Enrollment in a brain magnetic resonance study: results from the Women's Health Initiative Memory Study Magnetic Resonance Imaging Study (WHIMS-MRI)

UMMS Affiliation

Department of Medicine, Division of Preventive and Behavioral Medicine



Document Type



Aged; *Biomedical Research; Cognition Disorders; Estrogen Replacement Therapy; Female; Humans; Informed Consent; Logistic Models; *Magnetic Resonance Imaging; *Patient Selection; Randomized Controlled Trials as Topic; *Women's Health


Life Sciences | Medicine and Health Sciences | Women's Studies


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.

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Citation: Acad Radiol. 2007 May;14(5):603-12. Link to article on publisher's site

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