  We study the dimuon yield from open charm decays in the intermediate mass
region(IMR) in heavy-ion collisions at the CERN-SPS energy. We find that final
state rescatterings which broaden the $m_T$ spectrum of charmed mesons can
enrich the part of the phase space covered by the NA50 experiment, thus leading
to an apparent enhancement of IMR dileptons within the acceptance of the
experiment. Such an enhancement increases with the dimuon invariant mass and
the single muon energy cut-off.
