Study type: Medical/biological study (experimental study)

Blood-brain barrier permeability in rats is altered by exposure to magnetic fields associated with magnetic resonance imaging at 1.5 T med./bio.

By: Prato FS, Wills JM, Roger J, Frappier H, Drost DJ, Lee TY, Shivers RR, Zabel P
Published in: Microsc Res Tech 1994; 27 (6): 528-534
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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:
Modulation type: pulsed
Exposure duration: intermittent; 22.5 min (two times)
Exposure 2:
Modulation type: CW
Exposure duration: intermittent; 22.5 min (two times)
-
Exposure 3:
Modulation type: CW
Exposure duration: intermittent; 22.5 min (two times)
-

Exposure 1

Main characteristics
Frequency
Type
Exposure duration intermittent; 22.5 min (two times)
Modulation
Modulation type pulsed
Pulse width 30 ms
Rise time 1 ms
Fall time 1 ms
Packets per second 1,000
Additional info

switched on and off 105 times in every 1050 ms interval; 30 ms spin-echo; 1ms rise and fall times
Exposure setup
Exposure source
Distance between exposed object and exposure source 0.15 m
Chamber polyethylene cage
Setup group 1 in center, group 2 at a distance of 15 cm away from center
Sham exposure A sham exposure was conducted.
Additional info d = 15 cm from the electronic centre toward the magnet opening
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 1.5 T maximum - - -
Additional parameter details

SAR = ( <0,1 ; <0,03 ) W / Kg spatial encoding gradients 8 mT/m dB/dt = 0.4 T/s for group 1; dB/dt = 2.8 T/s for group 2

Exposure 2

Main characteristics
Type
Exposure duration intermittent; 22.5 min (two times)
Additional info static
Modulation
Modulation type CW
Exposure setup
Exposure source
Setup group 3 in center
Parameters

No parameters are specified for this exposure.

Exposure 3

Main characteristics
Frequency
Type
Exposure duration intermittent; 22.5 min (two times)
Additional info static
Modulation
Modulation type CW
Exposure setup
Exposure source
  • small bore animal MRI system (clear bore of 30cm)
Parameters

No parameters are specified for this exposure.

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated organ system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

MRI exposure under various conditions lead to altered permeability of the blood brain barrier in rats. Sham-exposure results were significantly different during day and night (greater difference than that caused by MRI exposure).

Study character:

Study funded by

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