Three-dimensional assessment of susceptibility-induced signal voids caused by active cardiac implants in the setting of 3.0T CMR

TL;DR

This study develops a detailed 3D assessment method to evaluate susceptibility-induced signal voids caused by active cardiac implants in 3.0T cardiac MRI, considering device type, orientation, and sequence parameters.

Contribution

It introduces a reproducible approach for characterizing signal voids and their influencing factors in cardiac MRI with active implants at 3.0T.

Findings

Void shape depends on B0-field orientation and sequence type.

Void volume varies with device and sequence.

Field disturbances exceed visual signal voids.

Abstract

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.