Weinsaft_Cardiology_book_temp 26/10/2009 12:24 Page 27
Imaging
Cardiac Imaging for Assessment of Left Ventricular Thrombus
Jason S Chinitz, MD,
1
Dorinna D Mendoza, MD,
1
Raymond J Kim, MD
2
and Jonathan W Weinsaft, MD
1
1. Greenberg Cardiology Division, Department of Medicine, Weill Cornell Medical College; 2. Duke Cardiovascular Magnetic Resonance Center
Abstract
Accurate detection of left ventricular (LV) thrombus is important, as thrombus provides a substrate for thromboembolic events and a rationale
for anticoagulation. Non-contrast echocardiography (echo) detects LV thrombus based on anatomical appearance. This approach can be
straightforward when thrombus is large in size and protuberant in shape, but challenging when thrombus is small or mural. While thrombi can
vary in size and shape, it can be intrinsically defined based on avascular tissue composition. Contrast-enhanced imaging can be used to
facilitate anatomical and tissue characterization approaches for thrombus detection. Contrast echo, which identifies thrombus based on
anatomical appearance, provides improved thrombus detection versus non-contrast echo. Both perfusion echo and delayed-enhancement
magnetic resonance imaging (MRI) assess thrombus based on tissue characteristics and improve diagnostic performance compared with MRI
or echo approaches that assess thrombus based on anatomical appearance. Tissue characterization is particularly advantageous for detection
of small or mural thrombus. This article reviews the role of cardiac imaging for LV thrombus, with a focus on recent advances in thrombus
detection as provided by contrast-enhanced imaging.
Keywords
Left ventricular thrombus, echocardiography, magnetic resonance imaging, contrast
Disclosure: Jonathan W Weinsaft, MD, is the recipient of a research grant from Lantheus Medical Imaging (echo contrast manufacturer). The remaining authors have no conflicts of
interest to declare.
Received: August 27, 2009 Accepted: September 22, 2009
Correspondence: Jonathan W Weinsaft, MD, Assistant Professor of Medicine, Greenberg Division of Cardiology, Weill Medical College of Cornell University, 525 East 68th Street,
Starr-4, New York, NY 10021. E: jww2001@med.cornell.edu
Accurate detection of left ventricular (LV) thrombus affects clinical thrombus based on tissue characteristics. Each of these contrast-
outcomes and therapeutic management, as thrombus provides a enhanced imaging approaches has been shown to provide incremental
substrate for thromboembolic events and a rationale for value over non-contrast echo for detection of LV thrombus.
anticoagulation. Relative risk (RR) for thrombus development is highest
among subjects with systolic heart failure or myocardial infarction (MI), This article reviews the role of cardiac imaging for LV thrombus, with a
reflecting a link between impaired LV blood stasis, pro-coagulant focus on recent improvements in thrombus detection as provided by
mediators, and thrombosis. As the prevalence of heart failure and contrast-enhanced imaging.
coronary artery disease (CAD) continues to increase, the clinical
importance of accurate diagnostic imaging for thrombus is heightened. Definition of Left Ventricular Thrombus
Anatomical Criteria
Non-contrast echocardiography (echo) is widely used to detect thrombus Thrombus has traditionally been identified based on its anatomical
based on its anatomical appearance. This imaging approach is effective appearance (see Figure 1A). Echo studies have generally defined
when thrombus is large in size or protuberant (intracavitary) in shape, but thrombus as a mass within the LV cavity with margins distinct from
can be challenging when thrombus is small or flat (mural). Recent studies ventricular endocardium and distinguishable from papillary muscles,
have reported that up to two-thirds of LV thrombi can be missed by chordae, trabeculations, or technical artifacts.
5,6
Additional features,
routine non-contrast echo, with mural or small thrombi least likely to be such as pattern of mobility,
7
size,
8
and associated ventricular wall motion
detected.
1–4
These limitations have spurred the use of contrast-enhanced abnormalities,
9–13
have each been used as adjuvant diagnostic criteria
imaging for improved thrombus detection. Two major imaging for thrombus. However, definition of thrombus based on anatomical
approaches have been used for this purpose: contrast can be used to appearance or functional criteria has several potential pitfalls. First,
opacify the LV cavity and thereby facilitate detection of thrombus based technical artifacts, such as ‘near field’ artifacts on echo imaging, can
on anatomical appearance; alternatively, contrast can be used to identify mimic thrombus and obscure assessment of the LV cavity. Second, other
© TOUCH BRIEFINGS 2009 27