A mammography image set for research purposes using BI-RADS density classification.

PURPOSE: Breast density categorization consistency is important when performing research, and minimization of interoperator and intraoperator variability is essential. This research aimed to validate a set of mammography images for visual breast density estimation to achieve consistency in future research projects and to determine observer performance. METHODS: Using the Breast Imaging Reporting and Data System (BI-RADS) as the visual grading scale, 50 mammography images were scored for density grade by 8 observers. RESULTS: Six of 8 observers achieved near-complete intraobserver agreement (kappa > 0.81). Strong agreement among observers (kappa = 0.61-0.8) was found in 10 of 28 paired observation episodes on the first iteration and 12 of 28 on the second. No observers demonstrated a delta variance above 1. Fleiss' kappa was used to evaluate concordance among all observers on the first and second iterations (first iteration, 0.64; second iteration, 0.56). DISCUSSION: This research illustrates the difficulties of comparing observer visual performance scores because differences can exist when studies are repeated by and among individuals. CONCLUSION: We confirmed that the 50 images were suitable for research purposes. Some variability existed among observers; however, overall density classification agreement was strong. Future research should include repeating this study with digitally acquired images.

Magnetic resonance imaging and explantation investigation of long-term silicone gel implant integrity.

BACKGROUND: Information about silicone gel implant longevity is sparse. Magnetic resonance imaging studies have superseded explantation studies in the search for data on their long-term integrity. Unfortunately, the majority of studies are based predominantly on second-generation implant cohorts. Although magnetic resonance imaging is acknowledged to be the best imaging modality, the results of any study are entirely dependent on its ability to differentiate ruptured from intact implants. METHODS: A single, textured, third-generation implant type was chosen, to reduce the number of variables. The largest cohort of patients in our database had subglandular Mentor Siltex gel implants (Mentor Medical Systems, Santa Barbara, Calif.). They were contacted and offered a magnetic resonance imaging scan. All patients with at least one radiologically ruptured implant were then offered explantation. RESULTS: One hundred forty-nine patients with bilateral subglandular implants (median +/- SD age, 8.9 +/- 2.3; range, 4.8 to 13.5 years) were imaged and reported by two independent radiologists. Twenty-three patients were reported to have 33 radiologically ruptured implants. Twenty-one patients (30 radiologically ruptured implants) agreed to explantation. Statistical analysis using maximum likelihood estimation of survival curve for cross-sectional data suggests that implant rupture starts at 6 to 7 years and that by 13 years approximately 11.8 percent of implants will have ruptured. CONCLUSION: Although these results cannot necessarily be extrapolated to other implant types and manufacturers, they provide further information about the natural history of implant integrity, better enabling us to counsel prospective and current implant recipients.