探讨单次屏气压缩感知实时电影成像在磁共振心室功能及应变评估中的可行性

Feasibility of Single-Breath-Hold Compressed Sensing Real-Time Cine Imaging for Assessment of Ventricular Function and Left Ventricular Strain in Cardiac Magnetic Resonance

目的探讨磁共振单次屏气压缩感知实时电影成像(single-breath-hold compressed sensing real-time cine imaging,CS-cine)在心室功能及应变评估中的可行性。方法前瞻性连续纳入70例受检者,所有患者均行心脏磁共振标准稳态自由进动电影成像(standard steady-state free precession cine imaging,sta-cine)和CS-cine。电影序列扫描方位:从心底到心尖的连续短轴位及左室两腔、三腔、四腔长轴位,同一受检者的两组电影图像扫描范围、层数、层厚、层间距等一致。对所有电影图像进行主观图像质量评价,并通过后处理软件分析得出左、右常规心室功能参数和左室应变参数。比较两组电影图像质量、常规心室功能参数及左室应变参数之间的差异。通过计算组内相关系数(ICC)验证CS-cine心室定量参数的重复性,采用Bland-Altman分析两组电影间心室定量参数的一致性。结果sta-cine组、CS-cine组电影的中位采集时间分别为272 s和21 s。sta-cine组、CS-cine组电影图像质量评分中位数分别为4分和2分,差异有统计学意义(P<0.001)。两组电影间常规心室功能参数比较:CS-cine所获得的射血分数(ejection fraction,EF)、舒张末期容积(enddiastolic volume,EDV)、搏出量(stroke volume,SV)均显著降低(P<0.001),而左、右室收缩末期容积(end-systolic volume,ESV)及左室心肌质量(left ventricular mass,LVmass)差异无统计学意义(P>0.05)。两组电影间应变参数比较:左室中部径向应变峰值(peak radial strain,PRS)、周向应变峰值(peak circumferential strain,PCS)及纵向应变峰值(peak longitudinal strain,PLS)差异均有统计学意义(P<0.001)。CS-cine各功能定量参数都具有较好的重复性(ICC=0.88~0.99),BlandAltman分析结果显示各参数测量中,右室容积功能及左室PCS、PLS测量有95%以上在一致性范围内,其余参数测量结果均有91%以上在一致性界值内,可认为两组电影测量结果一致性较好。结论CS-cine能够快速获取图像进行心功能定量分析,其分析所得常规心室功能参数及左室整体应变参数有较好的重复性。

Objective To explore the feasibility of single-breath-hold compressed sensing real-time cine imaging(CS-cine)in the assessment of ventricular function and left ventricular(LV)strain.Methods A total of 70subjects were enrolled prospectively,and all subjects underwent cardiac magnetic resonance imaging(cardiac MRI)using both the standard steady-state free procession cine(sta-cine)acquisition and a prototype CS-cine sequence.For both CScine and sta-cine imaging,continuous short-axis cine images were acquired from the base to the apex to cover the entire left ventricle,and long-axis cine images including two-,three-,and four-chamber views were also acquired.The scanning range,number of slices,slice thickness and intervals were kept identical for the two cine images of the same participant.Subjective evaluation of the image quality was performed on all cine images.For both sequences,the conventional function parameters of the left and the right ventricles and LV strain values were assessed with post-processing software analysis.The cine image quality,conventional ventricular function parameters,and LV strain values were compared between the two cine groups and the differences were examined.Inter-and intraobserver agreements for CS-cine images were measured using intraclass correlation coefficient(ICC).Bland-Altman analysis was performed to assess reproducibility between the two cine methods.Results The median scanning time of CS-cine was 21 s versus 272 s for sta-cine(P<0.001).The median image quality scores of two groups were significantly different,4 points for sta-cine and 2points for CS-cine(P<0.001).Bi-ventricular end-diastolic volumes(EDV),stroke volume(SV)and ejection fraction(EF)were significantly smaller in CS-cine(P<0.001).Nevertheless,no significant differences between the two groups in biventricular ESV or LV mass were observed(P>0.05).LV strain parameters,including the peak radial strain,peak circumferential strain and peak longitudinal strain derived from LV mid-ventricular slice,were significantly different in the two sequences(P<0.001).Moreover,CS-cine-derived functional parameters and strain measurements have a good correlation with those of sta-cine(for RV function parameters,and left ventricular PLS,PCS values,more than 95%points fell within the limits of agreement[LoA];meanwhile,more than 91%points fell within the LoA for other parameters)and inter-and intraobserver agreements were strong(ICC=0.88 to 0.99)for CS-cine.Conclusion CS-cine can well realize the rapid acquisition of cine images for quantitative analysis of cardiac function,and the conventional ventricular function parameters and LV globalized strain values obtained from CS-cine imaging have good reproducibility.