Biomedical subjects
Publications and source records attributed to P E Coleman.
The authors, in a careful prospective study, report the accuracy of MRI to be comparable to that of pneumoarthrography and arthroscopy in the diagnosis of internal derangements of the knee.
High field MRI of the brain occasionally exhibits imaging artifacts; most artifacts are obvious and easily recognized, but some are subtle and mimic disease. A thorough understanding of brain MRI artifacts is important to avoid potential diagnostic pitfalls. Some imaging techniques or procedures could be utilized to remove or identify artifacts. These include additional projections, different pulse sequence, and 90 degree shift of phase-encoding gradient. The use of respiratory gating or cardiac gating may also improve image quality by reducing some of the motion-related artifacts.
MRI has undergone an incredibly rapid evolution, and technical advances are continually occurring. MRI allows for high resolution imaging that can clearly demonstrate a variety of degenerative processes of the spine. High-resolution MRI that gives detailed anatomic information, coupled with the use of MR contrast agents, promises to change our diagnostic approach significantly for degenerative disk disease of the spine.
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Cosmetics can produce severe distortion of the orbital contents in MR imaging. This distortion, typical of compounds that exhibit a permanent magnetic moment, results from iron oxide in the pigments used to produce dark shades of makeup. In general, the artifact created by cosmetics does not interfere with interpreting routine head scans. However, if the orbital contents are the subject of clinical concern, the images may then be rendered nondiagnostic. The artifact created by the makeup is propagated along the frequency-encoding axis of the images.
The process of creating MR images frequently gives rise to artifacts in the final display. Many artifacts may be corrected or ameliorated through an understanding of their cause. This requires familiarity with scanner design; theory of operation; and image acquisition, generation, and display. Some artifacts are obvious, totally degrading the image; others are regional, leaving much of the scan undisturbed. In some cases, the degradation is permanent; in others, the data can be reprocessed or manipulated to yield artifact-free images. Some artifacts are overt and easily identified. Others, such as those caused by phase-shift or gradient-strength effects, are subtle and require careful observation for detection.