This is the answer page to Case 3 from the page titled What is the Value of the Lateral Chest Projection?

• What is the Value of the Lateral Chest Projection?
• Patterns of Consolidation
• Pneumoperitoneum
• Pneumoperitoneum- Radiographic Techniques



PA Chest


This 39 year old male was admitted to hospital with "Inflammation of the colon ? Crohns disease" He was noted to have bibasal ''crackles'' and was referred for chest radiography with a question of chest infection PA erect chest radiography was performed.






There is suboptimal inspiration There is loss of visualisation of the right heart border (silhouette sign) suggesting right middle lobe disease (? false silhouette sign). There is retrocardiac lung density and airbronchogram lines indicating LLL airspace opacity. The appearance is complicated by atelectasis and suboptimal inspiration. The radiographer noted a subtle sign of subdiaphragmatic air (arrowed)

The lateral projection image demonstrates air interposed between the liver and diaphragm

There is a large air/fluid level in the stomach The lateral projection image demonstrates air interposed between the liver and diaphragm (arrowed) This appearance indicates pneumoperitoneum from perforated hollow abdominal visus. Contrary to popular belief, research findings and the author's experience suggest that the lateral chest centred on the diaphragm is the most sensitive projection for detection of pneumoperitoneum. see Pneumoperitoneum and Pneumoperitoneum- Radiographic Techniques