RT Journal Article SR Electronic T1 Cerebral oxygen extraction fraction (OEF) measurement correlation in human brain tumors using an oxygen-sensitive MRI sequence and 15O PET JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 524 OP 524 VO 55 IS supplement 1 A1 Massoumzadeh, Parinaz A1 Najmi, Safa A1 Rajderkar, Dhanashree A1 An, Hongyu A1 McConathy, Jonathan A1 Vlassenko, Andrei A1 Su, Yi A1 Marcus, Daniel A1 Rich, Keith A1 Benzinger, Tammie YR 2014 UL http://jnm.snmjournals.org/content/55/supplement_1/524.abstract AB 524 Objectives To quantify and compare Oxygen Extraction Fraction (OEF) measurement in the normal brain and brain tumors using 15O positron emission tomography (PET) and oxygen sensitive magnetic resonance (MR)1,2 imaging. Methods 30 participants (20 with brain tumors) were recruited. MRI scans included standard clinical sequences (T1, FLAIR, T2*, SWI, etc.) and OEF-MR2, a two-dimensional multi-echo gradient spin echo sequence. Concurrent with the MR acquisition, subjects with brain tumors underwent PET scanning, which included 2 sets of 3 scans with serial inhalations of air with radiolabeled carbon monoxide (C15O) and radiolabeled oxygen (15O2), followed by an injection of radiolabeled water (H215O). MR and PET data were post-processed off line and co-registered to the anatomic T1 post-contrast images. Regions of interest (ROI) were defined based upon contrast-enhancing tumor areas, peritumoral (edema), contra-lateral normal white matter (NWM), and normal gray matter (NGM). Ratios of OEF (rOEF) of the lesions to NGM were obtained. Results There is a high correlation between two rOEF-PET measurements for tumor (R=0.82; slope=1.01), edema (R=0.88; slope=0.99), and NWM (R=0.87; slope=0.99). When lesions with SWI abnormalities (blood cloth, hemorrhage, calcification) are excluded, rOEF-MR and rOEF-PET correlate well for tumor (R=0.68; slope=1.14) and overall ROIs (R=0.85; slope =0.96). Conclusions Both MR and 15O PET can measure OEF in brain tumors and in peritumoral areas. BOLD MR fails in regions with signal loss on SWI or T2*. Both techniques have tremendous potential in offering new insights into the underlying physiology of brain tumors and their response to therapy. Research Support NIH UL1 RR024992; ISMRM 2012 Seed grant; ICTS-WUSTL; American Cancer Society (ACS); Siteman Cancer Center (58-010-52 IRG).