CDS | Interpreting Abdominal X-Ray Radiographs for Medical Students

Abdominal X-Rays

• An erect abdominal x-ray is advantageous over a supine film because it allows for better demonstration of free gas under the diaphragm.

Abbreviations and Definitions

• AXR stands for Abdominal X-Ray.

Radiation Dose

• An abdominal radiograph (AXR) has a radiation dose equivalent to 0.05-0.5 mSv.

Series on Interpreting Plain Abdominal Radiographs

• The subsequent parts of the series will cover the approach to interpreting plain abdominal radiographs, including normal and abnormal findings.

Decubitus Film

• A decubitus film is taken with the patient in the lateral decubitus position for abdominal radiographs.

Radiation Dose Equivalent of Different X-Rays

• A KUB (Kidneys, Ureters, Bladder) x-ray has a radiation dose equivalent to 50 posteroanterior chest x-rays.

Appearance of Metallic Objects

• A metallic object appears as a dense, white, or extremely opaque structure in a plain radiograph.

Distinguishing Normal Small Bowel from Normal Colon

• Normal small bowel is distinguished from normal colon by its feathery appearance and central location, while the colon is peripheral and has a haustral pattern.

'Mottled' Appearance

• A 'mottled' appearance in a plain radiograph indicates bowel ischemia or infarction.

Gas in the Portal Vein

• Finding gas in the portal vein on a plain radiograph is significant because it indicates bowel necrosis or infarction.

Appreciating Normality in Plain Radiographs

• The best approach to appreciate normality in plain radiographs is to examine the film systematically, assessing the lung bases, diaphragm, liver, spleen, kidneys, stomach, small bowel, and colon.

Gastric Pseudotumor

• A 'gastric pseudotumor' on a supine film represents a normal stomach bubble.

Differentiating Normal Small Bowel from Normal Colon

• Normal small bowel is differentiated from normal colon by its central location, feathery appearance, and lack of haustral pattern.

Assessing Technical Details

• The main purpose of assessing the technical details of an abdominal radiograph is to ensure the film is adequate for interpretation.

Viewing an Abdominal Radiograph

• When viewing an abdominal radiograph, one should note the patient's position, kilovoltage, and exposure.

Absence of Bowel Dilatation or Extraluminal Air

• The absence of bowel dilatation or extraluminal air on an abdominal radiograph indicates a low risk of bowel obstruction or perforation.

Densities in Chest Radiographs

• Differences in densities are important for clarity of outlines on chest radiographs.

Normal Finding in the Left Upper Quadrant

• A normal finding within the left upper quadrant on an abdominal radiograph is the stomach bubble.

Iatrogenic Structures

• Examples of iatrogenic structures that may be identified in an abdominal x-ray include surgical clips, intrauterine devices, and pacemakers.

Loss of Properitoneal Fat Planes

• The loss of properitoneal fat planes surrounding the major abdominal organs may indicate inflammatory or malignant processes.

Identifying Vertebrae

• The L3 or L4 vertebral body serves as a useful reference point for identifying vertebrae in an abdominal x-ray.

Iatrogenic Objects

• Examples of iatrogenic objects that may be identified in an abdominal x-ray include bullets, per rectum objects, and surgical staples.

Renal Outline

• The usual length of the renal outline in an abdominal x-ray is 10-12 cm.

Location of Kidneys

• The kidneys are usually located in the upper retroperitoneum in an abdominal x-ray.

Pelvic Structures

• If full within the pelvis, the bladder can be observed more clearly on an abdominal x-ray.

Artifacts

• Artifacts that may be seen on an abdominal x-ray include pyjama buttons, coins in pockets, or body piercings.