Figure 2.

US and CT of patient with perirectal abscess. Figure (A) demonstrates CT imaging of a patient with a perirectal abscess. Note the stranding in the soft tissue (white arrow) but lack of visualized abscess cavity as interpreted by the original radiologist, and (B) demonstrates sonographic imaging of the same patient (long axis orientation) with characteristic loss of soft tissue planes superior and lateral to an anechoic abscess cavity. An extension of the abscess cavity "points" towards the skin surface.