A novel tract imaging technique of the brainstem using phase difference enhanced imaging: normal anatomy and initial experience in multiple system atrophy

Abstract

PADRE imaging can offer a new form of tract imaging of the brainstem and may have the potential to reinforce the clinical utility of MRI in differentiating MSA from other conditions.

Visualization of the Medial and Lateral Geniculate Nucleus on Phase Difference Enhanced Imaging

“…8,9 One of the major concepts responsible for the power of the PADRE technique is the "phase difference selection," which enhances the magnetic properties of the target tissue. PADRE imaging classifies and selects various phase differences, ⌬, to enhance the different tissues, and enhances all of them on the magnitude image ͉͉ by the enhancing function w(⌬).…”

“…In this study, the positive phase difference (⌬) was selected to enhance myelin. 7,8 All images were calculated off-line with in-house software. All postprocessing of DTI and PADRE images was fully automatic without user intervention to eliminate operator bias.…”

“…Phase difference enhanced (PADRE) imaging yields a high tissue contrast that delineates specific white matter tracts and intracortical structures. [7][8][9] On high-spatial-resolution 3T PADRE images, small structures, including the central tegmental tract, the medial and dorsal longitudinal fascicules, and the stria of Gennari, which are difficult to appreciate on conven-tional MR images, are delineated. 7,8 Also, the contrast between specific white matter structure (eg, the optic radiation) is higher on PADRE than on conventional MR images.…”

“…[7][8][9] On high-spatial-resolution 3T PADRE images, small structures, including the central tegmental tract, the medial and dorsal longitudinal fascicules, and the stria of Gennari, which are difficult to appreciate on conven-tional MR images, are delineated. 7,8 Also, the contrast between specific white matter structure (eg, the optic radiation) is higher on PADRE than on conventional MR images. 7 We compared visualization of the MGN and LGN on PADRE, 2D-T2-weighted, STIR, proton attenuation-weighted (PD), and DTI acquired at 3T.…”

Characterizing the contrast of white matter and grey matter in high-resolution phase difference enhanced imaging of human brain at 3.0 T

“…Therefore, with variable selection of phase differences, this technique permits variation in tissue contrast using single MR data acquisition. Some of the PADRE images carry additional information that could not be revealed with previously applied phase techniques [12]. In recent years, the PADRE technique has been successfully employed for the delineation of certain fine cerebral anatomical structures that are difficult to identify on conventional MR images, such as the medial lemniscus, central tegmental tract, medial longitudinal fasciculi, and crural fibres [12,13].…”