Figure 14. “Dense waterfall” artifact related to the active flow of opacified fluid during scanning.
Transverse (A) and sagittal (B) 2D CTC images shows focal artifact in the left colon related to flowing tagged fluid, which consists of characteristic arciform white and black streaks. The flow between differential air-fluid levels (arrowhead) is best seen on the sagittal view (B). The associated 3D artifact (C) prevents adequate evaluation of the involved region (arrow). In such cases, the alternate position (E and F) is critical for assessment in such cases.