1.5T vs 3T MRI - artefakty w skanach

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1.5T versus 3T MRI


Chemical shift is a little confusing if without a basic understanding of the physics of MRI. When a body is placed into an MRI scanner, the Hydrogen protons in the body resonate (vibrate) to a specific frequency (hence the Resonance in MRI). This frequency will be slightly different in every part of the body (i.e., muscle, fat, water, blood, bones). Chemical shift is the spatial displacement of water and fat due to those differences in frequency. This artifact is not typically noticeable in a 1.5T scanner but doubles when seen in the 3T scanner.
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MRI of the prostate is very unique. The location of the prostate is deep in the pelvis which requires a great deal of signal to get diagnostic images.
If there are no prosthetic implants, this is easily achieved with a 3T scanner.
It is also achievable in a 1.5T scanner if a high quality specialty coil designed specifically for prostates is used (such as that employed by FirstScan).

However, there is one important image that is taken during the prostate scan called a Diffusion, which is very sensitive to the artifact discussed above called chemical shift.
If the rectum (which is located right behind the prostate) has a large amount of gas, it will cause severe artifact in the images.
In some cases, it can be to the point that the images are no good and cannot be interpreted by a radiologist. Therefore, it is very important that all the pre-scan patient preparations listed by the imaging center be followed as closely as possible.
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https://www.scanmed.com/single-post/201 ... sus-3T-MRI