Cardiovascular Magnetic Resonance Scan Research Articles

Using T1 mapping in cardiovascular magnetic resonance to assess congestive hepatopathy.

The goal of this study was to assess the ability of quantitative T1 cardiovascular magnetic resonance (CMR) imaging to calculate liver extracellular volume (ECV) in patients with varying degrees of congestive hepatopathy (CH). T1 measurements and ECV calculations were performed retrospectively in three cohorts of patients: normal cardiac function, tetralogy of fallot (TOF) repair and Fontan palliation. All CMR studies included modified look-locker inversion recovery (MOLLI) T1 mapping scans performed pre- and post-injection of a gadolinium-based contrast agent (GBCA). Pixel intensity data were manually collected from images of the liver and cardiac blood pool to determine contrast-induced changes in T1 for liver and blood. These data were then used to compute liver ECV. 172 subjects were included in the study. Of these, 140 subjects were normal cardiac function patients, 16 were TOF repair patients and 16 patients were with Fontan palliation. A statistically significant difference in both the liver native T1 and ECV measurements was found between patients with normal cardiac function vs. Fontan palliation patients (p<0.01). Our data indicate that measuring T1 maps both pre- and post-GBCA injection within CMR scan session can be used to follow progression of liver fibrosis. This technique has the potential to improve diagnosis and treatment of patients with chronic liver disease and liver fibrosis.

Developing a UK registry to investigate the role of cardiovascular magnetic resonance (CMR) in patients who activate the primary percutaneous coronary intervention (PPCI) pathway: a multicentre, feasibility study linking routinely collected electronic patient data

ObjectivesTo determine whether it is feasible to set up a national registry, linking routinely collected data from hospital information systems (HIS), to investigate the role of cardiovascular magnetic resonance (CMR)...

Dynamic fetal cardiovascular magnetic resonance imaging using Doppler ultrasound gating

BackgroundFetal cardiovascular magnetic resonance (CMR) imaging may provide a valuable adjunct to fetal echocardiography in the evaluation of congenital cardiovascular pathologies. However, dynamic fetal CMR is difficult due to the lack of direct in-utero cardiac gating. The aim of this study was to investigate the effectiveness of a newly developed Doppler ultrasound (DUS) device in humans for fetal CMR gating.MethodsFifteen fetuses (gestational age 30–39 weeks) were examined using 1.5 T CMR scanners at three different imaging sites. A newly developed CMR-compatible DUS device was used to generate gating signals from fetal cardiac motion. Gated dynamic balanced steady-state free precession images were acquired in 4-chamber and short-axis cardiac views. Gating signals during data acquisition were analyzed with respect to trigger variability and sensitivity. Image quality was assessed by measuring endocardial blurring (EB) and by image evaluation using a 4-point scale. Left ventricular (LV) volumetry was performed using the single-plane ellipsoid model.ResultsGating signals from the fetal heart were detected with a variability of 26 ± 22 ms and a sensitivity of trigger detection of 96 ± 4%. EB was 2.9 ± 0.6 pixels (4-chamber) and 2.5 ± 0.1 pixels (short axis). Image quality scores were 3.6 ± 0.6 (overall), 3.4 ± 0.7 (mitral valve), 3.4 ± 0.7 (foramen ovale), 3.6 ± 0.7 (atrial septum), 3.7 ± 0.5 (papillary muscles), 3.8 ± 0.4 (differentiation myocardium/lumen), 3.7 ± 0.5 (differentiation myocardium/lung), and 3.9 ± 0.4 (systolic myocardial thickening). Inter-observer agreement for the scores was moderate to very good (kappa 0.57–0.84) for all structures. LV volumetry revealed mean values of 2.8 ± 1.2 ml (end-diastolic volume), 0.9 ± 0.4 ml (end systolic volume), 1.9 ± 0.8 ml (stroke volume), and 69.1 ± 8.4% (ejection fraction).ConclusionHigh-quality dynamic fetal CMR was successfully performed using a newly developed DUS device for direct fetal cardiac gating. This technique has the potential to improve the utility of fetal CMR in the evaluation of congenital pathologies.

Dynamic changes in injured myocardium, very early after acute myocardial infarction, quantified using T1 mapping cardiovascular magnetic resonance

BackgroundIt has recently been suggested that myocardial oedema follows a bimodal pattern early post ST-segment elevation myocardial infarction (STEMI). Yet, water content, quantified using tissue desiccation, did not return to normal values unlike oedema quantified by cardiovascular magnetic resonance (CMR) imaging. We studied the temporal changes in the extent and intensity of injured myocardium using T1-mapping technique within the first week after STEMI.MethodsA first group (n = 31) underwent 3 acute 3 T CMR scans (time-point (TP) < 3 h, 24 h and 6 days), including cine, native shortened modified look-locker inversion recovery T1 mapping, T2* mapping and late gadolinium enhancement (LGE). A second group (n = 17) had a single scan at 24 h with an additional T2-weighted sequence to assess the difference in the extent of area-at-risk (AAR) compared to T1-mapping.ResultsThe mean T1 relaxation time value within the AAR of the first group was reduced after 24 h (P < 0.001 for TP1 vs.TP2) and subsequently increased at 6 days (P = 0.041 for TP2 vs.TP3). However, the extent of AAR quantified using T1-mapping did not follow the same course, and no change was detected between TP1&TP2 (P = 1.0) but was between TP2 &TP3 (P = 0.019). In the second group, the extent of AAR was significantly larger on T1-mapping compared to T2-weighted (42 ± 15% vs. 39 ± 15%, P = 0.025). No change in LGE was detected while microvascular obstruction and intra-myocardial haemorrhage peaked at different time points within the first week of reperfusion.ConclusionThe intensity of oedema post-STEMI followed a bimodal pattern; while the extent of AAR did not track the same course. This discrepancy has implications for use of CMR in this context and may explain the previously reported disagreement between oedema quantified by imaging and tissue desiccation.

Artefacts in 1.5\xa0Tesla and 3\xa0Tesla cardiovascular magnetic resonance imaging in patients with leadless cardiac pacemakers

BackgroundThere are limited data on patients with leadless cardiac pacemakers (LCP) undergoing magnetic resonance imaging. The aim of this prospective, single-center, observational study was to evaluate artefacts on cardiovascular magnetic resonance (CMR) images in patients with LCP.MethodsFifteen patients with Micra™ LCP, implanted at least 6 weeks prior to CMR scan, were enrolled and underwent either 1.5 Tesla or 3 Tesla CMR imaging. Artefacts were categorized into grade 1 (excellent image quality), grade 2 (good), grade 3 (poor) and grade 4 (non-diagnostic) for each myocardial segment. One patient was excluded because of an incomplete CMR investigation due to claustrophobia.ResultsLCP caused an arc-shaped artefact (0.99 ± 0.16 cm2) at the right ventricular (RV) apex. Of 224 analyzed myocardial segments of the left ventricle (LV) 158 (70.5%) were affected by grade 1, 27 (12.1%) by grade 2, 17 (7.6%) by grade 3 and 22 (9.8%) by grade 4 artefacts. The artefact burden of grade 3 and 4 artefacts was significantly higher in the 3 Tesla group (3 Tesla vs 1.5 Tesla: 3.7 ± 1.6 vs 1.9 ± 1.4 myocardial segments per patient, p = 0.03). A high artefact burden was particularly observed in the mid anteroseptal, inferoseptal and apical septal myocardial segments of the LV and in the mid and apical segments of the RV. Quantification of LV function and assessment of valves were feasible in all patients. We did not observe any clinical or device-related adverse events.ConclusionCMR imaging in patients with LCP is feasible with excellent to good image quality in the majority of LV segments. The artefact burden is comparable small allowing an accurate evaluation of LV function, cardiac structures and valves. However, artefacts in the mid anteroseptal, inferoseptal and apical septal myocardial segments of the LV due to the LCP may impair or even exclude diagnostic evaluation of these segments. Artefacts on CMR images may be reduced by the use of 1.5 Tesla CMR scanners.

3D whole-brain vessel wall cardiovascular magnetic resonance imaging: a study on the reliability in the quantification of intracranial vessel dimensions

BackgroundOne of the potentially important applications of three-dimensional (3D) intracranial vessel wall (IVW) cardiovascular magnetic resonance (CMR) is to monitor disease progression and regression via quantitative measurement of IVW morphology during medical management or drug development. However, a prerequisite for this application is to validate that IVW morphologic measurements based on the modality are reliable. In this study we performed comprehensive reliability analysis for the recently proposed whole-brain IVW CMR technique.MethodsThirty-four healthy subjects and 10 patients with known intracranial atherosclerotic disease underwent repeat whole-brain IVW CMR scans. In 19 of the 34 subjects, two-dimensional (2D) turbo spin-echo (TSE) scan was performed to serve as a reference for the assessment of vessel dimensions. Lumen and wall volume, normalized wall index, mean and maximum wall thickness were measured in both 3D and 2D IVW CMR images. Scan-rescan, intra-observer, and inter-observer reproducibility of 3D IVW CMR in the quantification of IVW or plaque dimensions were respectively assessed in volunteers and patients as well as for different healthy subjectsub-groups (i.e. < 50 and ≥ 50 years). The agreement in vessel wall and lumen measurements between the 3D technique and the 2D TSE method was also investigated. In addition, the sample size required for future longitudinal clinical studies was calculated.ResultsThe intra-class correlation coefficient (ICC) and Bland-Altman plots indicated excellent reproducibility and inter-method agreement for all morphologic measurements (All ICCs > 0.75). In addition, all ICCs of patients were equal to or higher than that of healthy subjects except maximum wall thickness. In volunteers, all ICCs of the age group of ≥50 years were equal to or higher than that of the age group of < 50 years. Normalized wall index and mean and maximum wall thickness were significantly larger in the age group of ≥50 years. To detect 5% - 20% difference between placebo and treatment groups, normalized wall index requires the smallest sample size while lumen volume requires the highest sample size.ConclusionsWhole-brain 3D IVW CMR is a reliable imaging method for the quantification of intracranial vessel dimensions and could potentially be useful for monitoring plaque progression and regression.

The effect of 1.5 T cardiac magnetic resonance on human circulating leucocytes.

Investigators have proposed that cardiovascular magnetic resonance (CMR) should have restrictions similar to those of ionizing imaging techniques. We aimed to investigate the acute effect of 1.5 T CMR on leucocyte DNA integrity, cell counts, and function in vitro, and in a large cohort of patients in vivo. In vitro study: peripheral blood mononuclear cells (PBMCs) were isolated from healthy volunteers, and histone H2AX phosphorylation (γ-H2AX) expression, leucocyte counts, and functional parameters were quantified using flow cytometry under the following conditions: (i) immediately following PBMC isolation, (ii) after standing on the benchside as a temperature and time control, (iii) after a standard CMR scan. In vivo study: blood samples were taken from 64 consecutive consenting patients immediately before and after a standard clinical scan. Samples were analysed for γ-H2AX expression and leucocyte counts. CMR was not associated with a significant change in γ-H2AX expression in vitro or in vivo, although there were significant inter-patient variations. In vitro cell integrity and function did not change with CMR. There was a significant reduction in circulating T cells in vivo following CMR. 1.5 T CMR was not associated with DNA damage in vitro or in vivo. Histone H2AX phosphorylation expression varied markedly between individuals; therefore, small studies using γ-H2AX as a marker of DNA damage should be interpreted with caution. Cardiovascular magnetic resonance was not associated with loss of leucocyte viability or function in vitro. Cardiovascular magnetic resonance was associated with a statistically significant reduction in viable leucocytes in vivo.

Redefining viability by cardiovascular magnetic resonance in acute ST-segment elevation myocardial infarction

In chronic myocardial infarction (MI), segments with a transmural extent of infarct (TEI) of ≤50% are defined as being viable. However, in the acute phase of an ST-segment elevation myocardial infarction (STEMI), late gadolinium enhancement (LGE) has been demonstrated to overestimate MI size and TEI. We aimed to identify the optimal cut-off of TEI by cardiovascular magnetic resonance (CMR) for defining viability during the acute phase of an MI, using ≤50% TEI at follow-up as the reference standard. 40 STEMI patients reperfused by primary percutaneous coronary intervention (PPCI) underwent a CMR at 4 ± 2 days and 5 ± 2 months. The large majority of segments with 1–25%TEI and 26–50%TEI that were viable acutely were also viable at follow-up (59/59, 100% and 75/82, 96% viable respectively). 56/84(67%) segments with 51–75%TEI but only 4/63(6%) segments with 76–100%TEI were reclassified as viable at follow-up. TEI on the acute CMR scan had an area-under-the-curve of 0.87 (95% confidence interval of 0.82 to 0.91) and ≤75%TEI had a sensitivity of 98% but a specificity of 66% to predict viability at follow-up. Therefore, the optimal cut-off by CMR during the acute phase of an MI to predict viability was ≤75% TEI and this would have important implications for patients undergoing viability testing prior to revascularization during the acute phase.

Early myocardial edema after acute myocardial infarction is stable and not bimodal in humans — Evidence from a large CMR multicenter study

BackgroundExperimental data reported a temporal pattern of myocardial edema following acute myocardial infarction (AMI). Therefore, the aim of this study was to assess the time course of myocardial edema in a large population of patients with ST-segment elevation myocardial infarction (STEMI). MethodsMyocardium at risk (MAR), infarct size (IS) and myocardial salvage index (MSI) were compared according to the time between infarction and cardiovascular magnetic resonance (CMR) imaging in a large multicenter STEMI cohort (n=795). CMR scans performed >8days (>192h) after AMI were excluded (n=23). Scans performed within 8days were reported at time-points 12–24h, 24–36h, 36–48h, and days 3 to 8 (192h). ResultsMAR/MSI and IS could be assessed in 693 and 755 patients, respectively. The extent of MAR over the first week after ischemia/reperfusion showed a slight rise and fall (p=0.029 in one-way analysis of variance). However, analysis of IS demonstrated a similar trend over time (p=0.026). Post-hoc testing did not reveal significant differences between particular time periods for both MAR and IS. A stable edematous reaction was also observed between 12‐24h, 24‐36h, 36‐48h and up to 8days after infarction in a more detailed analysis. MSI did not show statistically significant variations (p=0.147). Multivariate regression analysis did not identify the time of CMR acquisition as a predictor of MAR (p=0.709), IS (p=0.810) or MSI (p=0.916). ConclusionThese data do not confirm a temporal pattern of myocardial edema over the first week after AMI in humans.

Effect of Pregnancy on Ventricular and Aortic Dimensions in Repaired Tetralogy of Fallot.

BackgroundThe aim was to assess whether cardiovascular adaptation to pregnancy in women with repaired tetralogy of Fallot (TOF) adversely affects hemodynamic stability, in particular with respect to right ventricular (RV) dilatation, pulmonary regurgitation, or aortic root dilatation.Methods and ResultsThis was a retrospective cohort study of women with repaired TOF with paired cardiovascular magnetic resonance scans before and after their first pregnancy (baseline RV end systolic volume index 49 mL/m2 and RV end diastolic volume index 118 mL/m2) matched with a comparison group of nulliparous women with TOF. Cases were matched for age at baseline cardiovascular magnetic resonance scan, time between follow‐up of cardiovascular magnetic resonance scans, QRS duration, RV ejection fraction, and indexed RV end systolic and diastolic volume at baseline. Effect of pregnancy and time on parameters was assessed using mixed‐effects modelling. Nineteen women with repaired TOF who had completed their first pregnancy were identified and matched with 38 nulliparous women. We observed no deleterious effects of pregnancy on RV volumes, aortic dimensions, or exercise data. There was an effect of pregnancy observed in both left ventricular end diastolic volume and left ventricular stroke volume, consistent with a sustained small increase in left ventricular stroke volume attributed to pregnancy (53–55 mL/m2).ConclusionsWomen with repaired TOF and with mild‐to‐moderate RV dilatation considering pregnancy can be reassured that pregnancy is unlikely to cause deterioration in their cardiovascular status. We recommend that women are routinely assessed and followed up before and after pregnancy and that prepregnancy counseling is tailored to their individual clinical status.

Post-procedural myocardial infarction following surgical aortic valve replacement and transcatheter aortic valve implantation

Myocardial injury assessed using cardiac biomarker release is ubiquitous following surgical aortic valve replacement (SAVR) and transcatheter aortic valve implantation (TAVI), preventing accurate discrimination between focal myocardial infarction (MI) and global injury. Cardiovascular magnetic resonance (CMR) late gadolinium enhancement (LGE) imaging was used to compare rates of new MI following SAVR and TAVI. Identical CMR scans were obtained at baseline and six months post procedure in ninety-six patients undergoing SAVR (n=39) and TAVI (n=57). The rate of new MI was greater following SAVR than TAVI (SAVR, n=10 [26%] vs. TAVI, n=3 [5%], p=0.004). Infarct mass was similar between groups (SAVR 1.1±0.6 vs. TAVI 2.0±1.4 g, p=0.395). New MI did not impact on change in LV ejection fraction (SAVR:LGE[+]2.2±4.7 vs. LGE[-]0.9±8.0%, p=0.437, TAVI:LGE[+]-0.9±6.0 vs. LGE[-]2.0±7.8%, p=0.420). Thirty-four patients (60%) in the TAVI group had non-revascularised coronary artery disease (CAD) at the time of TAVI, of whom three (9%) had new MI. MI is an infrequent complication of TAVI but is more common following SAVR. Infarct size is small following both procedures. The low new infarct rate in TAVI, especially in the context of high rates of non-revascularised CAD, strengthens data from previous studies suggesting that coronary revascularisation pre-TAVI may be unnecessary.

Myocardial Damage Detected by Late Gadolinium Enhancement Cardiac Magnetic Resonance Is Uncommon in Peripartum Cardiomyopathy.

BackgroundIn peripartum cardiomyopathy, the prevalence of focal myocardial damage detected by late gadolinium enhancement (LGE) cardiovascular magnetic resonance is important to elucidate mechanisms of myocardial injury and cardiac dysfunction. LGE equates irreversible myocardial injury, but LGE prevalence in peripartum cardiomyopathy is uncertain.Methods and ResultsAmong 100 women enrolled within the Investigations of Pregnancy Associated Cardiomyopathy cohort, we recruited 40 women at 13 centers to undergo LGE cardiovascular magnetic resonance, enrolled within the first 13 weeks postpartum. Follow‐up scans occurred at 6 months postpartum, and death/transplant rates at 12 months. Baseline characteristics did not differ significantly in the parent cohort according to cardiovascular magnetic resonance enrollment except for mechanical circulatory support. LGE was noted only in 2 women (5%) at baseline. While left ventricular dysfunction with enlargement was prevalent at baseline cardiovascular magnetic resonance scans (eg, ejection fraction 38% [Q1–Q3 31–50%], end diastolic volume index=108 mL/m2 [Q1–Q3 83–134 mL/m2]), most women demonstrated significant improvements at 6 months, consistent with a low prevalence of LGE. LGE was not related to baseline clinical variables, ejection fraction, New York Heart Association heart failure class, or mortality. Neither of the 2 women who died exhibited LGE. LGE was inversely associated with persistent left ventricular ejection fraction at 6 months (P=0.006).ConclusionsFactors other than focal myocardial damage detectable by LGE explain the initial transient depressions in baseline left ventricular ejection fraction, yet focal myocardial damage may contribute to persistent myocardial dysfunction and hinder recovery in a small minority. Most women exhibit favorable changes in ventricular function over 6 months.Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique identifier: NCT01085955.

009 The effect of cardiac magnetic resonance on human circulating leukocytes

Aims Investigators have proposed that cardiovascular magnetic resonance (CMR) should have restrictions similar to those of ionising imaging techniques due to proposed alterations to leukocytes. We aimed to investigate the acute effect of CMR on leukocyte DNA integrity and cell viability in vitro, and in a large cohort of patients in vivo. Methods and results In vitro study: Peripheral blood mononuclear cells (PBMC) were isolated from healthy volunteers and assessed: 1) immediately following PBMC isolation, 2) after standing on the benchside as a temperature and time control, 3) after a standard CMR scan. Histone H2AX phosphorylation (γ-H2AX), an indicator of DNA damage, and leukocyte counts were quantified using flow cytometry. In vivo study: Blood samples were taken from 64 consecutive consenting patients immediately before and after a standard clinical scan. Samples were analysed for T cell count and γ-H2AX expression. CMR scanning was associated with a significant increase in leukocyte γ-H2AX expression, indicating DNA damage occurs. We also observed a trend towards a significant decrease in absolute leukocyte numbers in vitro following CMR. CMR was not associated with a significant change in γ-H2AX expression in vivo, although there were significant inter-patient variations. There was a significant reduction in circulating T cells following CMR. Conclusion CMR was not associated with DNA damage in vivo. γ-H2AX expression varied markedly between individuals, therefore small studies using γ-H2AX as a marker of DNA damage should be interpreted with caution. CMR was associated with a statistically significant reduction in viable leukocytes, although the clinical relevance of the magnitude is unclear. Further work is warranted to contextualise these findings and delineate their impact.

Prediction of cardiac complications for thalassemia major in the widespread cardiac magnetic resonance era: a prospective multicentre study by a multi-parametric approach.

Cardiovascular magnetic resonance (CMR) has dramatically changed the clinical practice in thalassemia major (TM), lowering cardiac complications. We prospectively reassessed the predictive value of CMR parameters for heart failure (HF) and arrhythmias in TM. We considered 481 white TM patients (29.48 ± 8.93 years, 263 females) enrolled in the Myocardial Iron Overload in Thalassemia (MIOT) network. Myocardial and liver iron overload were measured by T2* multiecho technique. Atrial dimensions and biventricular function were quantified by cine images. Late gadolinium enhancement images were acquired to detect myocardial fibrosis. Mean follow-up was 57.91 ± 18.23 months. After the first CMR scan 69.6% of the patients changed chelation regimen. We recorded 18 episodes of HF. In the multivariate analysis the independent predictive factors were myocardial fibrosis (HR = 10.94, 95% CI = 3.28-36.43, P < 0.0001), homogeneous MIO (compared with no MIO) (HR = 5.56, 95% CI = 1.37-22.51, P = 0.016), ventricular dysfunction (HR = 4.33, 95% CI = 1.39-13.43, P = 0.011). Arrhythmias occurred in 16 patients. Among the CMR parameters only the atrial dilation was identified as univariate prognosticator (HR = 4.26 95% CI=1.54-11.75, P = 0.005). CMR guided the change of chelation therapy in nearly 70% of patients, leading to a lower risk of iron-mediated HF and of arrhythmias than previously reported. Homogeneous MIO remained a risk factor for HF but also myocardial fibrosis and ventricular dysfunction identified patients at high risk. Arrhythmias were independent of MIO but increased with atrial dilatation. CMR by a multi-parametric approach dramatically improves cardiac outcomes and provides prognostic information beyond cardiac iron estimation.

Value of Cardiac Magnetic Resonance Imaging in Fabry Disease

&lt;p&gt;&lt;strong&gt;Abstract&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Background: &lt;/strong&gt;Cardiovascular magnetic resonance (CMR) can measure cardiac structure, function and characterize myocardial tissue. The full potential of CMR for Fabry disease (FD) is yet to be defined. The objective of the present work was to assess the clinical utility of CMR for the detection and classification of cardiac involvement in patients with FD.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods:&lt;/strong&gt; This is retrospective observational study of CMR scans performed in 99 unique FD patients from 2 hospitals in Argentina between April 2005 and October 2013. Diagnosis of FD was confirmed by measurement of alpha galactosidase A activity on plasma and peripheral leukocytes (males) or genetic testing (females).&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results:&lt;/strong&gt; Ninety nine FD patients (61 females and 38 males), mean age 35 SD 15 years, underwent CMR. Cardiac involvement was present in 56% of cases. Left ventricular hypertrophy (LVH) was present in 44% and left ventricular (LV) impairment in 8% (mean left ventricular ejection fraction 49%, range 40-54%). Late gadolinium enhancement (LGE) was present in 33% of cases and was more common with age and when LVH was present. Of the LVH patients, 59% had LGE compared to 13% without LVH (p&amp;lt;0.001).&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusion: &lt;/strong&gt;CMR is a useful diagnostic tool in detecting and classifying cardiac involvement of FD, including the detection of patients with LGE before LVH occurs.&lt;/p&gt;

Evolution of right ventricular size over time after tetralogy of Fallot repair: a longitudinal cardiac magnetic resonance study

It is commonly believed that pulmonary regurgitation (PR) after surgical repair of tetralogy of Fallot (TOF) leads to progressive right ventricular (RV) enlargement. However, progressive RV dilatation has never clearly been documented in this patient population. Therefore, we studied the size of the RV over time in patients after surgical TOF repair. Fifty-one consecutive patients after surgical TOF repair underwent at least two cardiovascular magnetic resonance (CMR) exams using a single CMR scanner. Patients with RV outflow tract obstruction, interventions other than the initial repair and CMR exams with use of sedation were excluded. Three subgroups with different repair techniques were studied: transannular patch repair [n = 22, age 17 ± 10 years], subvalvular patch repair [n = 15, age 22 ± 8 years], or non-patch repair/infundibulectomy (n = 14, age 28 ± 11 years). Right ventricular end-diastolic volume index (RVEDVI) and PR fraction did not change during the 37 ± 21 months follow-up between first and last CMR in the whole group (RVEDVI: 118 ± 23 mL/m2 vs. 119 ± 23 mL/m2, P = 0.720; PR fraction: 33% (23-40%) vs. 32% (24-39%), P = 0.268). RVEDVI remained stable in all subgroups (transannular patch: 120 ± 21 mL/m2 vs. 122 ± 22 mL/m2, subvalvular patch: 112 ± 23 mL/m2 vs. 111 ± 23 mL/m2, non-patch: 123 ± 28 mL/m2 vs. 123 ± 23 mL/m2, P = 0.827). RVEDVI at last CMR did not differ between groups (P = 0.301). This study shows no progression of RV dilatation in patients after surgical repair of TOF with moderately dilated RVs and significant PR during a 3-year follow-up. RV dilatation in our patient group seems to be independent from surgical repair techniques.

Defining left ventricular remodeling following acute ST-segment elevation myocardial infarction using cardiovascular magnetic resonance

BackgroundThe assessment of post-myocardial infarction (MI) left ventricular (LV) remodeling by cardiovascular magnetic resonance (CMR) currently uses criteria defined by echocardiography. Our aim was to provide CMR criteria for assessing LV remodeling following acute MI.MethodsFirstly, 40 reperfused ST-segment elevation myocardial infarction (STEMI) patients with paired acute (4 ± 2 days) and follow-up (5 ± 2 months) CMR scans were analyzed by 2 independent reviewers and the minimal detectable changes (MDCs) for percentage change in LV end-diastolic volume (%ΔLVEDV), LV end-systolic volume (%ΔLVESV), and LV ejection fraction (%ΔLVEF) between the acute and follow-up scans were determined. Secondly, in 146 reperfused STEMI patients, receiver operator characteristic curve analyses for predicting LVEF <50% at follow-up (as a surrogate for clinical poor clinical outcome) were undertaken to obtain cut-off values for %ΔLVEDV and %ΔLVESV.ResultsThe MDCs for %ΔLVEDV, %ΔLVESV, and %ΔLVEF were similar at 12%, 12%, 13%, respectively. The cut-off values for predicting LVEF < 50% at follow-up were 11% for %ΔLVEDV on receiver operating characteristic curve analysis (area under the curve (AUC) 0.75, 95% CI 0.6 to 0.83, sensitivity 72% specificity 70%), and 5% for %ΔLVESV (AUC 0.83, 95% CI 0.77 to 0.90, sensitivity and specificity 78%). Using cut-off MDC values (higher than the clinically important cut-off values) of 12% for both %ΔLVEDV and %ΔLVESV, 4 main patterns of LV remodeling were identified in our cohort: reverse LV remodeling (LVEF predominantly improved); no LV remodeling (LVEF predominantly unchanged); adverse LV remodeling with compensation (LVEF predominantly improved); and adverse LV remodeling (LVEF unchanged or worsened).ConclusionsThe MDCs for %ΔLVEDV and %ΔLVESV between the acute and follow-up CMR scans of 12% each may be used to define adverse or reverse LV remodeling post-STEMI. The MDC for %ΔLVEF of 13%, relative to baseline, provides the minimal effect size required for investigating treatments aimed at improving LVEF following acute STEMI.

Impact of microvascular obstruction on semiautomated techniques for quantifying acute and chronic myocardial infarction by cardiovascular magnetic resonance

AimsThe four most promising semiautomated techniques (5-SD, 6-SD, Otsu and the full width half maximum (FWHM)) were compared in paired acute and follow-up cardiovascular magnetic resonance (CMR), taking into account...

Right ventricular function following surgical aortic valve replacement and transcatheter aortic valve implantation: A cardiovascular MR study

ObjectiveThe response of the RV following treatment of aortic stenosis is poorly defined, reflecting the challenge of accurate RV assessment. Cardiovascular magnetic resonance (CMR) is the established reference for imaging of RV volumes, mass and function. We sought to define the impact of transcatheter aortic valve implantation (TAVI) and surgical aortic valve replacement (SAVR) upon RV function in patients treated for severe aortic stenosis using CMR. MethodsA 1.5T CMR scan was performed preoperatively and 6months postoperatively in 112 (56 TAVI, 56 SAVR; 76±8years) high-risk severe symptomatic aortic stenosis patients across two UK cardiothoracic centres. ResultsTAVI patients were older (80.4±6.7 vs. 72.8±7.2years, p<0.05) with a higher STS score (2.13±0.73 vs. 5.54±3.41%, p<0.001). At 6months, SAVR was associated with a significant increase in RV end systolic volume (33±10 vs. 37±10ml/m2, p=0.008), and decrease in RV ejection fraction (58±8 vs. 53±8%, p=0.005) and tricuspid annular plane systolic excursion (22±5 vs. 14±3mm, p<0.001). Only 4 (7%) SAVR patients had new RV late gadolinium hyper-enhancement with no new cases seen in the TAVI patients at 6months. Longer surgical cross-clamp time was the only predictor of increased RV end systolic volume at 6months. Post-TAVI, there was no observed change in RV volumes or function. Over a maximum 6.3year follow-up, 18(32%) of TAVI patients and 1(1.7%) of SAVR patients had died (p=0.001). On multivariable Cox analysis, the RV mass at 6m post-TAVI was independently associated with all-cause mortality (HR 1.359, 95% CI 1.108–1.666, p=0.003). ConclusionsSAVR results in a deterioration in RV systolic volumes and function associated with longer cross-clamp times and is not fully explained by suboptimal RV protection during cardiopulmonary bypass. TAVI had no adverse impact upon RV volumes or function.

Determination of Clinical Outcome in Mitral Regurgitation With Cardiovascular Magnetic Resonance Quantification

Surgery for severe mitral regurgitation is indicated if symptoms or left ventricular dilation or dysfunction occur. However, prognosis is already reduced by this stage, and earlier surgery on asymptomatic patients has been advocated if valve repair is likely, but identifying suitable patients for early surgery is difficult. Quantifying the regurgitation may help, but evidence for its link with outcome is limited. Cardiovascular magnetic resonance (CMR) can accurately quantify mitral regurgitation, and we examined whether this was associated with the future need for surgery. One hundred nine asymptomatic patients with echocardiographic moderate or severe mitral regurgitation had baseline CMR scans and were followed up for up to 8 years (mean, 2.5±1.9 years). CMR quantification accurately identified patients who progressed to symptoms or other indications for surgery: 91% of subjects with regurgitant volume ≤55 mL survived to 5 years without surgery compared with only 21% with regurgitant volume >55 mL (P<0.0001). A similar separation was observed for regurgitant fraction ≤40% and >40%. CMR-derived end-diastolic volume index showed a weaker association with outcome (proportions surviving without surgery at 5 years, 90% for left ventricular end-diastolic volume index <100 mL/m(2) versus 48% for ≥100 mL/m(2)) and added little to the discriminatory power of regurgitant fraction/volume alone. CMR quantification of mitral regurgitation was associated with the development of symptoms or other indications for surgery and showed better discriminatory ability than the reference-standard CMR-derived ventricular volumes. CMR may be able to identify appropriate patients for early surgery, with the potential to change clinical practice, although the clinical benefits of early surgery require confirmation in a clinical trial.