Cupping artifact

Abstract— It is well known that contamination of CT data with scattered radiation rednces reconstrncted CT numbers and introduces cupping artifacts in the reconstructed images. This effect is more pronounced in multi detector CT scanners with extended detector aperture mostly using cone-heam configurations, which are much less immune to scatter than fan-heam and single-slice CT scanners. Accurate... 

Contrary to the results for labile Ni, the gradients of relative concentrations of dissolved Ni obtained with the model including exudation (Model 3) matched water-extractable Ni data better (Fig. 2b). The curves produced by the other models were more discrepant. Water extracts may not represent real soil solutions and freezing of soil samples might have introduced additional artifacts. However, gradients of Ni concentration in soil solution were not available. Water-extractable Ni data in Fig. 2b are presented for orientation but caimot be used for proper model corroboration. All simulated curves were opposite to the trend implied by measured water-extractable Ni. Accumulation of solutes near the root is known for excluders or for situations where convective flow toward the root exceeds plant demand. This was not the case in our experimental system. In future experiments, the use of microsuction cups will enable comparison of simulated and measured dissolved Ni (Wenzel et al., 2001). 

The appearance of cupping and shadowing artifacts due to scatter can be very similar to those created by beam hardening (Ruehrnschopf and Kalender 1981). Contrary to beam hardening, however, a decrease in differential contrast and an increase in noise are typical consequences of scatter. 

Fig. 12.65a-f. Acetabular cup for hip replacement, a Photograph, b standard radiograph and c in vitro US appearance of an acetabular spiral screwed cup. US depicts the cup as a hyperechoic structure with reverberation artifact characterized by a series of external teeth arrowhead), d-f Schematic drawings of a sagittal view through the anterior hip illustrate d a normally positioned cup, e,f an anterior protruding cup resulting in e iliopsoas bursitis asterisks) and f tears of the undersurface of the iliopsoas muscle arrowheads). A, native acetabulum Ac, acetabular cup H, head of the prosthesis N, neck of the prosthesis F, femoral bone... 

The T, is the sum of Xp over all the possible jth processes of heat loss during cooling. Conducting experiments under identical conditions is necessary to minimize artifacts arising from processes such as radiation, source/drain volume ratio, exposure area, and container material. For instance, cooling one drop of 1 mL water needs shorter time than cooling one cup of 200 mL water at the same d, under the same conditions. 

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