Final answer:
The use of Number of Excitations (NEX) in MRI refers to repeating the same pulse sequence to enhance the signal-to-noise ratio of the image. It does not directly alter image contrast, flip angle, or field of view.
Step-by-step explanation:
Using Number of Excitations (NEX) in the context of magnetic resonance imaging (MRI) refers to Repeating the Same Pulse Sequence multiple times to improve the signal-to-noise ratio (SNR), which in turn can affect image quality. Each repetition allows for the signal generated by the excited nuclei to be recorded multiple times, thus enhancing the overall SNR of the acquired image.
In MRI, NEX does not directly increase image contrast or alter the flip angle; those are separate parameters that can be adjusted during the scan protocol. Similarly, NEX is not related to adjusting the field of view (FOV), which determines the size of the area being imaged and is adjusted based on the anatomical region of interest.
It's essential to note that while increasing NEX can improve image quality, it also results in a longer scan time, which may not always be feasible or comfortable for the patient.