A 3-T MR neuroimaging examinations can cause temporary decreases in hearing acuity, even if ear plugs were used during the scan, according to a study published in the journal Radiology.
Researchers from China performed a study to determine whether a single 51-minute exposure to acoustic noise during 3-T multisequence MR neuroimaging could affect the hearing threshold of healthy adults when earplugs and sponge mats were used as hearing protection.
The study included 26 healthy young adults who all underwent an automated auditory brainstem response (ABR) to test their hearing within 24 hours before the scan, 20 minutes after the scan, and again 25 days after the scan. The subjects used earplugs and motion-refraining sponge mats as hearing protection while undergoing 3-T MR neuroimaging imaging that included T1-weighted three-dimensional gradient-echo sequence, T2-weighted fast spin-echo sequence, diffusion-tensor imaging, diffusion-kurtosis imaging, T2*-weighted three-dimensional multiecho gradient-echo sequence, and blood oxygen level–dependent imaging.
The results showed a significantly increased mean threshold shift of 5.0 dB ± 8.1 (standard deviation) immediately after the MR examination compared with the baseline study. The left ear was 4.8 dB ± 9.2 and the right ear was 5.2 dB ± 6.9. This shift is below the temporary threshold shift of 40–50 dB associated with cochlea nerve changes. Automated ABR obtained at day 25 after MR imaging showed no significant differences from baseline (left ear: −2.3 dB ± 8.6; right ear: 0.4 dB ± 7.3).
The researchers concluded that 3-T MR neuroimaging examination with the acoustic noise at equivalent sound pressure level of 103.5–111.3 dBA lasting 51 minutes can cause temporary hearing threshold shift in healthy volunteers with hearing protection.