Magnetic Resonance Imaging (MRI) Practice Test

What type of coils are used with permanent magnets that have a vertical magnetic field?

1. Phased array coils

2. Surface coils

3. Array coils

4. Frequency coils

The correct answer is: Surface coils

Surface coils are commonly used with permanent magnets that generate a vertical magnetic field. These coils are designed to provide a high signal-to-noise ratio for imaging near the surface of specific anatomical regions. Since they are placed directly over the area of interest, surface coils excel in detecting signals from tissues that are close to the coil, making them highly effective for certain applications, such as imaging the brain or joints. The use of surface coils is particularly advantageous because they can be customized in size and shape to fit the anatomy being examined, allowing for improved imaging resolution and detail. Their ability to focus on a specific region helps to enhance the quality of the images obtained from areas closest to the coil placement. In contrast, other coil types like phased array coils and array coils are more typically used in systems with higher field strengths or where broader coverage is necessary. Frequency coils are not a standard classification used in MRI contexts, which makes surface coils the most appropriate choice for the scenario described.