Non-contrast ultrasound assessment of blood flow in clinical practice.

Since the first clinical use of ultrasound in the 1940s, significant advancements have been made in its applications. Color Doppler imaging and power Doppler imaging are considered the first and second generations of flow ultrasound assessment tools, respectively. Subsequently, the introduction of contrastenhanced ultrasound has significantly improved the assessment of arterial and venous vascular patterns in lesions and vessels.