Faculty Bibliography

OBJECTIVE:The aim of the study was to compare the distribution of Prostate Imaging and Reporting Data System (PI-RADS) scores, interreader agreement, and diagnostic performance of PI-RADS v2.0 and v2.1 for transition zone (TZ) lesions. METHODS:The study included 202 lesions in 202 patients who underwent 3T prostate magnetic resonance imaging showing a TZ lesion that was later biopsied with magnetic resonance imaging/ultrasound fusion. Five abdominal imaging faculty reviewed T2-weighted imaging and high b value/apparent diffusion coefficient images in 2 sessions. Cases were randomized using a crossover design whereby half in the first session were reviewed using v2.0 and the other half using v2.1, and vice versa for the 2nd session. Readers provided T2-weighted imaging and DWI scores, from which PI-RADS scores were derived. RESULTS:Interreader agreement for all PI-RADS scores had κ of 0.37 (v2.0) and 0.26 (v2.1). For 4 readers, the percentage of lesions retrospectively scored PI-RADS 1 increased greater than 5% and PI-RADS 2 score decreased greater than 5% from v2.0 to v2.1. For 2 readers, the percentage scored PI-RADS 3 decreased greater than 5% and, for 2 readers, increased greater than 5%. The percentage of PI-RADS 4 and 5 lesions changed less than 5% for all readers. For the 4 readers with increased frequency of PI-RADS 1 using v2.1, 4% to 16% were Gleason score ≥3 + 4 tumor. Frequency of Gleason score ≥3 + 4 in PI-RADS 3 lesions increased for 2 readers and decreased for 1 reader. Sensitivity of PI-RADS of 3 or greater for Gleason score ≥3 + 4 ranged 76% to 90% (v2.0) and 69% to 96% (v2.1). Specificity ranged 32% to 64% (v2.0) and 25% to 72% (v2.1). Positive predictive value ranged 43% to 55% (v2.0) and 41% to 58% (v2.1). Negative predictive value ranged 82% to 87% (v2.0) and 81% to 91% (v2.1). CONCLUSIONS:Poor interreader agreement and lack of improvement in diagnostic performance indicate an ongoing need to refine evaluation of TZ lesions.

PURPOSE/OBJECTIVE:The number and roles of US nonphysician practitioners (NPPs) have expanded considerably, but little is known about their use by radiology practices. The authors assessed characteristics and trends of radiology practices employing Medicare-recognized NPPs. METHODS:Using Medicare databases from 2017 through 2019, the authors mapped all nurse practitioners and physician assistants (together "NPPs") to employer groups for which all physicians were radiologists ("radiology practices"). Practices were characterized by size, geography, and radiologist characteristics. Temporal changes were assessed, and NPP employment likelihood was estimated using multivariate logistic regression modeling. RESULTS:As the number of US radiology practices declined by 36.5% (from 2,643 to 1,679) between 2017 and 2019, the number employing NPPs increased by 10.5% (from 228 [8.6%] to 252 [15.0%]). The number of radiologists in NPP-employing practices increased by 10.4% (from 6,596 [35.1%] to 7,282 [40.0%]) as the number of radiology-employed NPPs increased by 17.5% (from 588 to 691). Practices were more likely to employ NPPs when medium (odds ratio [OR], 1.31) or large (OR, 1.25) in size, when urban located (OR, 1.35), and as their percentages of interventional radiologists increased (OR, 5.53 per percentage point) (P < .01 for all). Practices were less likely to employ NPPs as mean radiologist years since completing training increased (OR, 0.99 per year; P < .01). CONCLUSIONS:Employment of NPPs by radiology practices has grown considerably in recent years, particularly in larger and urban practices and in those that employ more interventional and early-career radiologists. More work is necessary to better understand how this expanding use of NPPs affects the specialty.