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These procedures generally use lower frequencies than medical diagnostic ultrasound (from 0.7 to 2 MHz), but higher the frequency means lower the focusing energy. HIFU treatment is often guided by MRI. Focused ultrasound may be used to dissolve kidney stones by lithotripsy. Ultrasound may be used for cataract treatment by phacoemulsification.
Also, unlike ultrasonography of deep venous thrombosis, the procedure focuses mainly on superficial veins. Also, unlike the arterial ultrasound examination, blood velocity in veins has no diagnostic meaning. Veins are a draining system similar to a low pressure hydraulic system, with a laminar flow and a low velocity.
Focused assessment with sonography in trauma (commonly abbreviated as FAST) is a rapid bedside ultrasound examination performed by surgeons, emergency physicians, and paramedics as a screening test for blood around the heart (pericardial effusion) or abdominal organs (hemoperitoneum) after trauma.
Reflected ultrasound comes from an interface, such as the back wall of the object or from an imperfection within the object. The diagnostic machine displays these results in the form of a signal with an amplitude representing the intensity of the reflection and the distance, representing the arrival time of the reflection.
Medical ultrasound includes diagnostic techniques (mainly imaging techniques) using ultrasound, as well as therapeutic applications of ultrasound. In diagnosis, it is used to create an image of internal body structures such as tendons, muscles, joints, blood vessels, and internal organs, to measure some characteristics (e.g., distances and velocities) or to generate an informative audible sound.
Echogenicity (sometimes as echogenecity) or echogeneity is the ability to bounce an echo, e.g. return the signal in medical ultrasound examinations. In other words, echogenicity is higher when the surface bouncing the sound echo reflects increased sound waves.
T 2 *-weighted sequences are used to detect deoxygenated hemoglobin, methemoglobin, or hemosiderin in lesions and tissues. [2] Diseases with such patterns include intracranial hemorrhage, arteriovenous malformation, cavernoma, hemorrhage in a tumor, punctate hemorrhages in diffuse axonal injury, superficial siderosis, thrombosed aneurysm, phleboliths in vascular lesions, and some forms of ...
Knee or hip replacement are, by themselves, not indications to perform the procedure. [ 2 ] Serial follow-up the ultrasound exam is not necessary after an initially complete, normal study in individuals with DVT symptoms who have suspected pulmonary embolism and nondiagnostic ventilation/perfusion scans .