  Cosmic rays interacting with gas and photon fields in the Galaxy produce
interstellar gamma-ray emission (IGE), which accounts for almost 50% of the
photons detected at gamma-ray energies. Models of this IGE have to be very
accurate for interpreting the high-quality observations by present gamma-ray
telescopes, such as Fermi Large Area Telescope (LAT). Standard models of IGE,
used as reference models for analyses of the Fermi LAT data, show spatial
discrepancies with respect to the data, underlining the necessity of more
realistic models. The same CR electrons that produce the inverse-Compton
component of the IGE produce also interstellar synchrotron emission observed in
radio and microwave. However, present standard models do not take advantage of
results coming from studies of this interstellar synchrotron emission.
  Accounting for such results, in this work we show how they affect the
calculated spatial maps of the large-scale inverse-Compton component of the
IGE, which are usually used in studies of Fermi LAT data.
  It is found that these results significantly affect these spatial model maps
even at a 60% level. In particular, propagation models based on synchrotron
studies produce a more peaked inverse-Compton emission in the inner Galaxy
region with respect to the standard models used to analyze Fermi LAT data. The
conclusion is that radio and microwave observations can be included in a
multifrequency self-consistent approach for a more accurate modeling of the IGE
finalized to a physical comprehensive interpretation of gamma-ray data and its
present unexplained features. Model parameters are provided, which supply a
more realistic basis for high-energy gamma-ray studies.
