Purpose: The aim of this study was to investigate the visualization of smal
l venous vessels in the normal human brain at a field strength of 3 Tesla.
Methods: T2*-weighted, three-dimensional gradient-echo images were acquired
by exploiting the magnetic susceptibility difference between oxygenated an
d deoxygenated hemoglobin in the vasculature and microvasculature. The spat
ial resolution was 0.5 x 0.5 x 1 mm(3), and sequence parameters were varied
to obtain good vessel delineation. Improved visibility of venous vessels w
as obtained by creating phase mask images from the magnetic resonance phase
images and multiplying these by the magnitude images. Venograms were creat
ed by performing a minimum intensity projection over targeted volumes.
Results: Highly detailed visualization of venous structures deep in the bra
in and in the superficial cortical areas were obtained without administrati
on of an exogenous contrast agent; compared with similar studies performed
at 1.5 T, the echo time could be reduced from typically 40-50 ms to 17-28 m
s.
Conclusion: Imaging at high-field strength offers the possibility of improv
ed resolution and the delineation of smaller vessels compared with lower fi
eld strengths.