Interventional ultrasound, also known as ultrasonography, encompasses a range of invasive or surgical procedures guided by ultrasound imaging. While its widest application lies in intravascular ultrasound imaging for measuring atherosclerotic plaque, it has proven valuable in various medical fields.
In urology, ultrasound-guided interventions are employed for treatments like high intensity focused ultrasound (HIFU) in prostate conditions. The precise imaging provided by ultrasound aids in targeting the affected area and delivering therapeutic energy effectively.
In intraabdominal conditions, endoscopic ultrasound is frequently utilized. This technique combines ultrasound imaging with an endoscope to visualize and evaluate structures within the gastrointestinal tract, allowing for precise diagnoses and targeted interventions.
Ultrasound-guided procedures play a significant role in several medical specialties, including liver sonography, obstetric and gynecologic ultrasound, and thyroid ultrasound. These procedures involve interventions such as RF thermal ablation or biopsies, which are guided by real-time ultrasound imaging.
For instance, in liver sonography, ultrasound guidance is crucial for performing biopsies or RF thermal ablation, a technique used to treat liver tumors by delivering localized heat to destroy the abnormal tissue. The real-time imaging allows for precise needle placement and monitoring during the procedure.
In obstetric and gynecologic ultrasound, ultrasound-guided procedures, such as biopsies, can be performed to obtain tissue samples for diagnostic purposes. Additionally, ultrasound guidance is valuable during interventions like amniocentesis or fetal blood sampling, enabling accurate and safe procedures.
Thyroid ultrasound procedures often involve ultrasound-guided fine-needle aspiration biopsy (FNAB), which allows for the sampling of thyroid nodules for cytological examination. The ultrasound image helps guide the needle into the targeted area, ensuring accurate sampling and minimizing potential complications.
Overall, ultrasound-guided interventions provide minimally invasive and precise approaches to diagnosis and treatment. The real-time imaging capabilities of ultrasound contribute to enhanced accuracy, safety, and patient outcomes in procedures like biopsies, injections, and drainage.

See also Transurethral Sonography, Endocavitary Echography, and B-Mode Acquisition and Targeting.

Three tissue layers called tunicae, or coats, surround the lumen of an artery. The tunica intima (internal coat) is the innermost lining of an artery composed of endothelial cells and a thin layer of protein called the internal basement membrane.
The intima, as seen in intravascular ultrasound, is normally a thin layer supported by smooth muscle cells, fibroblasts and the internal elastic lamina; this layer thickens substantially, often eccentrically, in atherosclerosis.

(IVUS) For intravascular ultrasound a small IVUS catheter with a probe is introduced into the artery. The transducer transmits and receives acoustic energy through this catheter. The reflected acoustic energy is used to build a picture of the inside of the vessel. A IVUS image consists of three layers around the lumen, the intima, media and adventitia.
In addition, elastography or palpography could be used to evaluate the local mechanical properties of tissues (e.g. lipid pools in high-risk vulnerable atherosclerotic plaques). These techniques use the deformation caused by the intraluminal pressure generated by the probe.
A high strain region at the lumen vessel wall boundary has 88% sensitivity and 89% specificity for identifying vulnerable plaques. There are high strain values of 1% in soft plaques with increased strain up to 2% at the shoulders of the plaque, while calcified material shows low strain values (0-0.2%). The radial strain in the tissue is obtained by cross-correlation techniques on the radio frequency signal. The strain is color-coded and plotted as a complimentary image to the intravascular ultrasound echogram.

See also Interventional Ultrasound, Vascular Ultrasound.

Ipsilateral describes a structure on the same side; for example in a sonogram of the left internal carotid artery, the ipsilateral common carotid artery would be the left common carotid artery.

The term isoechogenic or isoechoic is used if different tissues have the same echogenicity and are not separate depictable.