Faculty Bibliography

OBJECTIVE: Prior studies in prostate diffusion-weighted magnetic resonance imaging (MRI) have largely explored the impact of b-value and diffusion directions on estimated diffusion coefficient D. Here we suggest varying diffusion time, t, to study time-dependent D(t) in prostate cancer, thereby adding an extra dimension in the development of prostate cancer biomarkers. METHODS: Thirty-eight patients with peripheral zone prostate cancer underwent 3-T MRI using an external-array coil and a diffusion-weighted image sequence acquired for b = 0, as well as along 12 noncollinear gradient directions for b = 500 s/mm using stimulated echo acquisition mode (STEAM) diffusion tensor imaging (DTI). For this sequence, 6 diffusion times ranging from 20.8 to 350 milliseconds were acquired. Tumors were classified as low-grade (Gleason score [GS] 3 + 3; n = 11), intermediate-grade (GS 3 + 4; n = 16), and high-grade (GS >/=4 + 3; n = 11). Benign peripheral zone and transition zone were also studied. RESULTS: Apparent diffusion coefficient (ADC) D(t) decreased with increasing t in all zones of the prostate, though the rate of decay in D(t) was different between sampled zones. Analysis of variance and area under the curve analyses suggested better differentiation of tumor grades at shorter t. Fractional anisotropy (FA) increased with t for all regions of interest. On average, highest FA was observed within GS 3 + 3 tumors. CONCLUSIONS: There is a measurable time dependence of ADC in prostate cancer, which is dependent on the underlying tissue and Gleason score. Therefore, there may be an optimal selection of t for prediction of tumor grade using ADC. Controlling t should allow ADC to achieve greater reproducibility between different sites and vendors. Intentionally varying t enables targeted exploration of D(t), a previously overlooked biophysical phenomenon in the prostate. Its further microstructural understanding and modeling may lead to novel diffusion-derived biomarkers.

PURPOSE: To examine changes in the utilization of procedures related to treatment of chronic venous insufficiency (CVI) in the Medicare population. MATERIALS AND METHODS: Service-specific claims data for phlebectomy, sclerotherapy, and radiofrequency (RF) and laser ablation were identified by using Medicare Physician Supplier Procedure Summary master files from 2005 through 2014. Longitudinal national utilization rates were calculated by using annual Medicare enrollment data from 2005 through 2013. Procedure volumes by specialty group and site of service were analyzed. RESULTS: Total annual claims for these procedures in the Medicare fee-for-service beneficiaries increased from 95,206 to 332,244 (Compound Annual Growth Rate [CAGR], 15%) between 2005 and 2014. Per 1,000 beneficiaries, overall utilization increased annually from 2.8 in 2005 to 9.4 in 2013. Most procedures were performed in the private office setting (92% in 2014). In 2014, radiologists had a 10% relative market share, compared with vascular surgeons, other surgeons, and cardiologists, who had 26%, 25%, and 14% market shares, respectively. Cardiologists had the fastest relative growth, with a CAGR of 51% compared with 23% for radiology, 12% for vascular surgery, and 13% for other surgery. Total venous RF ablation services grew with a CAGR of 31%, with radiology and cardiology growing most rapidly (40% and 79%, respectively). Total venous laser ablation services grew with a CAGR of 22%, with radiology growing 15% and cardiology growing most rapidly at 44%. CONCLUSIONS: Utilization of CVI procedures in the Medicare population increased markedly from 2005 through 2014. The overwhelming majority are performed in the private office setting by nonradiologists.

On 8 November 2016 the American electorate voted Donald Trump into the Presidency and a majority of Republicans into both houses of Congress. Since many Republicans ran for elected office on the promise to 'repeal and replace' Obamacare, this election result came with an expectation that campaign rhetoric would result in legislative action on healthcare. The American Health Care Act (AHCA) represented the Republican effort to repeal and replace the Affordable Care Act (ACA). Key elements of the AHCA included modifications of Medicaid expansion, repeal of the individual mandate, replacement of ACA subsidies with tax credits, and a broadening of the opportunity to use healthcare savings accounts. Details of the bill and the political issues which ultimately impeded its passage are discussed here.

PURPOSE: The aim of this study was to assess relationships between county-level variation in Medicare beneficiary imaging resource consumption and measures of population economic status. METHODS: The 2013 CMS Geographic Variation Public Use File was used to identify county-level per capita Medicare fee-for-service imaging utilization and nationally standardized costs to the Medicare program. The County Health Rankings public data set was used to identify county-level measures of population economic status. Regional variation was assessed, and multivariate regressions were performed. RESULTS: Imaging events per 1,000 Medicare beneficiaries varied 1.8-fold (range, 2,723-4,843) at the state level and 5.3-fold (range, 1,228-6,455) at the county level. Per capita nationally standardized imaging costs to Medicare varied 4.2-fold (range, $84-$353) at the state level and 14.1-fold (range, $33-$471) at the county level. Within individual states, county-level utilization varied on average 2.0-fold (range, 1.1- to 3.1-fold), and costs varied 2.8-fold (range, 1.1- to 6.4-fold). For both large urban populations and small rural states, Medicare imaging resource consumption was heterogeneously variable at the county level. Adjusting for county-level gender, ethnicity, rural status, and population density, countywide unemployment rates showed strong independent positive associations with Medicare imaging events (beta = 26.96) and costs (beta = 4.37), whereas uninsured rates showed strong independent positive associations with Medicare imaging costs (beta = 2.68). CONCLUSIONS: Medicare imaging utilization and costs both vary far more at the county than at the state level. Unfavorable measures of county-level population economic status in the non-Medicare population are independently associated with greater Medicare imaging resource consumption. Future efforts to optimize Medicare imaging use should consider the influence of local indigenous socioeconomic factors outside the scope of traditional beneficiary-focused policy initiatives.

OBJECTIVE: The objective of the present study is to assess the feasibility of a novel claims-based classification system for payer identification of academic radiologist subspecialties. MATERIALS AND METHODS: Using a categorization scheme based on the Neiman Imaging Types of Service (NITOS) system, we mapped the Medicare Part B services billed by all radiologists from 2012 to 2014, assigning them to the following subspecialty categories: abdominal imaging, breast imaging, cardiothoracic imaging, musculoskeletal imaging, nuclear medicine, interventional radiology, and neuroradiology. The percentage of subspecialty work relative value units (RVUs) to total billed work RVUs was calculated for each radiologist nationwide. For radiologists at the top 20 academic departments funded by the National Institutes of Health, those percentages were compared with subspecialties designated on faculty websites. NITOS-based subspecialty assignments were also compared with the only radiologist subspecialty classifications currently recognized by Medicare (i.e., nuclear medicine and interventional radiology). RESULTS: Of 1012 academic radiologists studied, the median percentage of Medicare-billed NITOS-based subspecialty work RVUs matching the subspecialty designated on radiologists' own websites ranged from 71.3% (for nuclear medicine) to 98.9% (for neuroradiology). A NITOS-based work RVU threshold of 50% correctly classified 89.8% of radiologists (5.9% were not mapped to any subspecialty; subspecialty error rate, 4.2%). In contrast, existing Medicare provider codes identified only 46.7% of nuclear medicine physicians and 39.4% of interventional radiologists. CONCLUSION: Using a framework based on a recently established imaging health services research tool that maps service codes based on imaging modality and body region, Medicare claims data can be used to consistently identify academic radiologists by subspecialty in a manner not possible with the use of existing Medicare physician specialty identifiers. This method may facilitate more appropriate performance metrics for subspecialty academic physicians under emerging value-based payment models.

Advancements in magnetic resonance imaging (MRI) and MRI-ultrasound (US)-fusion targeted biopsy have resulted in a paradigm shift in the diagnosis of prostate cancer by overcoming the limitations of systematic biopsy. Prebiopsy MRI and MRI-US-fusion biopsy results in an increased detection of clinically significant disease, reduction in the detection of indolent disease, and allows for tumor localization during targeted biopsy. With these advantages, we have adopted a prebiopsy MRI and MRI-US-fusion biopsy diagnostic care pathway for all men at risk for prostate cancer and have performed more than 1900 biopsies to date. Herein we present our institutional development of MRI-US-fusion biopsy and highlight our results in those men who have had a previous negative biopsy, no prior biopsy, and those with a prior cancer diagnosis who may be candidate for active surveillance. Risk stratification with biomarkers and nomograms may allow for further counseling on the need for biopsy and the risk of harboring clinically significant disease.

Active surveillance (AS) has emerged as a beneficial strategy for management of low risk prostate cancer (PCa) and prevention of overtreatment of indolent disease. However, selection of patients for AS using traditional 12-core transrectal prostate biopsy is prone to sampling error and presents a challenge for accurate risk stratification. In fact, around a third of men are upgraded on repeat biopsy which disqualifies them as appropriate AS candidates. This uncertainty affects adoption of AS among patients and physicians, leading to current AS protocols involving repetitive prostate biopsies and unclear triggers for progression to definitive treatment. Prostate magnetic resonance imaging (MRI) has the potential to overcome some of these limitations through localization of significant tumors in the prostate. In conjunction with MRI-targeted prostate biopsy, improved sampling and detection of clinically significant PCa can help streamline the process of selecting suitable men for AS and early exclusion of men who require definitive treatment. MRI can also help minimize the invasive nature of monitoring for disease progression while on AS. Men with stable MRI findings have high negative predictive value for Gleason upgrade on subsequently biopsy, suggesting that men may potentially be monitored by serial MRI examinations with biopsy reserved for significant changes on imaging. Targeted biopsy on AS also allows for specific sampling of concerning lesions, although further data is necessary to evaluate the relative contribution of systematic and targeted biopsy in detecting the 25-30% of men who progress on AS. Further research is also warranted to better understand the nature of clinically significant cancers that are missed on MRI and why certain men have progression of disease that is not visible on prostate MRI. Consensus is also needed over what constitutes progression on MRI, when prostate biopsy can be safely avoided, and how to best utilize this additional information in current AS protocols. Despite these challenges, prostate MRI, either alone or in conjunction with MRI-targeted prostate biopsy, has the potential to significantly improve our current AS paradigm and rates of AS adoption among patients moving forward.

To use Twitter to assess the immediate public response to the United States Preventive Services Task Force (USPSTF) 2013 draft guidelines on lung cancer screening with low-dose chest CT (LDCT). The number of tweets including the phrases "lung cancer screening," "lung CT," "chest CT," "low dose computed tomography," "low dose CT," or "LDCT" was recorded for 6 days before and after guidelines release. A systematic sample of 172 tweets from the week following release was coded for user type, tweet opinion, linked article source, and article opinion. Following guidelines' release, the number of daily tweets increased from 13 +/- 8 to 311 +/- 395. The 172 tweets in the week following release were tweeted by 166 unique users including: news organizations/online news gathering accounts (34.9%), general public (21.7%), physicians (12.0%, 6 radiologists), and businesses (11.4%). 23.3% of tweets provided opinion on the guidelines (50.0% favorable, 27.5% concerned toward screening). Most (91.3%) tweets contained links to a total of 46 unique articles, which were authored by lay press (41.3%), non-peer-reviewed medical press (32.6%), and hospital/medical practice websites (10.9%). Among these, 50.0% were favorable, citing mortality reduction (87.0%), published data supporting screening (50.0%), and early detection (43.5%), while 28.3% expressed concern, including false positives (58.9%) and radiation risk (39.1%). Twitter activity rose rapidly after the USPSTF draft guidelines on LDCT. Most users were non-physicians and frequently cited non-peer-reviewed articles. Users maintained an overall favorable view of screening, while expressing various concerns. Considerable opportunity exists for greater radiologist engagement in this online public dialog.

PURPOSE: To assess the impact of patient race and age on the performance of apparent diffusion coefficient (ADC) values for assessment of prostate cancer aggressiveness. MATERIALS AND METHODS: 457 prostate cancer patients who underwent 3T phased-array coil prostate MRI including diffusion-weighted imaging (DWI; maximal b-value 1000 s/mm2) before prostatectomy were included. Mean ADC of a single dominant lesion was measured in each patient, using histopathologic findings from the prostatectomy specimen as reference. In subsets defined by race and age, ADC values were compared between Gleason score (GS) /= 4 + 3 tumors. RESULTS: 81% of patients were Caucasian, 12% African-American, 7% Asian-American. 13% were <55 years, 42% 55-64 years, 41% 65-74 years, and 4% >/=75 years. 63% were GS /= 4 + 3. ADC was significantly lower in GS >/= 4 + 3 tumors than in GS /= 4 + 3 as well as optimal ADC threshold was Caucasian: 0.73//=75 years, 0.79//=75 years than <55 years or 55-64 years (100.0% vs. 53.6%-73.3%; P < 0.001). CONCLUSION: Patients' race and age may impact the diagnostic performance and optimal threshold when applying ADC values for evaluation of prostate cancer aggressiveness.