Manganese-enhanced Magnetic Resonance Imaging in Dilated Cardiomyopathy and Hypertrophic Cardiomyopathy.

Patients with dilated cardiomyopathy (n= 10) or hypertrophic cardiomyopathy (n= 17) underwent both gadoliniumand manganese contrast-enhanced magnetic resonance imaging and were compared with healthy volunteers(n= 20). Differential manganese uptake (Ki) was assessed using a two-compartment Patlak model. Compared withhealthy volunteers, reduction in T1 with manganese-enhanced magnetic resonance imaging was lower in patientswith dilated cardiomyopathy [mean reduction 257 ± 45 (21%) vs. 288 ± 34 (26%) ms,P< 0.001], with higher T1 at40 min (948 ± 57 vs. 834 ± 28 ms,P< 0.0001). In patients with hypertrophic cardiomyopathy, reductions in T1 wereless than healthy volunteers [mean reduction 251 ± 86 (18%) and 277 ± 34 (23%) vs. 288 ± 34 (26%) ms, with andwithout fibrosis respectively,P< 0.001]. Myocardial manganese uptake was modelled, rate of uptake was reducedin both dilated and hypertrophic cardiomyopathy in comparison with healthy volunteers (meanKi19 ± 4, 19 ± 3,and 23 ± 4 mL/100 g/min, respectively;P= 0.0068). In patients with dilated cardiomyopathy, manganese uptake ratecorrelated with left ventricular ejection fraction (r2= 0.61,P= 0.009). Rate of myocardial manganese uptake demon-strated stepwise reductions across healthy myocardium, hypertrophic cardiomyopathy without fibrosis and hyper-trophic cardiomyopathy with fibrosis providing absolute discrimination between the healthy myocardium andfibrosed myocardium (meanKi23 ± 4, 19 ± 3, and 13 ± 4 mL/100 g/min, respectively;P< 0.0001).