Imaging methods – Ultrasound

Ultrasound is an imaging method used in medicine to obtain images of the internal structures of the human body.

This method is based on the use of high-frequency sound waves to create images of internal organs and tissues. Ultrasound has become one of the most widely used diagnostic methods in medicine as it is non-invasive, non-radiating and painless.

How ultrasound works

Ultrasound works by emitting high-frequency sound waves into the patient’s body. These sound waves are emitted by a transducer, which is placed on the patient’s skin and emits sound waves at a frequency of approximately 2-18 MHz. Once emitted, these sound waves are reflected by the body tissues, and another transducer detects the reflected sound waves and converts them into electrical signals.

These signals are then processed by a computer and transformed into visual images of the body’s organs and tissues. Ultrasound can be used to obtain images of many body structures, including the heart, liver, lungs, pancreas, kidneys and other organs.

Applications of ultrasound

Ultrasound has a variety of applications in medicine and is used to diagnose a wide range of conditions and diseases.

Among the most common applications of ultrasound are diagnosing pregnancy and fertility problems, evaluating the heart and circulatory system, detecting tumors and other lesions, evaluating the liver and other internal organs, and guiding interventional procedures such as biopsies and other minimally invasive procedures.

Advantages and disadvantages of ultrasound

Ultrasound has many advantages over other imaging methods such as computed tomography (CT) and magnetic resonance imaging (MRI). Ultrasound is non-invasive, non-radiating and painless, making it a safer and more comfortable method for patients. Ultrasound is also cheaper and easier to access than other imaging methods.

However, ultrasound also has its drawbacks. Because ultrasound is based on sound waves, images can be affected by a variety of factors, such as gas or dense tissue obstruction, as well as the skills and experience of the operator performing the examination. Ultrasound can also be limited in its ability to visualize certain body structures, such as bones or deep tissues.

Whether it is the oral cavity or the whole body, pathologies require complementary explorations to be properly diagnosed and optimal treatment instituted.

There are a number of imaging methods that can be used to detect abnormalities, but in each case, we need to know how to choose the right one, adapted to the situation.

Complementary techniques should be performed in any situation where we suspect a pathology that could be confirmed by imaging.

Medicine is evidence-based, so we need as much information as possible to make a diagnosis.

Ultrasound is based on the transmission of ultrasound by means of a transducer, which functions alternately as transmitter and receiver.

At each ultrasound interface, some of the acoustic energy is reflected and generates the echoes and the rest of the energy is transmitted onwards to another interface.

The reflected ultrasound interacts with the transducer ceramics and generates electrical pulses. The received echoes are spaced in time corresponding to the spatial spacing of the interfaces that generated the echoes.

Doppler ultrasound studies the wavelength behavior of the received wave when the wave source and receiver are in relative motion. Thus, closer structures will be represented by red color, while more distant ones by blue color.

Information provided

The information that Doppler ultrasound can provide is as follows:

  • Presence of blood flow – existence of blood vessels

  • Direction of flow – which is the direction of blood flow

  • Speed of flow

  • The linear or turbulent nature of the flow – turbulence occurs when there is an obstacle in the path of the blood vessel being examined

  • Estimation of the number of red blood cells

Ultrasound is an accessible method of examination that provides useful data for diagnosis. It is not invasive or painful, so it does not cause discomfort to the patient.

It provides real-time information about the structures being examined, so the doctor can quickly draw conclusions about the affected structures.


The applicability of ultrasound is wide, it is useful in the detection and diagnosis of pathologies in the following regions:

  • Differentiating the consistency of a formation – we can detect with ultrasound whether a pathological formation is solid or has fluid content.

  • Inflammatory pathology of the salivary glands – stones or infections in the region of the salivary glands cause inflammation of the area concerned, detectable during radiological examination. Calculi are solid deposits in the ducts of the salivary glands. Calcium deposits can reduce or even inhibit saliva production. Clinical manifestations vary according to the degree of gland obstruction. The symptoms of this pathology are as follows:

-Limitation of mouth opening: by being located in the vicinity of the muscles, the inflamed salivary glands can compress them and prevent a wide, complete opening of the mouth.

-Facial asymmetry, located submandibular or genian, due to inflammation.

-Difficulties when swallowing: due to inflammation or insufficient saliva production

-Diffuse pain that may occur intraorally, in the ear or throat.

  • Carotid vascular pathologies

  • Tumors in the throat regions

  • Thyroid pathology – located in the anterior part of the throat, the thyroid secretes hormones with an important role in basal metabolism, protein formation, maintenance of optimal cholesterol levels and overall, in the normal development of the brain and all organs.


In conclusion, ultrasound is an important and widely used imaging method in medicine. This method provides detailed images of the body’s organs and tissues and is non-invasive, non-radiating and painless.

Ultrasound is used to diagnose a wide range of conditions and diseases and can be used to guide interventional procedures.

However, ultrasound also has drawbacks, such as limitations in visualizing certain body structures and damage to images from external factors.

In the future, we may see the development and improvement of ultrasound techniques to overcome these limitations and provide more accurate and detailed images.

We are also likely to see an increase in the use of ultrasound in medical practice due to its advantages over other imaging methods and lower costs.

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