Which imaging modality uses multiple X-ray measurements from different angles to create cross-sectional images?

• A. MRI
• B. CT scan
• C. Ultrasound
• D. Mammography

Answer: (B)

Computed tomography creates cross-sectional images by taking many X-ray measurements around the patient from different angles and then reconstructing them into slices. The scanner rotates around the body, collecting projections that are mathematically rebuilt into a volumetric set of axial images, which can be viewed as individual slices or in 3D. This cross-sectional capability is what makes CT distinct from other modalities. MRI uses magnetic fields and radiofrequency signals, not X-ray projections; ultrasound relies on sound waves to form images; and standard mammography provides 2D breast images rather than true cross-sectional slices.