Assessing the effects of subject motion on T₂ relaxation under spin tagging (TRUST) cerebral oxygenation measurements using volume navigators

Abstract

Purpose Subject motion may cause errors in estimates of blood T2 when using the T2-relaxation under spin tagging (TRUST) technique on non-compliant subjects like neonates. By incorporating three-dimensional volume navigators (vNavs) into the TRUST pulse sequence, independent measurements of motion during scanning permit evaluation of these errors. Methods The effects of integrated vNavs on TRUST-based T2 estimates were evaluated using simulations and in vivo subject data. Two subjects were scanned with the TRUST+vNav sequence during prescribed movements. Mean motion scores were derived from vNavs and TRUST images, along with a metric of exponential fit quality. Regression analysis was performed between T2 estimates and mean motion scores. Also, motion scores were determined from independent neonatal scans. Results vNavs negligibly affected venous blood T2 estimates and better detected subject motion than fit quality metrics. Regression analysis showed that T2 is biased upwards by 4.1 ms per 1 mm of mean motion score. During neonatal scans, mean motion scores of 0.6–2.0 mm were detected. Conclusion Motion during TRUST causes an overestimate of T2, which suggests a cautious approach when comparing TRUST-based cerebral oxygenation measurements of noncompliant subjects.

Exploring early human brain development with structural and physiological neuroimaging

“…Robust methods for MRI-based measurements of regional oxygen metabolism from mid-gestation through adulthood are still needed. Techniques for more accurate quantitative measures of regional cerebral oxygenation are being developed (Alderliesten et al, 2013; Bolar et al, 2011) and the effects of motion on oxygenation measures is being explored (Stout et al, 2017), but unpredictable fetal motion remains a significant challenge. Future work also needs to address the inaccuracies in CBF measurements that arise from making measurements without synchronizing to the neonatal or fetal heart rate.…”

Whole-slice mapping of GABA and GABA+ at 7T via adiabatic MEGA-editing, real-time instability correction, and concentric circle readout

“…In each TR, the required translation and rotation updates, as well as carrier frequency changes, were calculated online and applied in real-time on the MR scanner. These vNavs have been used previously in various MR experiments at 3T, including MRI (Alhamud et al, 2016;Reuter et al, 2015;Stout et al, 2017), MRS (Hess et al, 2013(Hess et al, , 2011, and MRSI (Bogner et al, 2014a(Bogner et al, , 2014bSaleh et al, 2016).…”

Quantitative assessment of cerebral venous blood T2 in mouse at 11.7T: Implementation, optimization, and age effect

“…It uses the spin‐tagging principle to separate blood signals from surrounding tissue signals, thereby minimizing partial volume effects and mitigating the influence of subjective voxel selections. Over the past few years, apart from the various technical studies on TRUST , this technique has been applied extensively to neonatal studies , aging studies , and a wide range of neurological and psychiatric disorders including Alzheimer's disease , multiple sclerosis , sickle cell disease , anorexia , cocaine addiction , cannabis users , hepatic encephalopathy , end‐stage renal disease , acute mountain sickness , children primary nocturnal enuresis , etc.…”