ABSTRACT

With the enormous effort devoted by scientists and researchers to making it more potent for clinical excellence, X-ray computed tomography (CT) has been one of the most popular imaging modalities in the clinic for saving patients' lives or improving their quality-of-life. In general, each aspect of CT's imaging performance may not be the best in the clinic in comparison to other imaging modalities. For instance, the contrast resolution of CT for soft tissue differentiation is not as high as that of PET/SPECT (positron emission tomography/single-photon emission computerized tomography) or MRI (magnetic resonance imaging), the temporal resolution of CT may be inferior to that of MRI when special pulse sequences, for example echo planner imaging (EPI), are employed. Furthermore, the spatial resolution of CT is not as good as that of ultrasound when only a small and shallow region of interest (ROI), for example carotid, is being imaged. However, putting all the resolutions together, it is quite fair to say that CT is the best and most robust imaging modality to fulfill the requirements imposed by the vast majority of clinical applications. This underlies the fact that CT has been playing 638an indispensable role in management of the diseases or accidents that are listed as the first five leading causes of death in the US (Table 32.1) (Heron 2016).