MRI Physics Chapter 9 Questions and Answers Rated A+

MRI Physics Chapter 9 Questions and Answers Rated A+ What is the primary function of k-space in MRI? It stores raw data before image reconstruction. How does increasing the number of phase-encoding steps affect image resolution? It improves resolution but increases scan time. What is the main purpose of applying a gradient in MRI? To spatially encode signals and create images. Why does a stronger magnetic field improve signal-to-noise ratio (SNR)? It increases the alignment of protons, enhancing signal strength. What happens to T1 relaxation time when the magnetic field strength increases? It becomes longer, requiring longer TR values for proper contrast. 2 Why is T2-weighted imaging useful for detecting pathology? It highlights fluid and edema, making abnormalities more visible. What is the purpose of the Fourier transform in MRI? It converts raw data from k-space into an image. How does decreasing slice thickness affect spatial resolution? It improves resolution but may reduce signal strength. What is the relationship between voxel size and image detail? Smaller voxels improve detail but require longer scan times. Why is gradient echo imaging more sensitive to magnetic field inhomogeneities? It does not use a 180-degree refocusing pulse, making it more susceptible to artifacts. How does increasing the echo time (TE) affect T2-weighted images? It enhances contrast between tissues with different T2 relaxation times. 3 What is the main advantage of parallel imaging techniques in MRI? They reduce scan times by acquiring fewer phase-encoding steps. Why does increasing the number of signal averages (NEX) improve image quality? It reduces noise by averaging multiple signals. How does a shorter TR (Repetition Time) affect T1-weighted images? It enhances T1 contrast but may reduce overall signal intensity. What effect does a longer TE have on image quality? It increases T2 weighting but can lead to more noise. Why is fat suppression used in MRI imaging? It removes fat signal to improve contrast and lesion detection. What is the role of RF pulses in MRI? They excite hydrogen protons and create measurable signals.