  We have recently developed a phantom that simulates acute ischemic stroke. We
attempted to visualize acute-stage cerebral infarction by applying virtual
monochromatic images to this phantom using dual-energy CT (DECT). Virtual
monochromatic images were created using DECT from 40 to 100 keV at every 10 keV
and from 60 to 80 keV at every 1 keV, under three energy conditions of tube
voltages with thin (Sn) filters. Calculation of the CNR values allowed us to
evaluate the visualization of acute-stage cerebral infarction. The CNR value of
a virtual monochromatic image was the highest at 68 keV under 80 kV / Sn 140
kV, at 72 keV under 100 kV / Sn 140 kV, and at 67 keV under 140 kV / 80 kV. The
CNR values of virtual monochromatic images between 65 and 75 keV were
significantly higher than those obtained for all other created energy images.
Therefore, optimal conditions for visualizing acute ischemic stroke were
achievable.
