MRI Physics Chapter 8 Questions and Answers Graded A+

MRI Physics Chapter 8 Questions and Answers Graded A+ What is the primary cause of ghosting artifacts in MRI? Patient motion during the scan How does increasing the field of view (FOV) affect resolution? It lowers resolution but captures a larger anatomical area What is the function of the pre-scan calibration in MRI? It optimizes system settings for better image quality Why is a quadrature coil used in MRI? To improve signal reception by detecting signals in two orientations What is the significance of bandwidth in MRI imaging? It affects SNR and reduces susceptibility to artifacts 2 How does slice gap influence image quality in multi-slice MRI? Too small a gap can cause cross-talk between slices What is the effect of increasing gradient strength in diffusion-weighted imaging? It enhances sensitivity to water movement in tissues Why are low flip angles used in gradient echo sequences? To maintain steady-state signal and reduce scan times What is the purpose of a saturation pulse in MRI? To suppress unwanted signals from specific tissues Why is T1 relaxation faster in fat than in water? Fat molecules have a higher interaction rate, leading to quicker relaxation What is the primary function of gradient coils in an MRI system? To spatially encode the MRI signal 3 How does increasing the magnetic field strength affect signal-to-noise ratio (SNR)? It increases SNR, improving image quality What is the purpose of the RF pulse in MRI? To excite hydrogen protons and flip their alignment Why is T2 relaxation important in MRI imaging? It helps differentiate tissues based on their decay rates What happens when the TR (Repetition Time) is shortened? It increases scan speed but reduces signal intensity Why is a 90-degree RF pulse commonly used in spin-echo sequences? It maximizes transverse magnetization for signal detection What is the role of phase encoding in MRI? To assign spatial location to signals in the image 4 Why is a Fourier transform used in MRI image reconstruction? To convert raw frequency data into a spatial image What effect does increasing the number of phase encoding