  Recent technical advancements allow cardiac MRI (CMR) examinations in the
presence of so-called MRI conditional active cardiac implants at 3.0T. However,
the artifact burden caused by susceptibility effects remain an obstacle. All
measurements were obtained at a clinical 3.0T scanner using an in-house
designed cubic phantom and optimized sequences for artifact evaluation (3D
gradient echo sequence, multi-slice 2D turbo spin echo sequence), as well as
reference sequences according to the ASTM were applied. Four representative
active cardiac devices and a generic setup were analysed regarding volume and
shape of the signal void. For analysis, a threshold operation applied to the
grey value profle of each data data set was used. The presented approach allows
the evaluation of signal void and shape even for larger implants such as ICDs.
The void shape is influenced by the orientation of the B0-field and the chosen
sequence type, as well as the distribution of magnetic material within the
implants. The void volume depends both on the device itself, and the sequence
type. Disturbances in the B0 and B1 fields exceed the visual signal void. This
work presents a reproducible and highly defined approach towards characterising
both signal void artifacts at 3.0T and their influencing factors.
