Calibration-free whole-brain CEST imaging at 7T with parallel transmit pulse design for saturation homogeneity utilizing universal pulses (PUSHUP).

Purpose: Chemical exchange saturation transfer (CEST) measurements at ultra-high field (UHF) suffer from strong saturation inhomogeneity. Retrospective correction of this inhomogeneity is possible to some extent, but requires a time-consuming repetition of the measurement. Here, we propose a calibration-free parallel transmit (pTx)-based saturation scheme that homogenizes the saturation over the imaging volume, which we call PUlse design for Saturation Homogeneity utilizing Universal Pulses (PUSHUP).

Whole brain snapshot CEST at 3T using 3D-EPI: Aiming for speed, volume, and homogeneity.

Purpose: CEST MRI enables imaging of distributions of low-concentrated metabolites as well as proteins and peptides and their alterations in diseases. CEST examinations often suffer from low spatial resolution, long acquisition times, and concomitant motion artifacts. This work aims to maximize both resolution and volume coverage with a 3D-EPI snapshot CEST approach at 3T, allowing for fast and robust whole-brain CEST MRI.

Whole-brain snapshot CEST imaging at 7 T using 3D-EPI.

Purpose: The aim of this work is to develop a fast and robust CEST sequence in order to allow the acquisition of a whole-brain imaging volume after a single preparation block (snapshot acquisition).

Methods: A 3D-CEST sequence with an optimized 3D-EPI readout module was developed, which acquires the complete k-space data following a single CEST preparation for 1 saturation offset. Whole-brain mapping of the Z-spectrum with 2 mm isotropic resolution is achieved at 68 saturation frequencies in 5 minutes (4.