We perform simulations of coherent backscattering enhancement, explicitly accounting for the finiteness of spatial coherence of radiation. Three plausible models are considered, which produce the broadening of the coherent backscattering angular profile with the loss of spatial coherence. These models show fair agreement with data obtained earlier for biological media. Additionally, the exact solution for the double scattering term is obtained; its numerical magnitude is shown to be non-dominant for evaluations in the biomedical area due to high scattering anisotropy.