Heidenreich Julius F, Veldhoen Simon, Metz Corona, Mendes Pereira Lenon, Benkert Thomas, Pfeuffer Josef, Bley Thorsten A, Köstler Herbert, Weng Andreas M
Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Strasse 6, 97080 Würzburg, Germany (J.F.H., S.V., C.M., L.M.P., T.A.B., H.K., A.M.W.); and Department of Application Development, Siemens Healthcare, Erlangen, Germany (T.B., J.P.).
Radiol Cardiothorac Imaging. 2020 Jun 25;2(3):e190162. doi: 10.1148/ryct.2020190162. eCollection 2020 Jun.
To evaluate three-dimensional (3D) ultrashort echo time (UTE) MRI regarding image quality and suitability for functional image analysis using gradient-echo sequences in breath-hold and with self-navigation.
In this prospective exploratory study, 10 patients (mean age, 21 years; age range, 5-58 years; five men) and 10 healthy control participants (mean age, 25 years; age range, 10-39 years; five men) underwent 3D UTE MRI at 3.0 T. Imaging was performed with a prototypical stack-of-spirals 3D UTE sequence during single breath holds (echo time [TE], 0.05 msec) and with a self-navigated "Koosh ball" 3D UTE sequence at free breathing (TE, 0.03 msec). Image quality was rated on a four-point Likert scale. Edge sharpness was calculated. After semiautomated segmentation, fractional ventilation was calculated from MRI signal intensity (FV) and volume change (FV). The air volume fraction (AVF) was estimated from relative signal intensity (aortic blood signal intensity was used as a reference). Means were compared between techniques and participants. The Wilcoxon signed rank test and Spearman rank correlation were used for statistical analyses.
Image quality ratings were equal for both techniques. However, stack-of-spirals breath-hold UTE was more susceptible to motion and aliasing artifacts. Mean FV was higher during breath hold than at free breathing (mean ± standard deviation in milliliters of gas per milliliters of parenchyma, 0.17 mL/mL ± 0.06 [minimum, 0.07; maximum, 0.34] vs 0.11 mL/mL ± 0.03 [minimum, 0.06; maximum, 0.17], = .016). Mean FV and FV were in good agreement (mean difference: at breath hold, -0.008 [95% confidence interval {CI}: 0.007, -0.024]; ρ = 0.97 vs free breathing, -0.004 [95% CI: 0.007, -0.016]; ρ = 0.91). AVF correlated between both techniques (ρ = 0.94).
Breath-hold and self-navigated 3D UTE sequences yield proton density-weighted images of the lungs that are similar in quality, and both techniques are suitable for functional image analysis.© RSNA, 2020.
评估三维（3D）超短回波时间（UTE）磁共振成像（MRI）的图像质量，以及其在屏气状态下使用梯度回波序列和自导航功能进行功能图像分析的适用性。
在这项前瞻性探索性研究中，10例患者（平均年龄21岁；年龄范围5 - 58岁；男性5例）和10名健康对照者（平均年龄25岁；年龄范围10 - 39岁；男性5例）在3.0 T磁场强度下接受3D UTE MRI检查。使用原型螺旋堆叠3D UTE序列在单次屏气时（回波时间[TE]，0.05毫秒）进行成像，并使用自导航“库什球”3D UTE序列在自由呼吸时（TE，0.03毫秒）进行成像。图像质量采用四点李克特量表进行评分。计算边缘锐度。在半自动分割后，根据MRI信号强度（FV）和体积变化（FV）计算分数通气量。根据相对信号强度估算空气体积分数（AVF）（以主动脉血信号强度作为参考）。比较不同技术和参与者之间的平均值。采用Wilcoxon符号秩检验和Spearman秩相关进行统计分析。
两种技术的图像质量评分相同。然而，螺旋堆叠屏气UTE更容易受到运动和伪影的影响。屏气时的平均FV高于自由呼吸时（每毫升实质组织中气体的平均毫升数±标准差，0.17 mL/mL ± 0.06 [最小值，0.07；最大值，0.34] 对比 0.11 mL/mL ± 0.03 [最小值，0.06；最大值，0.17]，P = 0.016）。平均FV和FV之间具有良好的一致性（平均差异：屏气时，-0.008 [95%置信区间{CI}：0.007，-0.024]；ρ = 0.97 对比自由呼吸时，-0.004 [95% CI：0.007，-0.016]；ρ = 0.91）。两种技术的AVF之间具有相关性（ρ = 0.94）。
屏气和自导航3D UTE序列产生的肺部质子密度加权图像质量相似，且两种技术均适用于功能图像分析。© RSNA，2020。
