Which coil is used for joint imaging?

• A. Head coil
• B. Body coil
• C. Surface or circumferential whole-volume coil
• D. Gamma camera

Answer: (C)

Maximizing signal-to-noise ratio by coil proximity is what drives coil choice for joint imaging. A surface coil sits directly on or around the joint, capturing MR signals from the nearby tissues with much higher SNR than a larger, distant coil. Wrapping a circumferential whole-volume coil around a limb gives uniform, close-range detection across the joint, enabling high-resolution images with small voxel sizes to visualize delicate structures like cartilage, ligaments, and small effusions. In contrast, a head coil is specialized for brain imaging, a body coil is larger and provides lower SNR for superficial joints, and a gamma camera is for nuclear medicine rather than MRI. So, using a surface coil or a circumferential whole-volume coil yields the best image quality for joints.