Comparison of Spin-Echo and Gradient-Echo T1-Weighted and Spin-Echo T2-Weighted Images at 3T in Evaluating Term-Neonatal Myelination

Abstract

SUMMARY:A prior clinical report of 3T MR imaging in subsequently healthy very premature neonates imaged at term-equivalent age found that both gradient recalled-echo-T1WI and spin-echo-T2WI showed higher rates of myelinated structures, compared with spinecho-T1WI. The current study set out to assess those rates on the same sequences at 3T in term neonates and thus consisted of 16 term neonates with normal-appearing MR imaging findings who subsequently had normal findings at clinical follow-up. Two neuroradiologists independently assessed 19 structures in those infants on all 3 sequences. Gradient recalled-echo-T1WI showed a slightly higher rate of myelination (57.2%-72.4% of all structures) and interobserver agreement ( ϭ 0.546, P Ͻ .0001) than spin-echo-T2WI (58.2%-64.8%; ϭ 0.468, P Ͻ .0001), while spin-echo-T1WI had the lowest myelination rate and agreement (25.0%-48.4%; ϭ 0.384, P Ͻ .0001). Both observers noted that the following structures were myelinated in 88%-100% of patients on gradient recalled-echo-T1WI: the brachium of the inferior colliculus, decussation of the superior cerebellar peduncle, habenular commissure, medial lemniscus, pyramidal decussation, posterior limb of the internal capsule, and superior cerebellar peduncle; on spin-echo-T2WI, there was myelination in 88%-100% of the following structures: the brachium of the inferior colliculus, decussation of the superior cerebellar peduncle, inferior cerebellar peduncle, medial lemniscus, and posterior limb of the internal capsule. In conclusion, this study confirmed that similar to the findings in termequivalent-age premature infants, myelination changes in term neonates may be best assessed on both gradient recalled-echo-T1WI and spin-echo-T2WI at 3T, and not on spin-echo-T1WI. ABBREVIATIONS:BIC ϭ brachium of the inferior colliculus; CST ϭ corticospinal tracts; DSCP ϭ decussation of the superior cerebellar peduncle; GRE ϭ gradient

Comparison of Silent and Conventional MR Imaging for the Evaluation of Myelination in Children

“…T 1 W silent imaging is a gradient-echo inversion recovery sequence, and recent studies have shown that when compared with T 1 W SE images, 3T T 1 W gradient-echo images depict a higher degree of myelination in both full-term neonates and term-equivalent age infants. 14 , 15 The results of our study are similar to those earlier reports; moreover, the use of an inversion recovery technique might have improved the T 1 contrast in our study.…”

Mapping of pathological change in chronic fatigue syndrome using the ratio of T1- and T2-weighted MRI scans

“…Indeed, most of the structures with increased T1w/T2w were involved with sensorimotor function. A diffusion study has reported higher values of fractional anisotropy (FA) in the right arcuate fasciculus in ME/CFS due to increase in myelination ( Tyan et al, 2015 , Sakuma et al, 1991 ) which is adjacent to the right ILF region reported here.…”

“…Therefore, T1w image data divided by T2w increases the WM to GM tissue contrast. Changes in tissue microstructure (myelin, iron, edema, and brain lesions) affect both T1w and T2w images and have been used separately to study myelination and iron in the human brain ( Tyan et al, 2015 , Bakshi et al, 2001 ). Whole brain T1w/T2w ratio maps have provided a sensitive measure, related to myelin and microstructural integrity in multiple sclerosis ( Beer et al, 2016 ) and schizophrenia ( Ganzetti et al, 2015 ).…”

Evaluation of neonatal brain myelination using the T1‐ and T2‐weighted MRI ratio

“…Additional analyses of different sequence types (e.g., 2D and 3D) are ongoing to see if sequence type affects contrast improvement. Optimal pulse sequence parameters for the visualization of myelin in term neonates may vary with field strength, 35 and the value of the ratio technique at 3T remains to be determined. Finally, it may be possible to fully automate the processing pipeline, which could open the door for real-time assessment at the radiologist's workstation.…”

“…Additional analyses of different sequence types (e.g., 2D and 3D) are ongoing to see if sequence type affects contrast improvement. Optimal pulse sequence parameters for the visualization of myelin in term neonates may vary with field strength, and the value of the ratio technique at 3T remains to be determined.…”