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


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.
Jaramillo
Sarah A
SA
Division of Public Health Sciences, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, USA.
Felton
Deborah
D
Andrews
Leeann
L
Desiderio
Lisa
L
Hallarn
Rose K
RK
Jackson
Sharon D
SD
Coker
Laura H
LH
Robinson
Jennifer G
JG
Ockene
Judith K
JK
Espeland
Mark A
MA
D000368:Aged; D035843:Biomedical Research; D003072:Cognition Disorders / Q000139:chemically induced / Q000175:diagnosis*; D015914:Estrogen Replacement Therapy / Q000009:adverse effects; D005260:Female; D006801:Humans; D007258:Informed Consent; D016015:Logistic Models; D008279:Magnetic Resonance Imaging; D018579:Patient Selection; D016032:Randomized Controlled Trials as Topic; D016387:Women's Health