Cardiac Magnetic Resonance for the Evaluation of Suspected Cardiac Thrombus: Conventional and Emerging Techniques

Summary

The goal of this article is to describe how cardiac magnetic resonance can be used for the evaluation and diagnosis of a suspected cardiac thrombus. The method presented will describe data acquisition as well as the pre-procedure and post-procedure protocol.

Abstract

We present the conventional cardiac magnetic resonance (CMR) protocol for evaluating a suspected thrombus and highlight emerging techniques. The appearance of a mass on certain magnetic resonance (MR) sequences can help differentiate a thrombus from competing diagnoses such as a tumor. T1 and T2 signal characteristics of a thrombus are related to the evolution of hemoglobin properties. A thrombus typically does not enhance following contrast administration, which also helps differentiation from a tumor. We also highlight the emerging role of T1 mapping in the evaluation of a thrombus, which can add another level of support in diagnosis. Prior to any CMR exam, patient screening and interviews are critical to ensure safety and to optimize patient comfort. Effective communication during the exam between the technologist and the patient promotes proper breath holding technique and higher quality images. Volumetric post processing and structured reporting are helpful to ensure that the radiologist answers the ordering services' question and communicates these results effectively. Optimal pre-MR safety evaluation, CMR exam execution, and post exam processing and reporting allow for delivery of high quality radiological service in the evaluation of a suspected cardiac thrombus.

Introduction

Cardiac magnetic resonance (CMR) imaging is an important diagnostic modality for the evaluation of cardiovascular function and pathology. Technological advances allow for reduced acquisition time, improved spatial and temporal resolution, as well as higher quality tissue characterization. These advances are particularly useful in the evaluation of cardiac masses.

Echocardiography remains the first line imaging modality for the initial evaluation of cardiac masses, specifically with respect to mass location, morphology, and physiologic impact. However, echocardiography is limited by poor tissue characterization, a restricted field of view, a....

Protocol

The following protocol follows the departmental clinical guidelines and is adherent to the institution’s human research ethics guidelines.

1. Prepare for MRI Data Acquisition

1. Conduct a safety screening.
   1. Evaluate for renal impairment⁸.
      1. Avoid gadolinium contrast in patients with stage 4 or 5 chronic kidney disease (estimated glomerular filtration rate <30 mL/min/1.71 m²) not on chronic dialysis, patients with end-stage renal disease on chronic dialysis, and patients with known or suspected acute kidney injury due to concerns for NSF.

Results

The CMR protocol designed for the evaluation and diagnosis of cardiac thrombus encompasses patient screening and preparation, data acquisition utilizing specific sequences, data post-processing, and report generation. Specific signal characteristics on given sequences can infer with high accuracy the diagnosis of a cardiac thrombus and differentiate these from the competing diagnosis of a cardiac tumor. Table 1 highlights the conventional and emerging CMR sequences that a.......

Discussion

With the increasing quality and frequency of diagnostic imaging, it is not uncommon to discover incidental cardiac masses when performing imaging for unrelated indications. Patients with cardiac masses are often asymptomatic, and if present, symptoms are typically nonspecific.

The diagnosis of cardiac thrombus is important not only for differentiating thrombus from benign or malignant cardiac tumors, but also for determining the need for anticoagulation and prevention of embolic events

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
MRI Scanner	Siemens Healthcare Erlangen, Germany	Magnetom Aera 1.5 Tesla	MRI scanner that will be used for the demonstration
Post processing software	Medis The Netherlands	Qmass software	post processing software for ventricular volumetric and T1 mapping analysis
Scanner processing software	Siemens Healthcare Erlangen, Germany	Myomaps	Scanner sequence package and post processing software