Correct option is D
Solution:
Let's analyze the statements:
(A) The static magnetic field used by MRI causes all the magnetically sensitive particles (protons) to align in the same direction. This is correct. MRI relies on aligning protons within a magnetic field to create the images.
(B) The pulse sequence used by MRI is an oscillating magnetic field that causes a perturbation in the static magnetic field. This is correct. The oscillating magnetic field (radiofrequency pulse) disturbs the alignment of the protons, which is essential for imaging.
(C) The receiver coil placed near a portion of the subject's body is a radiofrequency coil that records the relaxation time of protons. This is correct. The receiver coil captures the signals from protons returning to their equilibrium state after being disturbed by the pulse sequence.
(D) Various parameters of pulse sequence cannot be adjusted to maximize the ability to image certain substances. This is incorrect. In fact, MRI technicians can adjust several parameters, such as repetition time (TR), echo time (TE), and others to optimize the image quality for different tissues.
(E) The signal intensity received by the receiver coil can provide the location of the brain from which it is coming. This is incorrect. While MRI signals can provide the location of structures, simply measuring signal intensity alone does not directly identify the precise location of signals within the brain. It needs spatial encoding (via gradients) to determine the exact location.
