Myocardial deformation is a sensitive marker of sub-clinical myocardial dysfunction that carries independent prognostic significance across a broad range of cardiovascular diseases. It is now possible to perform 3D feature tracking of SSFP cines on cardiac magnetic resonance imaging (FT-CMR). This study provides reference ranges for 3D FT-CMR and assesses its reproducibility compared to 2D FT-CMR. One hundred healthy individuals with 10 men and women in each of 5 age deciles from 20 to 70 years, underwent 2D and 3D FT-CMR of left ventricular myocardial strain and strain rate using SSFP cines. Good health was defined by the absence of hypertension, diabetes, obesity, dyslipidaemia, or any cardiovascular, renal, hepatic, haematological and systemic inflammatory disease. Normal values for myocardial strain assessed by 3D FT-CMR were consistently lower compared with 2D FT-CMR measures [global circumferential strain (GCS) 3D − 17.6 ± 2.6% vs. 2D − 20.9 ± 3.7%, P < 0.005]. Validity of 3D FT-CMR was confirmed against other markers of systolic function. The 3D algorithm improved reproducibility compared to 2D, with GCS having the best inter-observer agreement [intra-class correlation (ICC) 0.88], followed by global radial strain (GRS; ICC 0.79) and global longitudinal strain (GLS, ICC 0.74). On linear regression analyses, increasing age was weakly associated with increased GCS (R 2 = 0.15, R = 0.38), peak systolic strain rate, peak late diastolic strain rate, and lower peak early systolic strain rate. 3D FT-CMR offers superior reproducibility compared to 2D FT-CMR, with circumferential strain and strain rates offering excellent intra-and inter-observer variability. Normal range values for myocardial strain measurements using 3D FT-CMR are provided.

To evaluate the use of the tissue tracking (TT) technique to measure myocardial strain left ventricular in post-Fontan children with preserved ejection fraction (pEF). Nineteen (male/female, 10/9) patients with univentricular hearts after completion of the Fontan circulation (post-Fontan group) and 19 age- and gender-matched healthy children (control group) were retrospectively enrolled. Cardiovascular magnetic resonance (CMR) imaging was conducted on a 1.5-T MRI scanner. Global and regional strains of the left ventricle in post-Fontan patients (EF > 55%) and controls were obtained using CMR-TT software. The Mann-Whitney U test was used to compare parameters between the two groups. Correlation between EF and strain was investigated using Pearson correlation coefficients. The Bland-Altman method was used to identify the inter- and intra-observer agreement in measurement of global strain. Global longitudinal strain was lower in post-Fontan patients than in healthy controls (- 18.87 ± 4.61 vs. -19.72 ± 1.58; P = 0.54), though the difference was not statistically significant. Global circumferential strain and global radial strain were significantly lower in post-Fontan patients than in healthy controls (- 14.55 ± 3.79 vs. -19.91 ± 1.97; P < 0.001; and 29.62 ± 8.41 vs. 36.85 ± 5.95; P = 0.01; respectively). The regional circumferential strain (RCS) decrease was marked in regional segments compare with post-Fontan patients and controls (basal, - 11.81 ± 2.98 vs. - 16.21 ± 2.72, P < 0.001; mid, - 15.05 ± 3.31 vs. - 20.17 ± 2.28, P = 0.005; apical, - 16.86 ± 3.09 vs. - 23.37 ± 2.62, P < 0.001). All circumferential and longitudinal parameters had an inter-observer ICC of ≥ 0.85, but this coefficient was lower for radial parameters. CMR-TT appears to be a feasible technique for identification of early myocardial dysfunction in post-Fontan with pEF.

Background: This study aimed to assess the severity of helix and vortex flow in pulmonary artery hemodynamic using 4-dimensional flow cardiac magnetic resonance (4D flow CMR) in patients with repaired tetralogy of Fallot (rTOF) and healthy child volunteers and to explore the relationship between pulmonary hemodynamic changes and right heart function. Methods: CMR studies were performed in 25 rTOF patients (15 M/10 F; 8.44±4.52 years) and 10 normal child volunteers (7 M/3 F; 8.2±1.22 years) on 3.0T MR scanners. Cardiac function was calculated in the patient and control groups. Systolic diameter, peak velocity, net flow, and regurgitation was quantified in the main pulmonary artery (MPA) plane, left pulmonary artery (LPA) plane, and right pulmonary artery (RPA) plane. The relationship between the hemodynamic parameters and quantitative flow indices and right ventricular (RV) function were analyzed through simple linear regression analysis using Pearson R-values. We analyzed differences in flow patterns between the 2 groups for the same slice. According to the severity of the helix and vortex flow in the 4D flow CMR, we categorized rTOF patients into the following groups: group 1, severe flow grading; group 2, mild flow grading; group 3, no flow grading; the control cases with no flow grade were included in group 4. We compared RV cardiac function, wall shear stress (WSS), and viscous energy loss (EL) between group 1+2 and group 3+4 using unpaired t-test analysis for normally distributed data and the Mann-Whitney test for non-normally distributed continuous variables. Results: RV end-diastolic volume index (EDV i ) (127.8±36.13 vs. 83.11±6.18, respectively; P<0.001), RV end-systolic volume index (ESV i ) (65.14±27.02 vs. 36.13±5.95, respectively; P<0.001), and ejection fraction (EF) (49.97±6.39 vs. 56.71±4.56, respectively; P=0.006,) were significantly different between the groups. The rTOF diameters of the MPA and RPA were significantly larger than those of the control group (19.74±4.01 vs. 14.97±2.37 for MPA, P=0.001; 12.04±3.28 vs. 8.99±1.23 for RPA, P=0.004, respectively). There were correlations between peak WSS and pulmonary regurgitation (PR) in the MPA (R=0.48, P=0.014), correlations between peak systolic EL and RVEDV (R=0.51, P=0.008), and between peak systolic EL and RVESV (R=0.51, P=0.009). The peak systole and diastole WSS of group 1+2 were significantly different compared to group 3+4 in the MPA (P<0.05). The peak systole and diastole EL of group 1+2 was significantly different from group 3+4 in the MPA (P<0.05). The peak systole EL of group 1+2 was significantly different from group 3+4 in the RPA (P<0.01). Conclusions: Increased peak WSS and EL were associated with pulmonary hemodynamic changes in the MPA and RPA. There might be an earlier marker of evolving hemodynamic inefficiency than that in traditional parameters. The better understanding of pulmonary artery hemodynamic assessment in rTOF may lead to a greater insight into pulmonary artery (PA)-RV interactions and how they ultimately impact RV fu...

BackgroundRight ventricular dilation and dysfunction is a common long‐term complication in patients with repaired pulmonary stenosis (rPS). Additionally, abnormal right and left ventricular interactions have been reported in right‐sided heart defect after intervention, including in pulmonary stenosis.PurposeTo analyze ventricular strain, remodeling, and left and right ventricular interactions in rPS patients with preserved right ventricular ejection fraction (RVEF) compared with healthy children using cardiac magnetic resonance.Study TypeA cross‐sectional study.PopulationIn all, 34 rPS patients and 10 healthy children volunteers (controls).Field Strength/Sequence3.0T/2D balanced steady‐state free precession (2D b‐SSFP) cine, late gadolinium enhancement (LGE), and 2D phase contrast (2D‐PC).AssessmentPulmonary regurgitation (PR) fractions of the main pulmonary artery, biventricular volumes, masses, function, and cardiac strain.Statistical TestsMann–Whitney U‐test, t‐test, Pearson correlation coefficients, Spearman's correlation coefficients, and intraclass correlation coefficients analysis were performed.ResultsFor group analysis, the right ventricular (RV) global circumferential strain and radial strain were significantly increased in patients when compared with controls (−13.57 ± 2.69 vs. −5.91 ± 3.16, P < 0.001; 25.31 ± 8.12 vs. 9.87 ± 5.32, P < 0.001, respectively). The fraction of PR displayed moderate correlation with right ventricular end‐diastolic volume index (RVEDVi) (r = 0.452, P = 0.022). RVEDVi and mass index were larger in patients vs. control (104.92 ± 27.46 vs. 85.15 ± 11.98, P = 0.016; 18.28 ± 4.95g/m2 vs. 11.67 ± 2.14 g/m2, P < 0.001, respectively). Patients presented with preserved left ventricular ejection function, but was lower than healthy controls (60.89% ± 4.89% vs. 65.95% ± 4.56%, P = 0.006). Regional circumferential strain of segment 3 of left ventricle (LV) were significantly decreased in patients (−7.79 ± 6.52 vs. −13.56 ± 3.22, P = 0.003).Data ConclusionCompensated increased RV strain, myocardial remodeling of RV, and adverse right and left ventricular interactions occur in rPS patients with preserved RVEF. The decreased interventricular septum strain may lead to impaired LV function due to RV dilation as a result of PR.Level of Evidence: 3Technical Efficacy Stage: 3J. Magn. Reson. Imaging 2020;52:129–138.