Breast MRI Clinical Image Review Category C: Artifacts (Revised 12-12-19)
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Modified on: Fri, 13 Dec, 2019 at 11:24 AM
Excessive artifacts on any image may interfere with image interpretation. Although some artifacts may be unavoidable on certain images, others may be indicators of errors in pulse sequence selection details, inadequate equipment, or lack of preventive maintenance at an MRI facility.
The artifacts listed below are among the most common. All required images should be assessed to determine if any of these artifacts are present, especially if they could potentially compromise the diagnostic value of the images. Images will be reviewed for excessive artifacts that may interfere with image quality. Reviewers will not downgrade images for visible markers used to identify nipples or lesions or the presence of clip or metallic artifacts, unless they obscure the cancer or an entire breast.
Common Breast MRI Artifacts |
Motion/ghosting | Appear as periodic replication or partial replications of bright structures along the phase-encoding direction and could be due to patient motion, fluid pulsation including cardiac or vascular pulsation, unstable gradients, or other causes. |
Non-uniform/heterogeneous fat suppression | Appear as uneven darkening of the fat signal in different portions of the image set and may be due to either a heterogeneous magnetic field or a heterogeneous radiofrequency (RF) field. |
Aliasing/wrap artifacts | The image appears wrapped around onto itself. This is due to signal-producing tissue outside the selected FOV wrapping back into the displayed FOV on the opposite side of the image. If image wrap occurs, it is usually along the phase-encoding direction. Increasing the FOV or applying phase oversampling are the two most effective ways of eliminating or minimizing wrap artifacts. |
Truncation/ringing artifacts (edge ringing) | Appear as periodic parallel lines or ringing adjacent to borders or tissue discontinuities, in either the phase-encoding or frequency-encoding directions. This is due to selection of too small a matrix in one or both in-plane directions, occurring most commonly in the phase-encoding direction. |
Non-uniform/heterogeneous signal within breasts | This is due to RF heterogeneity, receiver coil non-uniformities, non-functioning coil elements, improper patient positioning, or metal in the magnet or on the patient. |
Susceptibility | Appear as localized field distortion or non-uniformities produced by differing tissue magnetic susceptibilities (especially at air-tissue interfaces). |
Chemical shift | Occurs along the frequency-encoding direction at fat/water soft tissue interfaces as a thin intense band of high or low signal. |
Geometric distortion | Occurs when size, orientation or shape is not accurately represented on the image. |
Filtering | Occurs when excessive software smoothing is used to reduce apparent noise in the image. Excessive filtering or smoothing obscures true anatomical structure through image blur and can reduce image contrast. |
RF leak (zipper artifact) | Appear as linear hyperintense or variable intensity lines parallel to the phase-encoding direction, often caused by unwanted sources of RF signals originating within (e.g., light bulbs or other electronic equipment) or outside the scanner room (e.g., RF signals penetrating the scan room because the door is open, the RF seal between the door and frame is damaged, or RF shielding is inadequate). |
Misregistration of subtracted images | On subtracted images, incomplete subtraction of background tissue signals occurs because pre- and post-contrast images do not register properly, usually due to patient motion. |
Revision History for this Article |
Date | Section | Description of Revision(s) |
12-12-19 | All | Article created; FAQs incorporated; No criteria changes |
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