Quantitative T1 mapping of the normal brain from early infancy to adulthood

Abstract

Background Quantitative mapping of MRI relaxation times is expected to uncover pathological processes in the brain more subtly than standard MRI techniques with weighted contrasts. So far, however, most mapping techniques suffer from a long measuring time, low spatial resolution or even sensitivity to magnetic field inhomogeneity. Objective To obtain T1 relaxation times of the normal brain from early infancy to adulthood using a novel technique for fast and accurate T1 mapping at high spatial resolution. Materials and methods We performed whole-brain T1 mapping within less than 3 min in 100 patients between 2 months and 18 years of age with normal brain at a field strength of 3 T. We analyzed T1 relaxation times in several gray-matter nuclei and white matter. Subsequently, we derived regression equations for mean value and confidence interval. Results T1 relaxation times of the pediatric brain rapidly decrease in all regions within the first 3 years of age, followed by a significantly weaker decrease until adulthood. These characteristics are more pronounced in white matter than in deep gray matter. Conclusion Regardless of age, quantitative T1 mapping of the pediatric brain is feasible in clinical practice. Normal age-dependent values should contribute to improved discrimination of subtle intracerebral alterations.

Vendor‐neutral sequences and fully transparent workflows improve inter‐vendor reproducibility of quantitative MRI

“…Several methods such as inversion‐recovery spin‐echo (IR‐SE), 4 variable flip angle (VFA‐T1), 5 Look‐Locker IR, 6 and magnetization‐prepared two rapid‐echoes (MP2RAGE) 7 have gained popularity in MRI research. Although measured T1 values can exhibit up to 30% inter‐sequence variability in the same scan session for the same participant, 8 a selected T1 relaxometry method is much more reliable within‐site 9,10 . As for the multicenter stability, MP2RAGE appears to be a promising T1 mapping method at 7T, with a single vendor considered 11 .…”

“…Although measured T1 values can exhibit up to 30% inter-sequence variability in the same scan session for the same participant, 8 a selected T1 relaxometry method is much more reliable within-site. 9,10 As for the multicenter stability, MP2RAGE appears to be a promising T1 mapping method at 7T, with a single vendor considered. 11 On the other hand, substantial multicenter variability is reported for another popular whole-brain imaging method VFA-T1, both in vivo and in phantoms.…”

Decreased Need for Anesthesia during Ultra-Fast Cranial MRI in Young Children: One-Year Summary

“…The resulting low vulnerability to movement artifacts makes real-time MRI sequences particularly attractive for the imaging of infants and toddlers. In particular, in addition to rapid and accurate mapping of the T1 relaxation time [2], the T2-weighted volume coverage (VC) technique has already proven to be very effective for brain studies [3], despite its lower spatial resolution and tissue contrast. In brief, the method employs an undersampled radial gradient-echo sequence with SSFP contrast which sequentially acquires a series of shifted but highly overlapping slices in combination with nonlinear inverse image reconstruction with spatial regularization to a neighboring slice.…”

Vendor-neutral sequences and fully transparent workflows improve inter-vendor reproducibility of quantitative MRI

“…Several methods such as inversion-recovery spin-echo (IR-SE) 4 variable flip angle (VFA-T1) 5 Look-Locker IR 6 and magnetization-prepared two rapid-echoes 7 have gained popularity in MRI research. Although measured T1 values can exhibit up to 30% inter-sequence variability in the same scan session for the same participant 8 , a selected T1 relaxometry method is much more reliable within-site 9,10 . As for the multicenter stability, MP2RAGE appears to be a promising T1 mapping method at 7T with a single vendor considered across 8 imaging sites 11 .…”