Cardiovascular magnetic resonance in clinically suspected cardiac amyloidosis: noninvasive imaging compared to endomyocardial biopsy.

OBJECTIVES We sought to evaluate the diagnostic performance of cardiovascular magnetic resonance imaging (CMRI) for detection of cardiac amyloidosis compared with endomyocardial biopsy (EMB) in a clinical routine setting. BACKGROUND For the clinical workup of heart failure with restrictive filling, pattern cardiac amyloidosis is an important differential diagnosis that is difficult to verify with current noninvasive techniques, especially in the presence of myocardial hypertrophy. METHODS A total of 33 consecutive patients underwent both CMRI and EMB for workup of heart failure with restrictive filling pattern in combination with myocardial hypertrophy (n = 24) and/or clinical conditions often associated with cardiac amyloidosis (n = 18). RESULTS Cardiac amyloidosis was detected by EMB in 15 of the 33 patients. In patients with biopsy-proven cardiac amyloidosis, CMRI revealed a distinct pattern of late gadolinium enhancement, which was distributed over the entire subendocardial circumference, extending in various degrees into the neighboring myocardium. This pattern was found in 12 of the 15 patients diagnosed with cardiac amyloidosis by EMB, compared with only 1 individual in the group of 18 patients diagnosed with other myocardial diseases. Consequently, using this pattern as a diagnostic criterion, the sensitivity of CMRI for diagnosing cardiac amyloidosis was 80%, yielding a specificity of 94%. The positive predictive value was 92%, and the negative predictive value was 85%. CONCLUSIONS In patients with biopsy-proven cardiac amyloidosis, late gadolinium enhancement frequently occurs in a peculiar pattern. On the basis of the gold standard, EMB, noninvasive CMRI can be used to diagnose or rule out cardiac amyloidosis with good sensitivity and excellent specificity in a clinical routine setting.