Parinaz Massoumzadeh PhD, Presenter: Nothing to Disclose

Dhanashree Rajderkar MD, Abstract Co-Author: Nothing to Disclose

Hongyu An DSc, Abstract Co-Author: Nothing to Disclose

Jonathan Edward McConathy MD, PhD, Abstract Co-Author: Research Consultant, GLG Consulting Speakers Bureau, Eli Lilly and Company Research Consultant, General Electric Company

Joshua S. Shimony MD, PhD, Abstract Co-Author: Nothing to Disclose

Abraham Z. Snyder PhD, Abstract Co-Author: Nothing to Disclose

Yi Su PhD, Abstract Co-Author: Nothing to Disclose

Andrei Vlassenko MD, PhD, Abstract Co-Author: Nothing to Disclose

Xiaodong Zhang PhD, Abstract Co-Author: Nothing to Disclose

Jon J. Christensen, Abstract Co-Author: Nothing to Disclose

Sarah C. Jost MD, Abstract Co-Author: Nothing to Disclose

Daniel Scott Marcus PhD, Abstract Co-Author: Owner, Radiologics, Inc

Keith M. Rich MD, Abstract Co-Author: Nothing to Disclose

Tammie Smith Benzinger MD, PhD, Abstract Co-Author: Research Grant, Eli Lilly and Company

To quantify and compare the cerebral 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.  

30 participants (20 with brain tumors) were recruited. MRI included standard clinical sequences plus OEF-MR1; 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 inhalation of air with 40-75 mCi radiolabeled carbon monoxide (C15O), 40-75 mCi radiolabeled oxygen (15O2), and injection of 25-50 mCi radiolabeled water (H215O). MR and PET data were post-processed off line and registered to the anatomic T1 pre-and post-contrast images. Regions of interest were drawn based upon contrast-enhancing tumor areas, contra-lateral normal white matter (NWM), and normal gray matter (NGM) Ratios of OEF (rOEF) were obtained for lesions compared to normal tissue.

There is very good correlation between two OEF-PET measurements for tumor (R2=0.90 with slope of 0.82), and for rOEF (R2=0.93 and slope of 1.14). The OEF values of NWM are not significantly different between the OEF-PETmeasurements. OEF-MR and OEF-PET correlates well when subjects with SWI abnormalities (blood cloth, hemorrhage, calcification) are excluded (R=0.73).

Both MR and [15O] PET can measure OEF in brain tumors and in peritumoral edema.  Variable OEF measurements for tumor and edema may be implication for tumor grade and prognosis.  BOLD MR fails in regions with signal loss on SWI or T2*.  Both techniques have tremendous potential and may offer new insight into the underlying physiology of brain tumors and their response to therapy without requiring radiation or injected contrast.    References: 1  An and Lin (2000), "Quantitative measurements of cerebral blood oxygen saturation using magnetic resonance imaging." J. Cereb. Blood, Flow Metab 2 He and Yablonskiy (2007), "Quantitative BOLD: mapping of human cerebral deoxygenated blood volume and oxygen extraction fraction: default state." Magn Reson Med.  

Both MR and [15O] PET can measure OEF in brain tumors and in peritumoral edema and have potential to predict treatment response. BOLD MR fails in regions with signal loss on SWI or T2*.  

Massoumzadeh, P, Rajderkar, D, An, H, McConathy, J, Shimony, J, Snyder, A, Su, Y, Vlassenko, A, Zhang, X, Christensen, J, Jost, S, Marcus, D, Rich, K, Benzinger, T, MRI and PET Measurements of Oxygen Extraction Fraction in Patients with Brain Tumors.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13022813.html