CAMRT Radiography Practice Exam

Why is the caudal to cranial scanning direction commonly used in evaluating pulmonary embolism?

1. To enhance contrast visibility

2. To chase the contrast bolus

3. To minimize radiation exposure

4. To prevent motion artifacts

The correct answer is: To prevent motion artifacts

The direction of scanning from caudal to cranial is particularly advantageous in evaluating pulmonary embolism because it aligns with the natural flow of contrast material administered during the imaging process. By scanning in this manner, clinicians are able to effectively "chase" the contrast bolus as it travels through the vascular system, particularly into the pulmonary arteries where embolisms may occur. This approach optimizes the visibility of blood vessels and enhances the detection of any occlusions caused by emboli. Choosing this direction also aids in minimizing motion artifacts that can distort imaging results. This is particularly important in pulmonary imaging, where patient respiration can introduce motion. However, the primary reason for using the caudal to cranial approach in this context stems from the need to closely track the contrast as it moves, ensuring maximal clarity and diagnostic accuracy in identifying pulmonary embolism.