In which type of MRI system is the patient fully enclosed?

• A. Open MRI
• B. Closed MRI
• C. Extremity MRI
• D. Functional MRI

Answer: (B)

The correct answer is the type of MRI system where the patient is fully enclosed is Closed MRI. In Closed MRI systems, the magnetic field is generated by a large, cylindrical magnet that surrounds the patient completely as they lie on a table that slides into the machine. This design is beneficial for producing high-resolution images with excellent signal-to-noise ratios, thus allowing for detailed and accurate diagnostic information.

In contrast, Open MRI systems have a more open design that partially surrounds the patient, which can help alleviate feelings of claustrophobia for some patients but may sacrifice image quality compared to closed systems because of the lower field strength and increased distance from the magnet. Extremity MRI focuses specifically on imaging arms and legs rather than the whole body, often utilizing a smaller device that fits around the extremity being examined. Functional MRI (fMRI) is specifically used to assess brain activity by measuring changes in blood flow, rather than being defined by the enclosure of the patient.