Lowell Chang

Multimodal imaging of a mitral paravalvular abscess

A 63-year-old woman who presented with a 2-week history of fever and fatigue was found to have persistent group B β-hemolytic streptococcal bacteremia. A transesophageal echocardiogram (TEE) showed a mobile mass adhering to the mitral valve (MV). Two- and 3-dimensional TEE revealed a large echodense structure in the left atrium, adhering to the intra-atrial septum and posterior MV leaflet, along with a retrocardiac mass (Fig. 1). The patient was referred for cardiac magnetic resonance imaging. Steady-state free-precession images with T1 weighting showed a thickened posterior MV leaflet with vegetation, severe mitral regurgitation, and a myocardial mass involving the basal inferior wall of the left ventricle (LV) (Fig. 2). Dynamic first-pass perfusion images revealed a hypoperfused mass with no enhancement when compared with normal myocardium (Fig. 3A). Double-inversion-recovery (DIR) images with T1 weighting revealed mild heterogeneity of the mass (Fig. 3B). Pre- and post-contrast DIR and late-gadolinium-enhanced images with T1 weighting showed substantial peripheral enhancement with central hypointensity (Fig. 3C and Fig. 3D). The diagnosis was mitral paravalvular abscess (PA). The patient underwent debridement of the large abscess, along with MV replacement and reconstruction of the MV annulus and portions of the left atrial and LV wall with bovine pericardial patch. Fig. 1 A) Two- and B) 3-dimensional transesophageal echocardiograms show vegetation on the posterior mitral valve leaflet (arrows) and reveal a retrocardiac mass (arrowhead). Fig. 2 Steady-state free-precession magnetic resonance images in A) vertical long-axis and B) short-axis views show a mitral paravalvular mass (arrows). Fig. 3 Cardiac magnetic resonance reveals the mitral paravalvular abscess (arrows) by means of A) dynamic perfusion, B) pre- and C) post-contrast T1-weighted double-inversion recovery, and D) delayed enhancement modes.

A NOVEL UNGATED CARDIAC MAGNETIC RESONANCE PERFUSION PROTOCOL FOR THE DETECTION OF SIGNIFICANT SINGLE AND MULTIVESSEL CORONARY DISEASE IN PATIENTS WITH ATRIAL FIBRILLATION

Cardiovascular magnetic resonance (CMR) myocardial perfusion detection of significant obstructive coronary disease (CAD) is well established. With concerns of ECG-gating in arrhythmia and true-rest after regadenoson, we investigated the diagnostic accuracy and discrimination of a rapid rest-first

Incidental MRI findings of left ventricular myocardial scar in atrial fibrillation patients is associated with increased stroke risk

Background Left ventricular late gadolinium enhancement (LV-LGE) is a known incidental cardiac magnetic resonance (CMR) finding in atrial fibrillation (AF) patients and has recently been associated with increased mortality [1]. While LV-LGE is an indicator of poor prognosis in patients with cardiomyopathy, data on the clinical significance of incidental findings of LV-LGE in AF patients is still unavailable. We aimed to evaluate the association of this incidental finding to ischemic stroke in atrial fibrillation.

Initial results of a new very rapid rest/regadenoson stress myocardial perfusion protocol in patients with atrial fibrillation

Background Cardiovascular magnetic resonance (CMR) myocardial perfusion is a well established method for detection of significant obstructive coronary artery disease (CAD). In patients with arrhythmias, standard methods using ECGgating can result in poor image quality. Additionally, with typical stress/rest protocols, a true rest state may not be achieved after administration of regadenoson. However, rest-first may present issues with peri-infarct ischemia and so here we give little time for late enhancement by keeping rest and stress perfusion scans close in time. Given these issues, the two-fold aim of this study is to evaluate the accuracy of a rapid rest-first protocol using an ungated myocardial image pulse sequence.

Multimodality imaging assessment of a rare intracardiac mass: caseous calcification of the mitral valve annulus

A 75-year-old man with a poorly defined intracardiac mass on transthoracic echocardiogram was referred for further evaluation by cardiac magnetic resonance (CMR) imaging. CMR cine ( Panel A ) and dark blood ( Panel B ) images demonstrated a large, hypointense mass involving a mitral valve (MV) annulus. Perfusion images revealed no enhancement of the mass compared with normal myocardium …

Improved left atrial imaging in atrial fibrillation patients using novel ECG-gated vs. conventional non-gated cardiac MRA

Background In patients undergoing atrial fibrillation (AF) procedures, imaging of the left atrium (LA) and pulmonary veins (PV) is important for pre-ablation planning and to identify post ablation complications. Conventional MRA protocols use first-pass, non-gated sequences that require long breathholds. Quality of non-gated MRA’s can be challenging in sick or sedated patients. We developed a novel ECGgated, respiratory navigated MRA sequence less dependent on patient compliance, which yields better clarity of LA anatomy.

Pulmonary vein stenosis detection by early cardiac magnetic resonance imaging post-atrial fibrillation ablation

Summary Identification of early post-atrial ablation MRI characteristics can help predict the development of significant chronic pulmonary stenosis. Background Pulmonary vein stenosis (PVS) is a rare complication of atrial fibrillation (AF) ablation with a rate of significant stenosis, defined as >50%, of 1.3% in a recent multicenter study. As significant morbidity is associated with PVS, detection and surveillance with non-invasive imaging is routine. In this study, we hypothesized that prediction of PVS can be determined with early MRI to identify patients at risk for this complication. Methods A single-center, retrospective, 1:1 cohort to control matched study including patients with (23) and without (23) significant PVS 3 months post-ablation (3moPA) was performed. Study groups were selected from 925 patients who underwent AF ablation and serial MRI scanning. Inclusion criteria for both groups required a full set of three MRI scans: pre-ablation (pre), 24 hours post-ablation (24hrPA), and 3moPA. MRI scanning was performed on a 1.5T or 3T Siemens magnet. Of the 925 patients, 28 were found with significant stenosis on MRA 3moPA. The final PVS study cohort included 23/ 28 patients as 5 were excluded secondary to incomplete MRI scan sets. The control group was comprised of 23 age and sex-matched patients without significant stenosis 3moPA. PV cross-sectional areas were measured at the ostial/proximal portion of the vessels by 3D MRA (Figure 1). In patients with multiple stenotic PV’s, the most stenotic vein was selected for analysis. Results Out of 925 patients, we found 3% (28/925) incidence of significant PVS 3moPA. Of the 23/28 patients in the PVS study cohort, early PV narrowings of >20% on the 24hrPA scan were found in all (23/23, 100%) compared with significantly fewer in the control group (9/23, 39%) (p 20%) on the 24hrPA MRI scan. In addition, small PV caliber on baseline imaging appears to predispose to PVS with the LIPV involved disproportionately. Overall, MRI image characteristics are useful for predicting PVS and may help determine which patients will benefit from surveillance imaging.