Which imaging modality uses a magnetic field and radio waves to produce images?

Which imaging modality uses a magnetic field and radio waves to produce images?

• A. CT scan
• B. Ultrasound
• C. MRI
• D. X-ray

Answer: (C)

MRI uses a strong magnetic field to align hydrogen protons and radiofrequency pulses to disturb that alignment; when the protons realign, they emit signals that are captured and converted into detailed images. This combination of magnetic field and radio waves is unique to MRI, giving excellent soft-tissue contrast without using ionizing radiation. In contrast, CT and X-ray rely on ionizing radiation and differences in tissue density to create images, while ultrasound uses sound wave echoes. So the modality described—imaging produced from a magnetic field and radio waves—is MRI.

MRI uses a strong magnetic field to align hydrogen protons and radiofrequency pulses to disturb that alignment; when the protons realign, they emit signals that are captured and converted into detailed images. This combination of magnetic field and radio waves is unique to MRI, giving excellent soft-tissue contrast without using ionizing radiation. In contrast, CT and X-ray rely on ionizing radiation and differences in tissue density to create images, while ultrasound uses sound wave echoes. So the modality described—imaging produced from a magnetic field and radio waves—is MRI.