Background MR feature‐tracking (FT) is a novel technique that quantitatively calculates myocardial strain and can assess myocardial viability. Purpose To evaluate the feasibility of FT at rest and with low‐dose dobutamine (LDD), visual assessment of contractility with LDD and left ventricle (LV) end‐diastolic wall thickness (EDWT) in the assessment of viability in ischemic cardiomyopathy (ICM) patients compared to delayed gadolinium enhancement (DGE). Study type Prospective. Subjects Thirty ICM patients and 30 healthy volunteers. Field strength/Sequences A 1.5 T with balanced steady‐state free precession (bSSFP) cine and phase‐sensitive inversion prepared segmented gradient echo sequences. Assessment LDD (5 μg/kg/min and 10 μg/kg/min) was administered in the patient group. LV was divided into 16 segments and MR‐FT was derived from bSSFP cine images using dedicated software. Viable segments were defined as those with a dobutamine‐induced increase in resting MR‐FT values >20%, a dobutamine‐induced increase in systolic wall thickening ≥2 mm by visual assessment, ≤50% fibrosis on DGE, and resting EDWT ≥5.5 mm. Statistical tests One‐way analysis of variance (ANOVA), two‐sampled t‐test, paired samples t‐test, and receiver operating characteristic (ROC) curve analysis. A P value < 0.05 was considered statistically significant. Results Resting peak global circumferential (Ecc) and radial (Err) strains were significantly impaired in patients compared to controls (−11.7 ± 7.9 vs. −20.1 ± 5.7 and 19.7 ± 13.9 vs. 32.7 ± 15.4, respectively). Segments with no DGE (n = 354) and ≤ 50% (n = 38) DGE showed significant improvement of both Ecc and Err with LDD while segments with >50% DGE (n = 88) showed no improvement. In comparison to viable and nonviable segments identified by reference‐standard DGE, the sensitivity, specificity, and diagnostic accuracy of the four methods were: 74%, 92%, and 89%, respectively, for Ecc; 70%, 89%, and 86%, respectively, for Err; 67%, 88%, and 84% for visual assessment; and 39%, 90%, and 80% for EDWT. Data conclusion Quantitative assessment of MR‐FT, along with EDWT and qualitative visual assessment of myocardial contractility with LDD, are feasible alternative methods for the assessment of myocardial viability with moderate sensitivity and high specificity. Level of Evidence 1 Technical Efficacy Stage: 2

Background Hypertrophic cardiomyopathy (HCM) is one of the commonest inheritable cardiac disorders. Being a global disease with diffuse myocardial fibrosis, it has a wide range of adverse outcomes ending with sudden cardiac death. Cardiac magnetic resonance (CMR) with late gadolinium enhancement (LGE) has become a reference standard for visualization of focal myocardial fibrosis. In the setting of less severe or more diffuse fibrosis, LGE is unlikely to reveal the presence of abnormal tissue given the lack of normal myocardium as a reference. Direct measurement of myocardial T1 time (T1 mapping) may improve these methodologic problems of LGE CMR in the setting of diffuse retention of gadolinium-based contrast material. So, we aim at this study to evaluate the clinical application of CMRI native and post-contrast T1 relaxation in assessing diffuse myocardial fibrosis non-invasively in hypertrophic cardiomyopathy. Results There was a significant difference between the percent of fibrosis detected by measuring the extracellular volume percent compared to that detected by LGE, with the former detecting fibrosis in 45.1% of the examined cardiac segments while the latter showed fibrosis in 20.9% of the cardiac segments. Also, measuring the native T1 values showed evidence of fibrosis in about 32.2% of the cardiac segments superseding the percent of fibrosis detected using the LGE alone. The ejection fraction percent showed a negative correlation with the left ventricular mass with a correlation coefficient value of − 0.139 where both interstitial and replacement fibrosis play an important role in the pathophysiology of diastolic dysfunction as well as impairing the myocardial contractility. Also, in cases of obstruction, the extracellular volume (ECV) is more likely to increase in the basal anterior and antero-septal segments as well as the basal inferior segment with P values 0.015, 0.013, and 0.045, respectively. Conclusion Diffuse fibrosis was found to be difficult to be distinguished using LGE. The unique ability of CMR to use proton relaxation times provides a quantitative measurement to detect increased interstitial volume in diffuse myocardial fibrosis. Moreover, it showed that in cases of obstruction, the segments exposed to the highest pressure are more vulnerable to the fibrotic process denoting a relationship between the pressure gradient and the adverse myocardial remodeling.

Background: Tetralogy of Fallot (TOF) accounts for 10% of all CHD. It classically consists of ventricular septal defect (VSD), aortic overriding, right ventricular outflow tract (RVOT) obstruction, and RV hypertrophy. There are many anatomic variants, associated intracardiac and extracardiac anomalies that must be taken into consideration when imaging and planning the surgical procedure needed. Multi-detector computed tomography (MDCT), with its high spatial and temporal resolution, has a pivotal role in the evaluation of complex anatomical findings in both unrepaired and repaired TOF patients. Main body: Though MDCT has a limited role in the initial diagnosis of TOF, it is particularly important when there is a question about anatomy of pulmonary arteries (PAs) (whether sizable, hypoplastic, or atretic), presence of major aorto-pulmonary collaterals (MAPCAs) and presence of additional VSDs. Additionally, MDCT is crucial in the diagnosis of different anatomical variants of TOF. TOF patients with absent pulmonary valve classically have hugely dilated PAs which raise an important question about the degree and severity of airways compression. This question can be accurately answered by MDCT. TOF with double-outlet RV (DORV) has variable degrees of aortic override which can be assessed by MDCT. An atrio-ventricular septal defect (AVSD) is seen in about 13% of TOF cases and typically occurs in patients with Down syndrome. MDCT can assess the size and extent of inlet VSD and size of both ventricles (balanced or unbalanced AVSD). Coronary artery anomalies are common and important association. MDCT can identify the presence of a major coronary artery crossing the RVOT, a left anterior descending (LAD) from RCA, or a dual LAD. The clinical importance of these anomalies is its susceptibility to injury during ventriculotomy incision required for TOF repair necessitating changing the usual approach of surgery. Patients with reduced pulmonary blood flow undergo a systemic to pulmonary shunt. MDCT can assess the patency of the shunt, stenotic, or occluded segments. In surgically repaired TOF patients, MDCT can identify the sequalae and long-term complications including residual RVOT obstruction, conduit stenosis, RVOT patch aneurysm, RVH, and aortic root dilatation.Conclusion: MDCT is a safe and reliable imaging modality that provides accurate assessment of anatomical variants and associated anomalies of TOF.

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Background Cardiac resynchronization therapy (CRT) improves quality of life, exercise tolerance, and myocardial function in a considerable number of patients with heart failure (HF) and left bundle branch block. In addition, CRT decreases HF hospitalizations and overall mortality. However, structural, morbidity, and mortality improvements after CRT rate between 40 and 60%. Objective To compare the role of the cardiac magnetic resonance (CMR) and speckle-tracking echocardiography (STE) in expectation of response to CRT. Patients and methods We investigated the predictors of CRT response using CMR measurement of left ventricular (LV) volumes and function, CMR-derived mechanical dyssynchrony, scar percentage, and its relation to the site of LV lead implantation, in comparison with STE in prediction of CRT outcomes. Results A total of 35 patients with HF planned for CRT were included. Echocardiography was used to define the response to CRT (15% reduction in LV end-systolic volume 6 months after implantation). At follow-up, 18 (51.43%) patients were categorized as responders. Echocardiographic speckle-tracking radial strain analysis showed a significant LV dyssynchrony in responders versus nonresponders (radial mid-anteroseptal and posterior wall delays were 245.1 ms and 80.7 ms, respectively) (P<0.0001). LV radial dyssynchrony, as measured by CMR-feature tracking, was significantly higher in responders versus nonresponders (mean of SDt-16 of radial strain were 232.7 ms vs. 180.4 ms, P<0.0001), and median of radial mid-anteroseptal-to-inferolateral wall delay was 375 vs. 125.4 ms, P<0.0001). Late contrast-enhanced CMR was performed for scar assessment. It was noticed that scar percentage of LV mass was much higher in nonresponders (median 6.2 vs. 0%) (P=0.005). Conclusion CMR imaging offers the unique opportunity to predict the CRT outcomes by measurement of LV volumes, LV mechanical dyssynchrony (that well correlated with that of STE), and the total scar percentage and distribution in a single examination.