Three-Dimensional Turbo-Spin-Echo Amide Proton Transfer MR Imaging at 3-Tesla and Its Application to High-Grade Human Brain Tumors

Abstract

Purpose Amide proton transfer (APT) imaging is able to extend the achievable MRI contrast to the protein level. In this study, we demonstrate the feasibility of applying a turbo spin echo (TSE)-based, three-dimensional (3D) APT sequence into routine clinical practice for patients with brain tumors. Procedures Experiments were performed on a Philips 3T MRI scanner using an eight-channel phased-array coil for reception. A fast 3D APT sequence with a TSE acquisition was proposed (saturation power, 2 μT; saturation time, 500 ms; 8 slices). The gradient echo (GRE)-based field-mapping technique or water-saturation-shift-referencing (WASSR) technique was used to acquire B0 maps to correct for B0-induced artifacts in APT images. The test was performed on a box of homogenous protein solution, four healthy volunteers, and eight patients with high-grade gliomas. Results The experimental data from a homogenous, protein-containing phantom and healthy volunteers show that the sequence produced a uniform contrast across all slices. The average MTRasym(3.5ppm) values with GRE B0-corrected 3D APT imaging and WASSR-corrected 3D APT imaging were both comparable to the values obtained using the undemanding single-slice acquisition. The average APT image intensity was consistently higher in the tumor core than in the peripheral edema and in the contralateral normal-appearing white matter (both P < 0.001). Conclusion 3D APT imaging of brain tumors can be performed in about five minutes at 3T using a routine, commercial eight-channel SENSE coil.

Measurement of Lactate Content and Amide Proton Transfer Values in the Basal Ganglia of a Neonatal Piglet Hypoxic-Ischemic Brain Injury Model Using MRI

“…An off-resonance continuous-wave radiofrequency saturation pulse was used. APT single-section imaging was performed, and the saturation time, at 2 T excitation power, was 500 ms (the maximum time available for this body coil [22][23][24] ). The acquisition mode was TSE, and the factor was 38.…”

Downfield‐NOE‐suppressed amide‐CEST‐MRI at 7 Tesla provides a unique contrast in human glioblastoma

“…For these protein ST effects, several interesting correlations have been shown that might play a role in vivo and especially in pathologies: dependence on intracellular pH (5,(10)(11)(12)(13), protein concentration (8,13), or protein folding (14,15) and aggregation states (16). Already, the use for brain tumor detection (6,(17)(18)(19)(20), grading (21), and possible differentiation of tumor recurrence and radiation necrosis (22) has been shown to be feasible by proteinbased saturation transfer MRI.…”

Assessing Amide Proton Transfer (APT) MRI Contrast Origins in 9 L Gliosarcoma in the Rat Brain Using Proteomic Analysis

“…Amide proton transfer (APT) imaging [4, 5] is an important molecular MRI technique that is sensitive to endogenous mobile proteins and peptides in tissue [6]. Prior data suggest that there are consistent APT-weighted hyperintensities in animal glioma models [7, 8] and in high-grade gliomas in patients [9-11]. These studies show that APT imaging for malignant brain tumors has much potential, for example, to differentiate between tumor and peritumoral edema, to separate high-grade from low-grade gliomas, and to detect high-grade gliomas that do not show gadolinium enhancement, all without exposure to contrast agents.…”