The use of iodinated contrast agent is common in CT scanning of the head. However, the use of the agent is relatively costly, and may result in an adverse reaction in some patients. It is of interest to investigate the possibility of reducing the amount of contrast material without sacrificing the diagnostic information. We developed an algorithm and software to simulate "intermediate" images based on two input images of head CT scans performed on the same patient, captured at the same angle. A non-linear relationship between CT image intensity and the amount of contrast agent necessitates a guideline curve derived from the image statistics to generate visually realistic simulated CT images. The study shows that the saturation time detected is equivalent to 60 - 70 % of total injected contrast agent. The development also includes adjustable enhancement to the lesion area and its edges. By using the iodine-contrast-agent guided curves, the lesion area can be enhanced adjustably. For flexibility and immediate display, the edge can be scalable by a certain factor to add on the original image for image enhancement. Enhancement on lesion area and its edges improves the visualization quality.