OBJECTIVES: The aim of this study was to examine the value of native and 
post-contrast T1 relaxation in the differentiation between healthy and diffusely 
diseased myocardium in 2 model conditions, hypertrophic cardiomyopathy and 
nonischemic dilated cardiomyopathy.
BACKGROUND: T1 mapping has been proposed as potentially valuable in the 
quantitative assessment of diffuse myocardial fibrosis, but no studies to date 
have systematically evaluated its role in the differentiation of healthy 
myocardium from diffuse disease in a clinical setting.
METHODS: Consecutive subjects undergoing routine clinical cardiac magnetic 
resonance at King's College London were invited to participate in this study. 
Groups were based on cardiac magnetic resonance findings and consisted of 
subjects with known hypertrophic cardiomyopathy (n = 25) and nonischemic dilated 
cardiomyopathy (n = 27). Thirty normotensive subjects with low pre-test 
likelihood of cardiomyopathy, not taking any regular medications and with normal 
cardiac magnetic resonance findings including normal left ventricular mass 
indexes, served as controls. Single equatorial short-axis slice T1 mapping was 
performed using a 3-T scanner before and at 10, 20, and 30 minutes after the 
administration of 0.2 mmol/kg of gadobutrol. T1 values were quantified within 
the septal myocardium (T1 native), and extracellular volume fractions (ECV) were 
calculated.
RESULTS: T1 native was significantly longer in patients with cardiomyopathy 
compared with control subjects (p < 0.01). Conversely, post-contrast T1 values 
were significantly shorter in patients with cardiomyopathy at all time points (p 
< 0.01). ECV was significantly higher in patients with cardiomyopathy compared 
with controls at all time points (p < 0.01). Multivariate binary logistic 
regression revealed that T1 native could differentiate between healthy and 
diseased myocardium with sensitivity of 100%, specificity of 96%, and diagnostic 
accuracy of 98% (area under the curve 0.99; 95% confidence interval: 0.96 to 
1.00; p < 0.001), whereas post-contrast T1 values and ECV showed lower 
discriminatory performance.
CONCLUSIONS: This study demonstrates that native and post-contrast T1 values 
provide indexes with high diagnostic accuracy for the discrimination of normal 
and diffusely diseased myocardium.