RF inhomogeneity compensation in structural brain imaging

• Published in: Magnetic resonance in medicine Vol. 47; no. 2; pp. 398 - 402
• Main Authors: Deichmann, R., Good, C.D., Turner, R.
• Format: Journal Article
• Language: English
• Published: New York Wiley Subscription Services, Inc., A Wiley Company 01.02.2002; Williams & Wilkins
• Subjects: anatomical imaging; Biological and medical sciences; Brain - anatomy & histology; Echo-Planar Imaging - methods; Humans; Image Enhancement - methods; Image Processing, Computer-Assisted; Investigative techniques, diagnostic techniques (general aspects); Medical sciences; Miscellaneous. Technology; MP-RAGE; Radiodiagnosis. Nmr imagery. Nmr spectrometry; Reference Values; RF inhomogeneity; RF pulse; Sensitivity and Specificity; structural imaging; Gradient echo; Mathematical analysis; Compensation; Medical imagery; Technique; Image; Radiofrequency; Nuclear magnetic resonance imaging; Structural analysis; Brain (vertebrata)
• ISSN: 0740-3194; 1522-2594
• DOI: 10.1002/mrm.10050

Three‐dimensional T1‐weighted magnetization‐prepared rapid gradient‐echo (MP‐RAGE) sequences with centric phase encoding (PE) in the inner loop provide structural brain images with a high spatial resolution and high tissue contrast. A disadvantage of this sequence type is the susceptibility to inhomogeneities of the radiofrequency (RF) coil, which may result in poor image contrast in some peripheral regions. A special excitation pulse is presented which compensates for these effects in both the head/foot and anterior/posterior directions. This pulse has a duration of only 1.3 ms and is thus compatible with the short repetition times (TRs) required for MP‐RAGE imaging. It is shown experimentally that images acquired with the compensation pulse may be segmented without using intensity correction algorithms during data postprocessing. Magn Reson Med 47:398–402, 2002. © 2002 Wiley‐Liss, Inc.