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Objective:To explore the value of cardiac MRI (CMRI) in evaluating left atrial function in patients with postoperative tetralogy of Fallot (rTOF) and postoperative pulmonary stenosis (rPS).Methods:Totally 67 pediatric patients (49 with rTOF, 18 with rPS) with preserved left ventricular ejection fraction (EF) were recruited between January 2019 and October 2021 in Shanghai Children′s Medical Center, School of Medicine, Shanghai Jiao Tong University. Thirty-three healthy volunteers, matched in gender and age, were included as controls from July 2017 to August 2018. Left atrial EF, strain and strain rate of three phases (reservoir, conduit and pump), left atrial volume (maximum volume index, minimum volume index and pre-atrial contraction volume index) were measured with corresponding cardiac function analysis software. Then, the differences in these parameters were analyzed between the three groups by ANOVA or Kruskal-Wallis test with post hoc comparison and Bonferroni correction.Results:Compared with controls, patients with rTOF had lower reservoir function parameters (EF, strain and strain rate), conduit EF, conduit strain, and left atrial maximum volume index ( P<0.05), but higher pump EF ( P<0.05). In patients with rPS, only the reservoir strain rate decreased compared with controls ( P<0.05), and the remaining data showed no significant difference ( P>0.05). The reservoir and conduit EF and strain in patients with rPS were higher than those in patients with rTOF ( P<0.05). Conclusions:In patients with rTOF and rPS, left atrial function has changed despite the preservation of left ventricular EF, which may be an early marker of left ventricular diastolic dysfunction. In children with rTOF, left atrial reservoir and conduit functions decreased while the pump function increased. The reservoir and pump functions in rPS were better than those in rTOF. In addition, CMRI can detect left atrial dysfunction early before it enlarged.
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Objective:To investigate the value of whole-heart and volume-targeted balanced steady-state free precession(bSSFP) in the evaluation of coronary artery in children.Methods:Children with congenital heart disease and Kawasaki disease who underwent cardiac magnetic resonance imaging were retrospectively collected from January 2014 to December 2015, 197 cases(male: female 124∶73) were included according to the inclusion and exclusion criteria in this study. There were 189 cases of congenital heart disease and 8 Kawasaki disease, in which 23 cases had abnormal coronal arteries. Image quality of the coronary artery segments, the coronary artery origin and course, and coronary artery dimension in dual phase 3D bSSFP were analyzed. Chi-square test was used to evaluation the degree of accuracy and difference of coronal artery segments. T test was used to compare the diameter of left with right coronal artery in end systolic phase and mid to end diastolic phase.Results:Image quality was better in systolic phase than diastolic phase(3.9±0.5 and 3.5±0.7 respectively, P<0.001) for all cases. Combining the dual phases, the sensitivity, specificity and accuracy of dual phase 3D whole heart imaging in evaluating the coronal artery origin, course and shape was 100%. However, there was a little difference in revealing left anterior descending coronary artery, left circumflex artery and right coronary artery. There was significant difference in the clearly revealing the left anterior descending coronary artery and left circumflex artery( P<0.001). The left and right coronary artery dimension was larger in systolic phase than in mid-diastolic phase(left coronary artery 3.1±1.3 mm and 2.8±1.3 mm, respectively, right coronary artery(2.5±0.9) and(2.3±0.7)mm, respectively, P<0.001). Conclusion:Cardiac MR 3D bSSFP can retrospectively select coronary resting periods for optimal images, providing a more reliable imaging modality for the assessment of coronary arteries in children to make better clinical decision.
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Objective@#To investigate the feasibility of cine three-dimensional (3D) balanced steady-state free precession (b-SSFP) imaging combined with a non-local means (NLM) algorithm for image denoising in evaluating cardiac function in children with repaired tetralogy of Fallot (rTOF). @*Materials and Methods@#Thirty-five patients with rTOF (mean age, 12 years; range, 7–18 years) were enrolled to undergo cardiac cine image acquisition, including two-dimensional (2D) b-SSFP, 3D b-SSFP, and 3D b-SSFP combined with NLM. End-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), and ejection fraction (EF) of the two ventricles were measured and indexed by body surface index. Acquisition time and image quality were recorded and compared among the three imaging sequences. @*Results@#3D b-SSFP with denoising vs. 2D b-SSFP had high correlation coefficients for EDV, ESV, SV, and EF of the left (0.959– 0.991; p < 0.001) as well as right (0.755–0.965; p < 0.001) ventricular metrics. The image acquisition time ± standard deviation (SD) was 25.1 ± 2.4 seconds for 3D b-SSFP compared with 277.6 ± 0.7 seconds for 2D b-SSFP, indicating a significantly shorter time with the 3D than the 2D sequence (p < 0.001). Image quality score was better with 3D b-SSFP combined with denoising than with 3D b-SSFP (mean ± SD, 3.8 ± 0.6 vs. 3.5 ± 0.6; p = 0.005). Signal-to-noise ratios for blood and myocardium as well as contrast between blood and myocardium were higher for 3D b-SSFP combined with denoising than for 3D b-SSFP (p < 0.05 for all but septal myocardium). @*Conclusion@#The 3D b-SSFP sequence can significantly reduce acquisition time compared to the 2D b-SSFP sequence for cine imaging in the evaluation of ventricular function in children with rTOF, and its quality can be further improved by combining it with an NLM denoising method.
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Objective@#To investigate the feasibility of cine three-dimensional (3D) balanced steady-state free precession (b-SSFP) imaging combined with a non-local means (NLM) algorithm for image denoising in evaluating cardiac function in children with repaired tetralogy of Fallot (rTOF). @*Materials and Methods@#Thirty-five patients with rTOF (mean age, 12 years; range, 7–18 years) were enrolled to undergo cardiac cine image acquisition, including two-dimensional (2D) b-SSFP, 3D b-SSFP, and 3D b-SSFP combined with NLM. End-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), and ejection fraction (EF) of the two ventricles were measured and indexed by body surface index. Acquisition time and image quality were recorded and compared among the three imaging sequences. @*Results@#3D b-SSFP with denoising vs. 2D b-SSFP had high correlation coefficients for EDV, ESV, SV, and EF of the left (0.959– 0.991; p < 0.001) as well as right (0.755–0.965; p < 0.001) ventricular metrics. The image acquisition time ± standard deviation (SD) was 25.1 ± 2.4 seconds for 3D b-SSFP compared with 277.6 ± 0.7 seconds for 2D b-SSFP, indicating a significantly shorter time with the 3D than the 2D sequence (p < 0.001). Image quality score was better with 3D b-SSFP combined with denoising than with 3D b-SSFP (mean ± SD, 3.8 ± 0.6 vs. 3.5 ± 0.6; p = 0.005). Signal-to-noise ratios for blood and myocardium as well as contrast between blood and myocardium were higher for 3D b-SSFP combined with denoising than for 3D b-SSFP (p < 0.05 for all but septal myocardium). @*Conclusion@#The 3D b-SSFP sequence can significantly reduce acquisition time compared to the 2D b-SSFP sequence for cine imaging in the evaluation of ventricular function in children with rTOF, and its quality can be further improved by combining it with an NLM denoising method.
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Objective:To evaluate the feasibility of cardiac MRI three dimensional (3D) balanced steady state free precession (b-SSFP) cine imaging in evaluating cardiac function in children with repaired tetralogy of Fallot (TOF).Methods:Thirty children with repaired TOF underwent cardiac MRI examination at Shanghai Children′s Medical Cent er Affiliated to Shanghai Jiao Tong University School of Medicine, were retrospectively collected from April 2018 to October 2019. From June 2017 to August 2018, 10 healthy children were enrolled. Cardiac images of subjects were obtained using both two dimensional (2D) b-SSFP and 3D b-SSFP cardiac cine MRI and the total acquisition time was recorded. The image quality was scored using a 5-point scale, with a score≥3 as diagnostic image quality. The left and right ventricular end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), ejection fraction (EF), cardiac output (CO), and cardiac index (CI) were measured. The left and right ventricle parameters were compared using paired ttest or Wilcoxon test. The Pearson correlation or Spearman correlation analysis were used to evluate the correlation between the parameters measured with the 2 methods. Results:The acquisition time of 2D b-SSFP images was (426.5±13.0) s, and the total time of 3D b-SSFP images was (24.7±2.5) s. The 2D b-SSFP image quality score was better than 3D b-SSFP, and the differences were statistically significant (TOF patients: Z=-3.879, P<0.001; volunteers: Z=-2.646, P=0.003). All 2D and 3D b-SSFP image quality scores were ≥ 3 points, which can be used for clinical diagnosis. There were no statistically significant differences in cardiac function parameters between two series measurements in both TOF patients and volunteers ( P>0.05). For TOF patients, the left ventricular EDV, ESV, SV, EF, CO and right ventricular EDV, ESV, and SV showed highly positive correlation ( r>0.8, P<0.05). For volunteers, the left ventricular EDV, ESV, SV and right ventricular EDV and SV showed highly positive correlation ( r>0.8, P<0.05). Conclusion:Compared with the 2D b-SSFP sequence, 3D b-SSFP sequence with fairy good image quality can meet the diagnostic requirement and can accurately measure the cardiac function with shorter acquisition time. The 3D b-SSFP has a good application prospect in pediatric cardiac MRI.
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Objective To assess the application value of high time-resolved MR angiography (TR-MRA) in postoperative follow-up study of children with congenital heart diseases. Methods Seventy-three patients (median age 6 years, range 1-20 years) with congenital heart diseases who underwent TR-MRA scan after operation were retrospectively analyzed. Twenty-nine cases also were performed conventional contrast-enhanced MRA and forty-four cases were performed phase-contrast MRA. A 3D T1-weighted fast gradient-echo sequence was used for time-resolved three-dimensional MRA (10-20 dynamic data sets, less than three seconds per dynamic data set). The flow dynamics and morphology of pulmonary circulations, lung perfusion and collaterals flow direction were noted. All imaging quality was evaluated by using 5 scales. Left and right pulmonary artery flow volumes were measured and left and right pulmonary artery ratio was noted. SPSS22.0 was used in statistic analysis. The statistical analysis of comparing imaging quality was performed by using paired t-test. The intermodality agreement between TR-MRA and phase contrast in assessing left and right pulmonary perfusion was tested by Kappa coefficient. Results In 73 cases, imaging scores were over 3 and imaging quality was good enough for diagnosis. In 29 cases, there was no statistic difference between TR-MRA and conventional CE-MRA in demonstrating great vessels (P>0.05) except that CE-MRA scores(3.77 ± 0.39)was higher than TR-MRA scores(3.44 ± 0.55)of inferior vena cava (IVC). There was statistic difference(t=3.68,P=0.01)between two sequences. TR-MRA could qualitatively demonstrate the pulmonary perfusion comparing to the results of PC. In PC sequence, there were 8 cases with symmetric and 36 cases with asymmetric left and right pulmonary perfusion. In TR-MRA sequence, there were 6 cases with symmetric and 38 cases with asymmetric left and right pulmonary perfusion. There was an excellent agreement between PC and TR-MRA (Kappa=0.83,P=0.01). Conclusions TR-MRA not only supplies with high spatial resolution imaging which demonstrates postoperative great arteries anatomy and also with high temporal resolution imaging which can demonstrate the preferential or balanced pulmonary blood flow and collaterals flow direction. TR-MRA is a very important sequence in follow-up study of congenital heart disease.