Faculty Bibliography

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.

Technical advances in MRI have improved image quality and have led to expanding clinical indications for its use. However, long examination and interpretation times, as well as higher costs, still represent barriers to use of MRI. Abbreviated MRI protocols have emerged as an alternative to standard MRI protocols. These abbreviated MRI protocols seek to reduce longer MRI protocols by eliminating unnecessary or redundant sequences that negatively affect cost, MRI table time, patient comfort, image quality, and image interpretation time. However, the diagnostic information is generally not compromised. Abbreviated MRI protocols have already been used successfully for hepatocellular carcinoma screening, for prostate cancer detection, and for screening for nonalcoholic fatty liver disease as well as monitoring patients with this disease. It has been reported that image acquisition time and costs can be considerably reduced with abbreviated MRI prototcols, compared with standard MRI protocols, while maintaining a similar sensitivity and accuracy. Nevertheless, multiple applications still need to be explored in the abdomen and pelvis (eg, surveillance of metastases to the liver; follow-up of cystic pancreatic lesions, adrenal incidentalomas, and small renal masses; evaluation of ovarian cysts in postmenopausal women; staging of cervical and uterine corpus neoplasms; evaluation of müllerian duct anomalies). This article describes some successful applications of abbreviated MRI protocols, demonstrates how they can help in improving the MRI workflow, and explores potential future directions. ^©RSNA, 2019.

Purpose: To evaluate trends in transcatheter hemodialysis conduit procedures in the Medicare population over a recent 15-year interval. Materials: Aggregate national claims data were extracted from CMS PSPS Master Files from 2001-2015 for hemodialysis conduit angiography and thrombectomy procedures. Utilization was stratified by billing specialty and site of service. Additionally, individual claims data from 2004-2015 CMS 5% Research Identifiable Files were used to assess state-level utilization. Utilization was normalized per 100,000 Medicare fee-for-service beneficiaries. Result(s): From 2001-2015, hemodialysis conduit angiography utilization rates increased from 385 to 1,045 per 100,000 beneficiaries [compound annual growth rate (CAGR) +7.4%)], and thrombectomy rates increased from 114 to 168 (CAGR +2.8%). The CAGR for angiography was, by specialty, +1.5% for radiologists, +18.4% for surgeons, and +24.0% for nephrologists, and by site, +29.1% for office and +0.8% for hospital settings. Radiologists' overall market share of angiography decreased from 81.5% in 37.0%. By combination of specialty and site of service, angiography utilization growth was greatest for nephrologists in the office (from 5 to 265) and surgeons in the office (0 to 128). The greatest decline was for radiologists in the hospital (299 to 205). At the state level, there was marked heterogeneity in dialysis angiography utilization in 2015 [0 (Wyoming) to 1,1,73 (Georgia)], temporal change in angiography utilization from 2004-2015 [CAGR -100.0% (Wyoming) to +19.9% (Nevada)], and radiologists' 2015 market share [4.8% (Washington DC) to 100.0% (North Dakota)]. Nonetheless, radiologists' market share decreased in 49 states, and in some states dramatically (e.g., in Nevada, from 100.0% in 2004 to 6.7% in 2015). Conclusion(s): Transcatheter dialysis conduit angiography utilization has grown substantially, and more so than thrombectomy. This growth has been accompanied by a drastic market shift from radiologists in the hospital to nephrologists and surgeons in the office. Despite wide geographic heterogeneity across the U.S., decreasing radiologist market share has been observed in nearly every state.

Purpose: To assess changing utilization in extremity angiography from 2001 to 2016, focusing on relative shifts between modalities and provider specialties. Materials: Medicare PSPS Master Files from 2001-2016 were used to determine national utilization of traditional invasive catheter angiography, CTA, and MRA, normalized to extremities imaged per 100,000 beneficiaries. Result(s): From 2001 to 2016, extremity angiography increased from 769 to 1,352 total extremities imaged per 100,000 beneficiaries, largely attributable to massive early growth in CTA (22 in 2001 to 614 in 2009; plateau of 645 in 2016), with small changes in catheter angiography (702 to 676) and MRA (45 to 30). Extremity angiography shifted from 91% catheter, 6% MRA, 3% CTA in 2001 to 50% catheter, 48% CTA, and 2% MRA in 2016. For radiologists, overall angiography increased (488 to 733) due to a large increase in CTA (20 to 595) despite a large decrease in catheter (428 to 122), while MRA remained low (40 to 27); extremity angiography by radiologists shifted from 88% catheter, 8% MRA, and 4% CTA in 2001 to 81% CTA, 15% catheter, and 4% MRA in 2016. For cardiologists, there were increases in angiography overall (155 to 240) and catheter (153 to 205), and to a lesser extent in CTA (1 to 33); extremity angiography by cardiologists shifted from 99% catheter, <1% CTA, <1% MRA in 2001 to 85% catheter, 14% CTA, <1% MRA in 2016. For surgeons, overall angiography increased from 65 to 261 and was 99% catheter in both 2001 and 2016. Radiologists' market share of extremity angiography varied from 63% (2001) to 54% (2016). Despite a marked decrease in radiologists' share for catheter (61% to 17%), radiologists were the dominant provider throughout for CTA (89% to 92%) and MRA (89% to 90%). Conclusion(s): Utilization of extremity angiography in Medicare beneficiaries nearly tripled from 2001 to 2016, almost entirely due to the advent of CTA by radiologists. Cardiologists and surgeons acquired the large volume of catheter angiography given up by radiologists. Further work is necessary to assess if the growth of CTA represents additive (i.e., expanded patient populations being evaluated) vs. duplicative (i.e., same patients undergoing both tests) imaging.

Purpose: To explore variation in downstream costs associated with cartilage lesions incidentally detected on radiographs. Materials andMethods: The cohort was composed of 120 patients with incidental, not previously diagnosed, cartilage lesions seen on appendicular plain radiographs. The population was divided into three subgroups based on the interpreting radiologist's description: enchondroma, lowgrade cartilage lesion, and chondrosarcoma. Downstream events (follow-up imaging, office visits, biopsy, tumor resection) associated with the lesions were identified from the electronic medical record. American College of Radiology (ACR) Appropriateness Criteria were used to classify radiologists' recommendations. NationalMedicare rates were used to estimate costs of downstream events. Average cost per lesion was stratified, and cost ratios were computed among subgroups.
Result(s): Average downstream cost per lesion was $75.56. Costs were 4.6 times greater in patients under the age of 65 than over. Costs were 13.2 and 13.7 times higher when radiologists characterized lesions as chondrosarcoma versus low-grade cartilage lesion and enchondroma, respectively. There was no statistically significant difference in costs between the subgroups when accounting for size and location of lesions. Compared to when follow-up imaging was neither recommended nor obtained, costs rose from $0 to $26.03 per patient when follow-up imaging was recommended and obtained, and $62.21 per patient when followup imaging was obtained despite not being recommended. Costs rose from $0 to $14.83 per patient when radiologists' recommendations for follow-up were adherent to the ACR guidelines for management of incidental bone lesions. Costs were 2.3 times greater when ordering physicians overmanaged compared with radiologists' recommendations. No malignancy was pathologically proven in the cohort.
Conclusion(s): Costs for incidental cartilage lesions vary. Size and location of lesions do not have a significant effect on downstream costs; however, radiologists' characterization and recommendation have an impact. Therefore, it is imperative that radiologists accurately characterize such lesions and recommendations reflect the best value for patient care

BACKGROUND:Patient-specific 3D models are being used increasingly in medicine for many applications including surgical planning, procedure rehearsal, trainee education, and patient education. To date, experiences on the use of 3D models to facilitate patient understanding of their disease and surgical plan are limited. The purpose of this study was to investigate in the context of renal and prostate cancer the impact of using 3D printed and augmented reality models for patient education. METHODS:Patients with MRI-visible prostate cancer undergoing either robotic assisted radical prostatectomy or focal ablative therapy or patients with renal masses undergoing partial nephrectomy were prospectively enrolled in this IRB approved study (n = 200). Patients underwent routine clinical imaging protocols and were randomized to receive pre-operative planning with imaging alone or imaging plus a patient-specific 3D model which was either 3D printed, visualized in AR, or viewed in 3D on a 2D computer monitor. 3D uro-oncologic models were created from the medical imaging data. A 5-point Likert scale survey was administered to patients prior to the surgical procedure to determine understanding of the cancer and treatment plan. If randomized to receive a pre-operative 3D model, the survey was completed twice, before and after viewing the 3D model. In addition, the cohort that received 3D models completed additional questions to compare usefulness of the different forms of visualization of the 3D models. Survey responses for each of the 3D model groups were compared using the Mann-Whitney and Wilcoxan rank-sum tests. RESULTS:All 200 patients completed the survey after reviewing their cases with their surgeons using imaging only. 127 patients completed the 5-point Likert scale survey regarding understanding of disease and surgical procedure twice, once with imaging and again after reviewing imaging plus a 3D model. Patients had a greater understanding using 3D printed models versus imaging for all measures including comprehension of disease, cancer size, cancer location, treatment plan, and the comfort level regarding the treatment plan (range 4.60-4.78/5 vs. 4.06-4.49/5, p < 0.05). CONCLUSIONS:All types of patient-specific 3D models were reported to be valuable for patient education. Out of the three advanced imaging methods, the 3D printed models helped patients to have the greatest understanding of their anatomy, disease, tumor characteristics, and surgical procedure.

BACKGROUND:The value of dynamic contrast-enhanced (DCE) sequences in prostate MRI compared with noncontrast MRI is controversial. PURPOSE/OBJECTIVE:To evaluate the population net benefit of risk stratification using DCE-MRI for detection of high-grade prostate cancer (HGPCA), with or without high spatiotemporal resolution DCE imaging. STUDY TYPE/METHODS:Decision curve analysis. POPULATION/METHODS:Previously published patient studies on MRI for HGPCA detection, one using DCE with golden-angle radial sparse parallel (GRASP) images and the other using standard DCE-MRI. FIELD STRENGTH/SEQUENCE/UNASSIGNED:GRASP or standard DCE-MRI at 3 T. ASSESSMENT/RESULTS:Each study reported the proportion of lesions with HGPCA in each Prostate Imaging Reporting and Data System version 2 (PI-RADS v2) category (1-5), before and after reclassification of peripheral zone lesions from PI-RADS 3-4 based on contrast-enhanced images. This additional risk stratifying information was translated to population net benefit, when biopsy was hypothetically performed for: all lesions, no lesions, PI-RADS ≥3 (using NC-MRI), and PI-RADS ≥4 on DCE. STATISTICAL TESTS/UNASSIGNED:Decision curve analysis was performed for both GRASP and standard DCE-MRI data, translating the avoidance of unnecessary biopsies and detection of HGPCA to population net benefit. We standardized net benefit values for HGPCA prevalence and graphically summarized the comparative net benefit of biopsy strategies. RESULTS:For a clinically relevant range of risk thresholds for HGPCA (>11%), GRASP DCE-MRI with biopsy of PI-RADS ≥4 lesions provided the highest net benefit, while biopsy of PI-RADS ≥3 lesions provided highest net benefit at low personal risk thresholds (2-11%). In the same range of risk thresholds using standard DCE-MRI, the optimal strategy was biopsy for all lesions (0-15% risk threshold) or PI-RADS ≥3 on NC-MRI (16-33% risk threshold). DATA CONCLUSION/UNASSIGNED:GRASP DCE-MRI may potentially enable biopsy of PI-RADS ≥4 lesions, providing relatively preserved detection of HGPCA and avoidance of unnecessary biopsies compared with biopsy of all PI-RADS ≥3 lesions. J. Magn. Reson. Imaging 2019.

PURPOSE/OBJECTIVE:The aim of this study was to assess national and state-specific changes in emergency department (ED) chest imaging utilization from 1994 to 2015. METHODS:Using aggregate 100% Medicare Physician/Supplier Procedure Summary Master Files for 1994 to 2015, the annual frequency of chest imaging in Medicare Part B beneficiaries in the ED setting was identified, and utilization was normalized to annual Medicare enrollment as well as annual ED visits. Using individual Medicare beneficiary 5% research-identifiable files, similar determinations were performed for each state. RESULTS:Between 1994 and 2015, per 1,000 beneficiaries, ED utilization of chest radiography and CT increased by 173% (compound annual growth rate [CAGR] 4.9%) and 5,941.8% (CAGR 21.6%). Per 1,000 ED visits, utilization increased by 81% (CAGR 2.9%) and 3,915.4% (CAGR 19.2%), respectively. Across states, utilization was highly variable, with 2015 radiography utilization per 1,000 ED visits ranging from 82 (Wyoming) to 731 (Hawaii) and CT utilization ranging from 18 (Wyoming) to 76 (Hawaii). Between 2004 and 2015, most states demonstrated increases in the utilization of both radiography (maximal increase of CAGR 11.0% in Vermont) and CT (maximal increase of CAGR 21.0% in Maine). Nonetheless, utilization of radiography declined in four states and utilization of CT in a single state. CONCLUSIONS:Over the past two decades, ED utilization of chest imaging has increased. This was related not only to an increasing frequency of ED visits but also to increasing utilization per ED visit. Across states, utilization is highly variable, but with radiography and CT both increasing, the use of CT seems additive to, rather than replacing, radiography.

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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.