Gradient echo (GRE) and echo-planar sequences should be avoided because they accentuate susceptibility artifacts. in postoperative patients with metallic hardware. Iterative decomposition of water and fat with echo asymmetry and the least-squares estimation (IDEAL) is a recently developed sequence which separates fat and water with a very high signal-to-noise-ratio (SNR), is insensitive to magnetic field inhomogeneity and reduces metallic artifacts, e.g. However, it is not always possible and not always improves the image quality in a significant way. The artifacts are less prominent in fast SE (FSE) than in conventional SE sequences. The best way to reduce the severity of susceptibility artifacts caused by metallic foreign bodies is to use spin echo sequences (SE) with a short echo time (TE). вЂ“ group C вЂ“ foreign bodies that are not known to the MRI unit personnel because the patients forget about them, do not know about them or do not report them in the questionnaire they fill in before the examination.Дifferent sequences are sensitive to these objects to various degrees ( Figure 10). All examinations were performed with use of GE Signa HDxt scanners with a magnetic field strength of 1.5 T. The authors presented a gallery of such images. The aim of this article was to present different types of artifacts and appearances of various foreign bodies within the patientвЂ™s body in magnetic resonance imaging in order not to confuse them with pathological conditions. Spike noise artifacts, resembling checkered pattern on the clothes, are caused by static electricity from clothing or blankets and are not necessarily related to metal вЂ“ they may be caused by acrylic materials. We had a case of a patient who wore only a white singlet during the examination which seemed to be made of cotton (!) and the artifact disappeared after she had taken it off. Sometimes it is not necessarily a visible metallic element like in the case presented in Figure 10. In brain MRI such artificial FLAIR-hyperintensity in the subarachnoid space may lead to a false diagnosis of subarachnoid hemorrhage ( Figure 10A). in the clothes, may result in FLAIR-hyperintensity due to a magnetic susceptibility artifact. Metallic objects, not only within the patientвЂ™s body but also on the patient, e.g. Sagittal projection shows directly the source of the artifact located on the arm ( F вЂ“ FSE/T2, sag). The artifacts are almost invisible in SE/T1-weighted sequence ( D) and in FSE/T2 ( E вЂ“ note that only the lens in the right eye ball shows abnormal signal intensity). Gradient echo sequences ( B) and DWI ( C) are very sensitive to artifacts, especially those produced by metallic objects. This artifact from clothing ornament вЂ“ hyperintense signal on FLAIR sequence вЂ“ may raise the suspicion of subarachnoid hemorrhage. Describing in detail the procedures to avoid or limit the artifacts would go beyond the scope of this paper but technical ways to reduce them can be found in the cited literature. Some proposals of reducing artifacts have been mentioned. It is also necessary to take them into consideration when interpreting the images. Knowledge of different types of artifacts and their origin, and of possible foreign bodies is necessary to eliminate them or to reduce their negative influence on MR images by adjusting acquisition parameters. make-up, tattoos, hairbands, clothes, endovascular embolization, prostheses, surgical clips, intraorbital and other medical implants, etc. Metallic and other foreign bodies which may be found on and in patientsвЂ™ bodies are the main group of artifacts and these are the focus of this study: e.g. An artificially hyperintense signal on FLAIR images can result from magnetic susceptibility artifacts, CSF/vascular pulsation, motion, but can also be found in patients undergoing MRI examinations while receiving supplemental oxygen. Aliasing artifacts can be eliminated by increasing the field of view. Motion artifacts caused by breathing, cardiac movement, CSF pulsation/blood flow create a ghost artifact which can be reduced by patient immobilization, or cardiac/respiratory gating. A truncation artifact in the spinal cord could be misinterpreted as a syrinx.

A gallery of such images was presented in this manuscript. Radiologists are frequently not informed about the medical history of patients and face postoperative/other images they are not familiar with.

Artifacts in magnetic resonance imaging and foreign bodies within the patientвЂ™s body may be confused with a pathology or may reduce the quality of examinations.

Artifact meaning in it