Magnetization Transfer and Amide Proton Transfer MRI of Neonatal Brain Development

Abstract

Purpose. This study aims to evaluate the process of brain development in neonates using combined amide proton transfer (APT) imaging and conventional magnetization transfer (MT) imaging. Materials and Methods. Case data were reviewed for all patients hospitalized in our institution's neonatal ward. Patients underwent APT and MT imaging (a single protocol) immediately following the routine MR examination. Single-slice APT/MT axial imaging was performed at the level of the basal ganglia. APT and MT ratio (MTR) measurements were performed in multiple brain regions of interest (ROIs). Data was statistically analyzed in order to assess for significant differences between the different regions of the brain or correlation with patient gestational age. Results. A total of 38 neonates were included in the study, with ages ranging from 27 to 41 weeks' corrected gestational age. There were statistically significant differences in both APT and MTR measurements between the frontal lobes, basal ganglia, and occipital lobes (APT: frontal lobe versus occipital lobe P = 0.031 and other groups P = 0.00; MTR: frontal lobe versus occipital lobe P = 0.034 and other groups P = 0.00). Furthermore, APT and MTR in above brain regions exhibited positive linear correlations with patient gestational age. Conclusions. APT/MT imaging can provide valuable information about the process of the neonatal brain development at the molecular level.

White matter injury and neurodevelopmental disabilities: A cross-disease (dis)connection

“…It is still far from clinical applications; however, some promising results in neonates are available. In particular, Zheng et al demonstrated that protein content in the WM of neonates measured by amide proton transfer (APT) imaging correlates with age and could provide valuable data about brain maturation at the molecular level (Zheng et al, 2016).…”

Amide proton transfer imaging for differentiation of tuberculomas from high-grade gliomas: Preliminary experience

“…First proposed by Zhou et al, APT imaging is a relatively nascent imaging approach that draws upon CEST and MT imaging propositions. [31][32][33] APT sequence typically incorporates a long saturation pulse (0.5-2 seconds; to saturate more water protons) and an ensuing image acquisition component (usually 2D/3D; gradient echo/spin echo/echo planar imaging). APT imaging contrast is based on a non-invasive in vivo assessment of spin exchange between the tissue bulk water and amide protons of mobile endogenous proteins and peptides chains (which have their signature resonance frequency at 3.5 ppm downfield that of water in the Z spectrum).…”

“…Lately, this modality has shown promise in glioma evaluation [34][35][36] and assessment of brain maturation. 33,37 Brain maturation and myelination have seen an exponential decrease in the APTw signal (white matter > grey matter), reaching up to 0.18 (fitted MTR at 3.5 ppm) in the putamen and 0.87 (fitted MTR at 3.5 ppm) in the frontal white matter, with no significant changes in the latter part of the first decade. 37 Proteomic profiles of the gliomas have been shown to vary considerably according to their WHO grades.…”

“…We note that MT and APTw imaging generate contrast by interrogating different aspects (relatively immobile macromolecules and free proteins/polypeptides) of the tissue. 33 The molecular information provided by these sequences is likely complementary rather than identical. It remains to be seen which component of the inflammatory milieu in the perilesional parenchyma contributes to the changes in MTR asym .…”

Predicting cancer malignancy and proliferation in glioma patients: intra-subject inter-metabolite correlation analyses using MRI and MRSI contrast scans

“…Amide proton transfer imaging (APT) contrast, a type of CEST, detects cellular mobile proteins and peptides. Semi-solid magnetization transfer contrast (MTC) quantifies the number of macromolecular substances, such as structural proteins and carbohydrates (13)(14)(15). Increased metabolites and varied metabolism typically accompany the rapid growth of gliomas.…”