The quantitative accuracy of CT numbers in myocardial perfusion computed tomography (MPCT) is degraded by artifacts arising from the use of partial scan reconstruction (PSR), which is used in cardiac CT to improve temporal resolution. Full scans do not suffer from this artifact. PSR artifacts appear because of inconsistencies in the angular range of projection data used for partial scans due to physical effects such as scattering and beam hardening. We develop a method applicable to phase-correlated cardiac CT acquisitions that predicts the missing data to complete full scans and reducing the PSR artifacts significantly. The method does not require extra radiation exposure since does not need any a priori data. It can be readily applied to current myocardial perfusion CT protocols available in CT scanners.