Frequency and variability of late gadolinium "mid-wall" enhancement(MLE) depending on observer experience, image quality and underlying disease

Abstract

Objective : To evaluate the ability of an inexperienced observer (IO) to reliably assess mid-wall late enhancement (MLE) and to assess the prevalence of MLE in patients with various cardiac diseases. Background Late gadolinium enhancement (LGE) in cardiac MRI (cMRI) has been described as a valid tool to discriminate between cardiac diseases. It has been postulated that MLE especially occurs in patients with dilated cardiomyopathy (DCM) and myocarditis with a prognostic impact in these patients. Nevertheless, it can be difficult to differentiate true MLE from common artifacts as motion blur, partial volume effects (PVE) or wrong inversion times (TI), especially for the IO. Methods We examined 97 consecutive patients (64 male, 33 female, mean age 51 +/-20 years), which were referred to our department for a cMRI for various clinical indications (37 ischemic heart diseases (ICM), 16 myocarditis, 5 DCMs, 2 restrictive cardiomyopathies (RCM), 5 hypertrophic obstructive or non-obstructive cardiomyopathies, 8 congenital heart diseases (CHD), 12 patients with Objective To evaluate the ability of an inexperienced observer (IO) to reliably assess mid-wall late enhancement (MLE) and to assess the prevalence of MLE in patients with various cardiac diseases. Background Late gadolinium enhancement (LGE) in cardiac MRI (cMRI) has been described as a valid tool to discriminate between cardiac diseases. It has been postulated that MLE especially occurs in patients with dilated cardiomyopathy (DCM) and myocarditis with a prognostic impact in these patients. Nevertheless, it can be difficult to differentiate true MLE from common artifacts as motion blur, partial volume effects (PVE) or wrong inversion times (TI), especially for the IO. Methods We examined 97 consecutive patients (64 male, 33 female, mean age 51 +/-20 years), which were referred to our department for a cMRI for various clinical indications (37 ischemic heart diseases (ICM), 16 myocarditis, 5 DCMs, 2 restrictive cardiomyopathies (RCM), 5 hypertrophic obstructive or non-obstructive cardiomyopathies, 8 congenital heart diseases (CHD), 12 patients with experience and 1 experienced observer (EO) (3 years of experience). The results of the EO (Table 1) were considered as being the standard of reference. Results The IO described suspected MLE in 43/97 patients (44%), which were false positive in 28/43 (65%). Only 18/97 (19%) were true MLE. Reasons for false positives were wrong TI in 39% (Table 2), PVE (25%), microvascular obstruction (MO) mimicking MLE in 11% and artifacts. The 3 false negative cases were interpreted in 2 cases as motion artifacts and overlooked in one case by the IO. As expected the majority of patients with MLE presented with DCM and myocarditis. But also in patients with ischemic cardiomyopathy (ICM), restrictive cardiomyopathy (RCM), congenital heart disease (CHD) and the occurrence of symptomatic arrhythmias without an underlying structural heart disease MLE could be detected. Figures 1, 2, 3, 4. Conclusion MLE is a common finding not only in patients with DCM and myocarditis, but also in patients with ICM, RCM, CHD or patients with different arrhythmias without an underlying structural heart disease. Standardized criteria for the detection/definition of MLE are mandatory to reduce the number of false positive results, which can be higher than 50%, especially when cMRI is interpreted by an inexperienced cardiac MRI user.