Study type: Medical/biological study (experimental study)

Temperature, heart rate, and blood pressure changes associated with clinical MR Imaging at 1.5 T. med./bio.

Published in: Radiology 1987; 163 (1): 259-262

Aim of study (acc. to author)

To study temperature, heart rate, and blood pressure responses to high-field-strength magnetic resonance imaging (MRI) in patients who underwent procedures at exposures to radiofrequency irradiation above the whole-body specific absorption rate (SAR) of 0.4 W/kg.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 64 MHz
Modulation type: pulsed
Exposure duration: 15 min
  • SAR: 420 µW/g mean (whole body) (1.2 W/kg maximum value.)
Exposure 2:

Exposure 1

Main characteristics
Frequency 64 MHz
Type
Exposure duration 15 min
Modulation
Modulation type pulsed
Exposure setup
Exposure source
  • 1.5 T MR system, 55 cm body coil.
Parameters
Measurand Value Type Method Mass Remarks
SAR 420 µW/g mean measured whole body 1.2 W/kg maximum value.

Exposure 2

Main characteristics
Frequency
Type
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 1.5 T - - - -

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Investigated organ system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

Body temperature significantly increased an average of 0.2°C and the highest body temperature recorded after MRI was 37.5°C. No significant correlation between the change in body temperature and whole-body average SARs was found. Changes in skin temperatures were variable, depending on anatomic site: The largest change was 3.5°C, and the highest skin temperature recorded after imaging was 35.1°C. A modest correlation between the change in skin temperatures and whole-body average SARs was found. Average heart rate and average mean blood pressure measured immediately before imaging were not significantly different afterward. High-field-strength MRI at the whole-body average SARs of 0.42-1.2 W/kg examined was not associated with any temperature- or hemodynamic-related deleterious effects.

Study character:

Study funded by

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