Comparison of Improved Unidirectional Dual Velocity-Encoding MRI Methods.
Comparison of Improved Unidirectional Dual Velocity-Encoding MRI Methods.
复制标题
改进的单向双速度编码 MRI 方法的比较。
DOI：
10.1002/jmri.28305
复制
发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Uribe,Sergio
中科院分区：
文献类型：
--
作者：
Franco,Pamela;Ma,Liliana;Schnell,Susanne;Carrillo,Hugo;Montalba,Cristian;Markl,Michael;Bertoglio,Cristóbal;Uribe,Sergio
背景在相衬（PC）MRI中，已经提出了几种双速度编码方法来鲁棒地增加速度噪声比（VNR），包括标准双VENC（SDV）、最佳双VENC（ODV）、研究类型病例对照研究研究人群26名志愿者场强/序列1.5 T相位对比MRI，VENC为50、75和150 cm/s。评估由于我们获得了单VENC协议，我们使用高VENC（VENCH）的背景相位重建低VENC（VENCL）相位。统计检验Shapiro-Wilk正态性检验，采用Levene检验进行方差齐性的双因素方差分析，显著性水平通过Bonferroni的Tukey多重事后分析进行调整结果统计学分析无极端异常值，残差呈正态分布，方差齐性。我们发现统计上显着的噪声水平和展开方法之间的相互作用。这意味着非展开像素的数量随着噪声水平而增加。我们发现，当β= VENCL/VENCH= 1/2时，展开方法对噪声更鲁棒。事后检验显示ODV校正和其他方法之间存在显著差异，提供了最好的结果，关于未包裹像素的数量。Data ConclusionsAll methods performed similar without noise，但ODV校正方法对噪声更鲁棒，代价是更高的计算时间。
BackgroundIn phase‐contrast (PC) MRI, several dual velocity encoding methods have been proposed to robustly increase velocity‐to‐noise ratio (VNR), including a standard dual‐VENC (SDV), an optimal dual‐VENC (ODV), and bi‐ and triconditional methods.PurposeTo develop a correction method for the ODV approach and to perform a comparison between methods.Study TypeCase–control study.PopulationTwenty‐six volunteers.Field Strength/Sequence1.5 T phase‐contrast MRI with VENCs of 50, 75, and 150 cm/second.AssessmentSince we acquired single‐VENC protocols, we used the background phase from high‐VENC (VENCH) to reconstruct the low‐VENC (VENCL) phase. We implemented and compared the unwrapping methods for different noise levels and also developed a correction of the ODV method.Statistical TestsShapiro–Wilk's normality test, two‐way analysis of variance with homogeneity of variances was performed using Levene's test, and the significance level was adjusted by Tukey's multiple post hoc analysis with Bonferroni (P< 0.05).ResultsStatistical analysis revealed no extreme outliers, normally distributed residuals, and homogeneous variances. We found statistically significant interaction between noise levels and the unwrapping methods. This implies that the number of non‐unwrapped pixels increased with the noise level. We found that forβ= VENCL/VENCH= 1/2, unwrapping methods were more robust to noise. The post hoc test showed a significant difference between the ODV corrected and the other methods, offering the best results regarding the number of unwrapped pixels.Data ConclusionsAll methods performed similarly without noise, but the ODV corrected method was more robust to noise at the price of a higher computational time.Level of Evidence4Technical Efficacy Stage1