Abdomen AP Upright is a radiography positioning projection of the Abdomen. Erect against vertical Bucky, back straight, arms at sides. SID 40". The centering point is located 2 inches above iliac crest at midline. The central ray is horizontal, perpendicular to IR at 2 inches above iliac crest at midline. Image-quality criteria include both hemidiaphragms included at the top of the image, as much of the lower abdomen as possible below the diaphragm. A sample technique is 85 kVp with DR 10 or CR 25 mAs, at an SID of 40 inches (102 cm).
Anatomy demonstrated
- Bilateral diaphragm.
- Liver and spleen outlines.
- Stomach bubble.
- Small bowel loops.
- Colon.
- Properitoneal fat layer (flank stripe).
Patient preparation
- Verify patient identity using two identifiers.
- Ask patient to remove all radiopaque objects from the abdomen and pelvis.
- Position patient standing upright against vertical Bucky.
- Instruct patient to stand straight, arms at sides.
- Keep the patient upright at least 5 minutes (10-20 preferred) before the exposure.
- Have patient breathe normally; suspend respiration on expiration.
Position & centering point
2 inches above iliac crest at midline.
Central ray
Horizontal, perpendicular to IR at 2 inches above iliac crest at midline.
Exposure / technique
- kVp
- 85
- mAs
- DR 10 / CR 25
- SID
- 40" (102 cm)
- Notes
- Grid required. Use the shortest exposure time possible; the erect position with a horizontal beam is what shows air-fluid levels. Sample technique: DR 10 / CR 25 mAs at 85 kVp, 40 in SID, for a 21 cm part (Merrill's sample chart). Adjust for your equipment.
kVp and mAs are sample values. Use caution when applying them in your department.
Image-quality criteria
- Both hemidiaphragms included at the top of the image.
- As much of the lower abdomen as possible below the diaphragm.
- No rotation: iliac wings symmetric.
- Air-fluid levels, where present.
- Free air, if present, seen as a crescent under the right hemidiaphragm.
- No motion blur; structures sharp throughout.
Common errors
- 1 Patient upright under 5 minutes (10-20 is desirable), so small amounts of free air may not show.
- 2 Patient too weak to stay erect: take a lateral decubitus instead.
- 3 CR too low excludes diaphragm and upper abdomen.
- 4 Patient motion blurs the diaphragm; ribs and all gas bubble margins should be sharp.
Clinical indications
- Acute abdominal pain evaluation (obstruction, perforation, free air).
- Bowel obstruction assessment.
- Pneumoperitoneum detection.
- Abnormal masses.