Study type: Medical/biological study (experimental study)

Magnetic resonance imaging increases the blood-brain barrier permeability to 153-gadolinium diethylenetriaminepentaacetic acid in rats med./bio.

Published in: Brain Res 1990; 523 (2): 301-304

Aim of study (acc. to author)

To investigate the effects of MRI exposure on the permeability of blood-brain barriere to a radioactive tracer substance in rats.

Background/further details

In this study radioactive labelled diethylenetriaminepentaacetic acid (Gadolinum-DTPA) was used as tracer substance.

Endpoint

Exposure

Exposure Parameters
Exposure 1:
Exposure duration: 2 x 23.2 min
Exposure 2: 6.25 MHz
Modulation type: pulsed
Exposure duration: 2x 23,2 min
  • power: 263 W (at 50 Ohm)
Exposure 3: 10–200 Hz
Modulation type: pulsed
Exposure duration: 2x 23,2 min

General information

Aminals were exposed to multislice transverse 30 ms spin echo sequence.

Exposure 1

Main characteristics
Frequency
Type
Exposure duration 2 x 23.2 min
Exposure setup
Exposure source
  • bore magnet (resistive imager) of MRI system
Distance between exposed object and exposure source 0.32 m
Setup Rats were anaesthetized with 50 mg/kg sodium pentobarbital prior to the exposure. Immediately after the exposure rats were injected with 25 µCi of [153Gd]DTPA and then were immediately exposed again. During the sham exposure, all magnetic and RF fields were off but sound and vibration exposure was simulated through an audio playback of the noise produced by the imaging sequence.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 150 mT maximum - - -

Exposure 2

Main characteristics
Frequency 6.25 MHz
Type
Exposure duration 2x 23,2 min
Modulation
Modulation type cf. additional info, pulsed
Pulse width 2 ms
Repetition frequency 21 Hz
Additional info

Gaussian modulated pulses; with 2 or 4 ms;

Exposure setup
Exposure source
Distance between exposed object and exposure source 0.32 m
Parameters
Measurand Value Type Method Mass Remarks
power 263 W - cf. remarks - at 50 Ohm

Exposure 3

Main characteristics
Frequency 10–200 Hz
Type
Exposure duration 2x 23,2 min
Additional info 3 gradient fields in x-, y-, z-direction
Modulation
Modulation type cf. additional info, pulsed
Pulse width 2 ms
Repetition frequency 21 Hz
Additional info

Gaussian modulated pulses; wiusth 2 or 4 ms;

Exposure setup
Exposure source
Distance between exposed object and exposure source 0.32 m
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 400 mT maximum - - in x- and y-direction
magnetic flux density 150 mT maximum - - in z-direction

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated organ system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

The findings of this study suggest that magnetic fields like the applicated MRI exposure may alter the permeability of the blood-brain barrier of rats.

Study character:

Study funded by

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