BARIUM ENEMA | PA / AP PROJECTION

POSTEROANTERIOR and / or ANTEROPOSTERIOR PROJECTION : BARIIUM ENEMA

Pathology Demonstrated:

• Obstructions, including ileus, volvulus, and intussuception, are demonstrated. Double contrast media barium enema is ideal for demonstrating diverticulitis, polyps and mucosal changes.

Technical Factors:

• IR size - 35 x 43 cm (14 x 17 inches), lengwise
• Moving or stationary grid
• 100 to 125 kV range for Single Contrast
• 90 to 100 kV range for Double Contrast
• 80 to 90 kV range for Iodinated, water soluble contrast media.
• mAs 4

Shielding of Patient on AP or PA Barium Enema:

• Place lead shield over gonads only if such shielding does not cover pertinent anatomy.
• Female ovarian shielding is not possible for full size Barium enema radiograph.

Patient Position on AP/PA Barium Enema:

• Patient is prone or supine, with a pillow for the head.

Part Position:

• Align Mid Sagital Plane (MSP) to midline of table.
• Ensure that no body rotation occurs.

Central Ray for PA or AP Barium Enema:

• Central Ray is perpendicular to Image Receptor.
• Center Central Ray to level of iliac crest.
• Center IR to CR.
• Minimum SID is 40 inches (100 cm)

Collimation:

• Collimate on four sides of margins of IR.

Respiration:

• Suspend respiration and expose on expiration.

Notes:

• For most patient the enema tip can be removed before overhead filming is done, unless a retention type tip is used. This type generally should not be removed until the patient is ready to evacuate. 
• Include rectal ampulla at lower margin of radiograph. Determine department policy regarding inclusion of the left colic flexure on all patients if this area is adequately included in spot images during fluoroscopy.
• Most adult patients require two images if this area is to be included.
• For hypersthenic patients, use two 35 x 43 centimeter 14 x 17 inch cassettes placed crosswise to include the entire large intestine.

Radiographic Criteria for PA / AP Barium Enema:

Structure Shown of PA or AP Barium Enema:

PA Barium Enema on Hypersthenic Patient

• The transverse colon should be primarily barium filled on the PA and air filled on the AP with a double contrast study.
• Entire large intestine, including the left colic flexure, should be visible (see notes).

Position:

• No rotation should occur.
• The ala of the ilium and the lumbar vertebrae are symmetric.

Collimation and Central Ray:

• Only minimal collimation margins are seen on all four sides for adults.
• CR is centered at level of iliac crest.

Exposure Criteria:

• Appropriate technique should visualize the entire air and barium filled large intestine without overexposing the mucosal outlines of those sections of primarily air filled bowel on a double contrast study.
• Sharp structural margins indicate no motion.