Introduction
Magnetic Resonance Imaging(MRI) is used for
diagnostic purposes. It’s characteristic noise can be
harmful for people operating the MRI machine as well
as the patients who are undergoing MRI scan. This can
lead to development of changes in health like anxiety,
high blood pressure, tachycardia, irritability by
patients, temporary threshold shift(TTS) .As per this,
higher the resolution of scan, high Tesla MRI machine
needed which in turn translates into higher production
of sound . TTS is a condition in which there is
temporary shift in auditory threshold .This happen
when there is loud exposure of noise for short or long
period. TTS can occur for minutes or hours or days,
but the shift of the threshold comes to baseline after
sometime, when person is secluded from the loud noise.
PTA (pure tone audiometry) provides ear specific
thresholds, and uses frequency specific pure tones to
give place specific responses, so that the configuration
of a hearing loss can be identified. Increase in stiffness
of middle ear causes low frequency hearing loss
whereas increase in mass effect of middle ear causes
high frequency hearing loss.
Aim
Incidence of temporary threshold shift after MRI
(head and neck) in tertiary care centre.
Objective
To do an pure tone audiogram in patient before
MRI
To do an pure tone audiogram in patient
immediately after MRI
To do pure tone audiogram in patient 1 day after
MRI.
Methodology
A cross-sectional study was done to analyse the
pure tone audiogram results of patients before and
after doing MRI scan. 40 patients undergoing MRI
scan above 16years till 50years who came to saveetha
medical college ENT audiology were included in the
study. All patients who are medically unstable or
unconscious or history of previous ear disease were
excluded from the study. statistical analysis Paired t
test was done.
Result
The value is strongly significant which tell us that
there is temporary threshold shift after MRI. It was
confirmed by paired t test.
Conclusion
In my study the test value is significant which
suggest of temporary threshold shift after MRI. The
threshold shift is measured in above study by using
pure tone audiometry at different frequencies (500Hz,
1KHz, 2KHz).