What is another type of MRI coil used for close proximity imaging?

• A. Endocavity coils
• B. Surface coils
• C. Phased array coils
• D. Birdcage coils

Answer: (A)

The main idea here is that signal strength improves when the coil is very close to what you’re imaging. Endocavity coils are small, flexible coils that are placed inside a body cavity (such as endovaginal or endorectal) so they sit directly next to the tissue of interest. That close proximity dramatically boosts the signal-to-noise ratio for the region being imaged, allowing high-resolution images of internal pelvic structures or prostate tissue. That’s why endocavity coils are particularly suited for close-proximity imaging.

Surface coils sit on the skin and best image tissues near the surface, while phased array coils are multiple small elements that can be configured in various ways to improve SNR and enable parallel imaging, and birdcage coils are volume coils that provide uniform coverage for larger regions but aren’t specialized for close-in imaging.