Ultrasound

General Description

Ultrasound is a test that uses sound waves, which generate an echo when they strike tissues, to obtain images of the body. This technique allows the observation of internal organs and structures, as well as the movement of tissues and internal fluids in real-time.

This test is used to diagnose various diseases, detect malformations, monitor pregnancy, or guide specialists during other medical procedures (interventional ultrasound), such as biopsies. The most common types are abdominal, pelvic, vascular, breast, thyroid, or musculoskeletal ultrasounds.

There are various techniques for performing an ultrasound, which can be grouped into five main types:

• 2D Ultrasound: This is the most commonly used method for years. It provides two-dimensional, flat, grayscale images.
• 3D Ultrasound: It allows for depth and the viewing of three-dimensional images. The results come from a computer reconstruction of the images obtained through a conventional ultrasound.
• 4D Ultrasound: Technological advances allow images to be reconstructed in a minimal period, so they can be seen in three dimensions and in motion.
• 5D Ultrasound: Mainly used in prenatal exams without a diagnostic purpose. In addition to three-dimensional moving images, it provides greater clarity.

Doppler Ultrasound: This is commonly used in the diagnosis of vascular conditions, as it allows the assessment of the speed and direction of blood flow through veins and arteries.

Since it works when sound waves encounter soft tissues, ultrasound is not suitable for observing bones or organs containing air.

When is it indicated?

Ultrasounds are common during pregnancy, as they are used to monitor the growth of the fetus and the formation of its internal organs. They are typically performed at 12, 20, and 32-36 weeks of gestation.

Additionally, it is a useful test for detecting malformations, disorders of various organs, blood vessel obstructions, changes in blood flow, or stenosis in both adults and children.

Ultrasound provides results similar to those of a computed tomography (CT) scan, but since it is a faster and more cost-effective method, it is used more frequently.

How is it performed?

To facilitate obtaining images, a water-based gel is applied to the skin, which minimizes the formation of air pockets, allowing for clearer images. The transducer (a manual probe) is then moved over the area to be examined. This device emits sound waves and collects the echoes that bounce off the body, which a computer translates into images.

Sometimes, the transducer needs to be inserted into the body. This does not require surgical intervention, as natural body openings, such as the mouth (transesophageal ultrasound), the anus (transrectal ultrasound), or the vagina (transvaginal ultrasound), are used.

Risks

Ultrasound is harmless to patients, as it poses no risk to health.

What to expect from an ultrasound

The area being examined must be exposed, so clothing needs to be removed. Sometimes, patients undergoing an ultrasound are provided with a gown.

The position on the examination table varies depending on the organs being studied and the type of ultrasound being performed. Therefore, the patient may need to lie on their back, on their side, or in a gynecological examination position.

The gel used is usually cold when applied but becomes warmer during the procedure. It is a water-based substance that does not stain and is easily removed from both the skin and clothing.

The specialist may apply pressure at certain points with the transducer to improve image quality, but it should not cause pain. It may feel more uncomfortable when the bladder is full. In some cases, the patient may need to hold their breath to avoid distortion.

In extracorporeal ultrasounds, measures are taken to ensure that the introduction of the transducer is not painful, although it may cause discomfort.

All types of ultrasound are performed on an outpatient basis, with no need for hospitalization or follow-up observation. Generally, they last between 30 and 60 minutes.

The results are obtained immediately, although in some cases, they are explained to the patient a few days later during a consultation.

Specialties in which an ultrasound is requested

Ultrasounds are common in gynecology and obstetrics. They are also frequently requested in family and community medicine, internal medicine, dermatology, general surgery and digestive system surgery, angiography and vascular surgery, physical medicine, pediatrics, intensive care, rheumatology, oncology, urology, and endocrinology.