A stent delivery system comprising: a shape sensing wire configured to produce shape sensing data representative of a region of interest in a subject's vasculature; a stent delivery device configured to be disposed over the shape sensing wire, wherein the stent delivery device comprises a stent and an imaging element disposed distally of the stent, wherein the imaging element is configured to produce intravascular ultrasound imaging data representative of the region of interest; a computing system comprising: one or more processors; and memory storing instructions that, when executed by the one or more processors, cause the one or more processors to: receive a first plurality of signals corresponding to the shape sensing data; receive a second plurality of signals corresponding to the intravascular ultrasound imaging data; co-register the first signals and the second signals; characterized in that the one or more processors is further configured to: process the first signals and the second signals to generate a pre-deployment three-dimensional model of the region of interest; based on the pre-deployment three-dimensional model, determine a pre-deployment size characteristic of the region of interest; receive a stent-deployment signal indicative of the stent being deployed; receive a third plurality of signals corresponding to the shape sensing data after receiving the stent-deployment signal; receive a fourth plurality of signals corresponding to the intravascular ultrasound imaging data after receiving the stent-deployment signal; co-register the third signals and the fourth signals; process the third signals and the fourth signals to generate a post-deployment three-dimensional model of the region of interest; based on the post-deployment three-dimensional model, determine a post-deployment size characteristic of the region of interest; calculate a comparison of the pre-deployment size characteristic and the post-deployment size characteristic; and provide, to a monitor, the comparison. a shape sensing wire configured to produce shape sensing data representative of a region of interest in a subject's vasculature; a stent delivery device configured to be disposed over the shape sensing wire, wherein the stent delivery device comprises a stent and an imaging element disposed distally of the stent, wherein the imaging element is configured to produce intravascular ultrasound imaging data representative of the region of interest; a computing system comprising: one or more processors; and memory storing instructions that, when executed by the one or more processors, cause the one or more processors to: receive a first plurality of signals corresponding to the shape sensing data; receive a second plurality of signals corresponding to the intravascular ultrasound imaging data; co-register the first signals and the second signals; characterized in that the one or more processors is further configured to: process the first signals and the second signals to generate a pre-deployment three-dimensional model of the region of interest; based on the pre-deployment three-dimensional model, determine a pre-deployment size characteristic of the region of interest; receive a stent-deployment signal indicative of the stent being deployed; receive a third plurality of signals corresponding to the shape sensing data after receiving the stent-deployment signal; receive a fourth plurality of signals corresponding to the intravascular ultrasound imaging data after receiving the stent-deployment signal; co-register the third signals and the fourth signals; process the third signals and the fourth signals to generate a post-deployment three-dimensional model of the region of interest; based on the post-deployment three-dimensional model, determine a post-deployment size characteristic of the region of interest; calculate a comparison of the pre-deployment size characteristic and the post-deployment size characteristic; and provide, to a monitor, the comparison. one or more processors; and memory storing instructions that, when executed by the one or more processors, cause the one or more processors to: receive a first plurality of signals corresponding to the shape sensing data; receive a second plurality of signals corresponding to the intravascular ultrasound imaging data; co-register the first signals and the second signals; receive a first plurality of signals corresponding to the shape sensing data; receive a second plurality of signals corresponding to the intravascular ultrasound imaging data; co-register the first signals and the second signals; process the first signals and the second signals to generate a pre-deployment three-dimensional model of the region of interest; based on the pre-deployment three-dimensional model, determine a pre-deployment size characteristic of the region of interest; receive a stent-deployment signal indicative of the stent being deployed; receive a third plurality of signals corresponding to the shape sensing data after receiving the stent-deployment signal; receive a fourth plurality of signals corresponding to the intravascular ultrasound imaging data after receiving the stent-deployment signal; co-register the third signals and the fourth signals; process the third signals and the fourth signals to generate a post-deployment three-dimensional model of the region of interest; based on the post-deployment three-dimensional model, determine a post-deployment size characteristic of the region of interest; calculate a comparison of the pre-deployment size characteristic and the post-deployment size characteristic; and provide, to a monitor, the comparison.