In MRI, which coil is responsible for transmitting the RF pulse to the patient's body?

• A. Body coil
• B. Receiver-only surface coil
• C. Phased-array coil
• D. Multi-channel coil

Answer: (A)

The body coil is specifically designed for transmitting radiofrequency (RF) pulses to the patient's body in MRI. This coil is typically larger and covers a wide area, allowing it to provide effective transmission across various regions of the body. It plays a crucial role in generating the necessary magnetic field, which excites the hydrogen nuclei in the body, leading to the emission of signals that can be captured for image reconstruction.

Using a body coil for transmission is advantageous because its design optimizes the uniformity and strength of the RF pulse across a large volume, which is essential for imaging of the whole body or larger anatomical structures. This capability is fundamental for obtaining high-quality images with adequate signal strength.

In contrast, other coils mentioned focus more on receiving signals rather than transmitting RF pulses. The receiver-only surface coil and phased-array coils, while effective in receiving signals with high sensitivity from localized areas, do not perform the function of transmitting the RF energy into the patient. Multi-channel coils can encompass both transmitting and receiving functions but are often employed in conjunction with a body coil for transmission purposes.