title: Bloch-SiegertB1-Mapping Improves Accuracy and Precision of Longitudinal Relaxation Measurements in the Breast at 3 T.
abstract: Variable flip angle (VFA) sequences are a popular method of calculatingT1values, which are required in a quantitative analysis of dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI).B1inhomogeneities are substantial in the breast at 3 T, and these errors negatively impact the accuracy of the VFA approach, thus leading to large errors in the DCE-MRI parameters that could limit clinical adoption of the technique. This study evaluated the ability of Bloch-SiegertB1mapping to improve the accuracy and precision of VFA-derivedT1measurements in the breast. Test-retest MRI sessions were performed on 16 women with no history of breast disease.T1was calculated using the VFA sequence, andB1field variations were measured using the Bloch-Siegert methodology. As a gold standard, inversion recovery (IR) measurements ofT1were performed. Fibroglandular tissue and adipose tissue from each breast were segmented using the IR images, and the meanT1was calculated for each tissue. Accuracy was evaluated by percent error (%err). Reproducibility was assessed via the 95% confidence interval (CI) of the mean difference and repeatability coefficient (r). AfterB1correction, %err significantly (P< .001) decreased from 17% to 8.6%, and the 95% CI andrdecreased from ±94 to ±38 milliseconds and from 276 to 111 milliseconds, respectively. Similar accuracy and reproducibility results were observed in the adipose tissue of the right breast and in both tissues of the left breast. Our data show that Bloch-SiegertB1mapping improves accuracy and precision of VFA-derivedT1measurements in the breast.
authors.affiliation: Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee; Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee.
authors.forename: Jennifer G
authors.initials: JG
authors.lastname: Whisenant
authors.affiliation: Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee; Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee; Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee.
authors.forename: Richard D
authors.initials: RD
authors.lastname: Dortch
authors.affiliation: Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee; Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee; Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee.
authors.forename: William
authors.initials: W
authors.lastname: Grissom
authors.affiliation: Department of Biostatistics and Center for Quantitative Sciences, Vanderbilt University, Nashville, Tennessee.
authors.forename: Hakmook
authors.initials: H
authors.lastname: Kang
authors.affiliation: Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee; Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee.
authors.forename: Lori R
authors.initials: LR
authors.lastname: Arlinghaus
authors.affiliation: Institute for Computational and Engineering Sciences, and the Departments of Biomedical Engineering and Internal Medicine, The University of Texas at Austin, Austin, Texas.
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Yankeelov
keywords: T1 mapping; quantitative breast MRI; relaxometry