Abdominal X-ray Techniques and Analysis

Abdominal X-ray Projections

• Different projections exist for acquiring abdominal X-rays.
• The most common is the supine or erect anterior-posterior projection, where X-rays pass through the patient from front to back.
• (Fig. 1.34 & 1.35) illustrate this projection.

Normal Abdominal X-ray (AP View)

• (Fig. 1.35) displays a normal abdominal X-ray (AP view).
• Various organs and structures are visible, including the liver, spleen, kidneys, stomach, small intestine, colon, etc.
• The bowel's upper diameter limits (small bowel:3cm, colon:6cm, caecum:9cm) are general guidelines.

Interpretation of Normal Gas Patterns

• Gas/air within the bowel lumen creates a contrast against denser soft tissues.
• Differentiating between normal small and large bowel can be challenging, particularly when the bowel is distended.
• Normal bowel diameters (small bowel: 3cm, colon: 6cm, caecum: 9cm) are often used as reference points (3/6/9 rule).

Soft Tissues on Abdominal X-ray

• Notable soft tissues include the liver, spleen, kidneys, psoas muscles, bladder, and lung bases.
• The liver, typically a grey/bland area in the right upper quadrant (RUQ), is often evident with an upper edge that forms the right hemi-diaphragm.
• The breast shadow may overlay the liver. Markings of the right lung can be seen behind the liver.

Lung Bases on Abdominal X-rays

• Lung bases might be visible on posterior thoracic views, positioned behind the liver and diaphragm.
• (Fig. 1.37) illustrates this aspect.
• Costophrenic angles are possible landmarks.

Psoas Muscles on Abdominal X-rays

• The psoas muscles arise from lumbar vertebrae and combine with iliacus muscles.
• A near-straight line, representing these muscles' lateral edge, is often observed on X-rays.
• The iliacus muscles, lying over the iliac bones, are generally not directly visualized.
• Figure 1.38 provides an illustration.

Kidneys on Abdominal X-rays

• Kidneys' visibility is often due to contrast between the kidneys and surrounding low-density retroperitoneal fat.
• (Fig 1.39) depicts the kidneys.

Spleen on Abdominal X-rays

• The spleen typically lies in the left upper quadrant, adjacent to the left kidney.
• Visualized in (Fig 1.39).

Urinary Bladder on Abdominal X-rays

• The bladder's appearance varies based on its fullness.
• (Fig 1.41) is a representative image.

Bones on Abdominal X-rays

• Visible bones include lower ribs, lumbar spine, sacrum, coccyx, pelvis, and proximal femurs.
• Bones serve as landmarks for internal structures (e.g., transverse processes of the lumbar vertebrae, vesico-ureteric junctions).
• (Fig. 1.42) displays labeled abdominal and pelvic X-rays.

This quiz covers the various projections used in abdominal X-rays, particularly the supine and erect anterior-posterior views. It includes details on interpreting normal gas patterns and soft tissues observed in X-ray images. Understand the anatomy and normal diameter limits for bowel structures represented in X-rays.