An exact form for the magnetic field density of states for a dipole.
We present an analytical form for the density of states for a magnetic dipole in the center of a spherical voxel. This analytic form is then used to evaluate the signal decay as a function of echo time for different volume fractions and susceptibilities. The decay can be considered exponential only in a limited interval of time. Otherwise, it has a quadratic dependence on time for short echo times and an oscillatory decaying behavior for long echo times.
Cheng
Y C
YC
The MRI Institute for Biomedical Research, 8706 Manchester Road, Suite 102, Brentwood, MO 63144, USA. yxc16@po.cwru.edu
Haacke
E M
EM
Yu
Y J
YJ
D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008280:Magnetics; D055585:Physical Phenomena; D010825:Physics