Faculty Bibliography

OBJECTIVE. Nonphysician providers (NPPs) increasingly perform imaging-guided procedures, but their roles interpreting imaging have received little attention. We characterize diagnostic imaging services rendered by NPPs (i.e., nurse practitioners and physician assistants) in the Medicare population. MATERIALS AND METHODS. Using 1994-2015 Medicare Physician/Supplier Procedure Summary Master Files, we identified all diagnostic imaging services, including those billed by NPPs, and categorized these by modality and body region. Using 2004-2015 Medicare Part B 5% Research Identifiable File Carrier Files, we separately assessed state-level variation in imaging services rendered by NPPs. Total and relative utilization rates were calculated annually. RESULTS. Between 1994 and 2015 nationally, diagnostic imaging services increased from 339,168 to 420,172 per 100,000 Medicare beneficiaries (an increase of 24%). During this same period, diagnostic imaging services rendered by NPPs increased 14,711% (from 36 to 5332 per 100,000 beneficiaries) but still represented only 0.01% and 1.27% of all imaging in 1994 and 2015, respectively. Across all years, radiography and fluoroscopy constituted most of the NPP-billed imaging services and remained constant over time (e.g., 94% of all services billed in 1994 and 2015), representing only 0.01% and 2.1% of all Medicare radiography and fluoroscopy services. However, absolute annual service counts for NPP-billed radiography and fluoroscopy services increased from 10,899 to 1,665,929 services between 1994 and 2015. NPP-billed imaging was most common in South Dakota (7987 services per 100,000 beneficiaries) and Alaska (6842 services per 100,000 beneficiaries) and was least common in Hawaii (231 services per 100,000 beneficiaries) and Pennsylvania (478 services per 100,000 beneficiaries). CONCLUSION. Despite increasing roles of NPPs in health care across the United States, NPPs still rarely interpret diagnostic imaging studies. When they do, it is overwhelmingly radiography and fluoroscopy. Considerable state-to-state variation exists and may relate to local care patterns and scope-of-practice laws.

PURPOSE/OBJECTIVE:To assess characteristics of physicians and other providers frequently ordering intravenous pyelography (IVP). METHODS:The 2014 Medicare Referring Provider Utilization for Procedures data set was used to identify providers who ordered more than 10 IVP examinations ("high-ordering providers") in Medicare beneficiaries. The Medicare Provider and Other Supplier Public Use File and Physician Supplier Procedure Summary Master Files were used to obtain physician characteristics and total service counts, respectively. RESULTS:Of 18,344 IVPs performed in 2014 in Medicare fee-for-service beneficiaries, 6,321 (34.5%) were ordered by just 233 high-ordering providers. Of these, 220 (94.4%) were urologists. These urologists represented just 2.4% of all 8,981 Medicare-participating urologists and ordered an average of 27.1 IVPs (maximum 239). Urologists ordering IVPs (versus those not ordering IVPs) were more likely (P < .05) to practice in rural areas (6.4% versus 2.7%), be in practice more than 15 years (87.4% versus 71.2%), and be in practices with 100 members or fewer (71.3% versus 55.5%). They were also less likely (P < .05) to be female (3.2% versus 7.4%) and in academic practices (5.1% versus 10.7%). High-IVP-ordering urologists were more likely to practice in the South (54.1% versus 36.9%) or Midwest (30.0% versus 21.3%) and less likely to practice in the Northeast (5.0% versus 23.1%) or West (10.9% versus 18.6%). CONCLUSION/CONCLUSIONS:Although uncommonly performed, IVPs continue to be used in the Medicare population. Providers most likely to frequently order IVPs were later-career urologists in smaller and rural practices in the South. Targeting education and appropriate use criteria initiatives to high-ordering providers may help optimize utilization.

PURPOSE/OBJECTIVE:To analyze the changes in the work profiles of radiologists and the reporting time after the implementation of professional subspecialization in the radiology department of a Swiss university hospital. METHODS:In a retrospective analysis, the overall number of different radiologic examinations performed in the department of radiology of the largest Swiss university hospital was documented for 2014 and 2016 before and after the implementation of subspecialized reporting (subspecialities: abdominal, musculoskeletal, cardiothoracic, emergency, and pediatric imaging) in May 2015. For six selected radiologists, the number and types of reported examinations as well as the related radiology report turnaround times (RTATs) were analyzed in detail and compared between the two 1-year periods. RESULTS:Overall, there was a significant increase of 10.3% in the total number of examinations performed in the whole department in 2016 compared with 2014. For four of the six radiologists, the range of different types of examinations significantly decreased with the introduction of subspecialized reporting (p < 0.05). Furthermore, there was a significant change in the subset of the ten most commonly reported types of examinations reported by each of the six radiologists. Mean overall RTATs significantly increased for five of the six radiologists (p < 0.05). CONCLUSIONS:Implementation of subspecialized reporting led to a change in the structure and a decrease in the range of different examination types reported by each radiologist. Mean RTAT increased for most radiologists. Subspecialized reporting allows the individual radiologist to focus on a special field of professional competence but can result in longer overall RTAT.

BACKGROUND:Magnetic resonance imaging (MRI) of the prostate after a prior negative biopsy may reduce the need for unnecessary repeat biopsies. OBJECTIVE:To externally validate a previously developed nomogram predicting benign prostate pathology on MRI/ultrasound (US) fusion-targeted biopsy in men with a Prostate Imaging Reporting and Data System (PI-RADS) 3-5 region of interest and a prior negative 12-core systematic biopsy, and update this nomogram to improve its performance. DESIGN, SETTING, AND PARTICIPANTS/METHODS:A total of 2063 men underwent MRI/US fusion-targeted biopsy from April 2012 to September 2017; 104 men with a negative systematic biopsy followed by MRI-US fusion-targeted biopsy of a PI-RADS 3-5 region of interest (58%) met the study inclusion criteria. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS/UNASSIGNED:An MRI-based nomogram that had previously been developed in a multi-institutional clinical setting was externally validated. Predictive characteristics were age, prostate volume, MRI PI-RADS score, and prostate-specific antigen (PSA). Bayesian logistic regression was used to update the previous model. RESULTS AND LIMITATIONS/CONCLUSIONS:Median age of the external validation cohort was 68 yr, PSA was 7.2ng/ml, and biopsy confirmed benign pathology in 30% (n=31), suggesting a lower baseline risk compared with the nomogram development cohort. Receiver operating characteristic curve analysis showed areas under curve (AUCs) from 0.77 to 0.80 for nomogram validation. An updated model was constructed with improved calibration and similar discrimination (AUC 0.79). CONCLUSIONS:Age, prostate volume, PI-RADS, and PSA predict benign pathology on MRI/US fusion-targeted biopsy in men with a prior negative 12-core systematic biopsy. The validated and updated nomogram demonstrated high diagnostic accuracy and may further aid in the decision to avoid a biopsy in men with a prior negative biopsy. PATIENT SUMMARY/UNASSIGNED:We externally validated a clinically useful tool that predicts benign prostate pathology on magnetic resonance imaging/ultrasound fusion-targeted biopsy in men with a prior negative 12-core systematic biopsy and updated this predictive tool to improve its performance in patient counseling regarding the need for a repeat biopsy.

The Prostate Imaging Reporting and Data System version 2 (PI-RADS v2) was developed with a consensus-based process using a combination of published data, and expert observations and opinions. In the short time since its release, numerous studies have validated the value of PI-RADS v2 but, as expected, have also identified a number of ambiguities and limitations, some of which have been documented in the literature with potential solutions offered. To address these issues, the PI-RADS Steering Committee, again using a consensus-based process, has recommended several modifications to PI-RADS v2, maintaining the framework of assigning scores to individual sequences and using these scores to derive an overall assessment category. This updated version, described in this article, is termed PI-RADS v2.1. It is anticipated that the adoption of these PI-RADS v2.1 modifications will improve inter-reader variability and simplify PI-RADS assessment of prostate magnetic resonance imaging even further. Research on the value and limitations on all components of PI-RADS v2.1 is strongly encouraged.

PURPOSE/OBJECTIVE:Radiologists have historically participated as individuals in CMS pay-for-performance programs, but little is known about how radiologists perform under increasingly available group participation. We aimed to assess radiologists' relative national performance on CMS quality metrics using group versus individual participation. METHODS:Radiologists' group- and individual-level 2016 performance on Physician Quality Reporting System (PQRS) and non-PQRS Qualified Clinical Data Registry (QCDR) measures were obtained from the CMS national Physician Compare database and compared. RESULTS:Radiology groups reported an average 4.6 ± 2.0 quality measures; individual radiologists reported 2.3 ± 1.2 (P < .001). At least six measures were reported by 31.5% of groups versus 1.0% of individuals. Only one measure was reported by 5.4% of groups versus 33.0% of individuals. Groups reported 21 unique measures (20 via registries and one via QCDR). For 8 of the 11 measures reported by 20 or more groups, the average group performance rate was 3% or better than the average performance rate among radiologists participating as individuals (maximum 14% improvement with group participation versus individual participation for any individual measure). Group and individual performance were similar for the remaining three such measures. For measures reported by 20 or more groups in which a higher score indicates better performance, average group performance rates ranged from 86.2% to 98.9%. CONCLUSION/CONCLUSIONS:Compared with individual participation in CMS quality performance programs, radiologists participating as a group reported larger numbers of quality measures and achieved higher performance rates on those measures. Radiology practices seeking success under Medicare's new Quality Payment Program should carefully explore group participation.

OBJECTIVE. Given recent specialty attention to workforce diversity, we aimed to characterize potential gender differences in the practice patterns of interventional radiologists (IRs). MATERIALS AND METHODS. Using Medicare claims data, we identified IRs on the basis of the distribution of their billed clinical work effort and descriptively characterized practice patterns by gender. RESULTS. Women represented 8.2% (241/2936) of all IRs identified nationally. Female representation varied geographically (≤ 2% in nine states, ≥ 20% in three states) and by career stage (9.4% among early-career IRs and 6.4% among late-career IRs; 18.8% among early-career IRs in the Northeast). For both female IRs and male IRs, interventional case mixes were similar across service categories (e.g., venous and hemodialysis access, arterial and venous interventions, biopsies and drainages) and by procedural complexity (e.g., 5.7% vs 4.3% for low-complexity procedures and 59.5% vs 61.3% for high-complexity procedures). Average patient complexity scores were also similar for female (2.7 ± 12 [SD]) and male (2.8 ± 12) IRs. Female IRs spent slightly lower portions of their work effort rendering invasive services (66.5% vs 70.0%, respectively) and noninvasive diagnostic imaging (19.0% vs 22.2%) than male IRs but spent more time in evaluation and management clinical visits (14.5% vs 7.9%). Both female IRs and male IRs rendered a majority of their services to female patients (53.4% vs 53.1%). CONCLUSION. Although women remain underrepresented in interventional radiology, female IRs' interventional case composition, procedural complexity, and patient complexity are similar to those of their male colleagues. Female IRs' higher proportion of evaluation and management clinical visits supports the specialty's increased focus on longitudinal care so that interventional radiology will thrive alongside other clinical specialties.

PURPOSE/OBJECTIVE:To evaluate the changing use of transcatheter hemodialysis conduit procedures. METHODS:Multiple Centers for Medicare & Medicaid Services datasets were used to assess hemodialysis conduit angiography. Use was normalized per 100,000 beneficiaries and stratified by specialty and site of service. RESULTS:From 2001 to 2015, hemodialysis angiography use increased from 385 to 1,045 per 100,000 beneficiaries (compound annual growth rate [CAGR], +7.4%)]. Thrombectomy use increased from 114 to 168 (CAGR, +2.8%). Angiography and thrombectomy changed, by specialty, +1.5% and -1.3% for radiologists, +18.4% and +14.4% for surgeons, and +24.0% and +17.7% for nephrologists, respectively. By site, angiography and thrombectomy changed +29.1% and +20.7% for office settings and +0.8% and -2.4% for hospital settings, respectively. Radiologists' angiography and thrombectomy market shares decreased from 81.5% to 37.0% and from 84.2% to 47.3%, respectively. Angiography use showed the greatest growth for nephrologists in the office (from 5 to 265) and the greatest decline for radiologists in the hospital (299 to 205). Across states in 2015, there was marked variation in the use of angiography (0 [Wyoming] to 1173 [Georgia]) and thrombectomy (0 [6 states] to 275 [Rhode Island]). Radiologists' angiography and thrombectomy market shares decreased in 48 and 31 states, respectively, in some instances dramatically (eg, angiography in Nevada from 100.0% to 6.7%). CONCLUSIONS:Dialysis conduit angiography use has grown substantially, more so than thrombectomy. This growth has been accompanied by a drastic market shift from radiologists in hospitals to nephrologists and surgeons in offices. Despite wide geographic variability nationally, radiologist market share has declined in most states.

PURPOSE/OBJECTIVE:To assess subspecialty mix and case volumes of general and abdominal subspecialty radiologists interpreting abdominal MRI. METHODS:The 2016 CMS Physician/Supplier Procedure Summary Master File was used to obtain billed counts of radiologist-interpreted abdominal fluoroscopy, US, CT, and MRI examinations. The CMS Physician and Other Supplier Public Use File was used to assess the subspecialty mix and case volume of the radiologists interpreting those examinations. RESULTS:The fraction of all abdominal imaging examinations interpreted by generalists and abdominal subspecialty radiologists was 70.7% and 16.5% for fluoroscopy; 68.7% and 21.0% for US; 71.4% and 19.2% for CT; and 41.9% and 52.5% for MRI. In 2016, the fraction of general and abdominal radiologists interpreting > 50 fluoroscopy examinations on Medicare fee-for-service beneficiaries was 15.1% and 16.2%. For > 50 US examinations, the fraction was 61.5% and 60.5%; for > 50 CT examinations, 91.2% and 79.6%; and for > 50 MRI examinations, 4.0% and 28.5%. The fraction of abdominal imaging examinations interpreted overall by low-volume providers (those interpreting ≤ 50 examinations in 2016) was 59.5% for fluoroscopy, 17.5% for US, 6.3% for CT, and 50.6% for MRI. CONCLUSION/CONCLUSIONS:Nationally, most abdominal fluoroscopy, US, and CT examinations are interpreted by general radiologists, who have similar annual volumes of these examinations as abdominal subspecialty radiologists. In contrast, most abdominal MRI examinations are interpreted by abdominal subspecialty radiologists, who attain considerably higher volumes. These findings have implications for workforce planning and abdominal imaging fellowship design to ensure their graduates are optimally prepared to contribute to their future practices.