Final answer:
Increasing receiver bandwidth in MRI reduces chemical shift artifacts but may increase the severity of metal artifacts due to the amplified effect of magnetic field inhomogeneities around metal on the local resonance frequencies.
Step-by-step explanation:
Increasing the receiver bandwidth (rBW) in magnetic resonance imaging (MRI) can have various effects on image quality, specifically regarding chemical shift artifacts and metal artifacts. Chemical shift artifacts occur due to the difference in resonance frequencies between fat and water. A higher rBW helps to reduce chemical shift by making the MRI less sensitive to slight variations in frequency attributable to different chemical environments.
However, when it comes to metal artifacts, which are distortions in the MRI image resulting from the presence of metallic objects within the field of view, increasing the rBW has a less beneficial effect. Metal artifacts are partly due to magnetic field inhomogeneities caused by metal that affect the local resonance frequencies. Increasing the rBW tends to amplify these inhomogeneities, resulting in worse metal artifacts.