# Effect of Titanium Artifacts on Cholesteatoma in Magnetic Resonance Imaging After Reconstruction of the Middle Ear

## TL;DR

This study examines how titanium implants used in ear surgery affect MRI scans for detecting cholesteatoma recurrence.

## Contribution

The study quantifies MRI artifacts caused by titanium prostheses and their impact on cholesteatoma detection accuracy.

## Key findings

- Titanium implants cause MRI artifacts that may obscure small cholesteatoma.
- Larger prostheses create larger artifacts, reducing detection accuracy to 82.1%.
- False MRI results were all false negatives, indicating missed cholesteatoma cases.

## Abstract

Background/Objectives: Surgical removal is the treatment of choice for cholesteatoma control. Depending on the size, the surgery involves partial resection of the ossicular chain and, if necessary, the bony skull base. Titanium foreign materials (prostheses, meshes) can be used to restore sound transmission and to cover larger defects of the skull base. After the operation, recurrence and residual control are necessary. This can be achieved by means of second-look surgery or an MRI examination with a non-EPI DWI sequence. Similarly to other metal implants, artifacts may occur in the image due to the titanium used. In this study, we assessed the magnitude of the MRI hardware differences induced by titanium prostheses and meshes and whether these differences could obscure cholesteatoma detection. Methods: 28 MRI examinations (T1-, T2-, non-EPI DWI sequences) in 14 males and 14 females (5.2–92.4 years) after cholesteatoma surgery and single-staged implantation of a PORP, TORP, or titanium mesh were considered. The size of the respective artifacts was measured, and the mean artifact sizes of the respective prosthesis types were compared. A second look surgery was performed in all cases due to the MRI result or clinical findings. Both were also compared. Results: Artifacts occurred in all titanium foreign bodies depending on the used MRI sequence (PORP, TORP, Mesh). We found a positive association between the size of the prosthesis and the size of the artifact. All subsequent second-look surgeries confirmed the MRI examinations according to a positive control for the presence of cholesteatoma. The detection rate was 82.1%. All false results were false negatives, and there were no positive results. Conclusions: Titanium material-related artifacts might influence the MRI detectability of recurrent cholesteatoma. Small cholesteatoma might be missed by an MRI-based follow-up. This finding supports the reevaluation of single-stage versus staged reconstruction modern approaches.