High-speed whole-brain oximetry by golden-angle radial MRI.
OBJECTIVE
To determine whole-brain cerebral metabolic rate of oxygen (CMRO2), an improved imaging approach, based on radial encoding, termed radial OxFlow (rOxFlow), was developed to simultaneously quantify draining vein venous oxygen saturation (SvO2) and total cerebral blood flow (tCBF).


METHODS
To evaluate the efficiency and precision of the rOxFlow sequence, 10 subjects were studied during a paradigm of repeated breath-holds with both rOxFlow and Cartesian OxFlow (cOxFlow) sequences. CMRO2was calculated at baseline from OxFlow-measured data assuming an arterial O2saturation of 97%, and the SvO2and tCBF breath-hold responses were quantified.


RESULTS
Average neurometabolic-vascular parameters across the 10 subjects for cOxFlow and rOxFlow were, respectively: SvO2(%) baseline: 64.6 ± 8.0 versus 64.2 ± 6.6; SvO2peak: 70.5 ± 8.5 versus 72.6 ± 5.4; tCBF (mL/min/100 g) baseline: 39.2 ± 3.8 versus 40.6 ± 8.0; tCBF peak: 53.2 ± 5.1 versus 56.1 ± 11.7; CMRO2(µmol O2/min/100 g) baseline: 111.5 ± 26.8 versus 120.1 ± 19.6. The above measures were not significantly different between sequences (P > 0.05).


CONCLUSIONS
There was good agreement between the two methods in terms of the physiological responses measured. Comparing the two, rOxFlow provided higher temporal resolution and greater flexibility for reconstruction while maintaining high SNR. Magn Reson Med 79:217-223, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
Laboratory for Structural, Physiologic and Functional Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Wen
W
Cao
Laboratory for Structural, Physiologic and Functional Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Yulin V
YV
Chang
Laboratory for Structural, Physiologic and Functional Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Erin K
EK
Englund
Laboratory for Structural, Physiologic and Functional Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Hee Kwon
HK
Song
Laboratory for Structural, Physiologic and Functional Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Suliman
S
Barhoum
Laboratory for Structural, Physiologic and Functional Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Zachary B
ZB
Rodgers
Laboratory for Structural, Physiologic and Functional Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Michael C
MC
Langham
Laboratory for Structural, Physiologic and Functional Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Felix W
FW
Wehrli
D001921:Brain / Q000000981:diagnostic imaging* / Q000473:pathology*; D002560:Cerebrovascular Circulation; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D010092:Oximetry / Q000379:methods*; D010100:Oxygen / Q000737:chemistry; D010101:Oxygen Consumption / Q000502:physiology; D012119:Respiration; D059629:Signal-To-Noise Ratio
D010100:Oxygen
CMRO2; MR susceptometry; radial MRI