Relationship of cardiac magnetic resonance imaging and myocardial biopsy in the evaluation of nonischemic cardiomyopathy.

This study was performed to determine the relative role of cardiac magnetic resonance (CMR) imaging and endomyocardial biopsy (EMB) in the evaluation of cardiomyopathy. Sixty-six patients with a clinical diagnosis of nonischemic dilated cardiomyopathy or restrictive cardiomyopathy underwent both EMB and CMR imaging as part of their diagnostic evaluation. The authors retrospectively reviewed the results of these two methods to determine their diagnostic impact and congruency. CMR imaging provided data on cardiac anatomy, left ventricular volumes, mass, and function in 85% of the patients, uncovered fibrosis in 31%, myocardial ischemia in 7%, and fibrofatty infiltration in two patients. EMB provided the histologic findings of cardiomyocyte hypertrophy in 77% of patients and substantial interstitial fibrosis in 59%. Six patients had EMB-proven amyloid heart disease, which was detected by CMR imaging in two. CMR imaging showed patterns of late gadolinium enhancement supportive of infiltrative disease or inflammation in 6 patients with EMB-proven definite (n=3) or borderline (n=3) myocarditis, but failed to do so in two other patients with borderline and two with resolving myocarditis. At the present time, CMR imaging and EMB remain complementary procedures in the evaluation of cardiomyopathic conditions.