International Interobserver Variability of Breast Density Assessment.

PURPOSE: The aim of this study was to determine variability in visually assessed mammographic breast density categorization among radiologists practicing in Indonesia, the Netherlands, South Africa, and the United States. METHODS: Two hundred consecutive 2-D full-field digital screening mammograms obtained from September to December 2017 were selected and retrospectively reviewed from four global locations, for a total of 800 mammograms. Three breast radiologists in each location (team) provided consensus density assessments of all 800 mammograms using BI-RADS® density categorization. Interreader agreement was compared using Gwet's AC2 with quadratic weighting across all four density categories and Gwet's AC1 for binary comparison of combined not dense versus dense categories. Variability of distribution among teams was calculated using the Stuart-Maxwell test of marginal homogeneity across all four categories and using the McNemar test for not dense versus dense categories. To compare readers from a particular country on their own 200 mammograms versus the other three teams, density distribution was calculated using conditional logistic regression. RESULTS: For all 800 mammograms, interreader weighted agreement for distribution among four density categories was 0.86 (Gwet's AC2 with quadratic weighting; 95% confidence interval, 0.85-0.88), and for not dense versus dense categories, it was 0.66 (Gwet's AC1; 95% confidence interval, 0.63-0.70). Density distribution across four density categories was significantly different when teams were compared with one another and one team versus the other three teams combined (P < .001). Overall, all readers placed the largest number of mammograms in the scattered and heterogeneous categories. CONCLUSIONS: Although reader teams from four different global locations had almost perfect interreader agreement in BI-RADS density categorization, variability in density distribution across four categories remained statistically significant.

Two-view versus single-view mammography at subsequent screening in a region of the Dutch breast screening programme.

We retrospectively determined the effect of analogue two-view mammography versus single-view mammography at subsequent screens on breast cancer detection and determined financial consequences for a current digital mammography setting. Two screening radiologists reviewed the mammograms of 536 screen detected cancers (SDCs) and 171 interval cancers (ICs) with single-view mammography (medio-lateral-oblique view) at the last but one screen (SDCs) or latest screen (ICs). They determined whether two-view mammography at the last (but one) screen could have increased the cancer detection rate at that screening round. For subsequent screens, the radiologists also assessed the percentage of SDCs and ICs that had been missed at previous two-view screening mammography (SDC) or latest two-view screening (IC), respectively. Additional personnel and digital storage costs for standard two-view mammography at subsequent screening were calculated for digital screening. Two-view mammography could have facilitated earlier cancer detection in 40.9% (219/536) of SDCs and 39.8% (68/171) of ICs. For two-view screens, 24.4% of SDCs (213/871) were missed at previous two-view screening and 29.3% of ICs (110/375) were missed at the latest screen. Overall costs increase € 1.03/screen after implementation of digital two-view mammography. Standard two-view mammography at subsequent screening may modestly increase cancer detection at an earlier stage, whereas additional screening costs are limited.

Utilization and cost of diagnostic imaging and biopsies following positive screening mammography in the southern breast cancer screening region of the Netherlands, 2000-2005.

We prospectively assessed trends in utilization and costs of diagnostic services of screen-positive women in a biennial breast cancer screening program for women aged 50-75 years. All 2,062 women with suspicious findings at screening mammography in the southern region of the Netherlands between 1 January 2000 and 1 July 2005 (158,997 screens) were included. Data were collected on any diagnostic examinations, interventional procedures, and surgical consultations with two-year follow-up. We used national reimbursement rates to estimate imaging costs and percutaneous biopsy costs. Cost prices, charged by hospitals, were used to estimate open surgical biopsy costs and surgical consultation costs. The largest increase in utilization of diagnostic procedures per 100 referrals was observed for axillary ultrasound (from 3.9 in 2000 to 33.5 in 2005) and for stereotactic core biopsy (from 2.1 in 2000 to 26.8 in 2005). Per 100 referrals, the open surgical biopsy rate decreased from 34.7 (2000) to 4.6 (2005) and the number of outpatient surgical consultations fluctuated between 269.8 (2000) and 309.7 (2004). Mean costs for the diagnosis of one cancer were Euro1,501 and ranged from Euro1,223 (2002) to Euro1,647 (2003). Surgical biopsies comprised 54.1% of total diagnostic costs for women screened in 2000, but decreased to 9.9% for women screened in 2005. Imaging costs increased from 23.7 to 43.8%, percutaneous biopsy costs from 9.9 to 27.2%, and consultation costs from 12.3 to 19.1%. We conclude that diagnostic costs per screen-detected cancer remained fairly stable through the years, although huge changes in the use of different diagnostic procedures were observed.

Introduction of additional double reading of mammograms by radiographers: effects on a biennial screening programme outcome.

PURPOSE: To determine the effect of introducing radiographer double reading, in addition to standard radiologist double reading, on screening mammography outcome. METHODS: In period A, 66,225 mammograms were read by two screening radiologists. In period B, 78,325 mammograms were read by two radiographers in addition and radiologists were blinded to the referral opinion of the radiographers. Mammograms, for which only radiographers had suggested referral, (i.e. cases that would only be referred by technologists) were re-evaluated by the screening radiologists. Women were referred if at least one radiologist considered this necessary, and diagnostic costs of these additional referrals were estimated. RESULTS: In period A, 322 cancers were diagnosed after referral of 678 women. During period B, radiologists initially referred 1122 patients and 411 cancers were detected. Radiologists' referral rate was higher in period B than in period A (1.43% versus 1.02%, p<0.001), as well as the cancer detection rate per 1000 women screened (CDR) (5.25 versus 4.86, p=0.3). The positive predictive value of referral (PPV) was 36.6% versus 47.5% (p<0.001). In period B, radiologist review of 544 additional positive radiographer readings led to 102 extra referrals, with 29 additional cancers detected, resulting in an overall referral rate of 1.56% (compared to period A, p<0.001), an overall CDR of 5.62 (p=0.048) and an overall PPV of 35.9% (p<0.001). Workup expenses of the 102 additional referrals were euro60,274. CONCLUSION: Additional radiographer double reading detected cancers that would have been missed by radiologists. Mean expenses for diagnostic confirmation of these extra cancers was euro2078 per cancer.

Peripheral arterial disease: clinical and cost comparisons between duplex US and contrast-enhanced MR angiography--a multicenter randomized trial.

PURPOSE: To prospectively determine the clinical and economic consequences of replacing duplex ultrasonography (US) with contrast material-enhanced magnetic resonance (MR) angiography for the initial imaging work-up of patients with peripheral arterial disease (PAD). MATERIALS AND METHODS: This randomized multicenter study was approved by the institutional review board of each hospital, and all patients signed written informed consent prior to randomization. Patients with PAD who needed to undergo imaging work-up and who had an ankle-brachial pressure index (ABPI) of less than 0.90 were recruited by vascular surgeons between January 2002 and September 2003. Patients were randomly assigned to undergo contrast-enhanced MR angiography or duplex US. The primary outcome measure was cost. Secondary outcome measures included therapeutic confidence, changes in disease severity, and changes in quality of life (QOL) assessed during 6 months of follow-up. Indicators for disease severity were based on the Rutherford classification, treadmill walking distance, ABPI at rest, and ABPI after exercise. QOL was assessed with the Rating Scale, Short Form 36, EuroQol-5D, and VascuQol questionnaires. The cost of (additional) imaging procedures, therapeutic interventions, and outpatient visits were calculated from a hospital perspective (ie, all costs incurred inside the hospital were estimated, including physician costs). Data were evaluated by using the Student t test and a multivariable linear regression analysis. RESULTS: At 6 months, 352 patients (239 [68%] men, 113 [32%] women; mean age, 65 years) were analyzed. The use of contrast-enhanced MR angiography versus duplex US reduced the number of additional vascular imaging procedures by 42%; contrast-enhanced MR angiography was also associated with higher therapeutic confidence. Diagnostic costs for contrast-enhanced MR angiography were 167 euros (186 dollars) higher than those for duplex US (P < .001). No statistically significant differences were found for total cost, changes in disease severity, or changes in QOL between patients examined with duplex US and those examined with contrast-enhanced MR angiography (P > .05). CONCLUSION: Replacing duplex US with contrast-enhanced MR angiography for the initial imaging work-up of patients with PAD reduces the need for additional imaging, although diagnostic costs are higher.