Comparison of diastolic function parameters using MRI and SPECT

483 Objectives This study compares the relationship of 2 common diastolic function (DFx) parameters - peak filling rate (PFR) and time to peak filling (TTPF) using Magnetic Resonance Images (MRI) and technetium-99mTc-sestamibi myocardial perfusion Single-Photon Emission Computed Tomographic (SPECT) images. Methods 21 patients underwent gated SPECT and cardiac MR imaging with less than 2 hours between the studies. Endocardial contours on SPECT were automatically outlined over the entire cardiac cycle using the QGS algorithm. On MRI, endocardial contours were automatically propagated for all cardiac phases using manually outlined end-diastolic (ED) contours. For both modalities, the QGS algorithm quantifies DFx parameters using bicubic spline interpolation of the LV volume/time curve. The LV filling rate/time curve is computed from the first derivative of the volume/time curve. PFR corresponds to the peak value of the first derivative of the diastolic portion of the time–activity curve. Since ventricular filling is normalized to ED volume (EDV), the unit for PFR is EDV/s. TTPF (milliseconds) is the interval between ES and the PFR. Results Mean PFR using MRI and SPECT were 2.45±0.68 and 2.26±0.0.57 EDV/s respectively (p=0.06). PFR measured using MRI and SPECT correlated strongly (r=0.77, p Conclusions PFR obtained with SPECT and MRI although not similar, was well correlated. The correlation of PFR measured by MRI and SPECT was higher compared to TTPF measured by the two modalities.