Background Non-contrast spin-lock T1 Rho has shown the capability of detecting myocardial infarction in animal models.However, this approach has yet been systematically evaluated in clinical patients with chronic myocardial infarction.Methods Sixteen patients with documented chronic myocardial infarction underwent MRI scans using a protocol consisting of pre-contrast T1 Rho imaging and post-contrast late gadolinium enhancement imaging.The T1 Rho sequence was newly developed for the 3T system and can obtain a single-slice absolute T1 Rho map within one breath-hold.The data from the first 6 patients were used as a training set to determine the threshold to define the extent of myocardial infarction, in comparison with the late gadolinium enhancement.The other 16 patients were examined by using the optimized threshold value to measure the infarction size.The T1 Rho values in the infarcted and remote normal myocardial regions were obtained as well.Results All patients had evidence of myocardial infarction as detected by late gadolinium enhancement.The normal and infarcted tissues had T1 Rhos of 45.8 ± 7.4 ms and 100.0 ± 41.4 ms, respectively, which were consistent with the values obtained in animal studies.The extent of infarcted area measured by T1 Rho strongly correlates with that determined by the late gadolinium enhancement images (r2 =0.95).Conclusion This is the first report of a non-contrast T1 Rho method being used to assess chronic myocardial infarction in a clinical setting.Although further vigorous validation is warranted, the non-contrast T1 Rho method appears to be feasible for the diagnosis of chronic myocardial infarction, particularly for patients with renal insufficiency.