Late Enhancement MR Imaging Research Articles

Non-invasive Determination of Myocardial Lipid Content in Fabry Disease by 1H-MR Spectroscopy

In Fabry disease (FD), a progressive deposition of sphingolipids is reported in different organs. The present study applied 1H magnetic resonance spectroscopy (MRS) to investigate the myocardial lipid content in FD. In patients (PTS, n = 15) with genetically proven FD, 1H MRS of the heart was acquired in the same examination as routine cardiac cine and late enhancement MR imaging. Healthy volunteers (n = 11) without history of cardiac disease served as control (CTL). Myocardial triglycerides in vivo were quantified in 1H MRS. Left ventricular (LV) ejection fraction (EF) and late enhancement were assessed for the determination of LV systolic function, and onset or absence of myocardial fibrosis. All 1H MRS revealed resonances for intramyocardial triglycerides. Clinical parameters, e.g. EF (PTS 64 ± 2 % vs. CTL 61 ± 1 %) were similar in PTS and CTL or showed a non-significant trend (LV mass). Apart from a single patient with elevated myocardial triglycerides, no significant impact of Fabry disease on the triglyceride/water resonance ratio (PTS 0.47 ± 0.11 vs. CTL 0.52 ± 0.11 %) was observed in our patient cohort. A comprehensive cardiac evaluation of morphology, function as well as metabolism in Fabry PTS with suspected cardiac involvement is feasible in a single examination. No significant effect of myocardial triglyceride deposition could be observed in patients. The remarkably high myocardial triglyceride content in one patient with advanced FD warrants further studies in PTS with an extended history of the disease.

Estimation of tissue contractility from cardiac cine-MRI using a biomechanical heart model

The objective of this paper is to propose and assess an estimation procedure-based on data assimilation principles-well suited to obtain some regional values of key biophysical parameters in a beating heart model, using actual Cine-MR images. The motivation is twofold: (1) to provide an automatic tool for personalizing the characteristics of a cardiac model in order to achieve predictivity in patient-specific modeling and (2) to obtain some useful information for diagnosis purposes in the estimated quantities themselves. In order to assess the global methodology, we specifically devised an animal experiment in which a controlled infarct was produced and data acquired before and after infarction, with an estimation of regional tissue contractility-a key parameter directly affected by the pathology-performed for every measured stage. After performing a preliminary assessment of our proposed methodology using synthetic data, we then demonstrate a full-scale application by first estimating contractility values associated with 6 regions based on the AHA subdivision, before running a more detailed estimation using the actual AHA segments. The estimation results are assessed by comparison with the medical knowledge of the specific infarct, and with late enhancement MR images. We discuss their accuracy at the various subdivision levels, in the light of the inherent modeling limitations and of the intrinsic information contents featured in the data.

Abstract 4305: Long-term Follow-up Of Left Ventricular Function After Acute Myocardial Infarction Treated With Intracoronary Injection Of Autologous Bone Marrow Cells. The ASTAMI Study

Background: Long-term effects of cardiac autologous cell therapy are not well known. We performed a 3 year follow-up of the ASTAMI study. Patients with acute ST-elevation anterior wall myocardial infarctions were initially randomized to either intracoronary injection of autologous mononuclear bone marrow cells (mBMCs) (n=50) or control (n=50). At 6 months, LV ejection fraction improved in both groups, with no significant difference between groups. Methods: All eligible patients underwent MRI with a 1,5 T scanner (Siemens) 2–3 weeks, 6 months and mean(SD) 3,2 (0,2) years after myocardial infarction and stem cell injection. Infarct size was determined from gadolinium late-enhancement MR images. All images were analyzed by experienced observers blinded for treatment assignment. Left ventricular volumes were calculated by the area-length method. Results: There was no significant difference in EDV, ESV or LVEF between baseline and 3 years in neither group. Infarction volume was reduced at 3 years in both groups (p<0,001). No significant effects of mBMC treatment could be identified on LV volumes, LVEF or infarct size. Thus intracoronary injection of mBMCs in acute myocardial infarction does not improve global LV function over a 3 year follow-up. Left ventricular function after mBMC-treatment

Assessment of Myocardial Viability by Late Enhancement MR Imaging at 3.0 Tesla versus 1.5 Tesla

Purpose: In patients suffering from coronary artery disease, determination of myocardial viability by late enhancement (LE) MR imaging (MRI) is of increasing relevance. Despite good results at 1.5T, imaging at 3.0T should provide a significant improvement in contrast (CNR) and signal (SNR) to noise ratio. Aim of this study was to investigate SNR, CNR and image quality of LE-MRI at 3.0T in comparison to 1.5T.