In this study, we analyzed T2* value in the mid-left ventricular septum avid normoxia (T2*air) and hyperoxia (T2*oxy) in cases with normal, hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM). Oxygen-enhanced T2* cardiac magnetic resonance (CMR) showed the different delta T2* (T2*oxy – T2* air), reflecting myocardial blood-oxygen dependent (BOLD) effect. Oxygen-enhanced T2* CMR open up a new avenue for the study of the pathophysiology of cardiomyopathy. The ΔT2* was prolonged in DCM, stable in control and shortened in HCM, respectively. Oxygen-enhanced T2* CMR can assess the oxygen metabolism in the mid-left ventricular septum with various density of capillaries and myocardial cells. We also note the relationship between T2* value and late gadolinium enhancement (LGE) or left ventricular ejection fraction (LVEF).Researchers, radiologist, and physicians who are interested in CMR, especially with regard to myocardial oxygen metabolism in cases with cardiac disease.To estimate the diagnostic potential of oxygen-enhanced T2* CMR to characterize cardiomyopathy, as an alternative BOLD technique.Subjects: Consecutive 52 patients (31 men and 21 women; mean age of 55) whom were diagnosed as normal control (n=15), HCM (n=17) and DCM (n=20). MRI: All patients underwent 3 Tesla MR imaging (Achieva 3.0 T Quarsar Dual; Philips Healthcare, Best, The Netherlands) equipped with dual-source parallel radiofrequency transmission, 32-element cardiac phased-array coils used for radiofrequency reception and a 4-lead vector cardiogram. Short-axis black-blood T2* CMR was obtained within a single breath-hold using multi-echo gradient-echo sequence (TE=2.9 to 10.9msec, 6 point, n=42 or TE=1.2 to 16.4msec, 15point, n=10). A double inversion recovery pulse was applied on the R-wave during diastole. T2* measurement was performed in the mid-left ventricular septum. After acquisition of T2*air during room-air inhalation, the supplemental oxygen was administered for T2*oxy measurement through a breathing mask at the flow rate of 10 l/min. An exponential function was fitted to the data, as follows; Sn = S0e-TEn/T2* Subsequently, LGE images were obtained with an inversion-recovery T1 turbo field-echo sequence performed 10 minutes after contrast injection and acquired in the same orientation as the short axis cine images. Each Myocardial T2*air, T2*oxy, and ΔT2* (=T2*oxy - T2*air) was calculated. Evaluation: 1) The reproducibility of T2* measurements was evaluated by calculating concordance correlation coefficient (CCC) and intra-class correlation coefficient (ICC) by independent 2 readers. 2) One-way analysis of variance (ANOVA) and Turkey-Kramer test were performed for T2*air, T2*oxy and ΔT2* among normal control, HCM and DCM. 3) Two-way ANOVA was performed for T2*air, T2*oxy and ΔT2* among LGE and LVEF. 4) Typical images of T2*air and T2*oxy were also demonstrated.The reproducibility of T2* measurements was substantial for both inter- and intra observer agreement (CCC: 0.95<), and the estimated value of the reliability of averages of k ratings were almost perfect (Average of ICC: 0.99). By one-way ANOVA among normal control, HCM and DCM, myocardial T2*air showed statistically significant mean and standard deviation as 26.7±5.7, 28.4±5.2 and 23.2±3.7msec (*p<0.05). Myocardial T2*oxy showed no significant difference as 26.7±6.1, 26.8±4.9 and 25.9±4.7msec. Myocardial ΔT2* showed significant difference as -0.1±4.1, -1.6±4.1 and 2.7±5.7msec (*p<0.05: Figure 1). By two-way ANOVA myocardial T2*air, T2*oxy and ΔT2* showed mean difference as followings; 2.9 (NS: p=0.07), 1.7 (NS: p=0.77) and 3.4msec (*p=0.0297) for LGE and 3.6 (p=0.0233), 1.2 (NS: p=0.47) and 2.4msec (NS: p=0.12) for LVEF, respectively. T2*air and T2*oxy image showed close resemblance (Figure 2). The area of higher T2* value was extended from endoluminal side of the mid-left ventricular septum in T2*oxy, comparing to T2*air image (Figure 3). T2* CMR techniques enables clinically-feasible rapid parametric mapping of magnetic relaxation properties that has further expanding the range of unique tissue parameters from iron content to BOLD effect in the myocardium. T2*-weighted BOLD-MRI visualizes the perivascular signal change due to bulk susceptibility effect by the ratio of diamagnetic oxy-hemoglobin (oxy-Hb) and paramagnetic deoxy-hemoglobin (deoxy-Hb) in capillaries of the heart, that is well known as one of vessel rich organ. Oxygen-enhanced T2* CMR enables a non-invasive assessment of myocardial oxygen metabolism without use of contrast media or ionizing radiation. Oxygen inhalation drives relative increase of the diamagnetic oxy-Hb in the vascular lumen and decrease of the blood perfusion to myocardial cells. The prolongation of ΔT2* was observed in DCM cases (+1.7msec) and LGE positive cases (+3.4msec) that may reflects the increased BOLD effect due to hypo-consumption of oxygen. The shortening ofΔT2* was observed in HCM cases (-3.5msec) that may reflects the normal reaction for hypo-perfusion due to oxygen inhalation. Oxygen-enhanced T2* CMR provides a unique information about the myocardial signal change due to hyperoxia in cardiomyopathy.