超高加速压缩感知 4D 流技术在心脏内血流评估中的应用。
Highly Accelerated Compressed-Sensing 4D Flow for Intracardiac Flow Assessment.
机构信息
Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, South Carolina.
Department of Diagnostic and Interventional Radiology, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany.
出版信息
J Magn Reson Imaging. 2023 Aug;58(2):496-507. doi: 10.1002/jmri.28484. Epub 2022 Oct 20.
BACKGROUND
Four-dimensional (4D) flow MRI allows for the quantification of complex flow patterns; however, its clinical use is limited by its inherently long acquisition time. Compressed sensing (CS) is an acceleration technique that provides substantial reduction in acquisition time.
PURPOSE
To compare intracardiac flow measurements between conventional and CS-based highly accelerated 4D flow acquisitions.
STUDY TYPE
Prospective.
SUBJECTS
Fifty healthy volunteers (28.0 ± 7.1 years, 24 males).
FIELD STRENGTH/SEQUENCE: Whole heart time-resolved 3D gradient echo with three-directional velocity encoding (4D flow) with conventional parallel imaging (factor 3) as well as CS (factor 7.7) acceleration at 3 T.
ASSESSMENT
4D flow MRI data were postprocessed by applying a valve tracking algorithm. Acquisition times, flow volumes (mL/cycle) and diastolic function parameters (ratio of early to late diastolic left ventricular peak velocities [E/A] and ratio of early mitral inflow velocity to mitral annular early diastolic velocity [E/e']) were quantified by two readers.
STATISTICAL TESTS
Paired-samples t-test and Wilcoxon rank sum test to compare measurements. Pearson correlation coefficient (r), Bland-Altman-analysis (BA) and intraclass correlation coefficient (ICC) to evaluate agreement between techniques and readers. A P value < 0.05 was considered statistically significant.
RESULTS
A significant improvement in acquisition time was observed using CS vs. conventional accelerated acquisition (6.7 ± 1.3 vs. 12.0 ± 1.3 min). Net forward flow measurements for all valves showed good correlation (r > 0.81) and agreement (ICCs > 0.89) between conventional and CS acceleration, with 3.3%-8.3% underestimation by the CS technique. Evaluation of diastolic function showed 3.2%-17.6% error: E/A 2.2 [1.9-2.4] (conventional) vs. 2.3 [2.0-2.6] (CS), BA bias 0.08 [-0.81-0.96], ICC 0.82; and E/e' 4.6 [3.9-5.4] (conventional) vs. 3.8 [3.4-4.3] (CS), BA bias -0.90 [-2.31-0.50], ICC 0.89.
DATA CONCLUSION
Analysis of intracardiac flow patterns and evaluation of diastolic function using a highly accelerated 4D flow sequence prototype is feasible, but it shows underestimation of flow measurements by approximately 10%.
EVIDENCE LEVEL
2 TECHNICAL EFFICACY: Stage 1.
背景
四维（4D）流动磁共振成像允许对复杂流动模式进行定量分析；然而，其临床应用受到固有采集时间长的限制。压缩感知（CS）是一种加速技术，可大大减少采集时间。
目的
比较传统和基于 CS 的高度加速 4D 流动采集的心脏内流动测量。
研究类型
前瞻性。
受试者
50 名健康志愿者（28.0±7.1 岁，24 名男性）。
磁场强度/序列：全心脏时间分辨 3D 梯度回波，采用三方向速度编码（4D 流动），采用传统并行成像（3 倍）和 CS（7.7 倍）加速，在 3T 下进行。
评估
4D 流动 MRI 数据通过应用瓣膜跟踪算法进行后处理。两位读者分别定量评估采集时间、流量（mL/循环）和舒张功能参数（早期和晚期左心室峰值速度的比值[E/A]以及二尖瓣前向血流速度与二尖瓣环早期舒张速度的比值 [E/e']）。
统计检验
采用配对样本 t 检验和 Wilcoxon 秩和检验比较测量值。采用 Pearson 相关系数（r）、Bland-Altman 分析（BA）和组内相关系数（ICC）评估技术和读者之间的一致性。P 值<0.05 被认为具有统计学意义。
结果
与传统加速采集相比，CS 显著缩短了采集时间（6.7±1.3 分钟比 12.0±1.3 分钟）。所有瓣膜的正向流动测量值均显示出良好的相关性（r>0.81）和一致性（ICC>0.89），CS 技术的低估幅度为 3.3%-8.3%。舒张功能评估显示存在 3.2%-17.6%的误差：E/A 2.2[1.9-2.4]（传统）与 2.3[2.0-2.6]（CS），BA 偏差 0.08[-0.81-0.96]，ICC 0.82；E/e'4.6[3.9-5.4]（传统）与 3.8[3.4-4.3]（CS），BA 偏差-0.90[-2.31-0.50]，ICC 0.89。
数据结论
使用高度加速的 4D 流动序列原型分析心脏内流动模式和评估舒张功能是可行的，但它显示流量测量值约有 10%的低估。
证据水平
2 级技术功效：阶段 1。
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