Figure 63A: Axial contrast-enhanced CT scan of the appendix. The appendix is dilated and fluid-filled (arrows) with periappendiceal stranding. Figure 63B: Axial contrast-enhanced CT scan of the appendix of the same patient. The distal appendix is dilated and fluid-filled with appendiceal wall enhancement and periappendiceal stranding (arrow). An appendicolith is identified in the proximal appendix (arrowhead). Figure 63C: Grayscale ultrasound image of the right lower quadrant of a different patient shows a blind-ending, dilated tubular structure with thickened wall, consistent with a dilated, edematous appendix (arrows). Hypoechoic material fills the appendix. An echogenic round structure in the midappendix demonstrates posterior shadowing, compatible with an appendicolith (arrowhead). These findings are consistent with acute appendicitis.