A Claims-Based Method for Identification and Characterization of Practicing Interventional Radiologists

PURPOSE

To propose a research method for identifying "practicing interventional radiologists" using 2 national claims data sets.

MATERIALS AND METHODS

The 2015-2019 100% Medicare Part B data and 2015-2019 private insurance claims from Optum's Clinformatics Data Mart (CDM) database were used to rank-order radiologists' interventional radiology (IR)-related work as a percentage of total billed work relative value units (RVUs). Characteristics were analyzed at various threshold percentages. External validation used Medicare self-designated specialty with Society of Interventional Radiology (SIR) membership records; Youden index evaluated sensitivity and specificity. Multivariate logistic regression assessed practicing IR characteristics.

RESULTS

In the Medicare data, above a 10% IR-related work threshold, only 23.8% of selected practicing interventional radiologists were designated as interventional radiologists; above 50% and 90% thresholds, this percentage increased to 42.0% and 47.5%, respectively. The mean percentage of IR-related work among practicing interventional radiologists was 45%, 84%, and 96% of total work RVUs for the 10%, 50%, and 90% thresholds, respectively. At these thresholds, the CDM practicing interventional radiologists included 21.2%, 35.2%, and 38.4% designated interventional radiologists, and evaluation and management services comprised relatively more total work RVUs. Practicing interventional radiologists were more likely to be males, metropolitan, and earlier in their careers than other radiologists at all thresholds.

CONCLUSIONS

Most radiologists performing IR-related work are designated in claims data as diagnostic radiologists, indicating insufficiency of specialty designation for IR identification. The proposed method to identify practicing interventional radiologists by percent IR-related work effort could improve generalizability and comparability across claims-based IR studies.

Professional Services Rendered by Nurse Practitioners and Physician Assistants Employed by Radiology Practices: Characteristics and Trends From 2017 Through 2019

PURPOSE

With radiology practices increasingly employing nonphysician practitioners (NPPs), we aimed to characterize specific NPP clinical roles.

METHODS

Linking 2017 to 2019 Medicare data sets, we identified all claims-submitting nurse practitioners and physician assistants (together NPPs) employed by radiologists. NPP-billed services were identified, weighted by work relative value units, and categorized as (1) clinical evaluation and management (E&M), (2) invasive procedures, and (3) noninvasive imaging interpretation. NPP practice patterns were assessed temporally and using frequency analysis.

RESULTS

As the number of radiologist-employed NPPs submitting claims increased 16.3% (from 523 in 2017 to 608 in 2019), their aggregate Medicare fee-for-service work relative value units increased 17.3% (+40.0% for E&M [from 79,540 to 111,337]; +5.6% for procedures [from 179,044 to 189,003]; and +74.0% for imaging [from 5,087 to 8,850]). The number performing E&M, invasive procedures, and imaging interpretation increased 7.6% (from 329 to 354), 18.3% (from 387 to 458), and 31.8% (from 85 to 112), with 58.2%, 75.3%, and 18.4% billing those services in 2019. Paracentesis and thoracentesis were the most frequently billed invasive procedures. Fluoroscopic swallowing and bone densitometry examinations were the most frequently billed imaging services. By region, NPPs practicing as majority clinical E&M providers were most common in the Midwest (33.5%) and South (33.0%), majority proceduralists in the South (53.1%), and majority image interpreters in the Midwest (50.0%).

CONCLUSIONS

As radiology practices employ more NPPs, radiologist-employed NPPs' aggregate services have increased for E&M, invasive procedures, and imaging interpretation. Most radiologist-employed NPPs perform invasive procedures and E&M. Although performed by a small minority, imaging interpretation has shown the largest relative service growth.

Osteopathic Versus Allopathic Radiologist Workforce Characteristics: A Medicare Administrative and Claims Data Analysis

PURPOSE

Radiologist medical school pathways have received little attention in recent workforce investigations. With osteopathic enrollment increasing, we assessed the osteopathic versus allopathic composition of the radiologist workforce.

METHODS

Linking separate Medicare Doctors and Clinicians Initiative databases and Physician and Other Supplier Files from 2014 through 2019, we assessed (descriptively and using multivariate panel logistic regression modeling) individual and practice characteristics of radiologists who self-reported medical degrees.

RESULTS

Between 2014 and 2019, as the number of osteopathic radiologists increased 46.0% (4.7% to 6.0% of total radiologist workforce), the number of allopathic radiologists increased 12.1% (representing a relative workforce decrease from 95.3% to 94.0%). For each year since completing training, practicing radiologists were 3.7% less likely to have osteopathic (versus allopathic) degrees (odds ratio [OR] = 0.96 per year, P < .01). Osteopathic radiologists were less likely to work in urban (versus rural) areas (OR = 0.95), and compared with the Midwest, less likely to work in the Northeast (OR = 0.96), South (OR = 0.95), and West (OR = 0.94) (all P < .01). Except for cardiothoracic imaging (OR = 0.78, P = .24), osteopathic radiologists were more likely than allopathic radiologists to practice as general (rather than subspecialty) radiologists (range OR = 0.37 for nuclear medicine to OR = 0.65 for neuroradiology, all P < .01).

CONCLUSIONS

Osteopathic physicians represent a fast-growing earlier-career component of the radiologist workforce. Compared with allopathic radiologists, they more frequently practice as generalist radiologists, in rural areas, and in the Midwest. Given recent calls for greater general and rural radiology coverage, increasing osteopathic representation in the national radiologist workforce could improve patient access.

Characteristics of Radiologists Serving as Medical Malpractice Expert Witnesses for Defense Versus Plaintiff

PURPOSE

Previous studies have reported higher qualification characteristics for anesthesiologists, neurosurgeons, orthopedic surgeons, and otolaryngologists serving as defense (versus plaintiff) medical malpractice expert witnesses. We assessed such characteristics for radiologist expert witnesses.

METHODS

Using the Westlaw legal research database, we identified radiologists serving as experts in all indexed medical malpractice cases between 2010 and 2019. Online databases were used to identify years of practice experience and scholarly bibliometrics. Using Medicare claims, individual radiologist practice types and mixes were ascertained. Radiologists testifying at least once each for defense and plaintiff were excluded from our defense-only versus plaintiff-only comparative analysis.

RESULTS

Initial Boolean searches yielded 1,042 potential cases; subsequent manual review identified 179 radiologists testifying in 231 lawsuits: 143 testified in one case (58 defense, 85 plaintiff) and 36 testified in multiple cases (10 defense-only, 14 plaintiff-only, 12 both). The 68 defense-only experts had fewer years of practice experience than the 99 plaintiff-only experts (28.3 versus 31.8 years, P = .02), but the two groups were otherwise similar in both practice type (44.6% versus 54.9% academic, P = .62) and mix (63.8% versus 65.8% practiced as subspecialists, P = .37) and as well as numbers of publications (60.5 versus 62.8, P = .86), citations (1,994.1 versus 2,309.2, P = .56), and h-indices (17.2 versus 16.8, P = .89).

CONCLUSIONS

In contrast to other specialists, radiologists serving as medical malpractice expert witnesses for defense and plaintiff display similar qualifications across various characteristics. Published practice parameter guidelines and experts' ability to blindly review archived original images might together explain this interspecialty discordance.

Evolving Radiology Trainee Neuroimaging Workloads: A National Medicare Claims-based Analysis

RATIONALE AND OBJECTIVES

While radiology training programs aim to prepare trainees for clinical practice, the relationship between trainee, and national radiology workforce demands is unclear. This study assesses changing radiology trainee neuroimaging workloads nationwide for neuroimaging studies.

MATERIALS AND METHODS

Using aggregate Medicare claims files from 2002 to 2018, we identified all computed tomography (CT) and magnetic resonance (MR) examinations of the brain, head and neck, and spine (hereafter "neuroimaging") in Medicare fee-for-service beneficiaries nationwide. Using separate Medicare files, we calculated population utilization rates, and work relative value unit (wRVU) weights of all diagnostic neuroradiology services. Using claims modifiers, we identified services rendered by radiology trainees. Using separate national trainee enrollment files, we calculated mean annual per trainee wRVUs.

RESULTS

Between 2002 and 2018, total Medicare neuroimaging claims increased for both radiologists overall (86.1%) and trainees (162.5%), including increases in both CT (102.9% vs 196.8%), and MR (59.9% vs 106.6%). The national percentage of all radiologist neuroimaging wRVUs rendered by trainees increased 46.1% (3.8% of all wRVUs nationally in 2002 to 5.6% in 2018). National trainee increases were present across all neuroimaging services but greatest for head and neck CT (+86.5%). Mean annual per radiology trainee neuroimaging Medicare wRVUs increased +174.9% (42.1 per trainee in 2002 to 115.70 in 2018). Mean per trainee wRVU increases were greatest for spine CT (+394.2%) but present across all neuroimaging services.

CONCLUSION

As neuroimaging utilization in Medicare beneficiaries has grown, radiology trainee neuroimaging workloads have increased disproportionately.

Interpretations of Examinations Outside of Radiologists' Fellowship Training: Assessment of Discrepancy Rates Among 5.9 Million Examinations From a National Teleradiology Databank

Background: In community settings, radiologists commonly function as multispecialty radiologists, interpreting examinations outside of their fellowship training. Objective: To compare discrepancy rates for preliminary interpretations of acute community-setting examinations concordant versus discordant with interpreting radiologists' fellowship training. Methods: This retrospective study used the databank of a U.S. teleradiology company that provides preliminary interpretations for client community hospitals. The analysis included 5,883,980 acute examinations performed from 2012 to 2016 that were preliminarily interpreted by 269 teleradiologists with a fellowship of neuroradiology, abdominal radiology, or musculoskeletal radiology. When providing final interpretations, client on-site radiologists voluntarily submitted quality assurance (QA) requests if preliminary and final interpretations were discrepant; the teleradiology company's QA committee categorized discrepancies as major (n=8,444) or minor (n=17,208). Associations among examination type (common vs advanced), relationship between examination subspecialty and the teleradiologist's fellowship (concordant vs discordant), and major and minor discrepancies were assessed using three-way conditional analyses with generalized estimating equations. Results: For examinations with concordant subspecialty, major discrepancy rate was lower for common than advanced examinations [0.13% vs 0.26%; relative risk (RR) 0.50, 95% CI: 0.42, 0.60; p < .001]. For examinations with discordant subspecialty, major discrepancy rate was lower for common than advanced examinations (0.14% vs 0.18%; RR 0.81, 95% CI: 0.72, 0.90; p < .001). For common examinations, major discrepancy rate was not different between examinations with concordant versus discordant subspecialty (0.13% vs 0.14%; RR 0.90, 95% CI: 0.81, 1.01; p = .07). For advanced examinations, major discrepancy rate was higher for examinations with concordant versus discordant subspecialty (0.26% vs 0.18%; RR 1.45, 95% CI: 1.18, 1.79; p < .001). Minor discrepancy rate was higher among advanced examinations for those with concordant versus discordant subspecialty (0.34% vs 0.29%; RR 1.17, 95% CI: 1.001, 1.36; p = .04), but not different for other comparisons (p > .05). Conclusion: Major and minor discrepancy rates were not higher for acute community-setting examinations outside of interpreting radiologists' fellowship training. Discrepancy rates increased for advanced examinations. Clinical Impact: The findings support multispecialty radiologist practice in acute community settings. Efforts to match examination and interpreting radiologist subspecialty may not reduce diagnostic discrepancies.

Radiologist Characteristics Associated with Interpretive Performance of Screening Mammography: A National Mammography Database (NMD) Study

Background Factors affecting radiologists' performance in screening mammography interpretation remain poorly understood. Purpose To identify radiologists characteristics that affect screening mammography interpretation performance. Materials and Methods This retrospective study included 1223 radiologists in the National Mammography Database (NMD) from 2008 to 2019 who could be linked to Centers for Medicare & Medicaid Services (CMS) datasets. NMD screening performance metrics were extracted. Acceptable ranges were defined as follows: recall rate (RR) between 5% and 12%; cancer detection rate (CDR) of at least 2.5 per 1000 screening examinations; positive predictive value of recall (PPV1) between 3% and 8%; positive predictive value of biopsies recommended (PPV2) between 20% and 40%; positive predictive value of biopsies performed (PPV3) between the 25th and 75th percentile of study sample; invasive CDR of at least the 25th percentile of the study sample; and percentage of ductal carcinoma in situ (DCIS) of at least the 25th percentile of the study sample. Radiologist characteristics extracted from CMS datasets included demographics, subspecialization, and clinical practice patterns. Multivariable stepwise logistic regression models were performed to identify characteristics independently associated with acceptable performance for the seven metrics. The most influential characteristics were defined as those independently associated with the majority of the metrics (at least four). Results Relative to radiologists practicing in the Northeast, those in the Midwest were more likely to achieve acceptable RR, PPV1, PPV2, and CDR (odds ratio [OR], 1.4-2.5); those practicing in the West were more likely to achieve acceptable RR, PPV2, and PPV3 (OR, 1.7-2.1) but less likely to achieve acceptable invasive CDR (OR, 0.6). Relative to general radiologists, breast imagers were more likely to achieve acceptable PPV1, invasive CDR, percentage DCIS, and CDR (OR, 1.4-4.4). Those performing diagnostic mammography were more likely to achieve acceptable PPV1, PPV2, PPV3, invasive CDR, and CDR (OR, 1.9-2.9). Those performing breast US were less likely to achieve acceptable PPV1, PPV2, percentage DCIS, and CDR (OR, 0.5-0.7). Conclusion The geographic location of the radiology practice, subspecialization in breast imaging, and performance of diagnostic mammography are associated with better screening mammography performance; performance of breast US is associated with lower performance. ^©RSNA, 2021 Online supplemental material is available for this article.

Radiologist-Practice Separation: Recent Trends and Characteristics

PURPOSE

To assess recent trends and characteristics in radiologist-practice separation across the United States.

METHODS

Using the Medicare Physician Compare and Medicare Physician and Other Supplier Public Use File data sets, we linked all radiologists to associated group practices annually between 2014 and 2018 and assessed radiologist-practice separation over a variety of physician and group characteristics. Multivariate logistic regression modeling was used to estimate the likelihood of radiologist-practice separation.

RESULTS

Of 25,228 unique radiologists associated with 4,381 unique group practices, 41.1% separated from at least one group practice between 2014 and 2018, and annual separation rates increased 38.4% over time (13.8% from 2014 to 2015 to 19.2% from 2017 to 2018). Radiologist-practice separation rates ranged from 57.4% in Utah to 26.3% in Virginia. Separation rates were 42.8% for general radiologists versus 38.2% for subspecialty radiologists. Among subspecialists, separation rates ranged from 43.0% for breast imagers to 33.5% for cardiothoracic radiologists. Early career status (odds ratio [OR] = 1.286) and late (OR = 1.554) career status were both independent positive predictors of radiologist-practice separation (both P < .001). Larger practice size (OR = 0.795), radiology-only (versus multispecialty) group (OR = 0.468), academic (versus nonacademic) practice (OR = 0.709), and abdominal (OR = 0.820), musculoskeletal (OR = 0.659), and neuroradiology (OR = 0.895) subspecialization were independent negative predictors (all P < .05).

CONCLUSIONS

With over 40% of radiologists separating from at least one practice in recent years, the US radiologist workforce is highly and increasingly mobile. Because reasons for separation (eg, resignation, practice acquisition) cannot be assessed using administrative data, further attention is warranted given the manifold financial, operational, and patient care implications.

Practice Characteristics of the United States General Radiologist Workforce: Most Generalists Work as Multispecialists

RATIONALE AND OBJECTIVES

While subspecialty radiologists' practice patterns have received recent attention, little is known about the practice patterns of general radiologists. We aim to characterize this group (which represents most US radiologists).

MATERIALS AND METHODS

US radiologists' individual work efforts were assessed using the 2017 Medicare Provider and Other Supplier Public Use File and a previously validated wRVU-weighted claims-based classification system. Using prior criteria, radiologists without >50% work efforts in a single subspecialty were deemed generalists. For this study, a >25% subspecialty work effort threshold was deemed a subspecialty "focus area," and generalists with ≥2 subspecialty focus areas were deemed "multispecialists." Practice characteristics were summarized using various parameters.

RESULTS

Among 12,438 radiologists meeting existing claims-based criteria to be deemed generalists, 85.0% had ≥2 subspecialty focus areas of >25% work effort (i.e., multispecialists), 14.6% had one focus area, and 0.4% had no focus area. The fraction of generalists meeting multispecialist criteria was similar across radiologists' years in practice (range 84.7% to 85.4%), academic vs. nonacademic status (84.9% to 86.6%), and practice size (83.3% to 87.0%). Although general radiologist multispecialization varied geographically, a majority were multispecialists in all states (range 57.6% in VT to 93.9% in WY) and percentages were not associated with state-level population density (r = 0.013; p = 0.926).

CONCLUSION

The large majority of US general radiologists practice as multispecialists, and nearly all have at least one subspecialty focus area. The predominance of general radiologists' multispecialty focus across various practice types and locations supports their role in facilitating patient access to a range of radiologist subspecialties.

Gender Differences in Modality Interpretation Among Radiologists: An Exploratory Study of Occupational Horizontal Segregation

RATIONALE AND OBJECTIVES

Occupational "horizontal segregation," defined as disparity in the distribution of responsibilities between genders, could discourage women from seeking careers in radiology, as well as impact women within radiology in terms of compensation, promotion, and career advancement. We aimed to explore the existence of horizontal workplace segregation in radiology, as potentially manifested as intergender differences in the distribution of clinical work effort among imaging modalities for radiologists.

MATERIALS AND METHODS

Medicare-participating general radiologists, neuroradiologists, abdominal, cardiothoracic, and musculoskeletal radiologists were identified from the 2016 Medicare Physician and Other Supplier Public Use File. Work effort in radiography, ultrasound, CT, and MRI was stratified by gender. Univariable and multivariable analyses were performed.

RESULTS

22,445 radiologists were included (19.0% female; 19.6% in academic practices). At univariable analysis, female (vs. male) generalists had lower work effort in MRI (10.2% vs. 13.2%) (p < 0.001); abdominal radiologists had higher work effort in ultrasound (27.1% vs. 21.9%), with lower work effort in CT (53.7%. vs. 56.0%) and MRI (8.1%. vs. 9.4%) (p < 0.001); and musculoskeletal radiologists had higher work effort in radiography (41.6% vs. 34.8%) and less in MRI (44.8% vs. 49.6%) (p = 0.007). In multivariable analyses, female gender was independently associated with lower work effort in advanced imaging (CT and MRI) for generalists (coefficient, -0.020; p < 0.001), abdominal radiologists (coefficient, -0.042; p < 0.001), and neuroradiologists (coefficient -0.010; p = 0.035).

CONCLUSION

Horizontal occupational segregation exists in radiology with female radiologists devoting lower work effort to advanced imaging modalities. Further investigation is warranted to better understand the sources and downstream implications of such variation.

Changing National Medicare Utilization of Catheter, Computed Tomography, and Magnetic Resonance Extremity Angiography: A Specialty-focused 16-Year Analysis

To assess changing utilization of extremity angiography from 2001 to 2016, focusing on modalities and provider specialties. Medicare PSPS Master Files from 2001-2016 and POSPUF from 2016 were used to determine overall and specialty utilization of diagnostic catheter angiography (DCA), CT angiography (CTA), and MR angiography (MRA). From 2001 to 2016, extremity angiography increased from 1107 to 1590 extremities imaged per 100,000 beneficiaries, with rapid expansion of CTA (22 in 2001 to 619 in 2009; plateau of 645 in 2016), but declines in DCA (1039 to 914) and MRA (45 to 30). Over time, extremity angiography shifted from 94% DCA, 4% MRA, and 2% CTA to 58% DCA, 41% CTA, and 2% MRA. For radiologists, extremity angiography increased slightly (741 to 767) with increases in CTA (20 to 595) and large decreases in DCA (681 to 145), with MRA remaining low (40 to 27). Extremity angiography increased for cardiologists (197 to 349) and vascular surgeons (87 to 351), both overwhelmingly performing DCA. Radiologists' share of all extremity angiography shifted from 67% to 48%, with interventionalists (47%), generalists (43%), and abdominal radiologists (7.4%) providing most radiologist services in 2016. Throughout, radiologists were the dominant providers of CTA (89% to 92%) and MRA (89% to 90%). Extremity angiography utilization in Medicare beneficiaries increased nearly 50% from 2001 to 2016, largely related to CTA performed by radiologists. Of radiologists, interventionalists and generalists together render most services. Cardiologists and surgeons assumed a large share of DCA previously performed by radiologists.

Low-Volume and High-Volume Readers of Neurological and Musculoskeletal MRI: Achieving Subspecialization in Radiology

OBJECTIVE

Differentiate high- versus low-volume radiologists who interpret neurological (Neuro) MRI or musculoskeletal (MSK) MRI and measure the proportion of Neuro and MSK MRIs read by low-volume radiologists.

METHODS

We queried the 2015 Medicare Physician and Other Supplier Public Use File for radiologists who submitted claims for Neuro or MSK MRIs. Radiologists were classified as high-volume versus low-volume based on their work relative value units (wRVUs) focus or volume of studies interpreted using three different methodologies: Method 1, percentage of wRVUs in Neuro or MSK MRI; Method 2, absolute number of Neuro or MSK MRIs interpreted; and Method 3, both percentage and absolute number. Multiple thresholds with each methodology were tested, and the percentage of Neuro or MSK MRIs interpreted by low-volume radiologists was calculated for each threshold.

RESULTS

With Method 1, 33% of Neuro MRI and 50% of MSK MRI studies were interpreted by a radiologist whose wRVUs in Neuro or MSK MRI were less than 20% (Method 1). With Method 2, 22% of Neuro MRIs and 37% of MSK MRIs were interpreted by radiologists who read fewer than the mean number of Neuro or MSK MRIs interpreted by an "average full-time radiologist" whose wRVUs in Neuro or MSK MRI were approximately 20%. With Method 3, 38% of Neuro MRIs and 57% of MSK MRIs were interpreted by "low-volume" radiologists. If instead a 50% wRVU threshold is used for Methods One, Two, and Three, then 70%, 58%, and 77% of Neuro MRIs and 86%, 80%, and 90% of MSK MRIs are read by low-volume radiologists.

DISCUSSION

A large number of radiologists read a low volume of Neuro or MSK MRIs; these low-volume Neuro or MSK MRI radiologists read a substantial portion of Neuro or MSK MRIs. It is unknown which of the methods for distinguishing low-volume radiologists, combined with which threshold, may best correlate with high-performing or low-performing radiologists.

Clinical Practice Characteristics of Radiologists Based on American Board of Radiology Interventional Radiology Certification Status

OBJECTIVE. The objective of this study was to assess clinical practice characteristics of radiologists on the basis of American Board of Radiology (ABR) interventional radiology (IR) certification status. MATERIALS AND METHODS. Medicare-participating radiologists were linked with ABR diplomates using the ABR's public search engine. Radiologists with an interventional radiology/diagnostic radiology (IR/DR) certificate (offered since 2017) were deemed currently IR-certified (n = 2840), and those assigned a vascular and interventional radiology subspecialty certificate (now defunct by the ABR) were deemed previously IR-certified (n = 900). Physician characteristics were obtained from Centers for Medicare & Medicaid Services (CMS) data. RESULTS. Overall, the mean percentage work effort in IR was higher for radiologists currently IR-certified than it was for radiologists who were previously IR-certified (65.9% vs 30.6%). Although 41.2% of currently IR-certified diplomates had more than 90% IR work effort, 35.7% had 50% or less IR work effort. Radiologists with current IR certification versus those with previous IR certification were more likely to be in an academic practice (25.1% vs 8.4%), a larger practice (in a practice with ≥ 100 members, 41.2% vs 22.4%), and earlier career stages (≤ 20 years in practice, 46.5% vs 0.6%). Of the 10 services most commonly billed by currently versus previously IR-certified radiologists, two and zero, respectively, were invasive procedures. Of identified CMS-participating radiologists with more than 50% IR effort, 27.2% (727/2670) were neither previously nor currently IR-certified. CONCLUSION. Although radiologists maintaining IR certification have higher IR work effort than those whose IR certification has lapsed, they are heterogeneous with overall sizable noninvasive diagnostic imaging practices. Approximately one-quarter of radiologists with predominant IR practices have never obtained IR certification. Because current IR/DR maintenance of certification testing exclusively addresses IR practice, attention is warranted to ensure certification is relevant to all IR diplomates.

Board Certification Characteristics of Practicing Neuroradiologists

BACKGROUND AND PURPOSE

Insight into the status of neuroradiology subspecialty certification across the United States could help to understand neuroradiologists' perceived value of subspecialty certification as well as guide efforts to optimize pathways for broader voluntary certification participation. Our aim was to assess board certification characteristics of practicing US neuroradiologists.

MATERIALS AND METHODS

The American Board of Radiology public search engine was used to link Medicare-participating radiologists with American Board of Radiology diplomates. Among linked diplomates, 4670 neuroradiologists were identified on the basis of 3 criteria: current or prior neuroradiology subspecialty certification or currently >50% clinical work effort in neuroradiology based on work relative value unit-weighted national Medicare claims ("majority-practice neuroradiologists"). Subspecialty certification status was studied in each group, using Centers for Medicare & Medicaid Services data to identify additional physician characteristics.

RESULTS

Of 3769 included radiologists ever subspecialty certified, 84.1% are currently subspecialty certified. Of 1777/3769 radiologists ever subspecialty-certified and with lifetime primary certificates (ie, nonmandated Maintenance of Certification), only 66.6% are currently subspecialty certified. Of 3341 included majority-practice neuroradiologists, 73.0% were ever subspecialty certified; of these, 89.1% are currently subspecialty certified. Of 3341 majority-practice neuroradiologists, the fraction currently subspecialty certified was higher for those in academic (81.3%) versus nonacademic (58.2%) practices, larger versus smaller practices (72.1% for those in ≥100 versus 36.1% for <10-member practices), US regions other than the West (64.1%-70.6% versus 56.5%), fewer years in practice (77.5% for 11-20 years versus 31.3% for >50 years), and time-limited (73.5%) versus lifetime (54.9%) primary certificates.

CONCLUSIONS

More than one-quarter of majority-practice neuroradiologists never obtained neuroradiology subspecialty certification. Even when initially obtained, that certification is commonly not maintained, particularly by lifetime primary certificate diplomates and those in nonacademic and smaller practices. Further investigation is warranted to better understand neuroradiologists' decisions regarding attaining and maintaining subspecialty certification.

Diagnostic Radiologists' Participation in the American Board of Radiology Maintenance of Certification Program

OBJECTIVE. Physicians across specialties have expressed concerns about Maintenance of Certification (MOC) programs of American Board of Medical Specialties member boards, calling for research about MOC acceptance, adoption, and value. The purpose of this study was to characterize diagnostic radiologists' participation in the American Board of Radiology (ABR) MOC program, the framework for its new Online Longitudinal Assessment program. MATERIALS AND METHODS. Practicing U.S. radiologists were identified from the Centers for Medicare & Medicaid Services Physician and Other Supplier Public Use File. Corresponding ABR diplomate certification information was obtained through the ABR public search engine. Focused on diagnostic radiologists (defined as those whose only ABR certificate is in diagnostic radiology), MOC participation rates were calculated across various physician characteristics for those whose participation was mandated by the ABR (time-limited certificates) and for those whose participation was not mandated (lifetime certificates). RESULTS. Among 20,354 included diagnostic radiologists, 11,479 (56.4%) participated in MOC. Participation rates were 99.6% (10,058/10,099) among those whose MOC was ABR mandated and 13.9% (1421/10,225) among those whose participation was not mandated (p < 0.001). The rates of nonmandated participation were higher (all p < 0.001) for academic than for non-academic radiologists (28.0% vs 11.3%), subspecialists than for generalists (17.0% vs 11.5%), and those in larger practice groups (< 10 members, 5.0%; 10-49 members, 12.6%; ≥ 50 members, 20.7%). State-level rates of nonmandated participation varied from 0.0% (South Dakota, Montana) to 32.6% (Virginia) and positively correlated with state population density (r = 0.315). CONCLUSION. Although diagnostic radiologists with time-limited certificates nearly universally participate in MOC, those with lifetime certificates (particularly general radiologists and those in smaller and nonacademic practices) participate infrequently. Low rates of nonmandated participation may reflect diplomate dissatisfaction or negative perceptions about MOC.

Disparities over Time in Volume, Day of the Week, and Patient Complexity between Paracentesis and Thoracentesis Procedures Performed by Radiologists versus Those Performed by Nonradiologists

PURPOSE

To compare the disparities between the paracenteses and thoracenteses performed by radiologists with those performed by nonradiologists over time. Variables included the volume of procedures, the days of the week, and the complexity of the patient's condition.

MATERIALS AND METHODS

Using carrier claims files for a 5% national sample of Medicare beneficiaries from 2004 to 2016, paracentesis and thoracentesis examinations were retrospectively classified by physician specialty (radiologist vs nonradiologist), day of the week (weekday vs weekend), and the complexity of the patient's condition (using Charlson comorbidity index scores). The Pearson chi-square and independent samples t-test were used for statistical analysis.

RESULTS

Between 2004 and 2016, the proportion of all paracentesis and thoracentesis procedures performed by radiologists increased from 70% to 80% and from 47% to 66%, respectively. Although radiologists increasingly performed more of both services on both weekends and weekdays, the share performed by radiologists was lower on weekends. For most of the first 9 years across the study period, radiologists performed paracentesis in patients with more complex conditions than those treated by nonradiologists, but the complexity of patients' conditions was similar during recent years. For thoracentesis, the complexity of patients' conditions was similar for both specialty groups across the study period.

CONCLUSIONS

The proportion of paracentesis and thoracentesis procedures performed in Medicare beneficiaries by radiologists continues to increase, with radiologists increasingly performing most of both services on weekends. Nonetheless, radiologists perform disproportionately more on weekdays than on weekends. Presently, radiologists and nonradiologists perform paracentesis and thoracentesis procedures in patients with similarly complex conditions. These interspecialty differences in timing and complexity of the patient's condition differ from those recently described for several diagnostic imaging services, reflecting the unique clinical and referral patterns for invasive versus diagnostic imaging services.

In comparison with other abdominal imaging modalities, which radiologists interpret abdominal MRI?

PURPOSE

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

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.

Current Clinical Practice Patterns of Self-Identified Nuclear Medicine Specialists

OBJECTIVE

The objective of our study was to study patterns of services rendered by U.S. physicians who self-identify as nuclear medicine (NM) specialists.

MATERIALS AND METHODS

Recent Medicare physician claims and demographic files were obtained and linked. NM specialists were defined as physicians self-identifying NM as their primary specialty on claims or as any of their specialties during enrollment. Using other self-identified specialties, we classified physicians as nuclear radiologists, nuclear cardiologists, exclusively NM physicians, or Others. Our primary outcome measure was the percentage of NM effort (in work relative value units [WRVUs]) per physician per specialty group. Secondary outcome measures included physician sociodemographic parameters and most common uniquely rendered services.

RESULTS

Nationally, 1583 physicians self-identified as NM specialists during the calendar years 2012 through 2015. The distribution of WRVUs attributed to NM varied widely by specialty group; most nuclear radiologists and nuclear cardiologists devoted 10% or less of their effort to NM services whereas most NM physicians devoted 90% or more of their effort to NM services. NM specialists were most commonly nuclear radiologists (52.2%) and men (80.3%) and practiced in urban (98.4%) and nonacademic settings (62.9%). NM physicians interpreted more general NM studies, nuclear radiologists interpreted more cross-sectional imaging studies, and nuclear cardiologists interpreted mostly nuclear cardiology studies, with a majority of their overall work attributed to clinical evaluation and management (E/M). E/M services accounted for less than 2% of WRVUs for both nuclear radiologists and NM physicians.

CONCLUSION

The work patterns of U.S. NM specialists is highly variable. Most NM physicians practice 90% or more NM, whereas most nuclear radiologists and nuclear cardiologists practice 10% or less NM. Commonly performed services vary considerably by specialty group.

Physician Specialty and Radiologist Characteristics Associated with Higher Medicare Patient Complexity

RATIONALE AND OBJECTIVES

Meaningfully measuring physician outcomes and resource utilization requires appropriate patient risk adjustment. We aimed to assess Medicare patient complexity by physician specialty and to further identify radiologist characteristics associated with higher patient complexity.

MATERIALS AND METHODS

The average beneficiary Hierarchical Condition Category (HCC) risk scores (Medicare's preferred measure of clinical complexity) were identified for all physicians using 2014 Medicare claims data. HCC scores were compared among physician specialties and further stratified for radiologists based on a range of characteristics. Univariable and multivariable analyses were performed.

RESULTS

Of 549,194 physicians across 54 specialties, the mean HCC risk score was 1.62 ± 0.75. Of the 54 specialties, interventional radiology ranked 4th (2.60 ± 1.29), nuclear medicine ranked 16th (1.87 ± 0.45), and diagnostic radiology ranked 21st (1.75 ± 0.61). Among 31,175 radiologists, risk scores were higher (P < 0.001) for those with teaching (2.03 ± 0.74) vs nonteaching affiliations (1.72 ± 0.61), practice size ≥100 (1.94 ± 0.70) vs ≤9 (1.59 ± 0.79) members, urban (1.79 ± 0.69) vs rural (1.67 ± 0.59) practices, and subspecialized (1.85 ± 0.81) vs generalized (1.68 ± 0.42) practice patterns. Among noninterventional radiology subspecialties, patient complexity was highest for cardiothoracic (2.09 ± 0.57) and lowest for breast (1.08 ± 0.32) imagers. At multivariable analysis, a teaching affiliation was the strongest independent predictor of patient complexity for both interventional (β = +0.23, P = 0.005) and noninterventional radiologists (β = +0.21, P < 0.001).

CONCLUSIONS

Radiologists on average serve more clinically complex Medicare patients than most physicians nationally. However, patient complexity varies considerably among radiologists and is particularly high for those with teaching affiliations and interventional radiologists. With patient complexity increasingly recognized as a central predictor of clinical outcomes and resource utilization, ongoing insights into complexity measures may assist radiologists navigating emerging risk-based payment models.

Merit-Based Incentive Payment System Participation: Radiologists Can Run but Cannot Hide

PURPOSE

To optimize the flexibility and relevancy of its Merit-Based Incentive Payment System (MIPS), CMS exempts selected physicians and groups from participation and grants others relaxed reporting requirements. We assess the practical implications of such special status determinations.

METHODS

For a random sample of 1,000 Medicare-participating radiologists, the CMS MIPS Participation Lookup Tool was manually searched. Individual radiologists' and associated groups' participation requirements and special statuses were assessed.

RESULTS

Although only 55% of radiologists were required to participate in MIPS as individuals when considering only one associated taxpayer identification number (TIN), 83% were required to participate as individuals when considering all associated TINs. When using the group reporting option, 97% of radiology groups were required to participate. High participation requirements persisted across generalist and subspecialist radiologists, small and rural, and both academic and nonacademic practices. Non-patient-facing and hospital-based statuses were assigned to high fractions of individual radiologists (91% and 71%, respectively), but much lower fractions of group practices (72% and 25%). Rural and health professional shortage area statuses were assigned to higher percentages of groups (27% and 39%) than individuals (13% and 23%). Small practice status was assigned to 22% of individuals versus 16% of groups.

CONCLUSION

Although not apparent if only considering individual radiologist-TIN combinations, the overwhelming majority of radiologists will be required to participate in MIPS, at the individual or group level. Radiology groups are strongly encouraged to review their physicians' MIPS participation requirements and special statuses to ensure optimal performance scores and payment bonuses.

Historic Physician Quality and Reporting System Reporting by Radiologists: A Wake-up Call to Avoid Penalties Under the Medicare Access and CHIP Reauthorization Act (MACRA)

PURPOSE

The Medicare Access and CHIP Reauthorization Act (MACRA) Quality performance category is the successor to the Physician Quality and Reporting System (PQRS) program and now contributes to physicians' income adjustments based upon performance rates calculated for a minimum of six measures. We assess radiologists' frequency of reporting PQRS measures as a marker of preparedness for MACRA.

METHODS

Medicare-participating radiologists were randomly searched through the Physician Compare website until identifying 1,000 radiologists who reported at least one PQRS measure. Associations were explored between the number of reported measures and radiologist characteristics.

RESULTS

For PQRS-reporting radiologists, the number of reported PQRS measures was 1 (25.2%), 2 (27.3%), 3 (18.2%), 4 (19.3%), 5 (8.3%), and 6 (1.7%). The most commonly reported measures were "documenting radiation exposure time for procedures using fluoroscopy" (64.3%) and "accurate measurement of carotid artery narrowing" (56.8%). Reporting at least two measures was significantly (P < .001) more likely for nonacademic (77.3%) versus academic (44.9%) radiologists, generalists (82.7%) versus subspecialists (59.1%), and radiologists in smaller (≤9 members) (84.7%) versus larger (≥100 members) (39.7%) practices. Reporting six measures was significantly (P < .05) more likely for generalists (2.6%) versus subspecialists (0.4%).

CONCLUSION

Most PQRS-reporting radiologists reported only one or two measures, well below MACRA's requirement of six. Radiologists continuing such reporting levels will likely be disadvantaged in terms of potential payment adjustments under MACRA. Lower reporting rates for academic and subspecialized radiologists, as well as those in larger practices, may relate to such radiologists' reliance on their hospitals or networks for PQRS reporting. Qualified clinical data registries should be embraced to facilitate more robust measure reporting.