Whisenant Jennifer G, Dortch Richard D, Grissom William, Kang Hakmook, Arlinghaus Lori R, Yankeelov Thomas E
Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee; Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee.
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.
Tomography. 2016 Dec;2(4):250-259. doi: 10.18383/j.tom.2016.00133.
Variable flip angle (VFA) sequences are a popular method of calculating values, which are required in a quantitative analysis of dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI). inhomogeneities 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-Siegert mapping to improve the accuracy and precision of VFA-derived measurements in the breast. Test-retest MRI sessions were performed on 16 women with no history of breast disease. was calculated using the VFA sequence, and field variations were measured using the Bloch-Siegert methodology. As a gold standard, inversion recovery (IR) measurements of were performed. Fibroglandular tissue and adipose tissue from each breast were segmented using the IR images, and the mean was 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 (). After correction, %err significantly ( < .001) decreased from 17% to 8.6%, and the 95% CI and decreased 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-Siegert mapping improves accuracy and precision of VFA-derived measurements in the breast.
可变翻转角（VFA）序列是一种常用的计算值的方法，在动态对比增强（DCE）磁共振成像（MRI）的定量分析中是必需的。在3T时，乳腺中的不均匀性相当大，这些误差会对VFA方法的准确性产生负面影响，从而导致DCE-MRI参数出现较大误差，这可能会限制该技术在临床上的应用。本研究评估了布洛赫-西格特（Bloch-Siegert）映射提高乳腺中VFA衍生测量值的准确性和精密度的能力。对16名无乳腺疾病史的女性进行了重测MRI检查。使用VFA序列计算值，并使用布洛赫-西格特方法测量场变化。作为金标准，进行了反转恢复（IR）测量。利用IR图像对每个乳腺的纤维腺组织和脂肪组织进行分割，并计算每个组织的平均。通过误差百分比（%err）评估准确性。通过平均差异的95%置信区间（CI）和重复性系数（）评估再现性。校正后，%err显著（<.001）从17%降至8.6%，95%CI和分别从±94降至±38毫秒和从276降至111毫秒。在右乳腺的脂肪组织和左乳腺的两个组织中观察到了类似的准确性和再现性结果。我们的数据表明，布洛赫-西格特映射提高了乳腺中VFA衍生测量值的准确性和精密度。
