Synopsis

The purpose of the study was to assess the accuracy of left ventricular (LV) volumes and mass with innovative single breath-hold compression sensing (CS) cine CMR. 154 patients were enrolled for two techniques CMR cine. Two radiologists evaluated the image quality. LV volumes and mass were quantificationally analyzed. The image quality score of CS cine was slightly worse (4.7 ± 0.5 vs. 4.2 ± 0.7, Z = -5.934, p < 0.0001). All LV volumes and mass with two techniques were no significant differences (p > 0.05). CS cine CMR may replace the multiple breath-holds cine CMR.

Introduction: Accurate assessment of left ventricular (LV) function is crucial for therapeutic decision making and prognostic estimation of multifarious cardiac diseases.^1,2 Cardiac magnetic resonance (CMR) imaging is considered to be gold standard for the measures of LV volumes and mass.³ Commonly, standard cine CMR needs multiple breath-holds which restricts some patients with severe cardiopulmonary disease. The purpose of this investigation was to use compressed sensing (CS) cine CMR to evaluate the accuracy of LV function and mass.

Methods: 154 consecutive heart patients (104 males, mean age 45.1 ± 16.5 years) underwent 3.0T CMR (MAGNETOM Skyra, Siemens Healthcare, Erlangen, Germany). The patients were performed with single breath-hold CS cine after the multiple breath-holds standard cine. Both cines acquired a stack of 8-10 slices short-axis images and two-chamber, three-chamber, four-chamber long-axis images. The primary parameters of standard cine were listed in the following: TR = 4.46 ms, TE = 1.40 ms, temporal resolution = 41 ms, spatial resolution = 1.8 × 1.8 mm. The primary parameters of CS cine were listed in the following: TR = 4.23 ms, TE = 1.20 ms, temporal resolution = 41 ms, spatial resolution = 1.7 × 1.7mm. The image quality was classified and compared by image features (border of endomyocardium and epimyocardium, papillary muscle visualization, artifact, and so on) on a 5 point scale (1=nondiagnostic to 5=excellent).⁴ In addition, LV wall motion was evaluated. Abnormal motion included regional or global abnormality such as hypokinesia, akinesia, dyskinesia, and anuerysm.⁵ The end diastolic volume (EDV), end systolic volume (ESV), stroke volume (SV), LV mass (LVM), and ejection fraction (EF) of both techniques were quantitatively analyzed. Chi–square test, Wilcoxon matched-pairs signed-rank test, linear regression, and Bland-Altman analysis were performed for statistical analysis.

Results: The total scan time was 157.6 ± 8.1s for standard cine and 18.8 ± 1.3s for CS cine, respectively, which reduced approximately 88%. Compared with standard cine, the image quality score of CS cine was slightly decreased (4.7 ± 0.5 vs. 4.2 ± 0.7, Z = -5.934, p < 0.0001). However, the diagnostic image quality (score ≥ 3) of CS cine CMR for all patients was sufficient enough to evaluate LV volumes and mass. Figure 1 and Figure 2 displayed a set of short-axis views for a hypertrophic cardiomyopathy patient in diastole with two methods. Abnormal motion of LV wall motion evaluated by both techniques in 154 patients was not significantly different (50.9% for standard cine CMR vs. 47.5% for CS cine CMR, c2 =0.27, p = 0.603). All LV quantitative parameters calculated from standard cine and CS cine were no significant differences, as given in table 1. Furthermore, the analysis of LV volumes and mass showed excellent agreement (Figure 3. Bland-Altman analysis) and correlation (linear regression: R2 = 0.997, slope 0.998, p < 0.05 for EDV; R2 = 0.999, slope 1.006, p < 0.05 for ESV; R2 = 0.983, slope 0.955, p < 0.05 for SV; R2 = 0.999, slope 0.999, p < 0.05 for LVM; R2 = 0.994, slope 0.992, p < 0.05 for EF). Intraobserver and interobserver agreement and correlation of CS cine were excellent. Concretely, Bland-Altman analysis showed that difference varied from -0.6 to 0 and 0 to 0.08, respectively, and linear regression showed that slopes varied from 0.981 to 1.000 and 0.996 to 1.000, respectively.

Discussion: The decrease of CS cine scan time could satisfy the need of patients who could not hold their breath for a long time to undergo cine CMR. Slightly worse image quality of CS cine was considered due to fold-over artifacts. Single breath-hold CS cine CMR was proved to be able to evaluate ventricular wall motion. The comparative results of LV quantitative parameters manifested that single breath-hold CS cine CMR had enough accuracy and reproducibility. This study excluded patients of various types of arrhythmias. In consideration of CS cine being inherently insensitive to motion,⁴ image quality acquired by CS technique of arrhythmic patients may be better than standard cine CMR. Moreover, the reconstruction time of CS cine CMR lasted longer.

Conclusions: The results of this prospective study demonstrated that the accurate assessment of LV volumes and mass with single breath-hold CS cine CMR could be feasible. It may replace the multiple breath-holds cine CMR.

Acknowledgements

References

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