Ultrasound, also known as ultrasonography, is a non-invasive diagnostic imaging technique that uses high-frequency sound waves to produce real-time images of internal organs, soft tissues, blood vessels, and fetal development. It is widely used across multiple medical specialities, including obstetrics and gynaecology, cardiology, radiology, urology, and gastroenterology, due to its safety, accuracy, and lack of ionising radiation.

During an ultrasound examination, a trained technician or physician applies a water-based gel to the area being studied and moves a handheld transducer over the skin. The transducer emits sound waves that penetrate the body and reflect off tissues, creating detailed images displayed on a monitor. Doppler ultrasound can also be employed to assess blood flow, detect blockages, evaluate cardiac function, and monitor fetal circulation.

Ultrasound is commonly used to evaluate abdominal organs such as the liver, kidneys, pancreas, and gallbladder, detect fluid collections, guide needle biopsies, assess thyroid and breast lesions, monitor pregnancy, and perform echocardiography of the heart. It is also utilised in musculoskeletal imaging to examine tendons, ligaments, and soft tissue injuries. The procedure is painless, safe, and typically completed within 15–30 minutes, depending on the area examined. It is suitable for patients of all ages, including pregnant women and infants, and does not involve exposure to ionising radiation. Ultrasound findings are interpreted by radiologists or specialists to aid in diagnosis, treatment planning, and monitoring of disease progression. By providing real-time, accurate, and non-invasive imaging, ultrasound is a cornerstone of modern diagnostic medicine. It enables early detection of abnormalities, guides minimally invasive procedures, and supports effective clinical decision-making, significantly improving patient outcomes and safety.