Perirectal inflammatory disease: CT findings.

The findings on computed tomographic (CT) scans were reviewed in 42 patients with perirectal inflammatory disease and suspected perirectal abscesses. CT was reliable for use in distinguishing perirectal abscesses from cellulitis and in localizing both supralevator and infralevator abscesses. CT allowed correct diagnosis of 13 surgically proved perirectal abscesses in ten patients, including three with residual abscesses after surgical drainage.

CT of subpulmonic pleural effusions and atelectasis: criteria for differentiation from subphrenic fluid.

The ability to distinguish intrathoracic from intraabdominal fluid collections has important therapeutic implications. In the setting of peridiaphragmatic fluid collections CT accurately distinguishes between pleural and subphrenic fluid collections in most cases. Subpulmonic effusions represent a potential pitfall to CT diagnosis, however, because the atelectatic basilar lung segments appear on axial CT sections as a curvilinear band density that simulates the hemidiaphragm.