insights on the right ventricle. A cardiovascular magnetic resonance study

OBJECTIVES Pectus excavatum (PE) is often regarded as a cosmetic disease, while its effect on cardiac function is under debate. Data regarding cardiac function before and after surgical correction of PE are limited. We aimed to assess the impact of surgical correction of PE on cardiac function by cardiovascular magnetic resonance (CMR). METHODS CMR at 1.5 T was performed in 38 patients (mean age 21 ± 8.3; 31 men) before and after surgical correction to evaluate thoracic morphology, indices and its relation to three-dimensional left and right ventricular cardiac function. RESULTS Surgery was successful in all patients as shown by the Haller Index ratio of maximum transverse diameter of the chest wall and minimum sternovertebral distance [pre: 9.64 (95% CI 8.18–11.11) vs post: 3.0 (2.84–3.16), P < 0.0001]. Right ventricular ejection fraction (RVEF) was reduced before surgery and improved significantly at the 1-year follow-up [pre: 45.7% (43.9–47.4%) vs 48.3% (46.9–49.5%), P = 0.0004]. Left ventricular ejection fraction was normal before surgery, but showed a further improvement after 1 year [pre: 61.0% (59.3–62.7%) vs 62.7% (61.3–64.2%), P = 0.0165]. Cardiac compression and the asymmetry index changed directly after surgery and were stable at the 1-year follow-up [3.93 (3.53–4.33) vs 2.08 (1.98–2.19) and 2.36 (2.12–2.59) vs 1.38 (1.33–1.44), respectively; P < 0.0001 for both]. None of the obtained thoracic indices were predictors of the improvement of cardiac function. A reduced preoperative RVEF was predictive of RVEF improvement. CONCLUSIONS PE is associated with reduced RVEF, which improves after surgical correction. CMR has the capability of offering additional information prior to surgical correction

Effects of heart valve prostheses on phase contrast flow measurements in Cardiovascular Magnetic Resonance - a phantom study

Background: Cardiovascular Magnetic Resonance is often used to evaluate patients after heart valve replacement. This study systematically analyses the influence of heart valve prostheses on phase contrast measurements in a phantom trial. Methods: Two biological and one mechanical aortic valve prostheses were integrated in a flow phantom. B-0 maps and phase contrast measurements were acquired at a 1.5 T MR scanner using conventional gradient-echo sequences in predefined distances to the prostheses. Results were compared to measurements with a synthetic metal-free aortic valve. Results: The flow results at the level of the prosthesis differed significantly from the reference flow acquired before the level of the prosthesis. The maximum flow miscalculation was 154 ml/s for one of the biological prostheses and 140 ml/s for the mechanical prosthesis. Measurements with the synthetic aortic valve did not show significant deviations. Flow values measured approximately 20 mm distal to the level of the prosthesis agreed with the reference flow for all tested all prostheses. Conclusions: The tested heart valve prostheses lead to a significant deviation of the measured flow rates compared to a reference. A distance of 20 mm was effective in our setting to avoid this influence

Application of cardiac magnetic resonance imaging for the detection of cardiac alterations in obesity

Einleitung Die Entwicklung der vergangenen Jahre zeigt, dass der Anteil an Menschen mit Übergewicht oder Adipositas zunimmt und zukünftig zunehmen wird. In der letzen Zeit wurde viel über die endokrinen und metabolischen Eigenschaften des Fettgewebes bekannt. Dieses nimmt sowohl indirekt durch Inflammation und Verminderung der Insulinsensitivität als auch direkt durch Freisetzung freier Fettsäuren Einfluss auf den myokardialen Stoffwechsel. Zusammen mit der durch die größere Körpermasse hervorgerufenen Volumenbelastung ist das Herz adipöser Menschen einem hohen Risiko für myokardiales Remodelling ausgesetzt. Während im späteren Verlauf exzentrische Hypertrophie und Herzinsuffizienz als Komplikationen drohen, verändert das Myokard im Frühstadium seine mechanischen Eigenschaften durch Hypertrophie und Fibrose. Zunächst ist die frühdiastolische energieabhängige aktive Relaxation des Myokards gestört, später sinkt die Compliance. Es resultiert eine diastolische Dysfunktion. Einen solchen Verlauf frühzeitig zu erkennen und zu verhindern, dürfte von großem medizinischen und ökonomischen Interesse sein. Aufgabenstellung / Zielsetzung Ziel der Studie war es, mithilfe von Magnet- Resonanz-(MR-)Techniken die kardiale Struktur und Funktion im Kontext des metabolischen Milieus in einem Kollektiv augenscheinlich gesunder übergewichtiger und adipöser Frauen und Männer zu charakterisieren und die Auswirkungen einer kohlenhydratarmen, fettliberalisierten Diät (low-carb) gegenüber einer fettarmen, kohlenhydratliberalisierten Diät (low-fat) zu untersuchen. Methoden Es wurden 240 übergewichtige und adipöse Probanden zu einer sechsmonatigen entweder low-carb oder low-fat Diät randomisiert. Zusätzlich war ein dritter Studienarm vorgesehen, der im Rahmen einer klinischen Phase IV-Studie Rimonabant (20 mg/d) erhielt. Nach der negativen Neubewertung des Nutzen-Risikoprofils des Medikaments musste die Studie jedoch vorzeitig abgebrochen werden. Eine Verwertung der Follow- Up-Ergebnisse war daher nicht möglich. Neben laborchemischen Untersuchungen, ambulanter 24 h -Blutdruck-Messung und Spiroergometrie wurden zu Beginn und nach sechs Monaten eine MR-Tomographie und -Spektroskopie mit einem 1,5 T-MR- Scanner durchgeführt. Unter Verwendung einer Herzspule wurden mittels balancierter Steady-State-Free-Precession-Sequenz Cine-Aufnahmen des Herzens in der kurzen Achse sowie im 2-, 3-, und 4-Kammer-Blick erstellt. T1-gewichtete Turbo-Spin- und Gradienten-Echo-Sequenzen wurden zur Akquise thorakaler und abdomineller Schichtpakete genutzt. Unter Verwendung einer 1H-Single-Voxel-Spektroskopie- Sequenz wurde der relative myokardiale Triglyzerid-Gehalt (MTG) in einem 6-8 x 20 x 25 mm3 Voxel des interventrikulären Septums bestimmt. Ergebnisse Von 190 eingeschlossenen Probanden (Body-Mass-Index (BMI) 33,50 ± 4,07 kg/m2, 26,1 - 45,4 kg/m2) wurden von 93 Follow-Up-Daten erhoben. Bei den Baseline- Untersuchungen wiesen 48% der Studienteilnehmer eine Insulinresistenz auf. Zehn Probanden hatten einen hypertonen 24 h-Blutdruck. Die LV Ejektionsfraktion (EF) betrug 0,60 ± 0,05, der Cardiac Index (CI) 3,20 ± 0,52 l/min/m2, die LV Masse (LVM) 89,77 g (25% 78,64 g, 75% 105,77 g) und die maximale relative Sauerstoffaufnahme (VO2max) 22,04 ± 5,44 ml/min/kg. Die maximale frühdiastolische Füllungsrate (PFRe) ergab 555,28 ± 140,51 ml/s, PFRe/PFRa 1,42 ± 0,47, die frühdiastolische longitudinale Relaxationsgeschwindigkeit (E’) 11,26 ± 3,02 cm/s und E/E’ 7,12 ± 2,42. Es zeigte sich eine Assoziation der diastolischen Funktion zum Glukosemetabolismus, zur VO2max und zum LA Volumen (LAV). Die diastolische Funktion korrelierte negativ zum Alter. Der MTG war abhängig von VO2max. Nach der sechsmonatigen Interventionsphase konnten keine signifikanten Unterschiede in der Effektivität der Diäten festgestellt werden. Insgesamt reduzierte sich das Körpergewicht der Probanden um 7,76 ± 4,63 % (jeweils p <0,0005 zum Ausgangswert, p = ns zwischen den Diäten). Der systolische 24 h-Blutdruck (24 h-RR) verringerte sich (jeweils p <0,01 zum Ausgangswert, p = nicht signifikant (ns) zwischen den Diäten). Die EF änderte sich unter keiner der Diäten. Die LVM nahm um durchschnittlich 5,86 ± 5,63 % ab (jeweils p <0,0005 zum Ausgangswert, p = ns zwischen den Diäten). Der CI sank um 6,47 ± 16,04 % (jeweils p <0,0005 zum Ausgangswert, p = ns zwischen den Diäten). Die VO2max stieg (jeweils p <0,0005 zum Ausgangswert, p = ns zwischen den Diäten). Der Effekt der Diäten auf die Parameter der diastolischen Funktion war inkonsistent. PFRe, E’ und E/E’ sanken (jeweils p <0,005 zum Ausgangswert, p = ns zwischen den Diäten). PFRe/PFRa blieb unverändert. Der MTG nahm unter beiden Diäten um insgesamt 22,93 ± 36,21 % ab (jeweils p <0,05 zum Ausgangswert, p = ns zwischen den Diäten). Die Insulinsensitivität stieg (jeweils p <0,0005 zum Ausgangswert, p = ns zwischen den Diäten). Als unabhängige Faktoren der interventionsbedingten Änderungen der diastolischen Funktion wurden die Änderungen der Herzfrequenz (PFRe, E‘, E/E‘) und des Glukosemetabolismus (E‘, E/E‘) identifiziert. Diskussion Die identifizierten Fälle okkulter Insulinresistenz und arterieller Hypertonie weisen auf die häufige Komorbidität übergewichtiger und adipöser Menschen hin. Die Parameter der kardialen Struktur und Funktion waren insgesamt normwertig. Es wurde weiterhin gezeigt, dass sowohl low-carb als auch low-fat Diäten wirkungsvoll das Körpergewicht, die LVM und den MTG reduzieren. Der gesunkene CI in Verbindung mit dem niedrigeren systolischen 24 h-RR nach der Intervention lässt auf eine Verminderung der neurohumoralen Aktivierung schließen. Zur Erfassung der diastolischen Funktion wurde erfolgreich eine innovative magnetresonanztomographische Methode auf volumetrischer Basis verwendet. In der Anwendung zeigte sich jedoch, dass diese bedingt durch das aufwendige Post-Processing noch nicht für die klinische Routine geeignet ist. Da die Validierung noch aussteht, haben die Ergebnisse über die diastolische Funktion experimentellen Charakter. Die Wertekonstellation deutet auf eine Verbesserung dieser durch beide Diäten hin. Eine weitere Optimierung der Methoden und Bestätigung der Ergebnisse in neuen Studien sollte erfolgen. Sowohl low-carb als auch low-fat Diäten reduzieren wirksam das Körpergewicht und haben auf das kardiometabolische Milieu, den myokardialen Stoffwechsel sowie die kardiale Struktur und Funktion vorteilhafte Auswirkungen.Introduction The trend of the past few years shows that the proportion of overweight or obese people rises and in future will keep rising. Recently lots about the endocrine and metabolic effects of adipose tissue got known. It alters the myocardial metabolism indirectly via inflammatory processes and reduction of insulin sensitivity as well as directly by releasing free fatty acids. In combination with higher volume load due to greater body mass the heart of overweight or obese people is exposed to a higher risk of myocardial remodelling. In the later course this results in eccentric hypertrophy and heart failure whereas at earlier stages the intrinsic mechanical features of the myocardium is altered by hypertrophy and fibrosis. First the energy dependent active Relaxation in early diastole is impaired, later the myocardial compliance sinks. All this leads to diastolic dysfunction. To detect and prevent these developments at a reversible stage is of great medical and economic interest. Aim The goal of this study was to characterise the cardiac structure and function of obviously healthy overweight or obese women and men in the context of their metabolic milieus and to investigate the effects of a carbohydrate reduced, fat liberalised (low-carb) versus a fat reduced, carbohydrate liberalised (low-fat) diet using magnetic resonance (MR) techniques. Methods 240 overweight or obese subjects were randomised to an either six-month low-carb or low-fat diet. Additionally a third study group was intended in the setting of a phase IV-study taking Rimonabant 20mg/d. After negative risk-benefit analysis considering this drug the investigation had to be cancelled prematurely. As consequence the evaluation of the follow up data considering this subgroup was not possible. Besides laboratory studies, 24h-blood pressure measurements and spiroergometry at baseline and after six month MR tomography and spectroscopy were performed at a 1.5 T MR scanner. Using a 12 channel cardiac coil cine images of the heart in the 2, 3 and 4 chamber view were shot by a balanced steady state free precession sequence. T1 weighted turbo spin and gradient echo sequences were used to acquire thoracal and abdominal axial slices. Under involvement of a 1H single voxel spectroscopy sequence the relative myocardial triglyceride content (MTG) in a 6-8 x 20 x 25 mm3 voxel of the interventricular septum was assessed. Results Follow up data of 93 out of 190 included subjects (body mass index (BMI) 33.50 ± 4.07 kg/m2, 26.1 - 45.4 kg/m2) were recorded. At baseline 48 % of participants had insulin resistance. 10 subjects had a hypertensive 24 h blood pressure. The left ventricular (LV) ejection fraction was 0.60 ± 0.05, the cardiac index (CI) 3.20 ± 0.52 l/min/m2, LV mass (LVM) 89.77 g (25% 78.64 g, 75% 105.77 g) and peak oxygen consumption (VO2max) 22.04 ± 5.44 ml/min/kg. Peak early diastolic filling rate (PFRe) was 555.28 ± 140.51 ml/s, PFRe/PFRa 1.42 ± 0.47, early diastolic longitudinal lengthening velocity (E’) 11.26 ± 3.02 cm/s and E/E’ 7.12 ± 2.42. An association between the diastolic function and glucose metabolism, VO2max and left atrial (LA) volume was found. The diastolic function correlated negatively to age. MTG was dependent on VO2max. After the six-month intervention period no significant difference in diet efficacy could be regarded. Overall subjects lost 7.76 ± 4.63 % (p <0.0005 compared to baseline, p = not significant (ns) between groups) of body weight. The systolic 24 h blood pressure sank (p <0.01 compared to baseline, p = ns between groups). EF changed to none of the diets significantly. LVM decreased by 5.86 ± 5.63 % (p <0.0005 compared to baseline, p = ns between groups). CI got 6.47 ± 16.04 % (p <0.0005 compared to baseline, p = ns between groups) minor. VO2max rose significantly (p <0.0005 compared to baseline, p = ns between groups). The diets’ effect on parameters of diastolic function was inconsistent. PFRe, E’ and E/E’ sank (each p <0,005 compared to baseline, p = ns between groups). PFRe/PFRa remained unchanged. MTG decreased in response to both diets by 22.93 ± 36.21 % (p <0.05 compared to baseline, p = ns between groups). The insulin sensitivity grew (p <0,0005 compared to baseline, p = ns between groups). As independent variables of the intervention caused changes of the diastolic function the differences of the heart rate (PFRe, E’, E/E’) and glucose metabolism (E’, E/E’) were identified. Discussion The identified cases of occult insulin resistance and arterial hypertension show the frequent comorbidity of overweight or obese people. The parameters of cardiac structure and function were in the normal range. Additionally it was shown that both low-carb and low-fat diets effectively reduce body weight, LVM and MTG. The sunk CI in combination with the lowered systolic 24 h blood pressure allows to claim for an minor neurohumoral activation. For assessment of the diastolic function an innovative volumetry based MR method was employed. In the application however it emerged that due to the laborious post processing it is not yet suitable for clinical routine. As validation is still lacking, the results about the diastolic function have experimental character. The constellation of values indicates an improvement in consequence to both diets. A continuous optimization of methods and a confirmation of results in large multi centre trials should be performed. Both low-carb and low-fat diets effectively reduce body weight and have beneficiary effects on the cardiometabolic milieu, myocardial metabolism as well as cardiac structure and function

Quantification in cardiovascular magnetic resonance: agreement of software from three different vendors on assessment of left ventricular function, 2D flow and parametric mapping

Abstract Background Quantitative results of cardiovascular magnetic resonance (CMR) image analysis influence clinical decision making. Image analysis is performed based on dedicated software. The manufacturers provide different analysis tools whose algorithms are often unknown. The aim of this study was to evaluate the impact of software on quantification of left ventricular (LV) assessment, 2D flow measurement and T1- and T2-parametric mapping. Methods Thirty-one data sets of patients who underwent a CMR Scan on 1.5 T were analyzed using three different software (Circle CVI: cvi42, Siemens Healthineers: Argus, Medis: Qmass/Qflow) by one reader blinded to former results. Cine steady state free precession short axis images were analyzed regarding LV ejection fraction (EF), end-systolic and end-diastolic volume (ESV, EDV) and LV mass. Phase-contrast magnetic resonance images were evaluated for forward stroke volume (SV) and peak velocity (Vmax). Pixel-wise generated native T1- and T2-maps were used to assess T1- and T2-time. Forty-five data sets were evaluated twice (15 per software) for intraobserver analysis. Equivalence was considered if the confidence interval of a paired assessment of two sofware was within a tolerance interval defined by ±1.96 highest standard deviation obtained by intraobserver analysis. Results For each parameter, thirty data sets could be analyzed with all three software. All three software (A/B, A/C, B/C) were considered equivalent for LV EF, EDV, ESV, mass, 2D flow SV and T2-time. Differences between software were detected in flow measurement for Vmax and in parametric mapping for T1-time. For Vmax, equivalence was given between software A and C and for T1-time equivalence was given between software B and C. Conclusion Software had no impact on quantitative results of LV assessment, T2-time and SV based on 2D flow. In contrast to that, Vmax and T1-time may be influenced by software. CMR reports should contain the name and version of the software applied for image analysis to avoid misinterpretation upon follow-up and research examinations. Trial registration ISRCTN12210850. Registered 14 July 2017, retrospectively registered

Assessment of diastolic dysfunction: comparison of different cardiovascular magnetic resonance techniques.

AIMS Heart failure with preserved ejection fraction is still a diagnostic and therapeutic challenge, and accurate non-invasive diagnosis of left ventricular (LV) diastolic dysfunction (DD) remains difficult. The current study aimed at identifying the most informative cardiovascular magnetic resonance (CMR) parameters for the assessment of LVDD. METHODS AND RESULTS We prospectively included 50 patients and classified them into three groups: with DD (DD+, n = 15), without (DD-, n = 26), and uncertain (DD±, n = 9). Diagnosis of DD was based on echocardiographic E/E', invasive LV end-diastolic pressure, and N-terminal pro-brain natriuretic peptide. CMR was performed at 1.5 T to assess LV and left atrial (LA) morphology, LV diastolic strain rate (SR) by tissue tracking and tagging, myocardial peak velocities by tissue phase mapping, and transmitral inflow profile using phase contrast techniques. Statistics were performed only on definitive DD+ and DD- (total number 41). DD+ showed enlarged LA with LA end-diastolic volume/height performing best to identify DD+ with a cut-off value of ≥0.52 mL/cm (sensitivity = 0.71, specificity = 0.84, and area under the receiver operating characteristic curve = 0.75). DD+ showed significantly reduced radial (inferolateral E peak: DD-: -14.5 ± 6.5%/s vs. DD+: -10.9 ± 5.9%/s, P = 0.04; anterolateral A peak: DD-: -4.2 ± 1.6%/s vs. DD+: -3.1 ± 1.4%/s, P = 0.04) and circumferential (inferolateral A peak: DD-: 3.8 ± 1.2%/s vs. DD+: 2.8 ± 0.8%/s, P = 0.007; anterolateral A peak: DD-: 3.5 ± 1.2%/s vs. DD+: 2.5 ± 0.8%/s, P = 0.048) SR in the basal lateral wall assessed by tissue tracking. In the same segments, DD+ showed lower peak myocardial velocity by tissue phase mapping (inferolateral radial peak: DD-: -3.6 ± 0.7 ms vs. DD+: -2.8 ± 1.0 ms, P = 0.017; anterolateral longitudinal peak: DD-: -5.0 ± 1.8 ms vs. DD+: -3.4 ± 1.4 ms, P = 0.006). Tagging revealed reduced global longitudinal SR in DD+ (DD-: 45.8 ± 12.0%/s vs. DD+: 34.8 ± 9.2%/s, P = 0.022). Global circumferential and radial SR by tissue tracking and tagging, LV morphology, and transmitral flow did not differ between DD+ and DD-. CONCLUSIONS Left atrial size and regional quantitative myocardial deformation applying CMR identified best patients with DD