(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.

(MRgFUS) Magnetic resonance guided focused ultrasound is a surgical procedure that uses high intensity focused ultrasound waves to destroy tissue in combination with magnetic resonance imaging (MRI), which guides the treatment.
With focused ultrasound waves uterine fibroids are heated and destroyed (ablated) inside the MRI device , allowing the physician to plan, monitor and control the treatment with temperature sensitive images while it is in progress.

See also High Intensity Focused Ultrasound, and Interventional Ultrasound.

Transurethral echography or sonography is used to detect small tumors of the urinary bladder or to visualize the urethra and surrounding muscles with special transducers. The bladder neck can be visualized using a transrectal probe.
In addition, high intensity focused ultrasound provides treatment of benign prostatic hyperplasia and adenocarcinoma of the prostate. Small catheter-based sectored tubular or planar transducers with highly directional energy deposition and rotational control are used for precise treatment. Regions of the prostate can be selective coagulatet while monitoring and controlling the treatment with MRI.

See also Urologic Ultrasound, Lithotripsy, Reflux Sonography, Ultrasound Therapy, Interventional Ultrasound and Thermotherapy.

Ultrasound therapy uses high energy sound waves to treat different diseases. Historically, the use of ultrasonic waves in therapy began before the wide use as a diagnostic medical imaging tool. Dependend on the intensity, ultrasound therapy reach from the thermal effect used in physical therapy to the destruction of tissue with lithotripsy.

Types of ultrasound treatment:
See also Thermal Index, History of Ultrasound, Interventional Ultrasound, and B-Mode Acquisition and Targeting.

Ultrasound technology with its advancements is vital for delivering high-quality patient care. Innovations including high-frequency ultrasound, 3D//4D imaging, contrast enhanced ultrasound, elastography, and point-of-care ultrasound, have expanded the capabilities of ultrasound imaging and improved diagnostic accuracy.
B-Mode imaging, also known as brightness mode, is the fundamental technique in ultrasound imaging. It produces two-dimensional images based on the echoes received from tissues and organs. Understanding the principles of B-Mode imaging, such as gain adjustment, depth control, and image optimization, is crucial for obtaining diagnostically valuable images. M-Mode imaging, on the other hand, allows for the visualization of motion over time, enabling assessment of cardiac structures and function, as well as fetal heart rate.
High-frequency ultrasound refers to the use of ultrasound waves with frequencies greater than 10 MHz. This technology enables improved resolution, allowing for detailed imaging of superficial structures like skin, tendons, and small organs. High-frequency ultrasound has found applications in dermatology, ophthalmology, and musculoskeletal imaging.
Traditional 2D ultrasound has been augmented by the advent of 3D ultrasound technology. By acquiring multiple 2D images from different angles, this technique construct a volumetric representation of the imaged area. The addition of 4D ultrasound in real-time motion adds further value by capturing dynamic processes.
Doppler imaging employs the Doppler effect to evaluate blood flow within vessels and assess hemodynamics. Color Doppler assigns color to different blood flow velocities, providing a visual representation of blood flow direction and speed. Spectral Doppler displays blood flow velocities as a waveform, allowing for detailed analysis of flow patterns, resistance, and stenosis.
Contrast enhanced ultrasound employs microbubble contrast agents to enhance the visualization of blood flow and tissue perfusion. By injecting these agents intravenously, sonographers can differentiate between vascular structures and lesions. Elastography is a technique that measures tissue elasticity or stiffness. It assists in differentiating between normal and abnormal tissues, aiding in the diagnosis of various conditions such as liver fibrosis, breast lesions, and thyroid nodules.
Fusion imaging combines ultrasound with other imaging modalities, such as computed tomography (CT), magnetic resonance imaging (MRI), or positron emission tomography (PET). By overlaying or merging ultrasound images with those obtained from other modalities, the user can precisely locate and characterize abnormalities, guide interventions, and improve diagnostic accuracy. Fusion imaging has proven particularly useful in areas such as interventional radiology, oncology, and urology.
See also Equipment Preparation, Environmental Protection, Handheld Ultrasound, Portable Ultrasound and Ultrasound Accessories and Supplies.