Radiology, Vol 156, 749-752, Copyright © 1985 by Radiological Society of North America
MR imaging technology: maximizing the signal-to-noise ratio from a single tissue
RE Hendrick, FD Newman and WR Hendee
The pulse-sequence equations for spin-echo magnetic resonance imaging were
used to determine interpulse delay times that give the highest
signal-to-noise ratio from a single tissue. This theoretical result was
then verified experimentally using 1-, 2-, and 5-mM/l copper sulfate
solutions imaged on a 0.15-T resistive system. Theoretical analysis
determined the spin-echo interpulse delay times that maximize the
signal-to-noise ratio from a single tissue as TEopt = TEmin, the minimum
echo delay time permitted by the system, and, to a good approximation,
TRopt = 1.27 T1 + 1.90 TEmin, with T1 the longitudinal magnetic relaxation
time of the tissue. Phantom measurements of the signal-to-noise ratio in a
typical imaging system confirmed the theoretically determined TRopt values
to within 7%.
