In vivo blood T1 measurements at 1.5 T, 3 T, and 7 T

• Published in: Magnetic resonance in medicine 2013-10, Vol.70 (4), p.1082-1086
• Main Authors: Zhang, X., Petersen, E. T., Ghariq, E., De Vis, J. B., Webb, A. G., Teeuwisse, W. M., Hendrikse, J., van Osch, M. J. P.
• Format: Article
• Language: English
• Subjects: 7 T; arterial spin labeling; longitudinal relaxation time; magnetic field
• ISSN: 0740-3194; 1522-2594
• DOI: 10.1002/mrm.24550

The longitudinal relaxation time of blood is a crucial parameter for quantification of cerebral blood flow by arterial spin labeling and is one of the main determinants of the signal‐to‐noise ratio of the resulting perfusion maps. Whereas at low and medium magnetic field strengths (B0), its in vivo value is well established; at ultra‐high field, this is still uncertain. In this study, longitudinal relaxation time of blood in the sagittal sinus was measured at 1.5 T, 3 T, and 7 T. A nonselective inversion pulse preceding a Look‐Locker echo planar imaging sequence was performed to obtain the inversion recovery curve of venous blood. The results showed that longitudinal relaxation time of blood at 7 T was ∼ 2.1 s which translates to an anticipated 33% gain in the signal‐to‐noise ratio in arterial spin labeling experiments due to T1 relaxation alone compared with 3 T. In addition, the linear relationship between longitudinal relaxation time of blood and B0 was confirmed. Magn Reson Med, 70:1082–1086, 2013. © 2012 Wiley Periodicals, Inc.