Spectroscopic imaging with multidimensional pulses for excitation: SIMPLE

✍ Scribed by Daniel Spielman; John Pauly; Albert Macovski; Dieter Enzmann

• Book ID: 102952340
• Publisher: John Wiley and Sons
• Year: 1991
• Tongue: English
• Weight: 1014 KB
• Volume: 19
• Category: Article
• ISSN: 0740-3194
• DOI: 10.1002/mrm.1910190107

✦ Synopsis

Abstract

Proton spectroscopy and spectroscopic imaging in the human brain require the elimination of both water and lipid signals. Strong lipid signals from subcutaneous fat are usually eliminated by confining the excited volume to lie wholly within the skull. Water suppression, however, can be difficult due to both B~0~ and RF inhomogeneities, which are particularly troublesome in imaging experiments where a relatively large region‐of‐interest (ROI) is typical. In this paper, we discuss the use of multidimensional selective‐excitation pulses (e.g., pulses that are simultaneously selective along two axes) to both define the ROI and provide the necessary water suppression. Pulse sequences providing three‐dimensional localization along with water suppression that is insensitive to a range of B~0~ and RF inhomogeneities are described. Spectra and spectroscopic images (voxel volume = 3.4 cc, acquisition time = 38 min) of various ^1^H metabolites from a patient with an astrocytoma show clear differences between normal and cancerous tissues and demonstrate the ability of these techniques to be used in vivo.