Rationale and Objectives-The rates of enrollment of volunteers for brain magnetic resonance imaging (MRI) studies vary by demographic and clinical characteristics. We use data from a large MRI study to identify factors associated with differential enrollment and to examine potential biases this may produce in study results.Materials and Methods-Results from recruitment of 1,431 women into the MRI substudy of the Women's Health Initiative Memory Study (WHIMS-MRI) are described. A sensitivity analysis was conducted to estimate the degree of bias associated with missing data on estimates of risk factor relationships.Results-Of 2,345 women contacted from an established cohort of women older than 70 years of age, 72% consented to undergo screening for WHIMS-MRI. Scanning was ultimately completed on 61%. Completion rates varied according to a range of sociodemographic, lifestyle, and clinical characteristics that may be related to study outcomes. Plausible levels of selective enrollment in magnetic resonance imaging studies may produce moderate biases (< ±20%) in characterizations of risk factor relationships. Adverse events, such as claustrophobia, occurred during 1.7% of the attempted scans and, in 0.8% of instances, led to lost data.Conclusions-Enrollment of older women into brain imaging studies is feasible, although selection biases may limit how well study cohorts reflect more general populations.

Purpose To respond to increased public and programmatic demand to address underenrollment of clinical translational research studies, the authors examine participant recruitment practices at Clinical and Translational Science Award sites (CTSAs) and make recommendations for performance metrics and accountability. Method The CTSA Recruitment and Retention taskforce developed and, in 2010, invited representatives at 46 CTSAs to complete an online 48-question survey querying CTSA accrual and recruitment outcomes, practices, evaluation methods, policies, and perceived gaps in related knowledge/practice. Descriptive statistical and thematic analyses were conducted. Results Forty-six respondents representing 44 CTSAs completed the survey. Recruitment conducted by study teams was the most common practice reported (78–91%, by study type); 39% reported their institution offered recruitment services to investigators. Respondents valued study feasibility assessment as a successful practice (39%); their desired additional resources included feasibility assessments (49%) and participant registries (44%). None reported their institution systematically required justification of feasibility; some indicated relevant information was considered prior to IRB review (30%) or contract approval (22%). All respondents’ IRBs tracked study progress, but only 10% of respondents could report outcome data for timely accrual. Few reported written policies addressing poor accrual or provided data to support recruitment practice effectiveness. Conclusions Many CTSAs lack the necessary framework to support study accrual. Recommendations to enhance accrual include articulating institutional expectations and policy for routine recruitment planning; providing recruitment expertise to inform feasibility assessment and recruitment planning; and developing interdepartmental coordination and integrated informatics infrastructure to drive the conduct, evaluation, and improvement of recruitment practices.