Abdomen (PA prone view)

The PA prone radiograph is rarely performed and is often utilized when a patient is unable to lay supine. The projection is adequate for the examination of the abdominal cavity, however, not as practical for the renal structures due to magnification.

Indications

This view is useful in visualizing bowel obstruction, neoplasms, calcifications, ascites and as scout images in contrast medium studies of the abdomen (i.e. intravenous urography).

It is not ideal if the kidneys are the primary interest as there is magnification from an increased object to image distance.

Patient position

• the patient is prone, either on the x-ray table (preferred) or on a trolley
• patients should be changed into a hospital gown, with radiopaque items (e.g. belts, zippers) removed
• the patient should be free from rotation; both shoulders and hips equidistant from the table/trolley
• the x-ray is taken in full inspiration

Technical factors

• PA projection
•  centering point
  • the midsagittal place (equidistant from each PSIS) at the level of the iliac crest
• collimation
  • laterally to the lateral abdominal wall
  • superior to the diaphragm
  • inferior to the inferior pubic rami
• orientation
  • portrait
• detector size
  • 35 cm x 43 cm
• exposure
  • 70-80 kVp
  • 30-120 mAs; AEC should be used if available
• SID
  • 100 cm
• grid
  • yes

Image technical evaluation

• lateral abdominal wall should be included
• inferior pubic rami should be included inferiorly
• if possible, the diaphragm should be included superiorly
• the abdomen should be free from rotation with a symmetry of the:
  • ribs (superior)
  • iliac crests (middle)
  • obturator foramen (inferior)
• no blurring of the bowel gas due to respiratory motion

Practical points

For larger patients, it may be necessary to perform two x-rays using a landscape orientation of the detector to include the entire abdomen.

Exposure will need to be adjusted according to an imaging system (CR or DR) and patient size. Where possible mAs should be manipulated to ensure adequate image density and appropriate image contrast.

Ensure the patient has adequate head space to breath and hear instructions.