Activation of ProSense FAST is nonselective for tested cathepsins similar to the polymer-based ProSense, which is only weakly selective for cathepsin B. Conversely, the Cat B FAST agent is highly selective for cathepsin B. Thus, parallel measurements using the new agents and polymer-based ProSense can address the effect of the protease selectivity and to some extent also the potential effect of the polymer coil on the detection sensitivity of atherosclerosis associated inflammation. This evidence concerns the gene CTSS and atherosclerosis.