Influences of magnetic attachment for implant on MRI scanMaruo R, Imaizumi N, Muto R, Suzuki Y, Ohkubo C
Depart of Removable Prosthodontics，Tsurumi University School of Dental Medicine
Abstract【Introduction】
In recent years, due to advances in medical technology, MRI has been frequently used. Along with
this, it has been considered that metal artifacts during MRI scanning affect diagnosis. In this time,
influences of the magnetic attachment for implants on MRI were discussed.
【Materials and Methods】
Magnetic attachments for implants (Magfit MIP, Magfit IP), cast keeper, and healing abutment wereused as samples. Each sample was placed in an acrylic container (150 mm x 150 mm x 150 mm),and filled with an aqueous solution of nickel nitrate using an acrylic jig. Four types of imaging
methods were used: spin echo, F spin echo, STIR, and gradient ecoh. The images obtained byshooting were adjusted with ImageJ (NIH) and the area of the artifact was compared.
【Results, Discussion】
The magnetic attachments for implants showed obviously artifacts in all imaging methods, but there
were little artifacts in healing abutments. The gradient ecoh method produced the largest artifact
among the different imaging methods. The size of the artifact of Magfit IP was larger than for Magfit
MIP. The diameters of the artifact were about 15 to 20 mm for Magfit IP and approximately 15 mmfor Magfit MIP.

Introduction
In recent years, due to advances in medical technology, MRI has been used frequently. Along with
this, it has been considered that metal artifacts during MRI scanning affect diagnosis. In this time,
influences of the magnetic attachment for implants on MRI were discussed.

Materials and Methods

Fig.1 Sample details
Magnetic attachments for implants (Magfit MIP, Magfit IP), keeper for casting and healing
abutment were used as samples (Fig.1).

Each sample was placed in an acrylic
container (150 mm x 150 mm x 150 mm)
filled with an aqueous solution of nickel
nitrate. An acrylic jig was used to position
the sample in the center of the container. The
direction of the sample was the same toactual clinical situation (Fig.2).

Fig.2 Acrylic container and jig

Fig.3 Image processing

The obtained images were compared visually. The images were adjusted with ImageJ (NIH), andthe area of the artifact was compared (Fig. 3).
Table.1 Details of imaging method
AT1

SET2

GE
STIR

Four types of imaging methods were used: spin echo(SE) (T1-weighted image (T1), T2-weighted
image (T2), STIR) and gradient echo(GE) (Table.1).

Results, Discussion

T1

STIR

T2

GE

Fig.4 Imaging results (IDD)Fig.5 Imaging results of each sample (T1)

Fig.6 Artifact area (area ratio)
The magnetic attachments for implants showed obvious artifacts in all imaging methods, butthere were little artifacts in healing abutments. The gradient ecoh method produced the largest
artifact among the different imaging methods. The size of the artifact of Magfit IP was larger thanfor Magfit MIP. The diameters of the artifact were about 15 to 20 mm for Magfit IP andapproximately 15 mm for Magfit MIP.
In this study, the volume of samples greatly affected to the size of artifact compared to thediameter of the keeper and the strength of the attachment. There fore, replacement of the keeper
on the implant to the healing abutment during MRI scan would be necessary.