Human health and medicine

Ultrashort echo time imaging

Ultrashort echo time (UTE) imaging is a magnetic resonance imaging technique that captures signal within tens of microseconds, making short-T2 tissues like cortical bone, tendons, and lung visible on MRI.

Ultrasonic imaging

Ultrasonic imaging, or sonography, is a diagnostic method that images internal body structures in real time using high-frequency sound pulses and their echoes.

Ultrasonic Surgical Procedures

Ultrasonic surgical procedures (ultrasonic surgery, ultrasound surgery) use 20-60 kHz high-energy shock waves to cut, fragment, or remove tissue by mechanical cavitation rather than heat, via devices such as the HARMONIC scalpel, ultrasonic aspirators, and phacoemulsification.

Ultrasonography

Ultrasonography, also called sonography, is a portable, radiation-free imaging method using high-frequency sound waves to visualize internal organs and tissues, guide procedures, and diagnose conditions at the bedside.

Ultrasonography of chronic venous insufficiency of the legs

Duplex ultrasonography (DUS) of chronic venous insufficiency of the legs, also called venous duplex or venous mapping, is the reference-standard ultrasound test for venous reflux, using segment-specific cutoffs (>500 ms superficial, >1 s deep) with the patient standing.

Ultrasonography of deep vein thrombosis

Compression ultrasonography for deep vein thrombosis: first-line ultrasound test using vein noncompressibility, with Wells score and D-dimer, pooled sensitivity about 90-98% for proximal DVT.

Ultrasound ablation

Ultrasound ablation is a noninvasive method that focuses ultrasound energy inside the body to destroy targeted tissue by heating or cavitation, treating fibroids, prostate disease, tremor, and liver tumors.

Ultrasound biomicroscopy

Ultrasound biomicroscopy, or UBM, is a high-frequency ultrasound imaging technique that produces cross-sectional images of the eye's anterior segment at near-microscopic resolution, used mainly in glaucoma care.

Ultrasound computed tomography

Ultrasound computed tomography, or ultrasound tomography, is an imaging method that reconstructs cross-sectional maps of tissue sound speed and attenuation, developed mainly for breast cancer screening.

Ultrasound elastography

Ultrasound elastography is an imaging technique that measures the stiffness of soft tissue noninvasively, most often to stage liver fibrosis without biopsy and to characterize breast and thyroid lesions.

Ultrasound localization microscopy

Ultrasound localization microscopy (ULM) is a super-resolution medical ultrasound technique that localizes individual microbubble contrast agents to map microvasculature and blood flow, overcoming the resolution-penetration trade-off at centimeter depths.

Ultrasound microvessel imaging

Ultrasound microvessel imaging (UMI) is a family of ultrasound techniques that visualize blood flow in small vessels beyond conventional Doppler, including superb microvascular imaging and ultrasound localization microscopy.

Ultrasound molecular imaging

Ultrasound molecular imaging (USMI) is an imaging technique that uses ligand-bearing gas microbubbles, 1–10 µm across, to visualize molecular markers on vascular endothelium noninvasively and in real time.

Ultrasound surgery

Ultrasound surgery, known as high-intensity focused ultrasound (HIFU) or MR-guided focused ultrasound, destroys targeted internal tissue with focused beams and no incision, routinely treating uterine fibroids and essential tremor.

Ultrasound thalamotomy

Ultrasound thalamotomy is a noninvasive neurosurgical procedure in which MRI-guided focused ultrasound heats and destroys part of the thalamus to relieve medication-refractory tremor, first FDA-approved in 2016.

Ultrasound-guided biopsy

Ultrasound-guided biopsy is a percutaneous procedure in which real-time sonography directs a needle into a suspected lesion to obtain cells or tissue for diagnosis, best suited to superficial targets.

Ultrasound-guided injection

Ultrasound-guided injection is a procedure delivering corticosteroids or anesthetics into joints, tendon sheaths, bursae, or nerves while ultrasound imaging shows the needle tip in real time, improving accuracy over blind landmark-guided injections.

Oct 22, 2026

Ultrasound-triggered drug release

Ultrasound-triggered drug release is a drug delivery strategy in which externally applied ultrasound causes carriers such as microbubbles, liposomes, and nanoparticles to release drugs at a chosen body site.

Oct 20, 2026

Ultrasound, High-Intensity Focused, Transrectal

Transrectal high-intensity focused ultrasound (transrectal HIFU) ablates prostate tissue via a rectal transducer, treating prostate cancer and BPH; devices include Ablatherm and Sonablate, FDA-cleared since 2015.

Ultraviolet Therapy

Ultraviolet therapy (phototherapy, PUVA, narrowband UVB): controlled UV light treatment of skin diseases such as psoriasis, eczema, vitiligo, and mycosis fungoides, from Finsen's 1896 carbon-arc lamp to modern 311-nm lamps.

Uma M. Reddy

Uma M. Reddy is an American maternal-fetal medicine physician-scientist at Yale School of Medicine known for stillbirth research and elected to the National Academy of Medicine in 2024.

Uma R. Kotagal

Uma R. Kotagal is an American pediatrician and neonatologist who led healthcare quality and safety work at Cincinnati Children's and was elected to the National Academy of Medicine in 2009.

Umbilical cord

Umbilical cord: fetal-placental conduit with two arteries and one vein in Wharton jelly, 50–60 cm at term; carries oxygenated blood via the vein; delayed clamping 30–60 seconds is now recommended; single umbilical artery affects under 1% of pregnancies.

Umbilical hernia

An umbilical hernia is a bulge at the belly button where bowel or fat pushes through a weakness in the abdominal muscles, common in infants and adults.

Umbilical hernia repair

Umbilical hernia repair is surgery that closes a defect in the abdominal wall at the navel, using suture or mesh, open, laparoscopic, or robotic, in adults and children.

Umbilical vein

The umbilical vein is the single cord vessel carrying oxygenated placental blood to the fetus; normally the left of two embryonic veins, it becomes the ligamentum teres after birth and supports neonatal catheterization.

Umbralisib

Umbralisib (Ukoniq), an oral dual PI3Kδ/CK1ε inhibitor by TG Therapeutics, won accelerated FDA approval in February 2021 for relapsed/refractory marginal zone and follicular lymphoma; approval was withdrawn May 31, 2022 over UNITY-CLL survival and safety concerns.