Mapping of oxygen by imaging lipids relaxation enhancement: A potential sensitive endogenous MRI contrast to map variations in tissue oxygenation

Abstract

MOBILE arises as a promising noninvasive and sensitive tool for diagnosis and therapeutic guidance in disorders involving hypoxia.

Qualification of a Noninvasive Magnetic Resonance Imaging Biomarker to Assess Tumor Oxygenation

“…A segmented IR FISP (Inversion-Recovery Fast Imaging with Steady state Precession) sequence (SSFP FID mode) was used to acquire parametric images of T 1 relaxation time, as described previously (33). Briefly, the acquisition parameters were TR/TE/FA/BW/matrix ¼ 4 ms/1.2 ms/5 /100 kHz/64 Â 64, four segments, and a total acquisition time of 1 minute 20 seconds.…”

“…A series of 40 images (spaced by scan repetition time, TR ¼ 100 ms) with a slice thickness of 2 mm were acquired with a spatial resolution of 0.344 Â 0.344 mm. The images were then fitted using a home-made program written in Matlab (The MathWorks, Inc.) to determine the T 1 relaxation time in the regions of interest (ROI), as described previously (33).…”

“…By monitoring changes in the R 1 relaxation rate of the lipid peak rather than those in the water peak, sensitive estimates of variations in tissue oxygenation could be obtained (33,34). This sequence, with the acronym MOBILE for "mapping of oxygen by imaging lipids relaxation enhancement," has simultaneously been translated into the clinical setting because it enables noninvasive and sensitive measurements of changes in tissue oxygenation.…”

“…This sequence, with the acronym MOBILE for "mapping of oxygen by imaging lipids relaxation enhancement," has simultaneously been translated into the clinical setting because it enables noninvasive and sensitive measurements of changes in tissue oxygenation. Until now, MOBILE has been successfully applied in hypoxic mouse models mimicking physiopathological conditions such as tumor hypoxia, peripheral ischemia, cerebral ischemic stroke, and liver steatosis, as well as in the clinical setting in healthy volunteers (33) and in stroke patients (35).…”

Dynamic oxygenation measurements using a phosphorescent coating within a mammary window chamber mouse model

“…It is worth noting, that the MWC model is compatible with multi-modality imaging and would therefore allow comparison and validation of techniques under development for tissue oxygenation assessment, including those employing new magnetic resonance imaging techniques [17][18][19]. The phosphorescent coating technique could have application in other non-window chamber applications where oxygenation measurements are beneficial.…”