MEDRADSC 3DE3 Lecture Notes - Lecture 9: Spin–Lattice Relaxation, Chemical Shift, Field Of View

• School: McMaster University
• Department: Medical Radiation Sciences
• Course: MEDRADSC 3DE3
• Professor: Alana Trainor

Document Summary

Review: list 4 consequences of decreasing the tr. Shorter scan times, fewer slices, increased t1 weighting, decreased snr (when tr is very short: list 3 consequences of decreasing the phase matrix. Increased sr (good) - decreased snr, shorter scan time, truncation artifacts: list the 3 factors that affect snr & image contrast. Tr, te, flip angle: list the 3 consequences of decreasing the nsa. Shorter scan time, decreased snr, increased motion artifact: list the 3 consequences of decreasing the received bandwidth. Bc as the field strength increases, chemical shift b/n fat & water increases. You could increase frequency matrix, use an asymmetric fov if anatomy fits into a rectangle. Multiple imaging acquisitions are required to adequately evaluate patient - use several protocols over an area to bd all the tissue. Mri typically utilizes t1 weighted images with high intrinsic snr to evaluate anatomy & t2 weighted images with low snr but high intrinsic contrast to evaluate pathology.