Systems and methods for performing and assessing neuromodulation therapy are disclosed herein. One method for assessing the efficacy of neuromodulation therapy includes positioning a neuromodulation catheter at a target site within a renal blood vessel of a human patient and delivering neuromodulation energy at the target site with the neuromodulation catheter. The method can further include obtaining a measurement related to a blood flow rate through the renal blood vessel via the neuromodulation catheter. The measurement can be compared to a baseline measurement related to the blood flow rate through the renal blood vessel to assess the efficacy of the neuromodulation therapy. In some embodiments, the baseline and post-neuromodulation measurements are obtained by injecting an indicator fluid into the renal blood vessel upstream of the target site and detecting a transient change in vessel impedance caused by the indicator fluid.
