Polyp Conspicuity

As with optical colonoscopy, tagged stool frequently abuts a lesion. This makes polyps more conspicuous for detection (Figs. 4.8, 4.9, and 4.10). In these cases polyp conspicuity is improved using soft tissue settings. 

Fig. 4.9.a Small amount of barium abutting a lesion (arrowhead) in the sigmoid and hence improving polyp conspicu-ity. b Improved depiction of the lesion in soft tissue settings, c The prone view shows a partially collapsed sigmoid. The barium again delineates the lesion improving visualisation (white arrow)... 

It has been observed that polyp conspicuity decreases when pitch increases, in particular on three-dimensional reconstructions (Bachman et al 1997). 

Nevertheless, it was found that, regardless of the method used to develop competence, the result is a conspicuous increase in the concentration of the PolyP-PHB complexes in the plasma membranes. When formation of the complexes is prevented by any means, transformation is inhibited (Reusch et al, 1986 Huang and Reusch, 1995). DNA binding... 

Several species of stalked, plantlike hydrozoans and octo-corals form small colonies in shallow intertidal waters. These organisms spend part of their lives as medusae and part as polyps. Like anemones, they gather food with their small tentacles. A less common but more conspicuous cnidarian along the shore is the jellyfish. Most jellyfish found in the intertidal zone are simply washed in, although the stalked jellyfish makes its home there. 

Although sessile polyps have a high conspicuity, if located between folds (Fig. 8.11), those lesions may remain undetected in case the lesions are located on a semilunar fold (Fig. 8.12). 

An improvement in the detection performance can be achieved because CAD can reduce radiologists perceptual errors during the detection of polyps. These perceptual errors may be caused by the presence of normal structures that mimic polyps or by variable conspicuity of polyps, depending on the display method (Beaulieu et al. 1999 Fletcher et al. 1999 Johnson and Dachman 2000 Karadi et al. 1999 McFarland 2002). The absence of visual cues that normally exist with colonoscopy, such as mucosal color changes and a large number of images for each patient, also makes image interpretation tedious and susceptible to perceptual error. 

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