Artifacts are unavoidable in MRI. Even when the MR scanner is functioning correctly, specific imaging parameter choices will produce artifacts. This section describes the artifacts seen most commonly in cardiac MRI and proposes solutions for their reduction or removal.

Gradient Decay or Fall-Off
This artifact occurs as a result of excitation and reception of signal from tissue in the falloff zone of the spatial encoding gradients, particularly in the superior-inferior direction. Spatial encoding gradient fields decay from their maximum amplitude to zero outside the physical dimensions of the gradient coil. RF excitation and reception of signal from tissue
within the fall-off zone of these gradient fields results in tissue at an incorrect physical location being mapped onto the reconstructed image. This can also occur when the RF coil used for excitation is larger than the physical extent of the gradient encoding fields.

Some suggested Solutions:
? Use receive-only coils that do not extend beyond the anatomical region of interest.
? If anatomical coverage is large and multicoil element surface coils are used, only those
coils that cover the region of interest should be selected.
? Place saturation bands over those regions in the fall-off zone of the gradient fields.
? Use transmit-receive RF coils. For cardiac applications this is usually not practical
because the body RF coil typically must be used for transmission and provides images
with lower signal-to-noise ratio when used as a transmit-receive coil.
? For dual gradient systems, switch to the larger FOV gradient set.
? Apply any of the solutions listed to solve “aliasing” as will be described in the next article.