A system, comprising: a probe configured to: transmit ultrasound signals directed to a target blood vessel, and receive echo information associated with the transmitted ultrasound signals; and at least one processing device configured to: process the received echo information and generate a three-dimensional ultrasound image of the target blood vessel, obtain a flexible three-dimensional vascular model corresponding to the target blood vessel, wherein the flexible three-dimensional vascular model includes a statistical shape model derived from human samples and without using any mesh, and wherein the statistical shape model infers one of a statistical distribution, perform a shape fitting procedure of the flexible three-dimensional vascular model onto the three-dimensional ultrasound image of the target blood vessel, wherein the shape fitting procedure overlays the flexible three-dimensional vascular model onto the ultrasound image of the target blood vessel and morphs the flexible three-dimensional vascular model to match the ultrasound image of the target blood vessel, store a segmentation result based on the shape fitting procedure, and calculate, based on the segmentation result, measurements for the target blood vessel. a probe configured to: transmit ultrasound signals directed to a target blood vessel, and receive echo information associated with the transmitted ultrasound signals; and transmit ultrasound signals directed to a target blood vessel, and receive echo information associated with the transmitted ultrasound signals; and at least one processing device configured to: process the received echo information and generate a three-dimensional ultrasound image of the target blood vessel, obtain a flexible three-dimensional vascular model corresponding to the target blood vessel, wherein the flexible three-dimensional vascular model includes a statistical shape model derived from human samples and without using any mesh, and wherein the statistical shape model infers one of a statistical distribution, perform a shape fitting procedure of the flexible three-dimensional vascular model onto the three-dimensional ultrasound image of the target blood vessel, wherein the shape fitting procedure overlays the flexible three-dimensional vascular model onto the ultrasound image of the target blood vessel and morphs the flexible three-dimensional vascular model to match the ultrasound image of the target blood vessel, store a segmentation result based on the shape fitting procedure, and calculate, based on the segmentation result, measurements for the target blood vessel. process the received echo information and generate a three-dimensional ultrasound image of the target blood vessel, obtain a flexible three-dimensional vascular model corresponding to the target blood vessel, wherein the flexible three-dimensional vascular model includes a statistical shape model derived from human samples and without using any mesh, and wherein the statistical shape model infers one of a statistical distribution, perform a shape fitting procedure of the flexible three-dimensional vascular model onto the three-dimensional ultrasound image of the target blood vessel, wherein the shape fitting procedure overlays the flexible three-dimensional vascular model onto the ultrasound image of the target blood vessel and morphs the flexible three-dimensional vascular model to match the ultrasound image of the target blood vessel, store a segmentation result based on the shape fitting procedure, and calculate, based on the segmentation result, measurements for the target blood vessel.