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Comparing average breast fat content results from two different protocols at 1.5T and 3T: Can the data be pooled?

Authors

  • Sofia Chavez PhD,,

    Corresponding author
    1. Centre for Addiction and Mental Health, Research Imaging Centre, Toronto, ON, Canada
    2. University of Toronto, Psychiatry, Toronto, ON, Canada
    • Address reprint requests to: S.C., 250 College St. PET-G1/B72, Toronto, ON, Canada M5T 1R8. E-mail: sofia.chavez@camhpet.ca

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  • Greg Stanisz PhD

    1. University of Toronto, Medical Biophysics, Toronto, ON, Canada
    2. Sunnybrook Research Institute, Imaging Research, ON, Canada
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Abstract

Purpose

To compare the total breast fat content computed from two separate studies, performed on different scanners and with different protocols, with the goal of defining a relationship to allow pooling the data.

Materials and Methods

Twelve healthy volunteer women were scanned with two different protocols on the same day. The protocols differed in four important aspects: vendors (GE vs. Philips), scanner main magnetic field strengths (1.5T vs. 3T), pulse sequences (2D fast spin-echo vs. 3D spoiled gradient-echo), and water/fat separation techniques. The resulting water and fat maps were processed with in-house software to extract breast tissue slice-wise. Percent fat content was calculated for each breast, per subject.

Results

Total percent fat contents (averaged across both breasts) resulting from both protocols were plotted against each other, on a subject-by-subject basis, revealing a strong correlation (R2 > 0.99), with an overestimation of the fat content from Protocol 1 relative to Protocol 2. The proposed T2 TE-correction for Protocol 1 improves the correlation while decreasing the discrepancy between protocols.

Conclusion

Total breast fat content of healthy women resulting from the two protocols can be pooled using a linear relationship. The proposed T2 TE-corrected Protocol 1 is expected to yield accurate fat content. J. Magn. Reson. Imaging 2014;40:890–898. © 2013 Wiley Periodicals, Inc.

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