Magnetic resonance imaging protocols for examination of the neurocranium at 3 T

Abstract

The increasing availability of high-field (3 T) MR scanners requires adapting and optimizing clinical imaging protocols to exploit the theoretically higher signal-to-noise ratio (SNR) of the higher field strength. Our aim was to establish reliable and stable protocols meeting the clinical demands for imaging the neurocranium at 3 T. Two hundred patients with a broad range of indications received an examination of the neurocranium with an appropriate assortment of imaging techniques at 3 T. Several imaging parameters were optimized. Keeping scan times comparable to those at 1.5 T we increased spatial resolution. Contrast-enhanced and non-enhanced T1-weighted imaging was best applying gradient-echo and inversion recovery (rather than spin-echo) techniques, respectively. For fluid-attenuated inversion recovery (FLAIR) imaging a TE of 120 ms yielded optimum contrast-to-noise ratio (CNR). High-resolution isotropic 3D data sets were acquired within reasonable scan times. Some artifacts were pronounced, but generally imaging profited from the higher SNR. We present a set of optimized examination protocols for neuroimaging at 3 T, which proved to be reliable in a clinical routine setting.

Sensitivity of T2-weighted FSE sequences towards physiological iron depositions in normal brains at 1.5 and 3.0�T

“…However, it has been shown that the use of SE sequences throughout the basal ganglia may significantly improve the sensitivity in the evaluation of patients with neurodegenerative disorders because of the increased sensitivity of SE sequences to magnetic susceptibility effects [8]. Recently, a new generation of whole-body MR imaging units with field strengths of 3.0 T has become increasingly available for routine imaging and currently is undergoing clinical evaluation [16].…”

Usefulness of Contrast-Enhanced T1-Weighted Sampling Perfection with Application-Optimized Contrasts by Using Different Flip Angle Evolutions in Detection of Small Brain Metastasis at 3T MR Imaging: Comparison with Magnetization-Prepared Rapid Acquisition of Gradient Echo Imaging

“…Given some disadvantages of 3T units, such as specific absorption rate (SAR) limitations and low contrast between gray and white matter of the brain on T1-weighted SE images, GE techniques that allow lower SAR, higher gray-white contrast, and rapid acquisition of 3D images are generally used for T1-weighted brain imaging at 3T. 5,6 Furthermore, because the contrast enhancement effect at 3T is higher than that at 1.5T, several studies have suggested that 3D contrast-enhanced GE images provide higher detectability of small brain metastases than 2D contrast-enhanced SE T1-weighted images when a 3T system is used. 7,8 Although high SAR at 3T makes it difficult to obtain T1-weighted 3D images with an SE-type sequence, recent technologic innovations, including parallel imaging, k-space trajectory, and variable flip angles, have solved the problem.…”

Brain Gray Matter Changes in Migraine Patients With T2-Visible Lesions

“…12,13 In this study, we applied VBM analysis to brain images acquired with a 3-T magnet to investigate whether changes in GM density are present in migraine patients with evidence of WM damage on conventional MRI compared with healthy controls. In case such changes were detected, additional analysis was preplanned in an attempt to provide some clues about their nature through the investigation of their correlation with patients' demographic characteristics (age, disease duration), clinical manifestations of the disease (presence/absence of aura), and extent of macroscopic visible lesions.…”