Figure 3

Comparison of the different quantification approaches on simulated data sets – spots of varying height. (a) Performance of area-based and function fit approaches for simulated single Gaussian-shaped spots of varying intensity. The function fit yielded correct VUSs for all intensities, although the area-based approach increasingly underestimated the volume at lower intensities. The intensities are indicated as multiples of the threshold that was used for defining the areas in the area-based approach. The inlay shows representative line profiles of relatively high- and low-intensity spots. The red area corresponds to the periphery of the spot, which would be omitted by an area-based approach. For the spot with the lower intensity, the red area comprises a higher percentage of the overall signal of the spot. 200 images per data point. (b) Performance of the area-based and function fit approaches for simulated single Lorentz-shaped spots of varying intensity. While our method consistently overestimated the VUS by approximately 20 percent, the area-based approach yielded an increasing level of underestimation at decreasing spot intensities. 200 images per data point. (c) Performance of the area-based and function fit approaches for simulated single diffusion model-based spots of varying intensity. While our method consistently overestimated the VUS by approximately 5 percent, the area-based approach yielded an increasing level of underestimation at decreasing spot intensities. 200 images per data point.