Physiology sensing intraluminal device with index for spectral flow assessment, and associated devices, systems, and methods

An intraluminal sensing system is provided, which includes an intraluminal device. The intraluminal device includes a flexible elongate member that can be positioned within a body lumen of a patient, and an ultrasound sensor at a distal portion of the flexible elongate member and configured to emit an ultrasound pulse in a longitudinal direction and to receive ultrasound echoes from the pulse. The system also includes a processor circuit in communication with the ultrasound sensor. The processor circuit is configured to compute a velocity spectrum of particles moving within the body lumen based on the received ultrasound echoes and, based on the velocity spectrum, compute a skew index indicative of a position or alignment of the ultrasound sensor within the body lumen. The processor circuit is also configured to output an indication of the skew index.