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Corneal temperature changes induced by high-field-strength MR imaging with a head coil
1Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048.
Radiology
|June 1, 1988
Summary
Magnetic resonance (MR) imaging can increase corneal temperature. This study found that MR imaging with a head coil causes minor corneal temperature increases, posing no thermal hazard to ocular tissues.
Area of Science:
- Medical Imaging
- Ophthalmology
- Biophysics
Background:
- High-field-strength/high-frequency magnetic resonance (MR) imaging systems carry a risk of tissue heating.
- The eye's susceptibility to temperature elevation is due to its limited blood supply.
Purpose of the Study:
- To measure corneal temperature changes in patients undergoing MR imaging.
- To assess the thermal risk to ocular tissues from clinical MR imaging.
Main Methods:
- Corneal temperatures were measured in 33 patients before and after MR imaging.
- A 1.5-T (64-MHz) imager with a transmit/receive head coil was used.
- Peak specific absorption rates (SAR) ranged from 2.54 to 3.05 W/kg.
Main Results:
- A statistically significant increase in average corneal temperature was observed (32.7°C ± 0.7°C before, 33.2°C ± 0.5°C after; P < .001).
- The mean temperature increase was 0.5°C, with a maximum of 1.8°C.
- The highest recorded corneal temperature was 34.4°C.
Conclusions:
- Clinical MR imaging using a head coil at the studied SARs results in minor corneal temperature elevations.
- These temperature increases do not appear to present a thermal hazard to ocular tissue.
- The findings suggest current MR imaging protocols are safe regarding ocular thermal effects.