  An updated investigation of QCD sum rules for the first two moments of rho
meson spectral functions, both in vacuum and in-medium, is performed with
emphasis on the role of the scale related to spontaneous chiral symmetry
breaking in QCD. It is demonstrated that these lowest moments of vector current
spectral distributions do permit an accurate sum rule analysis with controlled
input including QCD condensates of the lowest dimensions, whereas higher
moments are subject to uncertainties from higher dimensional condensates.
Possible connections with Brown-Rho scaling are discussed. The factorization
approximation for four-quark condensates is shown not to be applicable in any
of the cases studied.
