# Decrease of 7T MR short-term effects with repeated exposure

## TL;DR

Repeated 7T MRI scans lead to fewer short-term effects like dizziness and nausea over time, with no significant increase in motion during scans.

## Contribution

This study provides evidence that repeated exposure to 7T MRI reduces subjective short-term effects and improves comfort.

## Key findings

- Dizziness, inconsistent movement, nausea, and headache decreased significantly with repeated 7T MR examinations.
- Comfort during 7T MR examinations improved significantly as the number of sessions increased.
- There was no significant increase in motion or peripheral nerve stimulation with repeated exposure.

## Abstract

Although participants in 7 T magnetic resonance (MR) studies tolerate ultra-high field (UHF) well, subjectively experienced short-term effects, such as dizziness, inconsistent movement, nausea, or metallic taste, are reported. Evidence on subjectively experienced short-term effects in multiple exposures to UHF MR is scarce. The purpose of this study is to investigated experience of short-term effects, and occurrence of motion in healthy subjects exposed to seven weekly 7 T MR examinations.

A questionnaire on short-term effects was completed by participants in an fMRI motor skill study. Seven UHF MR examinations were conducted over 7 weeks (exposure number: 1 to 7). Changes of experienced short-term effects were analyzed. Motion in fMRI images was quantified.

The questionnaire was completed 360 times by 67 participants after one to seven 7T MR examinations. Logistic mixed model analysis showed a significant association between dizziness, inconsistent movement, nausea, and headache and the examination numbers (p<0.03). Exposure to repeated examinations had no significant effect on peripheral nerve stimulation (PNS) or motion of the subjects. The overall experience of a 7T examination improved significantly (p<0.001) with increasing examination numbers.

During multiple 7T examinations, subjects adapt to the strong static field. The short-term effects dizziness, inconsistent movement, nausea, and headache decrease over time as the MR sessions continue and experienced comfort increases. There was no significant difference in motion during the multiple fMRI examinations.