[Proposal for contrast-amplified image reconstruction methods by adjusting computed tomography value scale in three-dimensional image processing].

To create three-dimensional computed tomography angiography (3D-CTA) images of blood vessels, it is important to acquire a high-contrast original image of the blood vessels and the surrounding tissues. However, reexamination is likely to be needed if, due to the condition of the examinee, insufficient contrast enhancement is achieved. This prompted us to design a method of amplifying image contrast using software that simply adds the CT value to each corresponding pixel of the original image, i.e., the same image is added after the scan. This prevents spatial and time discontinuities with the original image. The CT value of the original image can also be increased arbitrarily to any value by adjusting the weighting level of the added image. The difference in CT values between the pixels can thus be amplified without changing the contours of the original image. Since this method enables the original image's contrast to be amplified by post-processing, i.e., without increasing radiation load exposure or employing additional contrast medium, it is a technique with high clinical utility.