Diastolic functional indices based on trans-mitral blood flow velocities are pre-load dependent and early diastolic filling can be diminished by activities such as inspiration or Valsalva maneuver1. Cardiac cine MR images are typically acquired during suspended respiration and therefore could induce systemic bias in the estimation of left ventricular diastolic function. In this study, we evaluate the impact of respiratory suspension on the computation of volume-based diastolic indices using peak velocity-based Doppler echo measured ratio of early peak velocity (E) to peak velocity during atrial contraction (A) measured at the tip of the mitral leaflets as the reference.All imaging for this IRB approved prospective study was performed on a 1.5T commercial MR scanner (Achieva, Philips Healthcare) in 11 volunteers (3m/8f; age 42(20-60)yrs). MRI: Identical imaging parameters were used for breath held (BH), and free breathing (FB) cine SSFP sequences (TR/TE/flip angle: 3/1.5/60°); acqd voxel size: 2.25x2.25x8 mm3; SENSE:2, temp res: 10-15ms; acq time: 18 RR intervals/slice; covering the LV in short-axis orientation. FB pulse sequence is described in2. Echocardiography: Subjects were transported to ultrasound (Philips Healthcare, IE 33) on the same scanner bed to minimize physiologic variation and E/A ratio was obtained. Data Analysis: CMR expert drawn endocardial contour at end diastole was propagated across the cardiac phases by a semi-automated algorithm. Resultant LV contours were manually adjusted by CMR expert if needed. From these contours time-LV volume curve was further analyzed using a custom-written software in MATLAB™. The raw LV volume curve was upsampled by a factor of 4, and the derivative of the time-volume curve was estimated using the method described in [3]. Following parameters were calculated from these curves: peak volume change rates during the early filling phase (REFP) and late filling phase (RLFP), LV volume changes during early filling phase (VEFP) and late filling phase (VLFP). We defined REFP/RLFP and VEFP/VLFP ) as MR determined LV volume based surrogates of velocity based echo index of E over A ratio. Linear regression and Bland-Altman (BA) analysis was performed on the results obtained with MR and echo to obtain slope (m), coefficient of determination (r2), bias (mean of difference), and limits of agreement(LA, 1.96* stdev of diff).High frame rate cine SSFP sequence during free breathing provides cine MR images with adequate temporal resolution to estimate MR based indices (REFP/RLFP, VEFP/VLFP) of diastolic function. Doppler based E/A ratios (mean 1.23, range 0.67–1.68) were in good agreement with REFP/RLFP for FB (m= 2.0, r2= 0.5, bias= -0.4, LA = 1.0) and BH (m= 1.69, r2= 0.4, bias= -0.2, LA = 0.9). Doppler based E/A ratios were in good agreement with VEFP/VLFP for FB (m= 2.42, r2= 0.5, bias= -1.2, LA = 1.4) and BH (m= 1.59, r2= 0.3, bias= -0.8, LA = 1.0). However, the bias for both diastolic indices between FB and BH acquisitions was more than 10% (Figure 2). The peak volume change rate during systolic ejection phase (RSEP) was unchanged while REFP (19.7%), RLFP (7.2%) and stroke volume (9.6%) were higher in FB compared to BH (Table 1). The VEFP was higher by 15% while VLFP (-7.0%) was lower in FB compared to BH (Table 1).The volume based REFP/RLFP and VEFP/VLFP ratios derived from high temporal resolution cine MR correlated well with velocity based E/A ratio from echo. The complex interactions between respiratory and cardiovascular systems have direct impact on the measurement of volume-based diastolic indices. This indicates that volume based diastolic indices, if used for longitudinal follow up, need to be acquired preferably under free breathing condition to avoid inconsistent level of respiratory suspension.