Investigation of stress in dogs during an MRI examination in response to hearing protection.

The aim of the present study was to investigate whether the wearing of hearing protection has a positive influence on stress levels during an MRI examination in dogs under anaesthesia. To this end, the stress hormones cortisol and arginine vasopressin (AVP) were measured in the saliva of patients wearing hearing protection during an MRI scan, as well as in the control group without hearing protection, before and after the scan. Pulse rate and noise level were also measured during the MRI. It was shown that salivary cortisol concentrations in dogs without hearing protection increased during the MRI examination, while those in the control group with hearing protection remained the same (p<0.05). The pulse range was greater in the control group without hearing protection, although not statistically significant. The maximum loudness during the MRI examination, measured at 200 cm from the gantry, was 87 dB(A). The results on the loudness during mri scan highlight that hearing protection should always be used to minimise hearing damage and possibly the stress level for dogs.