Camargo Gabriel C, Erthal Fernanda, Sabioni Leticia, Penna Filipe, Strecker Ralph, Schmidt Michaela, Zenge Michael O, Lima Ronaldo de S L, Gottlieb Ilan
Casa de Saúde São José, Rio de Janeiro, Brazil; Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
Clínica de Diagnóstico por Imagem, Rio de Janeiro, Brazil.
Magn Reson Imaging. 2017 May;38:138-144. doi: 10.1016/j.mri.2017.01.002. Epub 2017 Jan 6.
Segmented cine imaging with a steady-state free-precession sequence (Cine-SSFP) is currently the gold standard technique for measuring ventricular volumes and mass, but due to multi breath-hold (BH) requirements, it is prone to misalignment of consecutive slices, time consuming and dependent on respiratory capacity. Real-time cine avoids those limitations, but poor spatial and temporal resolution of conventional sequences has prevented its routine application. We sought to examine the accuracy and feasibility of a newly developed real-time sequence with aggressive under-sampling of k-space using sparse sampling and iterative reconstruction (Cine-RT).
Stacks of short-axis cines were acquired covering both ventricles in a 1.5T system using gold standard Cine-SSFP and Cine-RT. Acquisition parameters for Cine-SSFP were: acquisition matrix of 224×196, temporal resolution of 39ms, retrospective gating, with an average of 8 heartbeats per slice and 1-2 slices/BH. For Cine-RT: acquisition matrix of 224×196, sparse sampling net acceleration factor of 11.3, temporal resolution of 41ms, prospective gating, real-time acquisition of 1 heart-beat/slice and all slices in one BH. LV contours were drawn at end diastole and systole to derive LV volumes and mass.
Forty-one consecutive patients (15 male; 41±17years) in sinus rhythm were successfully included. All images from Cine-SSFP and Cine-RT were considered to have excellent quality. Cine-RT-derived LV volumes and mass were slightly underestimated but strongly correlated with gold standard Cine-SSFP. Inter- and intra-observer analysis presented similar results between both sequences.
Cine-RT featuring sparse sampling and iterative reconstruction can achieve spatial and temporal resolution equivalent to Cine-SSFP, providing excellent image quality, with similar precision measurements and highly correlated and only slightly underestimated volume and mass values.
采用稳态自由进动序列的分段电影成像（Cine-SSFP）是目前测量心室容积和质量的金标准技术，但由于需要多次屏气（BH），它容易出现连续层面的错位，耗时且依赖呼吸能力。实时电影成像避免了这些限制，但传统序列较差的空间和时间分辨率阻碍了其常规应用。我们试图研究一种新开发的实时序列（Cine-RT）的准确性和可行性，该序列使用稀疏采样和迭代重建对k空间进行激进欠采样。
在1.5T系统中，使用金标准的Cine-SSFP和Cine-RT获取覆盖两个心室的短轴电影堆栈。Cine-SSFP的采集参数为：采集矩阵224×196，时间分辨率39ms，回顾性门控，每层平均8个心动周期，每次屏气1 - 2层。对于Cine-RT：采集矩阵224×196，稀疏采样净加速因子11.3，时间分辨率41ms，前瞻性门控，实时采集，每层1个心动周期，一次屏气采集所有层面。在舒张末期和收缩末期绘制左心室轮廓以得出左心室容积和质量。
连续41例窦性心律患者（15例男性；41±17岁）成功纳入。Cine-SSFP和Cine-RT的所有图像质量均被认为极佳。Cine-RT得出的左心室容积和质量略有低估，但与金标准Cine-SSFP高度相关。观察者间和观察者内分析在两个序列之间呈现相似结果。
具有稀疏采样和迭代重建功能的Cine-RT可以实现与Cine-SSFP相当的空间和时间分辨率，提供极佳的图像质量，具有相似的精确测量结果，容积和质量值高度相关且仅略有低估。
