJECTIVE: Evaluate women's anxiety and experience undergoing screening mammography during the COVID-19 pandemic. METHODS: An IRB-approved anonymous survey was administered to women receiving screening mammography across six sites in the U.S. and Singapore from October 7, 2020, to March 11, 2021. Using a 1-5 Likert scale, women rated their pre- and post-visit anxiety regarding having their mammogram during the COVID-19 pandemic, importance of observed COVID-19 precautions, and personal risk factors for breast cancer and severe COVID-19 illness. Post-visit change in anxiety was evaluated. Multivariable logistic regression was used to test associations of pre-visit anxiety with breast cancer and COVID-19 risk factors. RESULTS: In total, 1086 women completed the survey. Of these, 59% (630/1061) had >1 breast cancer risk factor; 27% (282/1060) had >1 COVID-19 risk factors. Forty-two percent (445/1065) experienced pre-visit anxiety. Pre-visit anxiety was independently associated with risk factors for severe COVID-19 (OR for >2 vs 0 risk factors: 2.04, 95% confidence interval [CI]: 1.11-3.76) and breast cancer (OR for >2 vs 0 risk factors: 1.71, 95% CI: 1.17-2.50), after adjusting for age and site. Twenty-six percent (272/1065) of women reported post-visit anxiety, an absolute 16% decrease from pre-visit anxiety (95% CI: 14%-19%, P < 0.001). Provider masking (941/1075, 88%) and physical distancing (861/1085, 79%) were rated as the most important precautions. CONCLUSION: Pre-visit anxiety was associated with COVID-19 or breast cancer risk factors and declined significantly after screening mammography. Provider masking and physical distancing were rated the most important precautions implemented by imaging clinics.

The Dense Breast Clinic: Initial Experience of a Patient-Centered Breast Imaging Clinic.

OBJECTIVE: Establish a radiologist-run consultation clinic to review breast density and supplemental screening exams (SSEs) directly with patients in response to breast density reporting laws. METHODS: Breast radiologists opened and staffed a clinic for formal patient consultations regarding breast density and SSEs. An IRB-approved questionnaire assessed patient knowledge of breast density, SSEs, and encounter satisfaction. Comparative statistical analyses were performed on knowledge-based questions. RESULTS: From February 2019 to February 2021, 294 reimbursable consultations were performed with 215 patients completing pre- and post-consultation questionnaires (survey response rate, 73%). Median patient age was 58 years (range, 34-86 years) and 9% (19/210) had a personal history of breast cancer. An increase in patient knowledge of breast density and SSEs was observed as follows: breast density categories (9% correct pre-consultation (20/215), 86% correct post-consultation (185/215), P < 0.001), dense breast effects on cancer risk (39% correct pre-consultation (83/215), 84% post-consultation (180/215)), mammogram sensitivity (90% correct pre-consultation (193/215), 94% post-consultation (201/215)), and increased cancer detection with SSEs (82% correct pre-consultation (177/215), 95% post-consultation (205/215)) (P < 0.001). Post-consultation, 96% (200/209) were satisfied with the usefulness of information, 89% (186/209) strongly agreed they had sufficient knowledge of SSEs, and 81% (167/205) agreed they would like future opportunities to meet with a breast radiologist. CONCLUSION: A consultation clinic staffed by breast radiologists focused on breast density and supplemental breast cancer screening can provide personalized patient counseling, engage patients in shared decision making, assist referring clinicians, and support high quality patient-centered care.

Contrast-Enhanced Mammography for Newly Diagnosed Breast Cancer in Women With Breast Augmentation: Preliminary Findings.

In 17 women with newly diagnosed breast cancer who underwent contrast-enhanced mammography (CEM) and MRI, both modalities were found to be concordant for the index cancer. In six of the 17 women, CEM showed an additional lesion that was confirmed by MRI. Of these six additional lesions, three were multifocal, one was multicentric, and two were contralateral; two of the six were malignant. MRI did not identify any additional cancers that were not identified on CEM. CEM may have a role in women with breast augmentation and either a contraindication or limited access to MRI.

Breast MRI ordering practices in a large health care network.

The purpose of this study was to evaluate providers' ordering practices and perceptions of breast magnetic resonance imaging (MRI) in an academic network in order to better understand and educate a referral base. An online survey was distributed to primary care providers (PCPs) and specialists in our hospital and community practices. Questions included provider demographics, current ordering practices, challenges to ordering, and perceptions about breast MRI. Of 525 ordering providers, 134 responded (26% response rate). Of 134 providers, 57 (42%) order breast MRI in practice. Of those who do not, the most consistent reason was a lack of familiarity with the use of breast MRI (32/77 [42%] of cases). Of 57 cases, 45 (79%) order less than 10 exams annually. The most frequent indication is for high-risk screening (40/47 [84%]). PCPs order fewer breast MRI compared with specialists (P = 0.01). Both PCPs and specialists have mixed perceptions of the clinical utility of breast MRI. However, 30% of all providers are ordering more breast MRI since the enactment of breast density legislation in Massachusetts. Furthermore, 29% report they would order breast MRI more often to screen women with dense breasts if there was a low cost option. Referring provider surveys are useful tools for assessing a radiology practice. Our study suggests a growing clinical interest in breast MRI for screening; however, there is a need for provider education on the clinical utility of breast MRI. Increasing the radiologist's role in targeted educational interventions may help improve awareness and lead to more appropriate utilization of resources.

Proposed biopsy performance benchmarks for MRI based on an audit of a large academic center.

Performance benchmarks exist for mammography (MG); however, performance benchmarks for magnetic resonance imaging (MRI) are not yet fully developed. The purpose of our study was to perform an MRI audit based on established MG and screening MRI benchmarks and to review whether these benchmarks can be applied to an MRI practice. An IRB approved retrospective review of breast MRIs was performed at our center from 1/1/2011 through 12/31/13. For patients with biopsy recommendation, core biopsy and surgical pathology results were reviewed. The data were used to derive mean performance parameter values, including abnormal interpretation rate (AIR), positive predictive value (PPV), cancer detection rate (CDR), percentage of minimal cancers and axillary node negative cancers and compared with MG and screening MRI benchmarks. MRIs were also divided by screening and diagnostic indications to assess for differences in performance benchmarks amongst these two groups. Of the 2455 MRIs performed over 3-years, 1563 were performed for screening indications and 892 for diagnostic indications. With the exception of PPV2 for screening breast MRIs from 2011 to 2013, PPVs were met for our screening and diagnostic populations when compared to the MRI screening benchmarks established by the Breast Imaging Reporting and Data System (BI-RADS) 5 Atlas® . AIR and CDR were lower for screening indications as compared to diagnostic indications. New MRI screening benchmarks can be used for screening MRI audits while the American College of Radiology (ACR) desirable goals for diagnostic MG can be used for diagnostic MRI audits. Our study corroborates established findings regarding differences in AIR and CDR amongst screening versus diagnostic indications.

The Effect of the Controversial US Preventive Services Task Force Recommendations on the Use of Screening Mammography.

PURPOSE: The 2009 release of updated US Preventive Services Task Force (USPSTF) recommendations on screening mammography differed sharply from those of the American Cancer Society, the ACR, and the American College of Obstetricians and Gynecologists. The aim of this study was to ascertain the effect of these recommendations on the utilization of screening mammography in the Medicare population. METHODS: The Medicare Part B Physician/Supplier Procedure Summary Master Files from 2005 through 2010 were used to determine the annual utilization rate of screening mammography from 2005 to 2010. A utilization trend line was plotted for those years. RESULTS: The utilization rate of screening mammography per 1,000 women in the Medicare population was 311.6 in 2005 and increased gradually each year to 322.9 in 2009 (a compound annual growth rate of 0.9%). However, after the USPSTF recommendations were issued in late 2009, this rate decreased abruptly to 309.1 (-4.3%) in 2010. CONCLUSIONS: The abrupt decrease in the utilization of screening mammography in 2010 was in sharp contrast to the previous slow annual increases in its utilization from 2005 to 2009. Because there are no other factors to explain a decrease of this magnitude, it would seem that the USPSTF recommendations and the ensuing publicity resulted in a decrease in the utilization of screening mammography in the Medicare population in the first year after issuance of the new recommendations.

Educational Videos: An Effective Tool to Improve Training in Interventional Breast Procedures.

PURPOSE: Using the iPad application Explain Everything™, the authors created a "how to" video for stereotactic breast core biopsy to enhance their breast imaging curriculum. The objective was to show that video integration into residency training enhances resident learning. METHODS: A pretest was provided to all 40 radiology residents (postgraduate years 2-5) at the authors' institution. The test included 20 questions on the video content, 15 similarly framed control questions on material that was not included in the video, and four demographic questions. Questions were randomly ordered, and trainees were not informed that both types of questions were included. Residents were given one week to watch the 20-minute video before completing a posttest that included the same 35 content questions presented in a different order. Three logistical questions were also included. Results for the video and the control questions were analyzed separately and compared. RESULTS: Thirty of 40 residents (75%) participated (6-9 residents each year). The average scores for the video and control pretest were 7.7 of 20 (38.5%) and 7.8 of 15 (52%) and for the posttest were 13.8 of 20 (69%) and 7.8 of 15 (52%), respectively. This corresponds to a 30.7% mean improvement on the video-content questions compared with a 0% improvement for the control test (P < .001). Similar improvement was seen across all four postgraduate years and on an individual level. CONCLUSIONS: This instructional video added significantly to resident learning in the short term. Further study on the long-term role of educational videos in radiology residency training seems warranted.

Increased Cancer Detection Rate and Variations in the Recall Rate Resulting from Implementation of 3D Digital Breast Tomosynthesis into a Population-based Screening Program.

PURPOSE: To compare the recall and cancer detection rates (CDRs) at screening with digital breast tomosynthesis (DBT) with those at screening with two-dimensional (2D) mammography and to evaluate variations in the recall rate (RR) according to patient age, risk factors, and breast density and among individual radiologists at a single U.S. academic medical center. MATERIALS AND METHODS: This institutional review board-approved, HIPAA-compliant prospective study with a retrospective cohort included 85 852 asymptomatic women who presented for breast cancer screening over a 3-year period beginning in 2011. A DBT unit was introduced into the existing 2D mammography screening program, and patients were assigned to the first available machine. Ten breast-subspecialized radiologists interpreted approximately 90% of the examinations. RRs were calculated overall and according to patient age, breast density, and individual radiologist. CDRs were calculated. Single and multiple mixed-effect logistic regression analyses, χ(2) tests, and Bonferroni correction were utilized, as appropriate. RESULTS: The study included 5703 (6.6%) DBT examinations and 80 149 (93.4%) 2D mammography examinations. The DBT subgroup contained a higher proportion of patients with risk factors for breast cancer and baseline examinations. DBT was used to detect 54.3% more carcinomas (+1.9 per 1000, P < .0018) than 2D mammography. The RR was 7.51% for 2D mammography and 6.10% for DBT (absolute change, 1.41%; relative change, -18.8%; P < .0001). The DBT subgroup demonstrated a significantly lower RR for patients with extremely or heterogeneously dense breasts and for patients in their 5th and 7th decades. CONCLUSION: Implementing DBT into a U.S. breast cancer screening program significantly decreased the screening RR overall and for certain patient subgroups, while significantly increasing the CDR. These findings may encourage more widespread adoption and reimbursement of DBT and facilitate improved patient selection.

The increasing role of radiologists in thoracic diagnosis: more thoracic biopsies are performed percutaneously.

PURPOSE: The rate of thoracic biopsies overall and by type of biopsy from 1998 to 2010 is not known. The aim of this study was to examine the utilization rate of various types of thoracic biopsies within the Medicare population. METHODS: Source data was obtained from the CMS Physician/Supplier Procedure Summary Master Files from 1998 to 2010. Allowed primary claims submitted for percutaneous thoracic biopsy, bronchoscopic thoracic biopsy, and surgical thoracic biopsy were extracted. Annual volume and utilization rates were calculated and analyzed by biopsy type and provider type. RESULTS: Total thoracic biopsy volume in 1998 was 176,125 and in 2010 was 167,911 (-4.7%). The utilization rate for all thoracic biopsies decreased from 5.47 per 1,000 in 1998 to 4.76 per 1,000 (-13.0%) in 2010. The percutaneous biopsy utilization rate increased 3.6% from 1998 to 2010, while the rate for surgical biopsy decreased by 20.9% and the rate of bronchoscopic biopsy decreased by 19.6% during the same time period. In 2010, radiologists performed 96.4% (58,679) of all percutaneous biopsies. Radiologists' thoracic biopsy market share increased from 26.2% (46,084 of 176,125) in 1998 to 35.0% (58,700 of 167,911) in 2010 (+33.6%). CONCLUSIONS: The overall rate of thoracic biopsy decreased from 1998 to 2010, with fewer biopsies being performed surgically and bronchoscopically and more biopsies being performed percutaneously. Radiologists are responsible for an increasing role in thoracic diagnosis, as they have increased market share of thoracic biopsies. These findings may be the result of changing trends toward less invasive procedures, changing patterns of reimbursement, and increased availability of percutaneous biopsy.

The increasing role of nonradiologists in performing ultrasound-guided invasive procedures.

PURPOSE: Recent proliferation of mobile diagnostic ultrasound (US) units and improved resolution have allowed for widespread use of US by more providers, both for diagnosis and US-guided procedures (USGP). This study aims to document recent trends in utilization for USGP in the Medicare population. METHODS: Source data were obtained from the CMS Physician Supplier Procedure Summary Master Files from 2004 to 2010. Allowed billing claims submitted for USGP were extracted and volume was analyzed by provider type and setting. Compound annual growth rates were calculated. RESULTS: The total utilization rate for all USGP was 2,425 per 100,000 in 2004 and 4,870 in 2010, an increase of 100.8% (+2,445 per 100,000) with a compound annual growth rate of 12.3%. The year 2010 represents the first year that nonradiologists as a group performed more USGP than radiologists, at 922,672 versus 794,497 examinations, respectively. Nonradiologists accounted for 72.2% (599,751 of 830,925) of the USGP volume growth from 2004 to 2010. Most 2010 claims were submitted by radiologists (n = 794,497; 46.3%) and surgeons (n = 332,294; 19.4%). The largest overall volume increases from 2004 to 2010 were observed among radiologists, surgeons, anesthesiologists, rheumatologists, midlevel providers, primary care physicians, nonrheumatologist internal medicine subspecialists, and the aggregate of all other provider types. CONCLUSION: The year 2010 represents the first year that nonradiologists performed more USGP than radiologists. From 2004 to 2010, radiologists and surgeons experienced only modest growth in USGP volume, whereas several other provider types experienced more rapid growth. It is likely that many procedures that were previously performed without US guidance are now being performed with US guidance.