Interventional ultrasound refers to real-time ultrasound guidance for minimally invasive procedures. Applications include core needle biopsy of solid masses (breast, thyroid, liver, kidney, lymph nodes), aspiration of cysts and fluid collections, placement of drainage catheters, vascular access guidance, amniocentesis, chorionic villus sampling, and joint or soft tissue injections. The needle is visualized as a hyperechoic line on the ultrasound image, guiding the operator to the target. Real-time guidance improves accuracy and reduces complications compared to landmark-based or CT-guided techniques.