Professional and Linguistic Assessments Board (PLAB) Practice Exam

Which diagnostic imaging technique is used to rule out a fracture of the calcaneus?

1. X-ray

2. CT scan

3. Ultrasound

4. MRI

The correct answer is: X-ray

The use of X-rays is the standard initial imaging technique for evaluating suspected fractures, including those of the calcaneus (the heel bone). X-rays are readily available, cost-effective, and provide a good overview of bone structures. They can effectively show whether there is a fracture present by revealing any discontinuity in the bone cortex, displacement, or alignment issues. In the case of the calcaneus, X-rays can help identify common types of fractures associated with this area, such as those resulting from falls or severe impact. They are typically performed in multiple views, such as lateral and axial views, to give a comprehensive assessment. Other imaging modalities, like CT scans, may be used for a more detailed evaluation if a fracture is suspected but not clearly visible on X-ray. However, CT scans are not routinely the first step due to their higher cost and radiation dose. Ultrasound is generally not used for bone assessment and is more suited for soft tissue evaluations. MRI provides excellent detail for soft tissues and can identify bone marrow edema indicating a fracture or stress injury, but it is not usually the first choice for acute fracture diagnosis.