Oxygen challenge magnetic resonance imaging in healthy human volunteers

Abstract

Oxygen challenge imaging involves transient hyperoxia applied during deoxyhaemoglobin sensitive (T2*-weighted) magnetic resonance imaging and has the potential to detect changes in brain oxygen extraction. In order to develop optimal practical protocols for oxygen challenge imaging, we investigated the influence of oxygen concentration, cerebral blood flow change, pattern of oxygen administration and field strength on T2*-weighted signal. Eight healthy volunteers underwent multi-parametric magnetic resonance imaging including oxygen challenge imaging and arterial spin labelling using two oxygen concentrations (target FiO 2 of 100 and 60%) administered consecutively (two-stage challenge) at both 1.5T and 3T. There was a greater signal increase in grey matter compared to white matter during oxygen challenge (p < 0.002 at 3T, P < 0.0001 at 1.5T) and at FiO 2 ¼ 100% compared to FiO 2 ¼ 60% in grey matter at both field strengths (p < 0.02) and in white matter at 3Tonly (p ¼ 0.0314). Differences in the magnitude of signal change between 1.5T and 3T did not reach statistical significance. Reduction of T2*-weighted signal to below baseline, after hyperoxia withdrawal, confounded interpretation of two-stage oxygen challenge imaging. Reductions in cerebral blood flow did not obscure the T2*-weighted signal increases. In conclusion, the optimal protocol for further study should utilise target FiO 2 ¼ 100% during a single oxygen challenge. Imaging at both 1.5T and 3T is clinically feasible.

Oxygen Challenge Imaging Reveals Differences in Metabolic Activity Between Kurtosis Lesion and Diffusion/Kurtosis Lesion Mismatch in a Rodent Model of Acute Stroke

“…A longer time of repetition (1500 ms) was used to reduce the T1 effects. Different experiments have evaluated the effect of oxygen inhalation on CBF values, but with different results 16,25,26 . The same animal species and stroke modes as those used in our study were used previously.…”

“…If there is sufficient oxygen supply, a large amount of deoxyhemoglobin will be converted into oxyhemoglobin, which could cause a significant increase in the T2* value. Combined OC and T2* mapping sequences have been studied in humans and animals 12–17 …”

“…Combined OC and T2* mapping sequences have been studied in humans and animals. [12][13][14][15][16][17] In this study, we combined OC and MRI to evaluate metabolic activity in the ischemic brain of Sprague Dawley (SD) rats.…”

Clinical Imaging of the Penumbra in Ischemic Stroke: From the Concept to the Era of Mechanical Thrombectomy

“…In addition to the search for these specific biomarkers, the bibliographic coupling also contains a selection of alternative marker imaging based on hemodynamics. The MRI cluster presents 3 articles for hemodynamic assessment as a marker of tissue activity with MRI SWI ( 135 , 136 ) and MRI T2 ⋆ -weighted imaging ( 137 ). Two articles relate to near infrared spectroscopy for hemodynamic, side-bed, AIS patient monitoring.…”

Preclinical Validation of the Therapeutic Potential of Glasgow Oxygen Level Dependent (GOLD) Technology: a Theranostic for Acute Stroke

“…PFC’s ability to deliver oxygen to hypoxic tissue, along with the paramagnetic properties of oxygen and the different effects of oxy- and deoxyhaemoglobin on the blood oxygen level dependent (BOLD) T2* signal has been utilised to identify penumbral tissue in series of studies by our group [14–21]. These unique characteristics make PFCs potential agents with dual diagnostic [14] and therapeutic properties: providing an efficient carrier for paramagnetic oxygen and enhancing oxygen delivery to hypoxic brain tissue through any remaining plasma flow.…”