Evaluation of Cardiac Shunts With 4D Flow Cardiac Magnetic Resonance: Intra- and Interobserver Variability.

BACKGROUND: In the last decade, the capacity of magnetic resonance (MR) to evaluate congenital anomalies has improved substantially. To date, only a few studies have evaluated the value of 4D-flow MRI in shunt assessments. PURPOSE/HYPOTHESIS: To assess the intra- and interobserver variability of 4D-flow MRI in patients diagnosed with cardiac/extracardiac shunt. Secondarily, to assess the feasibility of directly measuring the shunt and to determine the prognostic correlation with the pulmonary-to-systemic (Qp/Qs) flow ratio. STUDY TYPE: Retrospective. POPULATION: In all, 18 patients with cardiac shunt diagnosis. FIELD STRENGTH/SEQUENCE: 1.5 T/4D phase-contrast MRI. ASSESSMENT: Pulmonary and systemic flows were measured at different locations to assess the internal consistency by two observers (twice by one, and once by the other). The Qp/Qs ratio was calculated. When feasible, direct flow was quantified by planimetry. STATISTICAL TESTS: Spearman's rho correlation coefficient was used to assess the relationship between pulmonary/systemic flows measured at different levels and to compare the jet characteristics with prognostic data as right ventricle volume. Intra- and interobserver variability were determined by Bland-Altman plots and interobserver correlation. RESULTS: The most common shunt type (n = 10; 55.5%) was ostium secundum atrial septal defect (ASD). Direct visualization and quantification of shunt flow was possible in all studies. Pulmonary and systemic flows showed a strong correlation between these measures (Spearman's rho [r] of 0.872 and 0.899). The mean Qp/Qs ratio was 1.61(0.62). Mean flow rate was 2.01(1.68) l/min. The mean jet diameter was 11.88 (5.44) mm. Intraobserver (r = 0.97) and interobserver correlation (ICC = 0.95) for the Qp/Qs calculation were both excellent. Direct measurement of flow was strongly correlated (r = 0.98; ICC = 0.95). Correlation was strong between Qp/Qs and direct jet flow (r = 0.76 and 0.77), Qp/Qs and mean jet diameter (r = 0.79 and 0.94), and Qp/Qs with jet area (r = 0.77 and 0.94). DATA CONCLUSION: Measurement of the Qp/Qs ratio and direct shunt quantification using 4D-flow MRI was feasible, and highly reproducible. Internal consistency was excellent, with low intra- and interobserver variability. Correlation between the Qp/Qs ratio, direct flow measurement, mean diameter, and jet area was strong. EVIDENCE LEVEL: 3 TECHNICAL EFFICACY: Stage 2 J. Magn. Reson. Imaging 2020;52:1055-1063.

Myocardial Blood Flow Quantification Using Stress Cardiac Magnetic Resonance Improves Detection of Coronary Artery Disease.

BACKGROUND: Myocardial blood flow (MBF) and myocardial perfusion reserve (MPR) using stress cardiovascular magnetic resonance (CMR) have been shown to identify epicardial coronary artery disease. However, comparative analysis between quantitative perfusion and conventional qualitative assessment (QA) remains limited. OBJECTIVES: The aim of this multicenter study was to test the hypothesis that quantitative stress MBF (sMBF) and MPR analysis can identify obstructive coronary artery disease (obCAD) with comparable performance as QA of stress CMR performed by experienced physicians in interpretation. METHODS: The analysis included 127 individuals (mean age 62 ± 16 years, 84 men [67%]) who underwent stress CMR. obCAD was defined as the presence of stenosis ≥50% in the left main coronary artery or ≥70% in a major vessel. Each patient, coronary territory, and myocardial segment was categorized as having either obCAD or no obCAD (noCAD). Global, per coronary territory, and segmental MBF and MPR values were calculated. QA was performed by 4 CMR experts. RESULTS: At the patient level, global sMBF and MPR were significantly lower in subjects with obCAD than in those with noCAD, with median values of sMBF of 1.5 mL/g/min (Q1-Q3: 1.2-1.8 mL/g/min) vs 2.4 mL/g/min (Q1-Q3: 2.1-2.7 mL/g/min) (P < 0.001) and median values of MPR of 1.3 (Q1-Q3: 1.0-1.6) vs 2.1 (Q1-Q3: 1.6-2.7) (P < 0.001). At the coronary artery level, sMBF and MPR were also significantly lower in vessels with obCAD compared with those with noCAD. Global sMBF and MPR had areas under the curve (AUCs) of 0.90 (95% CI: 0.84-0.96) and 0.86 (95% CI: 0.80-0.93). The AUCs for QA by 4 physicians ranged between 0.69 and 0.88. The AUC for global sMBF and MPR was significantly better than the average AUC for QA. CONCLUSIONS: This study demonstrates that sMBF and MPR using dual-sequence stress CMR can identify obCAD more accurately than qualitative analysis by experienced CMR readers.

Comparative Cardiac Magnetic Resonance-Based Feature Tracking and Deep-Learning Strain Assessment in Patients Hospitalized for Acute Myocarditis.

This study sought to examine the correlation between left ventricular (LV) myocardial feature tracking (FT) and deep learning-based strain (DLS) analysis in the diagnostic (CMRd) and follow-up (CMRf) cardiac magnetic resonance imaging of patients with acute myocarditis. The retrospective study included 17 patients with acute myocarditis and 20 healthy controls. The CMRd took place within 14 days of symptom onset, while the CMRf took place at least 2 months after the event. The global-circumferential FT (FTc) and global-circumferential DLS (DLSc) were analyzed. The continuous variables were compared using paired t-tests or the Wilcoxon test, whereas Pearson's test or Spearman's test was used to evaluate the correlation between the continuous variables. The time between the CMRd and CMRf was 5 months [3-11]. The LV ejection fraction (LVEF) was 55 ± 6 and 59 ± 4%, p = 0.008, respectively, and 94.1% of the patients showed late gadolinium enhancement (LGE) and myocardial edema on the CMRd. Significantly lower FTc (-16.1 ± 2.2% vs. -18.9 ± 1.9%, p = 0.001) and DLSc (-38.1 ± 5.2% vs. -41.3 ± 4.5%, p = 0.015) were observed with respect to the controls. Significant increases in the FTc (-16.1 ± 2.2 vs. -17.5 ± 1.9%, p = 0.016) and DLSc (-38.1 ± 5.2 vs. -39.8 ± 3.9%, p = 0.049) were found between the CMRd and CMRf, which were unrelated to the LGE. The LVEF correlated well with the FTc (r = 0.840) and DLSc (r = 0.760). Both techniques had excellent reproducibility, with high intra- (FTc = 0.980, DLSc = 1.000) and inter-observer (FTc = 0.970, DLSc = 0.980) correlation. There was correlation between the LV DLSc/FTc and LVEF in the patients with acute myocarditis according to the CMRd and CMRf.

White-Matter Lesions and Cortical Cerebral Blood Flow Evaluation by 3D Arterial Spin-Labeled Perfusion MRI in Asymptomatic Divers: Correlation with Patent Foramen Ovale Ocurrence.

Cerebral white-matter lesions (cWML) can be caused by dilation of Virchow-Robin spaces or may correspond to true lacunar ischemic lesions. The aim of our study was to evaluate in asymptomatic divers the relationship between the presence of patent foramen ovale (PFO) and cWML, as well as their possible effects on cortical cerebral blood flow (CBF) by magnetic resonance (MRI) through the arterial spin labeling (ASL) sequence. Transthoracic echocardiography was performed for the identification of PFO, and cerebral magnetic resonance including the 3D-ASL sequence for CBF quantification. Thirty-eight divers, with a mean age 45.8 ± 8.6 years, were included. Nineteen healthy volunteers, mean age 41 ± 15.2 years, served as the control group. A total of 28.9% of divers had completed more than 1000 dives. It was found that 26.3% of divers presented with PFO in the echocardiographic study. cWML was evidenced in 10.5% of diver MRI studies. There was no statistically significant relationship between the presence of PFO and cWML (p = 0.95). We observed a lower blood flow in all brain areas assessed by the 3D-ASL sequence in the group of divers, compared with the control group. We did not find statistical differences in CBF as a function of the presence or absence of PFO, number of dives, or cWML evidence.

A papillary fibroelastoma with myxoma camouflage: a case report.

Background: Benign cardiac tumours are infrequent in clinical practice and, of these, cardiac myxoma is the one with the highest incidence. Given that a left intraventricular presentation is rare, other differential diagnoses such as papillary fibroelastoma should be considered. Case summary: A 73-year-old woman patient with cardiac mass detected in transthoracic echocardiography (TTE) after a transient ischaemic attack. At TTE 2D-3D, a left intraventricular mass anchored at the level of the anterolateral papillary muscle was detected. Subsequently, cardiac magnetic resonance (CMR) was performed for mass characterization. This revealed behaviour in T1 (isointense with respect to myocardium), T2 (hyperintense), very prolonged T1-mapping (1848 msg), and T2-mapping (161 msg) values, without gadolinium uptake in the first-pass perfusion sequence, but with intense uptake in late enhancement sequences. Previous findings were compatible with a diagnosis of papillary fibroelastoma. The mass was resected intraoperatively and, although its macroscopic appearance pointed to a diagnosis of cardiac myxoma, it was finally confirmed to be a papillary fibroelastoma by pathological anatomy. Discussion: In cases where the size of the mass and its mobility allow tissue characterization by CMR, a diagnosis of papillary fibroelastoma and its differentiation with cardiac myxoma are feasible by this cardiac imaging technique.

4D-Flow Cardiac Magnetic Resonance Imaging in Chronic Aortic Dissection Assessment: A Powerful Qualiquantitative Diagnostic Tool.

4-dimensional-flow cardiac magnetic resonance in patients with aortic dissection in chronic/post repair phase as a complementary diagnostic tool for anatomic-functional evaluation. Quali-quantitative analysis of 3 patients with this pathology clearly showing the true/false lumen, quantitative flow in false lumen, and helping in discerning lumen origin from different arterial vessels. (Level of Difficulty: Advanced.).

Cardiac magnetic resonance in recovering COVID-19 patients. Feature tracking and mapping analysis to detect persistent myocardial involvement.

BACKGROUND: Post-COVID-19 patients may incur myocardial involvement secondary to systemic inflammation. Our aim was to detect possible oedema/diffuse fibrosis using cardiac magnetic resonance imaging (CMR) mapping and to study myocardial deformation of the left ventricle (LV) using feature tracking (FT). METHODS: Prospective analysis of consecutively recruited post-COVID-19 patients undergoing CMR. T1 and T2 mapping sequences were acquired and FT analysis was performed using 2D steady-state free precession cine sequences. Statistical significance was set to p < 0.05. RESULTS: Included were 57 post-COVID-19 patients and 20 healthy controls, mean age 59 ± 15 years, men 80.7%. The most frequent risk factors were hypertension (33.3%) and dyslipidaemia (36.8%). The contact-to-CMR interval was 81 ± 27 days. LV ejection fraction (LVEF) was 61 ± 10%. Late gadolinium enhancement (LGE) was evident in 26.3% of patients (19.3%, non-ischaemic). T2 mapping values (suggestive of oedema) were higher in the study patients than in the controls (50.9 ± 4.3 ms vs 48 ± 1.9 ms, p < 0.01). No between-group differences were observed for native T1 nor for circumferential strain (CS) or radial strain (RS) values (18.6 ± 3.3% vs 19.2 ± 2.1% (p = 0.52) and 32.3 ± 8.1% vs 33.6 ± 7.1% (p = 0.9), respectively). A sub-group analysis for the contact-to-CMR interval (<8 weeks vs ≥ 8 weeks) showed that FT-CS (15.6 ± 2.2% vs 18.9 ± 2.6%, p < 0.01) and FT-RS (24.9 ± 5.8 vs 33.5 ± 7.2%, p < 0.01) values were lower for the shorter interval. CONCLUSIONS: Post-COVID-19 patients compared to heathy controls had raised T2 values (related to oedema), but similar native T1, FT-CS and FT-RS values. FT-CS and FT-RS values were lower in post-COVID-19 patients undergoing CMR after < 8 weeks compared to ≥ 8 weeks.

Myocardial strain in nonischemic dilated cardiomyopathy with feature tracking. Feasibility and prognostic implications.

INTRODUCTION AND OBJECTIVES: Myocardial strain analysis could provide additional information to left ventricular ejection fraction (LVEF) in nonischemic dilated cardiomyopathy (NIDC). Our aim was to analyze the feasibility of left ventricular strain evaluation using cardiac magnetic resonance feature tracking (FT) in NIDC, and to determine its clinical and prognostic impact. METHODS: We retrospectively included consecutive patients with NIDC who underwent cardiac magnetic resonance. Left ventricular global longitudinal, circumferential and radial strain were obtained from standard cine sequences using FT analysis software. We evaluated their association with a composite endpoint (heart failure, implantable cardioverter-defibrillator in secondary prevention, or death). RESULTS: FT analysis could be performed in all of the 98 patients (mean age 68±13 years, 72% men). Intra- and interobserver concordance was good for global longitudinal and circumferential strain but was worse for radial strain. Global circumferential strain was independently associated (OR, 1.16; P=.045) with LVEF normalization during follow-up and was the only morphological parameter independently associated with the composite endpoint (OR, 1.15; P=.038). A cutoff value <-8.2% was able to predict the incidence of this event during follow-up (log-rank 4.6; P=.032). CONCLUSIONS: Left ventricular strain analysis with FT is feasible and reproducible in NIDC. Global circumferential strain was able to predict LVEF recovery and the appearance of major cardiovascular events during follow-up.

4D Flow Cardiovascular Magnetic Resonance Versus 3D Transesophageal Echocardiography in a Mitral Paravalvular Leak.

Three-dimensional transesophageal echocardiography and 4-dimensional flow magnetic resonance imaging as complementary techniques in the preoperative planning of a mitral paravalvular leak allow the evaluation of its location, shape, and size and qualitative-quantitative analysis of mitral regurgitant orifice. (Level of Difficulty: Intermediate.).