Sebastian M. Haberkorn

Myocardial T2 mapping reveals age- and sex-related differences in volunteers

BackgroundT2 mapping indicates to be a sensitive method for detection of tissue oedema hidden beyond the detection limits of T2-weighted Cardiovascular Magnetic Resonance (CMR). However, due to variability of baseline T2 values in volunteers, reference values need to be defined. Therefore, the aim of the study was to investigate the effects of age and sex on quantitative T2 mapping with a turbo gradient-spin-echo (GRASE) sequence at 1.5 T. For that reason, we studied sensitivity issues as well as technical and biological effects on GRASE-derived myocardial T2 maps. Furthermore, intra- and interobserver variability were calculated using data from a large volunteer group.MethodsGRASE-derived multiecho images were analysed using dedicated software. After sequence optimization, validation and sensitivity measurements were performed in muscle phantoms ex vivo and in vivo. The optimized parameters were used to analyse CMR images of 74 volunteers of mixed sex and a wide range of age with typical prevalence of hypertension and diabetes. Myocardial T2 values were analysed globally and according to the 17 segment model. Strain-encoded (SENC) imaging was additionally performed to investigate possible effects of myocardial strain on global or segmental T2 values.ResultsEx vivo studies in muscle phantoms showed, that GRASE-derived T2 values were comparable to those acquired by a standard multiecho spinecho sequence but faster by a factor of 6. Besides that, T2 values reflected tissue water content. The in vivo measurements in volunteers revealed intra- and interobserver correlations with R2=0.91 and R2=0.94 as well as a coefficients of variation of 2.4% and 2.2%, respectively. While global T2 time significantly decreased towards the heart basis, female volunteers had significant higher T2 time irrespective of myocardial region. We found no correlation of segmental T2 values with maximal systolic, diastolic strain or heart rate. Interestingly, volunteers´ age was significantly correlated to T2 time while that was not the case for other coincident cardiovascular risk factors.ConclusionGRASE-derived T2 maps are highly reproducible. However, female sex and aging with typical prevalence of hypertension and diabetes were accompanied by increased myocardial T2 values. Thus, sex and age must be considered as influence factors when using GRASE in a diagnostic manner.

Myocardial T2 Mapping Increases Noninvasive Diagnostic Accuracy for Biopsy-Proven Myocarditis

Detection of myocardial inflammation in patients with clinically suspected acute myocarditis (sAMC) is of prognostic importance but remains a challenge in routine clinical practice [(1)][1]. Compared with endomyocardial biopsy (EMB), the diagnostic gold standard, cardiovascular magnetic resonance (

Cardiovascular Magnetic Resonance Relaxometry Predicts Regional Functional Outcome After Experimental Myocardial InfarctionCLINICAL PERSPECTIVE

Background— Cardiovascular magnetic resonance with gadolinium-based contrast agents has established as gold standard for tissue characterization after myocardial infarction (MI). Beyond accurate diagnosis, the value of cardiovascular magnetic resonance to predict the outcome after MI has yet to be substantiated. Methods and Results— Recent cardiovascular magnetic resonance approaches were systematically compared for quantification of tissue injury and functional impairment after MI using murine models with permanent left anterior descending coronary artery ligation (n=14) or 50 minutes ischemia/reperfusion (n=13). Cardiovascular magnetic resonance included native/postcontrast T1 maps, T2 maps, and late gadolinium enhancement at days 1 and 21 post-MI. For regional correlation of parametric and functional measures, the left ventricle was analyzed over 200 sectors. For T1 mapping, we used retrospective triggering with variable flip angle analysis. Sectoral analysis of native T1 maps already revealed in the acute phase after MI substantial discrepancies in myocardial tissue texture between the 2 MI models (native T1 day 1: permanent ligation, 1280.0±162.6 ms; ischemia/reperfusion, 1115.0±140.5 ms; P<0.001; n=14/13), which were later associated with differential functional outcome (left ventricular ejection fraction day 21: permanent ligation, 24.5±7.0%; ischemia/reperfusion, 33.7±11.6%; P<0.05; n=14/13). At this early time, any other parameter was indicative for the subsequent worsening of left ventricular ejection fraction in permanent ligation mice. Linear regression of acute individual measures with contractile function in corresponding areas at day 21 demonstrated for early native T1 values the best correlation with the later functional impairment (R2=0.94). Conclusions— The present T1 mapping approach permits accurate characterization of local tissue injury and holds the potential for sensitive and graduated prognosis of the functional outcome after MI without gadolinium-based contrast agents.

T2-Mapping CMR increases the diagnostic sensitivity for detection of myocardial inflammation in patients with possible myocarditis - a prospective endomyocardial biopsy-controlled study

Myocarditis has been reported in up to 20% of sudden cardiac death in young adults and is a frequent precursor of dilated cardiomyopathy. Unfortunately, the diagnostic tools for detection of myocarditis are still imperfect: Sensitivity of endomyocardial biopsy (EMB) is reduced largely due to the inherent sampling error. Cardiac magnetic resonance (CMR) offers the advantage of analysing the whole myocardium, but contrast-enhanced as well as T2weighted CMR exhibit inadequate sensitivity, especially during early stages of inflammation. Our hypothesis was that quantitative T2 relaxation mapping increases diagnostic sensitivity in CMR-based diagnosis of myocarditis. Methods We carried out a prospective observational study in patients with probable acute myocarditis characterized by clinical presentation, new global or regional wall abnormalities or arrhythmias or hsTNT-elevation. Of the 55 patients screened, two patients did not undergo CMR (1 pacemaker, 1 ECLS-support) and 16 patients refused EMB. The remaining 37 patients underwent EMB and CMR examination (1.5 T, Archieva, Philips) within 36h. Histological evaluation was performed by two independent pathologists (hematoxylin eosin staining, picrosirius red, IH CD68, CD45R0 and CD3) and by molecular analysis for viral replication/genome. CMR data were analysed blinded with respect to ventricular volumes and ejection fraction as well as T2, LGE and Strain Encoded (SENC)Imaging. A GRASE sequence (15 Echoes separated by 10ms, res: 2x2x10 mm2, 3 short axis slices) was used for localized T2 mapping. Age-matched volunteers (37) served as controls for ROC curve analysis in terms of quantitative T2-mapping. Results were compared by two-sided t-Test; p<0.05 was considered significant. Results

CMR-guidance of passively tracked endomyocardial biopsy in an in vivo porcine model

Endomyocardial biopsy (EMB) is considered to be the diagnostic gold-standard in detection of myocardial-inflammation. EMB is usually conducted under fluoroscopy without any specific target information. Specific target-information provided by cardiovascular magnetic resonance (CMR) may improve specificity of EMB. The aim was to investigate feasibility and safety of CMR-guided and targeted EMB in a preclinical-model using passively-tracked devices. Procedures were performed on a MRI-System equipped with an Interventional Software-Platform for real-time imaging. Ex vivo experiments were conducted to optimize visibility of the guide-sheath. In vivo experiments were conducted in 2 pigs for technical feasibility assessment and in 4 pigs after acute myocardial infarction to test feasibility of guided and lesion targeted EMB. For anatomical real-time imaging a single-shot-balanced-SSFP-sequence was applied. Myocardial targets were identified under real-time imaging (single-shot-T2 (sshT2) and single-shot Late-Gadolinium-Enhancement (sshLGE) sequences). Ex vivo experiments demonstrated best visibility of continuously labelled guide-sheath. CMR-guided EMB was feasible in all cases without major complications. Likewise, lesion-targeting endomyocardial biopsy was feasible in two cases. Biopsies exhibited appropriate sizes and qualities. Real-time lesion sequences revealed comparable CNR values to clinical-protocols. Real-time imaging of lesions showed following signal- and contrast-to-noise ratios (SNR/CNR): SNR of sshT2- and sshLGE was 124 ± 35 and 67 ± 51 respectively, whereas CNR was 81 ± 30 and 57 ± 44. This study demonstrates feasibility and safety of CMR-guided and basically targeted EMB with passively-tracked devices. Signal-to-noise ratios of real-time sequences is non-inferior to standard sequences for lesion detection. CMR-guidance may improve diagnostic accuracy of EMB since CMR can detect myocardial-targets under real-time-imaging.

Role of T2 mapping in left ventricular reverse remodeling after TAVR

BACKGROUND Patients with severe aortic stenosis (AS) are subjected to left ventricular hypertrophy (LVH) with increasing morbidity and mortality. Transcatheter aortic valve replacement (TAVR) induces reverse left ventricular remodeling which can be monitored by cardiovascular magnetic resonance (CMR). CMR is able to analyze myocardial tissue properties by magnetic relaxation times (parametric CMR). The objective of this study was to study myocardial T2 relaxation in reverse ventricular remodeling after TAVR. METHODS Forty-three patients with severe AS (19 males, 81.9 ± 4.9 years) underwent CMR with T2 mapping before and 6 months after TAVR. A cohort of age- and gender-matched volunteers served as controls. Analyzed parameters included left ventricular ejection fraction (LV-EF), mass indexed to body surface area (LVMi), interventricular septum thickness (IVS), end-diastolic volume (LVEDV), global longitudinal strain (GLS), peak diastolic strain rate (SRe) and myocardial T2 values. RESULTS CMR characteristics for patients with AS displayed LVH concomitant to elevated myocardial T2 values, reduced GLS and SRe. Patients with T2 values above 70.2 ms at baseline were characterized by eccentric hypertrophy with reduced LV-EF. T2 values decreased after TAVR (67.4 ± 3.4 to 63.3 ± 4.2 ms, p < 0.01) during left ventricular remodeling. Patients with T2 values above 70.2 ms at baseline exhibited pronounced reverse remodeling which proved to be a significant predictor of LV-EF improvement and LVEDV reduction in uni- and multivariate analyses. CONCLUSIONS Multiparametric CMR can be used to characterize myocardial hypertrophy due to severe AS and to monitor myocardial adaptations after TAVR. It may provide additional information in the prediction of left ventricular remodeling after TAVR.

State of the Art in Cardiovascular T2 Mapping: on the Way to a Cardiac Biomarker?

Purpose of ReviewParametric mapping fosters the role of cardiovascular magnetic resonance in its unique capability to evaluate myocardial tissue without the use of contrast agents. While there is a large body of literature highlighting the role of T1 mapping, the role of T2 mapping is less clear. This review aims to address the latest evidences for added clinical value of T2 mapping.Recent FindingsT2 mapping shows superior diagnostic accuracy in myocarditis, transplant rejection, and cardiac involvement in lupus erythematosus. Moreover, T2 values predict major adverse cardiovascular events in myocarditis and enable therapy monitoring in lupus erythematosus as well as after heart transplantation. In ischemic cardiomyopathy, T2 mapping discriminates acute from chronic injury and provides additional information for patient risk stratification.SummaryT2 mapping provides a robust, quantifiable non-contrast-enhanced myocardial biomarker. However, there is no standardization in acquisition protocols, which formulates the future need for standardization ahead of multi-center trails.

Acute regadenoson stress prefusion testing using cardiac MRI is a valuable test of high predictive value for risk stratification of COPD-patients with NSTEM

Background The diagnostic dilemma of patients suffering from chronic obstructive pulmonary disease (COPD) presenting with symptoms equivalent to an acute coronary syndrome (ACS) and slightly elevated high sensitive troponine in the observational range (hsTnT 14-53 ng/l) is complex. Prognostic impact of elevated hsTnT demand further investigation. Comorbidities of COPD and coronary artery disease are frequent, risk factors congruent. The acute setting demands a safe and easily conductible test to identify coronary problems reliably. Echocardiographic imaging quality is often low due to emphysema. Adenosine is contraindicated due to its bronchospasmic effect. The new vasodilatator regadenoson does not bear this limitation. This study aims to evaluate feasibility and prognostic power of regadenoson stress cMRI in the above described population.

MRI relaxation parameters predict functional outcome after experimental myocardial infarction

Background Characterization of infarcted myocardial tissue by current cardiovascular magnetic resonance (CMR) methods is predominantly carried out after i.v. application of Gadolinium (Gd)-based contrast agents (CA). However, recent advances in CMR enable the acquisition of parametric maps making use of endogenous tissue properties for diagnostic purposes, which may supersede the need for injection of CA. In the present study, we systematically compared myocardial tissue characterization by Gd-based techniques with intrinsic T1/T2 mapping and their correlation with local cardiac function after experimental myocardial infarction (MI).

Primary cardiac sarcoma: a rare disease with rapid progression

A 70-year-old male patient was admitted to our hospital with progressive dyspnoea. Besides an intermediate risk for coronary artery disease, the patient showed Troponin T (TnT) levels of 45 pg/mL. According to guidelines, we performed a coronary angiography. Panel 1A shows the coronary angiogram of the left coronary artery with mild arteriosclerosis (arrow and arrowhead) without indication for coronary intervention. Surprisingly, the following echocardiography identified a 6 × 5 cm structure in front of the right ventricle. With a patient history of melanoma the suspect …