Ultrasound Overview and Types

Ultrasound Overview

     Ultrasound (also termed sonography, ultrasonography, and Doppler study) is a non-invasive diagnostic medical technique that uses high frequency sound waves to produce images of the internal structures of the body. These sound waves are not detectable by human hearing.
     Using ultrasonography, a technician or doctor moves a device called a transducer (probe) over part of your body. The transducer emits sound waves which bounce off the internal tissues, and creates images from the waves that bounce back. Different densities of tissues, fluid, and air inside the body produce different images that can be interpreted by a physician, typically a radiologist (a physician who specializes in imaging technologies). Many studies are done by a trained technologist (sonographer) and then interpreted by a radiologist.

 Ultrasound Uses
     Ultrasound can be used as a diagnostic or screening tool to confirm medical disorders or to assist in performing medical procedures. It is also used as a therapeutic tool in treating musculoskeletal problems, renal stones (kidney stones), and gallstones.


 Diagnostic or Screening Uses

• Obstetrics and gynecology: Pregnancy ultrasound (or fetal ultrasound) is used to assess the progression of the fetus. Vaginal ultrasound, pelvic ultrasound, or transvaginal ultrasound is used to diagnose growths or tumors of the ovary, uterus, and Fallopian tubes. It can be used to assess non-pregnancy related issues as well:

1. lower abdominal pain 
2. ovarian cysts 
3. uterine fibroids 
4. uterine growths 
5. endometriosis

• Cardiology: Echocardiography (heart ultrasound) is a common way to evaluate the overall function of the heart. It is used to evaluate the flow of blood through the chambers and valves of the heart. It also assesses the strength of the heart beat and the volume of blood pumped through. Echocardiography is often used for the following:

1. heart valve problems, such as mitral valve prolapse or aortic stenosis; 
2. congestive heart failure; 
3. blood clots due to irregular heart beats such as in atrial fibrillation; 
4. abnormal fluid collections around the heart, such as pericardial effusions; and 
5. pulmonary artery hypertension.

• Blood vessels: Ultrasound is useful in detecting problems with most of the larger blood vessels in the body. Using Doppler ultrasound technology, the flow of blood through the vessels can be observed and measured. Narrowing of vessels (stenosis) or widening of vessels (dilatation, also referred to as aneurysms) can be detected. Ultrasound testing of blood vessels includes:

1. carotid ultrasound, 
2. abdominal aorta ultrasound for abdominal aortic aneurysm, and 
3. blood clots in veins (superficial or deep venous thrombosis, or DVT).

• Abdominal structures: Abdominal ultrasound is used to evaluate the solid organs within the abdominal cavity, including the liver, gallbladder, pancreas, kidneys, and bladder.

1. Renal ultrasound is used to evaluate the function and structure of the kidneys. Swelling around the kidney with blockage in the urinary tract can be seen with ultrasound, making abdominal ultrasound useful in detecting kidney stones. 
2. Liver ultrasound is used to find abnormalities in the liver tissue and ducts. 
3. Gallbladder ultrasound can screen for gallstones or an infected gallbladder. 
4. Appendix ultrasound is used in children or pregnant women, where it is necessary to avoid radiation from a CT scan (computerized tomography).

• Testicular ultrasound: Used to diagnose testicular torsion, epididymitis (testicle infection), and testicular masses. 
• Neck ultrasound: The thyroid and parathyroid glands can be imaged to detect nodules, growths, and tumors. 
• Breast ultrasound: Used to image the breasts and to guide biopsy of breast masses to evaluate for breast cancer. 
• Knee ultrasound: Ultrasound can be used to evaluate the structures in the back of the knee to determine if a Baker's Cyst is present. 
• Eye ultrasound: An eye ultrasound is used to look at the back of the eye (retina). It is often used when a patient has cataracts that make looking into the eye difficult. The test may help diagnose retinal detachment. It can also assist in cataract surgery. 
• Skin ultrasound: Ultrasound can be used to help find certain types of foreign bodies that may become lodged in the skin.