Validation of T₂‐based oxygen extraction fraction measurement with ¹⁵O positron emission tomography

Abstract

Purpose: To evaluate the accuracy of T 2-based whole-brain oxygen extraction fraction (OEF) estimation by comparing it with gold standard 15 O-PET measurements. Methods: Sixteen healthy adult subjects underwent MRI and 15 O-PET OEF measurements on the same day. On MRI, whole-brain OEF was quantified by T 2-relaxation-under-spin-tagging (TRUST) MRI, based on subject-specific hematocrit. The TRUST OEF was compared to the whole-brain averaged OEF produced by 15 O-PET. Agreement between TRUST and 15 O-PET whole-brain OEF measurements was examined in terms of intraclass correlation coefficient (ICC) and in absolute OEF values. In a subset of 10 subjects, test-retest reproducibility of whole-brain OEF was also evaluated and compared between the two modalities. Results: Across the 16 subjects, the mean whole-brain OEF of TRUST and 15 O-PET were 36.44 ± 4.07% and 36.45 ± 3.65%, respectively, showing no difference between the two modalities (P = .99). TRUST whole-brain OEF strongly correlated with that of 15 O-PET (N = 16, ICC = 0.90, P = 4 × 10 −7). The coefficient-of-variation of TRUST and 15 O-PET whole-brain OEF measurements were 1.79 ± 0.67% and 2.06 ± 1.55%, respectively, showing no difference between the two modalities (N = 10, P = .64). Further analyses on the effect of hematocrit revealed that correlation between PET OEF and TRUST OEF with assumed hematocrit remained significant (ICC = 0.8, P < 2 × 10 −5). Conclusion: Whole-brain OEF measured by TRUST was in excellent agreement with gold standard 15 O-PET, with highly comparable accuracy and reproducibility.

A Noninvasive Method for Quantifying Cerebral Metabolic Rate of Oxygen by Hybrid PET/MRI: Validation in a Porcine Model

“…The current study presents the first simultaneous comparison of OxFlow to 15 O-H2O and 15 O-O2 PET, and no significant differences were found between techniques. This agreement is in accordance with two recent studies comparing MR measurements of SvO2 to either PET or direct measures from the jugular blub (25,26).…”

Multi‐Parametric Evaluation of Cerebral Hemodynamics in Neonatal Piglets Using Non‐Contrast‐Enhanced Magnetic Resonance Imaging Methods

“…In this work, we used the TRUPC MRI technique to quantify OEF in two major cerebral veins: the SSS which drains the majority of cerebral cortical veins, the falx cerebri, meninges, diploic veins, and emissary veins; and the ICV which is formed by the unification of the thalamostriatal, septal, and choroidal veins and drains deep brain regions including thalami and basal ganglia. Among them, OEF at SSS has been shown to be correlated well with whole‐brain averaged OEF measured by 15 O‐PET 34 . We found that EtCO 2 correlated positively with PC‐based CBF but negatively with OEF at SSS, and there existed a negative correlation between OEF at SSS and CBF (both PC‐based and ASL‐based).…”

Brain Oxygen Extraction and Metabolism in Pediatric Patients With Sickle Cell Disease: Comparison of Four Calibration Models

“…T 2 -based MR oximetry such as TRUST MRI has been exploited widely due to its non-invasive property, less model assumption, short scan time and high reproducibility (Lu and Ge, 2008;Lu et al, 2012;Xu et al, 2012;Jiang et al, 2018Jiang et al, , 2021. However, inconsistent results have been reported on whether OEF and CMRO 2 are increased, decreased or unaffected in sickle cell disease (Jordan et al, 2016;Bush et al, 2018bBush et al, , 2021Juttukonda et al, 2019Juttukonda et al, , 2020Li et al, 2020;Václavů et al, 2020;Prussien et al, 2021;Vu et al, 2021) The original bovine model was derived from bovine blood, which is thought to have similar magnetic properties as normal human blood (Lu et al, 2012).…”