Engineering / Computed Tomography / Computer Simulation / Singular value decomposition / Temporal Correlation / Perfusion / Image Enhancement / Time Factors / X ray Computed Tomography / Blood Flow Velocity / Rectal Cancer / Region of Interest / Contrast Media / Tumor Imaging / Perfusion / Image Enhancement / Time Factors / X ray Computed Tomography / Blood Flow Velocity / Rectal Cancer / Region of Interest / Contrast Media / Tumor Imaging