Analysing the response in R2* relaxation rate of intracranial tumours to hyperoxic and hypercapnic respiratory challenges: initial results.
OBJECTIVE
To investigate the response in R2* relaxation rate of human intracranial tumours during hyperoxic and hypercapnic respiratory challenges.


METHODS
In seven patients with different intracranial tumours, cerebral R2* changes during carbogen and CO(2)/air inhalation were monitored at 3 T using a dynamic multigradient-echo sequence of high temporal and spatial resolution. The R2* time series of each voxel was tested for significant change. Regions of interest were analysed with respect to response amplitude and velocity.


RESULTS
The tumours showed heterogeneous R2* responses with large interindividual variability. In the 'contrast-enhancing' area of five patients and in the 'non-tumoral' tissue most voxels showed a decrease in R2* for carbogen. For the 'contrast-enhancing' area of two patients hardly any responses were found. In areas of 'necrosis' and perifocal 'oedema' typically voxels with R2* increase and no response were found for both gases. For tissue responding to CO(2)/air, the R2* changes were of the same order of magnitude as those for carbogen. The response kinetic was generally attenuated in tumoral tissue.


CONCLUSIONS
The spatially resolved determination of R2* changes reveals the individual heterogeneous response characteristic of intracranial human tumours during hyperoxic and hypercapnic respiratory challenges.
Müller
A
A
Department of Radiology, University of Bonn, Sigmund-Freud-Straße 25, 53105 Bonn, Germany.
Remmele
S
S
Wenningmann
I
I
Clusmann
H
H
Träber
F
F
Flacke
S
S
König
R
R
Gieseke
J
J
Willinek
W A
WA
Schild
H H
HH
Mürtz
P
P
D000328:Adult; D000368:Aged; D000465:Algorithms; D001932:Brain Neoplasms / Q000473:pathology*; D002245:Carbon Dioxide / Q000737:chemistry; D005260:Female; D006801:Humans; D006935:Hypercapnia; D018496:Hyperoxia; D007700:Kinetics; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000737:chemistry; D012119:Respiration; D013997:Time Factors
D002245:Carbon Dioxide; C011700:carbogen; D010100:Oxygen