CAMRT - Canadian Association of Medical Radiation Technologists Radiographic Procedures: Body Cavities Questions and Answers — Questions and Answers
Question 1: A patient is sent to the imaging department for a chest x-ray to rule out a small pneumothorax on the right side. In addition to the standard PA inspiration view, which of the following projections would be MOST beneficial to demonstrate this condition?
- Right lateral decubitus
- AP Lordotic
- PA expiration (Correct answer)
- Left lateral decubitus
Correct answer: PA expiration
A PA expiration chest x-ray is valuable for demonstrating a small pneumothorax. During expiration, the volume of the lungs decreases, which increases the relative density of the lung tissue. This makes the collection of free air in the pleural space (pneumothorax) more conspicuous and easier to visualize compared to the standard full inspiration view.
Question 2: For an AP erect abdomen radiograph, what is the recommended vertical centering point for the central ray to ensure the diaphragm is included?
- At the level of the iliac crest
- Approximately 5 cm superior to the iliac crest (Correct answer)
- At the level of the xiphoid process
- Midway between the xiphoid process and iliac crest
Correct answer: Approximately 5 cm superior to the iliac crest
To ensure the diaphragm is included on an AP erect abdomen, the central ray should be directed horizontally to the midsagittal plane and vertically approximately 5 cm (2 inches) superior to the level of the iliac crests. This higher centering is crucial for detecting free intraperitoneal air (pneumoperitoneum), a primary indication for this projection.
Question 3: Which of the following radiographic positions is specifically designed to demonstrate a small, free-flowing pleural effusion in a patient who is unable to stand?
- Lateral decubitus (Correct answer)
- AP axial lordotic
- Dorsal decubitus
- Ventral decubitus
Correct answer: Lateral decubitus
A lateral decubitus projection, with a horizontal x-ray beam, is the primary method for demonstrating fluid in the pleural cavity (pleural effusion) for non-ambulatory patients. To visualize the fluid, the patient is positioned to lie on the affected side, allowing the fluid to layer out along the dependent lateral chest wall.
Question 4: A physician orders an acute abdominal series on a patient who is too ill to stand. To assess for free intraperitoneal air, which projection best replaces the standard erect abdomen view?
- AP supine abdomen with a 15-degree cephalic angle
- Dorsal decubitus abdomen
- Right lateral decubitus abdomen
- Left lateral decubitus abdomen (Correct answer)
Correct answer: Left lateral decubitus abdomen
When a patient cannot stand for an erect abdomen, the left lateral decubitus projection is the standard substitute for detecting free intraperitoneal air. Placing the patient on their left side allows free air to rise and be visualized superiorly, against the homogenous density of the liver, and away from the gastric bubble.
Question 5: On a diagnostically acceptable PA chest radiograph, what is the minimum number of posterior ribs that should be visualized above the diaphragm to indicate adequate inspiration?
- 7
- 8
- 10 (Correct answer)
- 12
Correct answer: 10
A key evaluation criterion for a PA chest radiograph is adequate inspiration. This is generally confirmed when at least 10 posterior ribs are visible above the diaphragm. Visualizing fewer than 10 ribs can suggest a poor inspiratory effort, which may obscure pathology or mimic disease.
Question 6: Which of the following palpable anatomical landmarks is the most commonly used and reliable for centering a routine supine AP abdomen radiograph?
- Xiphoid process
- Iliac crest (Correct answer)
- Anterior Superior Iliac Spine (ASIS)
- Pubic symphysis
Correct answer: Iliac crest
The iliac crest is the most common and reliable landmark for centering a supine AP abdomen (KUB) radiograph. Centering the central ray to the midsagittal plane at the level of the iliac crests typically ensures that the resulting image includes the required anatomy, from the diaphragm to the pubic symphysis.
CAMRT - Canadian Association of Medical Radiation Technologists Radiographic Procedures: Body Cavities Questions and Answers
A patient is sent to the imaging department for a chest x-ray to rule out a small pneumothorax on the right side.
In addition to the standard PA inspiration view, which of the following projections would be MOST beneficial to demonstrate this condition?