Radiologic-Pathologic Correlation of Primary and Secondary Cardiomyopathies: MR Imaging and Histopathologic Findings in Hearts from Autopsy and Transplantation

Abstract

Cardiac magnetic resonance (MR) imaging with late gadolinium enhancement (LGE) is used to detect and assess the myocardial damage seen with a variety of cardiomyopathies. Gadolinium-based contrast material accumulates in the expanded interstitial space of the myocardium. Areas with LGE correspond to replacement fibrosis, fibrofatty change, epithelioid granuloma, inflammatory cell infiltration, cardiomyocyte necrosis, and amyloid deposition-conditions that represent a focal increase in interstitial space. Areas without LGE correspond to interstitial or plexiform fibrosis, mildly degenerated cardiomyocytes, inflammatory cell infiltration, and diffuse amyloid deposition-conditions that represent diffuse increases in interstitial space. LGE MR imaging cannot depict these diffuse changes and does not enable quantitative evaluation of this increased interstitial space because on inversion-recovery MR images, the inversion time is adjusted to null the signal from normal-appearing or the least enhancing regions of the myocardium. Thus, the absence of LGE does not always indicate normal myocardial tissue. The use of current T1 mapping techniques enables one to overcome these drawbacks of LGE imaging, detect diffuse myocardial abnormalities, and perform quantitative analysis of the interstitial space. The authors describe the histopathologic and corresponding cardiac MR imaging findings of hypertrophic cardiomyopathy, dilated cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, cardiac sarcoidosis, giant cell myocarditis, and cardiac amyloidosis-mainly those seen on LGE MR images-as assessed by using whole-heart specimens obtained from autopsy or transplantation. RSNA, 2017.

Current Understanding of the Pathophysiology of Myocardial Fibrosis and Its Quantitative Assessment in Heart Failure

“…On CMR, diffuse myocardial hypertrophy including both the ventricles and atria is observed with thickened valve leaflets and pericardial effusion. After gadolinium administration, there may be a circumferential pattern of LGE, preferentially affecting the subendocardium, but sometimes showing a patchier transmural pattern (Hashimura et al, 2017). For valvular heart disease, the hyper-enhancement of the myocardium may not be discoverable, since cardiac remodeling is not apparent in early progression of the disease, but it is noteworthy that valve function can be effectively evaluated by CMR.…”

“…Reactive fibrosis is present in many types of diseases, including aging and hypertension. Infiltrative fibrosis is relatively rare and is caused by progressive deposition of insoluble proteins (amyloidosis) or glycosphingolipids (Anderson-Fabry disease) in the interstitial space (Hashimura et al, 2017). Eventually, both interstitial and infiltrative fibrosis can lead to cardiomyocyte apoptosis and replacement fibrosis (Hashimura et al, 2017).…”

“…Infiltrative fibrosis is relatively rare and is caused by progressive deposition of insoluble proteins (amyloidosis) or glycosphingolipids (Anderson-Fabry disease) in the interstitial space (Hashimura et al, 2017). Eventually, both interstitial and infiltrative fibrosis can lead to cardiomyocyte apoptosis and replacement fibrosis (Hashimura et al, 2017). Regardless of its type, myocardial fibrosis is a complicated process resulting in the accumulation of the extracellular matrix (ECM).…”

The Advancement of Postmortem Investigations in Sudden Cardiac Death

“…Morphologically, it is characterized by left ventricular (LV) wall thickness, asymmetrical septal hypertrophy and mid-ventricular obstruction. On the other hand, dilated cardiomyopathy, which has both a genetic and non-genetic components, is associated with dilation of the left and right ventricles, thrombi may be observed in the cardiac chambers, and wall thickness may be increased or decreased [20]. Arrhythmogenic right ventricular dysplasia is another type of cardiomyopathy that can be associated with SCD; it is heritable disease with an autosomal dominant pattern whose genetic mutation has been localized on chromosome 1.…”

Invited Commentary on “Radiologic-Pathologic Correlation of Primary and Secondary Cardiomyopathies”

“…The reviewed cardiomyopathies are apt, as they are some of the most common and/or diagnostically challenging cardiomyopathies encountered in clinical practice. Our comments are intended to supplement the excellent content presented by Hashimura et al (3) and address additional aspects of MR imaging that were not within the scope of their review.…”