(3) A special projection of the sigmoid colon (LPO) is sometimes done.
Details are as follows:
Anatomical. Sigmoid colon overlying the sacrum and left wing.
Film. 14 x 17.
(c) Position. Patient supine. Left hip down, right hip and trunk rotated
up to 30 to 60 (LPO-lateral posterior oblique) as indicated by fluoroscopy.
(d) CR. Align to center of film. Place area outlined fluoroscopically
over the center of the film.
Precaution. Suspended respiration.
(4) A special projection of the rectum (LAT) is also required at times
(figures 2-18 and 2-19). Details are as follows:
(a) Anatomical. Rectal ampulla, rectum, sigmoid, and a portion of the
Film. 10 x 12-inch.
(c) Position. Patient is left lateral recumbent position. Knees partially
flexed for support with a point 2 inches anterior post skin surface over the centerline of
table to upper border of film.
Align. CR to center of film.
(e) Precaution. Respiration suspended. Patient should be in true
lateral position and will sometimes require buttressing.
(5) The double-contrast (air contrast) barium enema involves the
simultaneous use of two types of contrast media--radiopaque in the form of residual
barium adhering to the mucosa; and radiolucent, or air, which is introduced by means of
an insufflator. In general, the procedure is as follows.
(a) Fluoroscopy and radiography are accomplished as for single-
contrast study. That is, the patient is screened, the colon is filled with contrast medium,
and exposures are made of the filled colon. The patient is then instructed to evacuate
as rapidly as possible (20-30 seconds).