1. A method of scanning an object, the method comprising the steps of: a) performing a native CT (nCT) scan and a CTA scan with a CT scanner on the object to obtain a set of images, wherein the performing at least one of the nCT scan and the CTA scan further comprises: performing the nCT scan with the CT scanner on the object to obtain an nCT image; and performing the CTA scan with the CT scanner on the object to obtain a CTA image; wherein the set of images includes the nCT image and the CTA image; b) detecting, via a configured hardware processor, characteristics of a region of interest based on the set of images, wherein the detecting further comprises: performing a registration on the nCT image and the CTA image to establish a spatial correlation; and detecting the characteristics of the region of interest based on the spatial correlation between the registered nCT image and the CTA image; and c) performing a CTP scan on the region of interest with the CT scanner by adopting the detected characteristics as at least one scan parameter to obtain a CTP image.