Which of the following factors is related to decreasing the area of received signal when using a small coil?

The focus of this question is on the relationship between coil size and the area of the received signal in MRI imaging. Using a smaller coil results in a decreased area of received signal primarily because smaller coils are designed to cover a smaller anatomical region. This reduction in size allows the coil to be more sensitive to the signals coming from that specific area, which can improve the quality of the received signal from a localized region.

When a coil is smaller, it inherently has a reduced coverage area compared to larger coils. Thus, while a smaller coil may enhance sensitivity for the area it is positioned over, it also contributes to a limited field of reception. This characteristic is crucial when performing targeted imaging, as it can accurately capture the desired anatomy while minimizing the influence of signals from surrounding tissues, which might otherwise degrade image quality.

Other aspects like signal-to-noise ratio (SNR) and artifact sensitivity are influenced by various factors, but the direct consequence of a smaller coil is a decreased area of the received signal, making option C the most pertinent to the question.