Cardiac MRI in Diagnosis, Clinical Management, and Prognosis of Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia

Aiden Abidov, Isabel Oliva, Frank I Marcus, FRANK I MARCUS

• Publisher: Academic Press
• Year: 2016
• Print ISBN:
  9780128012833
• eBook ISBN:
  9780128014356
• Topic: Scienze biologiche
• Subtopic: Immunologia

Cardiac MRI in Diagnosis, Clinical Management and Prognosis of Arrhythmogenic Right Ventricular Cardiomyopathy / Dysplasia provides up-to-date information regarding the most effective diagnostic protocols and CMR sequences for the evaluation of patients with suspected or known ARVC/D. It includes CMR protocol summaries and clinical algorithms presented as flow diagrams, many of which have never been previously published. The book contains case reports from the practice and database of Dr. Frank I. Marcus, world renowned ARVC/D expert; as well as input from imaging experts from a large academic center with unique RV pathology imaging experience. This title is the perfect pocket companion for cardiologists, pediatric cardiologists, cardiac imaging and electrophysiology specialists as well as cardiology researchers. - The only comprehensive MRI reference focused and dedicated on the utilization of MRI in screening, diagnosis, therapeutic guidance and prognostic assessment of ARVC/D. - Provides evidence based diagnostic and prognostic algorithms for management of patients with known and suspected ARVC/D. - Contains concise clinical CMR acquisition protocol and evidence-based summaries of recommendations and multiple practical tips and tricks shared by experts in the field. - Includes practical guidelines helping to determine pre-test and post-test likelihood of ARVC/D; as well as CMR evidence of the disease progression. - Accompanying website provides complementary videos important for the understanding of ARVC diagnosis.

Chapter 1

Introduction

Frank I. Marcus

Aiden Abidov    Department of Medicine/Division of Cardiology and Department of Medical Imaging, University of Arizona, Tucson, AZ, USA

This book aims to evaluate the role of the MRI in the diagnosis, clinical management, and prognosis of arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D). You may ask “Isn't this too narrow a focus for this rare disease?” Let us evaluate this concern.

First, ARVC/D is now more frequently diagnosed as it is becoming better known. It is estimated that it occurs in 1:5000 individuals but it may be present in a higher incidence since one may have a pathological gene for this disease yet have little or no clinical manifestations. This is known as a lack of association of genotype and phenotype. Thus, ARVC/D may be a less rare disease than is presently thought. In addition, since it is a cause of sudden cardiac death, particularly in the young, it is important to be able to recognize it in order to prevent this catastrophic event.

Another question is, why should we focus our attention on one imaging modality, the MRI, particularly when this imaging modality is more expensive and less readily available than 2D echocardiography? In contrast to echocardiography, an MRI can provide more accurate quantitative evaluation of the right ventricular function and structure. Specifically, it can accurately access right ventricular ejection fraction as well as segmental wall motion abnormalities of the right ventricle. Based on hundreds of published papers, cardiac MRI is a useful diagnostic imaging modality in patients suspected of having ARVC/D and is particularly valuable since important limitations of MRI (such as the need for breathholding, inability to scan patients with permanent pacemakers or ICDs, etc.) have largely been overcome. The finding of abnormal right ventricular function or structure by 2D echocardiogram in a patient suspected of having ARVC/D should be confirmed by MRI since the latter is more reliable for the diagnosis. It is also important that the radiologist/cardiologist who is interpreting the MRI should be aware of normal variants of the right ventricular contractility patterns, particularly that of an apparent bulging of the right ventricular free wall at the insertion of the right ventricular papillary muscle.

Other questions include the age at which ARVC/D is manifest. Should an MRI be done in children who have the genetic abnormality but no clinical manifestation of the disease? How rapidly do the abnormalities of the RV change in this disease? This would determine how frequently the MRI should be reassessed in first-degree relatives who may have no or minimal symptoms.

An important consideration is the increased safety of MRI, especially absence of exposure to ionizing radiation and nephrotoxic iodine contrast. This allows sequential MRI studies in young patients without increased associated risk of imaging. Excellent spatial resolution and safety of cardiac MRI makes it an ideal methodology for follow-up of patients with known or suspected ARVC/D.

Finally, the MRI is useful in differential diagnosis that includes several conditions mimicking ARVC/D, such as cardiac sarcoidosis, left-to-right supraventricular shunts, and myocarditis. Also, in some cases, myocardial–pericardial adhesions can cause abnormal right ventricular wall motion. The use of gadolinium contrast to detect and localize scar/fibrosis in the left or right ventricular myocardium is unique to MRI, as is the ability of cardiac MRI to provide effective tissue characterization, including fibro-fatty infiltration, inflammation, thrombosis, etc.

Recent developments in the field of advanced echocardiography, cardiac CTA, and nuclear cardiology have many interesting applications that could significantly enhance the armamentarium of physicians in the diagnosis and management of ARVC/D. In this book, we included a brief overview of novel non-MRI-based imaging methodologies that are useful in this disease.

In summary, there are many important clinical areas of interest reflecting the role of the MRI and other rapidly developing cardiac imaging methodologies in patients with ARVC/D. In our book, we provide our readers with a convenient overview of these areas.

However, there are three types of problems with cardiac imaging in general, and cardiac MRI in particular for the evaluation of ARVC/D. (Fig. 1.1):

Figure 1.1 Problems encountered in evaluation and management of patients with known or suspected ARVC/D.

1. The problem of ordering the right test for the patient's age and clinical presentation. Patients with known or suspected ARVC/D are a highly heterogeneous group and include patients with confirmed ARVC/D, asymptomatic gene carriers, and relatives of patients with ARVC/D, as well as patients with suspected or possible ARVC/D. There is significant disagreement about which test should be utilized in these populations, which one is the most effective for screening, and whether the layered testing concept should be considered in the “borderline” cases. The Modified Task Force criteria focused on the specificity of echo and MRI measurements of ARVC/D and possibly at the expense of sensitivity, particularly of early or clinically “silent” disease cases.

2. The problem of performing a good-quality diagnostic MRI. For years, we have been reviewing MRI studies of patients with either known or probable disease performed in imaging laboratories from many centers in the United States and abroad. There is marked variability of the diagnostic quality of these studies. Also, there are many MRI protocols utilized in different centers. Current lack of standardization in MRI protocols for the ARVC/D patients is concerning. There is an urgent need to improve this situation.

3. The problem of interpreting results of the MRI study. Even negative results in particular clinical populations may mean just one negative diagnostic criterion among many others that must be considered in such a complex diagnosis as ARVC/D. At times the decision-making process is based completely on the imaging study. A false-negative study can be associated with increased risk, and a false-positive test may dramatically change the patient's life and have long-lasting consequences both for the patient and for the society. One of these situations we have encountered is implantation of ICDs in young patients who have borderline tests, or tests that are negative but are interpreted as positive even though other diagnostic tests were not considered. Recently, with the development of genetic testing, interpretation of imaging test results in association with genetic defects in asymptomatic individuals raises important clinical decisions. These patients may be subjected to changes in their occupation, limitations in their athletic activities (such as college sports) and lifestyle even though their anatomic data do not suggest an increased risk.

In this book, we address these problems and provide quick access to evidence-based algorithms and methods utilized currently in the state-of-the-art imaging laboratories. We have utilized an exhaustive literature search, but we also give readers flow diagrams, clinical algorithm schemes, and figures. Easy access to these data may save time and effort in reaching important clinical decisions and utilize an important principle of the modern imaging: “The right test for the right patient.”

This book provides a quick reference to assist with standardization of the imaging protocols, particularly for the practicing imagers and clinicians who may encounter patients with known or suspected ARVC/D. This book is designed to be user friendly. We provide clinical examples as well as online tools and videos to illustrate interesting cases from our practice.

We hope to have the readers' feedback and maintain online communication with interested clinicians and researchers in order to further enhance the potential of cardiac MRI and other imaging modalities in the diagnosis and management of ARVC/D.

Chapter 2

Arrhythmogenic Cardiomyopathy: History and Pathology

Gaetano Thiene

Stefania Rizzo

Kalliopi Pilichou

Cristina Basso Department of Cardiac, Thoracic and Vascular Sciences, University of Padua Medical School, Padua, Italy

Abstract

Arrhythmogenic right ventricular cardiomyopathy is a life-threatening morbid entity, which drew the attention of the scientific community being a significant cause of premature death. In the modern era, it has been first reported in the late 1960s and 1970s as a cause of right ventricular hemodynamic impairment and electrocardiographic abnormalities (epsilon wave). Soon after, autopsy studies demonstrated that young people, especially athletes, may die suddenly and instantaneously because abrupt lethal cardiac arrhythmias, namely ventricular ...

Table of contents

• Cover
• Title page
• Table of Contents
• Copyright
• Dedication
• Acknowledgment
• List of Contributors
• Chapter 1: Introduction
• Chapter 2: Arrhythmogenic Cardiomyopathy: History and Pathology
• Chapter 3: Definition, Clinical Features, and Classification of ARVC/D. Task Force Criteria for ARVC/D
• Chapter 4: CMR Features of ARVC/D
• Chapter 5: Current Cardiac MRI Protocols for Known and Suspected ARVC/D
• Chapter 6: Association of Phenotype and Genotype in the Diagnosis and Prognosis of ARVC/D in the Adult Population
• Chapter 7: Diagnostic Evaluation of Children with Known or Suspected ARVC/D
• Chapter 8: Differential Diagnosis of ARVC/D
• Chapter 9: Special Cases and Special Populations: Tips and Tricks to Obtain a Diagnostic CMR
• Chapter 10: Prognostic Value of Cardiac MRI in ARVC/D
• Chapter 11: Echocardiographic Applications in the Diagnosis and Management of Patients with ARVC
• Chapter 12: Other Imaging Modalities in the Evaluation of Patients with ARVC/D
• Chapter 13: Selected Clinical Cases from Our Practice
• Subject Index