The emerging role of magnetic resonance imaging and multidetector computed tomography in the diagnosis of dilated cardiomyopathy

Diagnostic Role of Cardiovascular Magnetic Resonance Imaging in Dilated Cardiomyopathy

Aims  The purpose of the study was to compare the accuracy of cardiac magnetic resonance (CMR) with echocardiography for the evaluation of ventricular dysfunction in patients of dilated cardiomyopathy (DCM). Further, we evaluated the potential of CMR for myocardial tissue characterization. Design  Prospective observational. Materials and Methods  A total of 30 patients with suspected DCM prospectively underwent cardiac magnetic resonance (MR) using a 1.5 Tesla MR scanner, with appropriate phased-array body coils. Dynamic sequences after injection of 0.1 mmol/kg of body weight of gadolinium-based intravenous contrast (Magnevist) were acquired for each patient, after which delayed images were obtained at an interval of 12 to 15 minutes. Myocardial tagging was performed in all patients for assessment of wall motion abnormalities. Each MR examination was interpreted with two radiologists for chamber dimensions and ventricular dysfunction as well as morphologic characteristics with disagreement resolved by consensus. All patients included in the study were taken up for MR evaluation after cardiological evaluation through echocardiography and the results for both the studies were compared. Data were analyzed through standard statistical methods. Conclusion  CMR is a comprehensive diagnostic tool, which can estimate the ventricular function more precisely than echocardiography. CMR reliably differentiates between ischemic and nonischemic etiologies of DCM based on patterns of late gadolinium enhancement (LGE) and based on the presence or absence of LGE, which helps to estimate the degree of myocardial fibrosis. Thereby it can be a useful tool in establishing risk stratification, predicting prognosis, and thus instituting appropriate therapy in DCM patients.

Myocardial wall thinning predicts transmural substrate in patients with scar-related ventricular tachycardia

BACKGROUND

Scar-related ventricular tachycardia (VT) arises from specific substrate according to etiology.

OBJECTIVE

The purpose of this study was to evaluate the relationship between wall thinning (WT) on multidetector computed tomography (MDCT) and local abnormal ventricular activity (LAVA) in patients with ischemic cardiomyopathy (ICM), postmyocarditis (PMC), and dilated cardiomyopathy (DCM).

METHODS

Forty-two patients (40 male, age 58 ± 13 years, 22 ICM, 11 PMC, 9 DCM) underwent MDCT before a combined endo-/epicardial VT ablation procedure. WT (<5 mm) and severe wall thinning (SWT) (<2 mm) area on MDCT were compared to the prevalence of endo-/epicardial LAVA during sinus rhythm.

RESULTS

WT and SWT were found on MDCT in 36 (86%) and 20 (48%) with 42 ± 37 cm² and 26 ± 24 cm², respectively. SWT was frequently detected in ICM (ICM 77% vs PMC 27% vs DCM 0%, P <.001). LAVA were frequently observed on the endocardium in ICM and on the epicardium in PMC. Endo-/epicardial facing LAVA were frequently found within SWT areas (91% in <2 mm, 9% in 2-5 mm, and 0% in >5 mm, P < .001). In SWT areas, the presence of endocardial LAVA in ICM and epicardial LAVA in PMC predicted opposite facing LAVA with sensitivity and specificity of 78% and 48% and 79% and 98%, respectively. SWT predicted epicardial LAVA in ICM and endocardial LAVA in PMC with sensitivity and specificity of 89% and 100%, and 100% and 100%, respectively.

CONCLUSION

SWT is frequently found in ICM and PMC but is not common in DCM. SWT predicts LAVA on the opposite side of the wall (epicardial in ICM and endocardial in PMC), indicating transmural VT substrate. MDCT is useful for identifying VT substrate and helpful for understanding the mechanisms of the location of VT substrate domain.

Role of cardiac magnetic resonance in the evaluation of dilated cardiomyopathy: diagnostic contribution and prognostic significance

Dilated cardiomyopathy (DCM) represents the final common morphofunctional pathway of various pathological conditions in which a combination of myocyte injury and necrosis associated with tissue fibrosis results in impaired mechanical function. Recognition of the underlying aetiology of disease and accurate disease monitoring may be crucial to individually optimize therapeutic strategies and stratify patient's prognosis. In this regard, CMR has emerged as a new reference gold standard providing important information for differential diagnosis and new insight about individual risk stratification. The present review article will focus on the role of CMR in the evaluation of present condition, analysing respective strengths and limitations in the light of current literature and technological developments.

[Magnetic resonance imaging of dilated cardiomyopathy]

Dilated cardiomyopathy (DCM) is the most common type of cardiomyopathy with a prevalence of 1 out of 2,500 in adults. Due to mild clinical symptoms in the early phase of the disease, the true prevalence is probably even much higher. Patients present with variable clinical symptoms ranging from mild systolic impairment of left ventricular function to congestive heart failure. Even sudden cardiac death may be the first clinical symptom of DCM. The severity of the disease is defined by the degree of impairment of global left ventricular function. Arrhythmias, such as ventricular or supraventricular tachycardia, atrioventricular (AV) block, ventricular extrasystole and atrial fibrillation are common cardiac manifestations of DCM. Magnetic resonance imaging (MRI) plays an important role in the exact quantification of functional impairment of both ventricles and in the evaluation of regional wall motion abnormalities. With its excellent ability for the assessment of myocardial structure, it is becoming increasingly more important for risk stratification and therapy guidance.