Comparison of Magnetic Resonance Imaging and Transesophageal Echocardiography in Detection of Thrombus in the Left Atrial Appendage

Abstract

Background and Purpose-A noninvasive technique of visualizing the left atrial appendage (LAA) and its thrombus in patients with atrial fibrillation would be of great interest. This study examined the utility of MRI for the assessment of thrombus in the LAA. Methods-We evaluated 50 subjects with nonrheumatic continuous atrial fibrillation and a history of cardioembolic stroke.Each patient received an MRI and a transesophageal echocardiography (TEE) on the same day for thrombus detection in the LAA. Both double-and triple-inversion recovery sequences were used for the MRI evaluations. Results-In all subjects, the LAA was readily visualized with MRI. High-intensity masses in the LAA were clearly distinguishable from the LAA wall in the triple-inversion recovery sequences. Concordance between detection of high-intensity mass with MRI and thrombus with TEE was high: no mass (MRI), no thrombus (TEE), 31 patients; mass (MRI), thrombus (TEE), 16 patients; and mass (MRI), no thrombus (TEE), 3 patients (overall ϭ0.876, SEϭ0.068). Conclusions-MRI

The Role of CMR Imaging for the Differential Diagnosis of Right-Sided Intracardiac Masses: A Case Report

“…The CMR can not replace the TTE or TEE in cases while the patient has undergone the implantation of CMR incompatible metallic devices, such as heart pacemaker or pacing wires. Moreover, the claustrophobia or obesity may technically limit the ability to apply this diagnostic procedure [29]. What is more, the safety issues, related to underlying renal function, have to be concerned prior to administration of gadolinium contrast agent.…”

Velocity encoded cardiovascular magnetic resonance to assess left atrial appendage emptying

“…Considering the well established association between reduced LAA emptying velocities and thrombus formation in the LAA, VENC-CMR could be an attractive adjunctive non-invasive tool in this context [1,2]. A comprehensive CMR protocol including measurements of LA fibrosis, LAA dimensions and passive LAA emptying velocities could potentially improve risk stratification in patients with AF [8-11]. Furthermore, Donal et al reported a high specificity of e-wave velocities by TEE during AF to predict recovery of active LAA emptying after AF ablation [19].…”

“…Such a protocol could incorporate information on LA dimensions and function, LAA emptying, LA fibrosis as well as on aortic plaque morphology and flow characteristics to improve current risk stratification for stroke [8-13]. Second, VENC-CMR LAA flow measurements could be combined with MR angiographies of the LA and pulmonary veins that are frequently performed in clinical routine before AF ablation procedures [25].…”

“…Cardiovascular magnetic resonance (CMR) offers unique features in patients at risk for stroke: Apart from the ability to detect LAA thrombi and to measure LAA dimensions, LA fibrosis quantified by Late Gadolinium Enhancement (LGE) CMR was recently proposed as a novel marker for high-risk patients [8-11]. Furthermore, plaques with retrograde flow in the descending aorta can be assessed by CMR as a potential non-cardiac source for cerebral embolism [12,13].…”

The Role of Multimodality Cardiac Imaging in the Management of Patients with Atrial Fibrillation

“…On the basis of their study, Ohyama et al [45] reported that CMR correctly identified all 16 patients with thrombi on TEE, but also produced three false-positive results among 50 patients (negative predictive value, 100%; positive predictive value, 84%), with an overall agreement of K=0.88. However, identification of spontaneous echo contrast was suboptimal.…”