T2'- and PASL-based perfusion mapping at 3 Tesla: influence of oxygen-ventilation on cerebral autoregulation.
OBJECTIVE
To use T2'-mapping together with Pulsed Arterial Spin Labeling (PASL) providing quantitative information of deoxygenation level and cerebral blood flow (CBF) in the cerebral gray matter to obtain simultaneous information about the cerebral oxygen metabolism and the resulting cerebral vasoreactivity under normoxic and hyperoxic conditions.


METHODS
Twelve young, healthy volunteers underwent MRI under normoxic and hyperoxic conditions performing PASL and high-resolution, motion-corrected T2* and T2-mapping to calculate T2'values. Regions of interest (ROI) were placed in the frontoparietal cortex and thalamus by manual and automatic segmentation. For each ROI, mean normoxic T2'- and CBF values were extracted and compared with the same parameters assessed under hyperoxic ventilation.


RESULTS
A hyperoxic-induced decrease of the CBF could be shown in the frontoparietal cortex (P = 0.009). The T2 values of frontoparietal cortex decreased under hyperoxic inhalation compared with normoxia (P = 0.01), whereas T2' remained unchanged.


CONCLUSIONS
Motion-corrected high-resolution T2'-maps can be used together with PASL to evaluate the DeoxyHb content in relation to CBF in the cerebral gray matter. We could show that cortical CBF decreases under hyperoxic inhalation in healthy young subjects, whereas the T2' values remained constant. These data suggest that hyperoxic-induced vasoconstriction may protect the brain against hyperoxemia.
Institute of Neuroradiology, University Hospital, Goethe University Frankfurt am Main, Frankfurt am Main, Germany. marlies.wagner@kgu.de
Marlies
M
Wagner
Jörg
J
Magerkurth
Steffen
S
Volz
Alina
A
Jurcoane
Oliver C
OC
Singer
Tobias
T
Neumann-Haefelin
Friedhelm E
FE
Zanella
Ralf
R
Deichmann
Elke
E
Hattingen
D000328:Adult; D001921:Brain / Q000378:metabolism* / Q000473:pathology*; D002533:Cerebral Angiography / Q000379:methods*; D005260:Female; D006706:Homeostasis / Q000187:drug effects; D006801:Humans; D018496:Hyperoxia / Q000378:metabolism* / Q000473:pathology; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D010100:Oxygen / Q000008:administration & dosage / Q000378:metabolism*; D010101:Oxygen Consumption; D014018:Tissue Distribution; D055815:Young Adult
D010100:Oxygen