Evidence of red cell alignment in the magnetic field of an NMR spectrometer based on the diffusion tensor of water

The alignment of human erythrocytes in aqueous suspensions in the magnetic field B-0 (called the z-direction) of an NMR spectrometer was shown by calc ulating the diffusion tensor for water in the sample. The diffusion was mea sured using a pulsed-held-gradient spin-echo NMR method. The extent of diff usion anisotropy for water was exemplified by the values of the apparent di ffusion coefficients with erythrocytes of normal shape and volume: for a ty pical experiment the values for the x-, y-, and z-directions were (6.88 +/- 0.17) x 10(-10), (7.07 +/- 0.17) x 10(-10), and (10.20 +/- 0.17) x 10(-10) m(2) s(-1), respectively. Cells in hypo- and hyperosmotic media were also studied and they too showed the anisotropy of the apparent diffusion coeffi cients but the extents were different. A new method of data analysis was de veloped using the Standard Add-On Packages in a Mathematica program, The ex perimental findings support evidence of erythrocyte alignment that was prev iously obtained with a high-field-gradient q-space method. (C) 2000 Academi c Press.