Late gadolinium enhancement cardiovascular MR for the Detection of Pre-Existent L

描述（由申请人提供）：心房颤动（AF）是一种常见的心律失常，影响近1%的美国人口。通过活组织检查、尸检分析和电生理测试，在房颤患者中发现左心房（LA）纤维化。然而，纤维化的作用尚不清楚-它是房颤的前兆，维持房颤，还是房颤的结果。心血管磁共振（CMR）能够使用晚期钆增强（LGE）技术以无与伦比的精度识别疤痕。然而，薄的心肌LA壁对识别疤痕提出了挑战，特别是对于没有窦性心律的患者。本方案旨在改进LGE方法检测预先存在的疤痕。首先，利用32元相控阵心脏线圈提高信噪比，提高LGE CMR方法的空间分辨率。图像边缘增强将减少在LGE图像，使用新的脉冲序列修改，以保持必要的脂肪抑制。注射造影剂后疤痕增强的时间研究将区分疤痕和图像伪影。许多房颤患者不处于窦性心律。我们提出了一种减少由RR可变性引起的伪影的方法。使用这种LGE CMR方法，我们将在接受导管消融、微创手术或药物治疗之前对对照受试者和患者进行研究。治疗前检测到的疤痕将与临床结果相关。它也将与其他检测疤痕的方法相关——导管消融患者的左心房电图，以及手术患者的组织学分析。本提案将建立LGE CMR作为检测房颤患者先前存在的纤维化的方法。

DESCRIPTION (provided by applicant): Atrial fibrillation (AF) is a common arrhythmia, affecting almost 1% of the US population. Left atrial (LA) fibrosis has been identified in patients with AF, using biopsies, post-mortem analysis, and electrophysiological testing. However, the role of fibrosis is not known-whether it is a precursor to AF, maintains AF, or is a result of AF. Cardiovascular magnetic resonance (CMR) is capable of identifying scar with unparalleled precision, using the late gadolinium enhancement (LGE) technique. However, the thin myocardial LA wall presents challenges to identifying scar, especially for patients not in sinus rhythm. This proposal aims to improve the LGE method for detecting pre-existent scar. Firstly, the spatial resolution of LGE CMR method will be increased using increased SNR from a 32-element phased array cardiac coil. Image edge- enhancement will be reduced in the LGE images, using novel pulse sequence modifications to maintain necessary fat-suppression. A time-study of scar enhancement after injection of contrast agent will discriminate between scar and image artifacts. Many AF patients are not in sinus-rhythm. We propose a method for reducing artifacts due to RR variability. Using this LGE CMR method, we will study control subjects and patients prior to undergoing treatment either by catheter ablation, minimally invasive surgery, or drug therapy. The scar detected prior to therapy will be correlated with clinical outcomes. It will also be correlated with other methods for detecting scar--electrical mapping of the left atrium in patients undergoing catheter ablation, and histological analysis in patients undergoing surgery. This proposal will establish LGE CMR as method for detecting pre- existent fibrosis in AF patients. PUBLIC HEALTH RELEVANCE: Atrial fibrillation (AF) is a common arrhythmia. Some patients with AF have scar in their left atium, resulting from AF, or possibly causing AF. Cardiovascular magnetic resonance (CMR) is capable of identifying scar with unparalleled precision. However, the left atrial wall is a thin myocardial structure, presenting challenges to identifying scar. Furthermore, AF patients often have arrhythmias, which reduce image quality. We propose improving the CMR method for detecting scar in AF patients. Using this CMR scar method, we will study patients prior to undergoing treatment either by catheter ablation, minimally invasive surgery procedures, or drug therapy. The scar detected prior to therapy will be correlated with the later success of the therapy. It will also be correlated with other methods for detecting scar--electrical mapping of the left atrium and histological analysis in patients undergoing surgery. This study will result in a non- invasive method for identifying left atrial scar by CMR.