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

Publication Date


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.

DOI of Published Version



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

Journal/Book/Conference Title

Academic radiology

Related Resources

Link to article in PubMed

PubMed ID