We present spectrally-resolved multi-photon induced fluorescence (TPIF) and second harmonic generation (SHG) imaging of porcine arterial wall tissue sections, both native tissues and damaged tissues subject to a proprietary therapy based on photo-activated crosslinking of collagen and other structural proteins in the arterial wall, a proposed treatment for peripheral artery disease termed non-invasive vascular scaffolding (NVS). We employ a spectrally-resolved multi-photon imaging system, based on a closed loop piezoelectric stage, a transmission grating and an EMCCD. From the spectrally-resolved multiphoton emission, we form ratiometric images of select spectral bands associated primarily with collagen (SHG) and elastin (TPIF). The ratiometric images aid in identifying representative regions for comparing the native and treated tissue sections, as well as reducing sensitivity to variations in intensity caused by scattering or attenuation of the excitation beam. Our aim is to use these ratios as a metric of the tissue structure and composition, indicating the relative contribution of collagen and elastin to the observed nonlinear signals. We note the photochemical modification results in a recovery of SHG intensity similar to the native artery, with the hypothesis that cross-linking of the compressed collagen fibrils in the arterial wall during the light activation step results in the formation of the NVS.