Repeatability of quantitative MRI measurements in normal breast tissue.
OBJECTIVE
To evaluate the variability and repeatability of repeated magnetic resonance imaging (MRI) measurements in normal breast tissues between and within subjects.


METHODS
Eighteen normal premenopausal subjects underwent two contrast-enhanced MRI scans within 72 hours or during the same menstrual phase in two consecutive months. A subset of nine women also completed diffusion-weighted imaging (DWI). Fibroglandular tissue (FGT) density and FGT enhancement were measured on the contrast-enhanced MRI. Apparent diffusion coefficient (ADC) values were computed from DWI. Between- and within-subject coefficients of variation (bCV and wCV, respectively) were assessed. Repeatability of all measurements was assessed by the coefficient of repeatability (CR) and Bland-Altman plots.


RESULTS
The bCV of FGT density and FGT enhancement at visit 1 and visit 2 ranged from 47% to 63%. The wCV was 13% for FGT density, 22% for FGT enhancement, and 11% for ADC. The CRs of FGT density and FGT enhancement were 0.15 and 0.19, respectively, and for ADC, it was 6.1 x 10(-4) mm(2)/s.


CONCLUSIONS
We present an estimate of the variability and repeatability of MR measurements in normal breasts. These estimates provide the basis for understanding the normal variation of healthy breast tissue in MRI and establishing thresholds for agreement between measurements.
Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA.
Sheye O
SO
Aliu
Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA.
Ella F
EF
Jones
Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA.
Ania
A
Azziz
Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA.
John
J
Kornak
Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA.
Lisa J
LJ
Wilmes
Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA.
David C
DC
Newitt
Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA.
Sachiko A
SA
Suzuki
Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA.
Catherine
C
Klifa
Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA.
Jessica
J
Gibbs
Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA.
Evelyn C
EC
Proctor
Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA.
Bonnie N
BN
Joe
Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA.
Nola M
NM
Hylton