What Is An Ultrasound?

The ultrasound, or sonographer, is an important medical imaging tool that uses sound waves to produce images of the internal structures of the body. Doctors use ultrasound to diagnose the causes of various health conditions, including inflammation, pain, and infection.

An ultrasound exam is useful to assess the health of an embryo or fetus in pregnant women. Obstetrical ultrasound also helps produce images of the brain and hips in infants. Medical ultrasound has a wide range of applications, such as diagnosing cardiovascular disease, guide biopsies, and assess damage after a heart attack.

Besides, it does not use ionizing radiation, which makes it a safe procedure. The non-invasive nature of ultrasound makes it an affordable imaging tool. Ultrasound examination does not require any special preparations.

However, the doctor may advise the patient to leave jewellery at home, refrain from drinking or eating beforehand, and wear comfortable clothing. In today’s article, we will focus on ultrasound technology, history, applications, differences with x-rays, and more.

What is Ultrasound Imaging?

An ultrasound test uses sound waves to produce pictures of internal body structures. Also known as sonography, ultrasound is a safe, painless, and non-invasive procedure used by doctors to diagnose different health conditions. A transducer is a small probe used in ultrasound that senses and generates energy.

Doctors usually place the device directly on the patient’s skin to start the diagnostic procedure. The process involves the transmission of sound waves from the probe into the body. The high-frequency sound waves enter the body through the gel.

The sound waves interact with the internal structures and bounce back to the probe. A computer uses these sound waves to produce images. Unlike x-rays, ultrasound exams do not involve the use of radiation.

The device enables health professionals to capture images in real-time. The images produced can accurately show the structures and movements of the internal organs. Ultrasound imaging is a useful tool that can also display blood flowing through the vessels.

Ultrasound imaging helps doctors diagnose and treat a wide range of health conditions. Conventional ultrasound can display the images in flat sections of the patient’s body. In contrast, modern ultrasound devices use cutting-edge technology that can produce three-dimensional images.

History of Ultrasound

Ultrasound is a common medical imaging device used today by health professionals. Tom Brown and Ian Donald used ultrasound for the first time in 1956. Donald and Brown developed the prototype for ultrasound in the early 50s, but it had various loopholes. Let’s delve into this subject to know the events that led to the development of ultrasound.

1794Lazzaro Spallanzani was a physiologist who studied echolocation among bats. Although Spallanzani did not specifically study ultrasound technology, his research focused on ultrasound physics.
1877Jacques and Pierre Currie made substantial efforts to discover piezoelectricity. It was an important discovery to ultrasound because the device uses sound waves via the piezoelectric effect.
1915Paul Langevin created a device that would detect objects in the ocean. Langevin invented the first transducer called the hydrophone.
1920-1940European football teams used a specific type of physical therapy to treat eczema and inflammatory pain. Many historians associate it with ultrasound.
1942Karl Dussik used a sonogram for medical diagnosis. He carried out the procedure by transmitting an ultrasound beam through a human skull to detect tumours.
1948George D. Ludwig developed A-mode ultrasound equipment to detect gallstones.
1951Douglas Howry and Joseph Holmes invented B-mode ultrasound equipment, which had a two-dimensional B-mode linear compound scanner. John Reid and John Wild developed a handheld B-mode ultrasound device to detect breast tumours.
1953Hellmuth Hertz and Inge Elder used an echo test control device to perform an echocardiogram.
1958Dr. Ian Donald invented the first ultrasound device and incorporated it into the Obstetrics and gynecology field of medicine.

How Does Ultrasound Work?

Ultrasound is a high-quality medical imaging technique, which uses high-frequency sound waves. It is a technique that shows similarity with a submarine sonar and echolocation used by dolphins, whales, and bats.

The machine uses a probe to transmit 1-5 megahertz sound pulses into the patient’s body. The sound waves travel into the body and reach the tissues, i.e. between the soft tissue and fluid or soft tissue and bone.

Some of the sound waves bounce back, which are collected by the probe. Other sound waves travel into the body to reach another boundary and then travel back to the probe. The probe collects the reflected waves and sends them to the machine.

Next, the machine measures the distance from the probe to the boundaries (tissues or organs) using the speed and time of waves. Typically, the machine sends millions of sound waves and echoes into the body and receives them back. A doctor can move the probe along the surface of the patient’s body at various angles to obtain different views.

Moreover, a basic ultrasound machine consists of a transducer probe, central processing unit (CPU), transducer pulse controls, display, cursor, and disk storage device. It is essential to know that a transducer probe sends and receives waves.

The CPU controls the electrical power and transducer probe to measure the reflected sound waves. A transducer pulse control changes the frequency, amplitude, and duration of the sound waves emitted from the probe.

Once the CPU process the ultrasound data, it produces an image, which is displayed on the screen. The cursor is used for data input and collection from the display or screen. The ultrasound machine has a disk storage device that stores the produced images. The printer prints the medical images produced by the machine.

Types of Ultrasounds

Ultrasounds are non-invasive procedures performed to get images of the internal organs and structures within the body. As mentioned above, an ultrasound machine uses high-frequency sound waves that echo off the tissue and produce images using the recorded sounds. Let us talk about types of ultrasounds.

Obstetric Ultrasound

It uses sound waves to produce images of an embryo or fetus within the mother’s womb. Obstetric is the most common type of ultrasound that can produce images of the uterus and ovaries. Obstetric ultrasound does not use ionizing radiation, which means it does not cause any significant harm to the mother and baby. Research shows that most doctors prefer this type of ultrasound to monitor a pregnant woman and her unborn baby.

Diagnostic Ultrasound

It is an imaging method that produces high-quality images of the internal structures of the body. The images provide useful information to the health professional who uses them to diagnose and treat a wide range of health conditions.

Abdominal Ultrasound

Abdominal ultrasounds help health professionals to assess the cause of swelling, pain, and other symptoms in the stomach. It is also helpful in checking for kidney stones, tumours, liver diseases, and other health conditions. Most often, a doctor performs an abdominal ultrasound to detect the aortic aneurysm.

Pelvic ultrasound

It is a diagnostic exam that produces pictures of structures and organs within the female pelvis. Pelvic ultrasounds help doctors to visualize the female pelvic organs, such as the vagina, cervix, uterus, ovaries, and fallopian tubes. Pelvic ultrasounds are divided into three categories, which are transabdominal, transvaginal, and transrectal.


A transabdominal ultrasound is an external procedure, which involves the doctor placing a gel on the abdomen and then move the handheld unit around the stomach. The device transmits high-frequency sound waves that produce an image, called a sonogram.

The doctor sees the image on a computer display or TV monitor. Doctors use transabdominal ultrasounds for diagnostic purposes. However, sometimes, they also use it for obstetric purposes.


Health professionals perform transvaginal ultrasounds to get images of a woman’s uterus, cervix, ovaries, tubes, and pelvic area. The doctor inserts a probe into the vagina and sends out waves, which reflect off the structures in the area. A computer receives the reflected waves and produces images, which are used by the doctor to diagnose conditions like cervical cancer.


A doctor performs a transrectal ultrasound to assess different conditions with the prostate gland. The procedure involves the doctor inserting a probe into a woman’s rectum and sends out waves through the rectal wall.

A computer receives the reflected waves and processes them to create images of the prostate gland. Transrectal exams help diagnose different symptoms, such as difficulty urinating, detect abnormalities in the prostate gland, and investigate a nodule.

Chest ultrasounds

It is used to assess the esophagus, trachea, lungs, heart, and lymph nodes. A doctor performs the chest ultrasound to visualize the organs and structures in the chest area and from the outside of the body. It is also used to assess blood flow to the organs in this area and identify liquid in the lungs and chest cavity.

Types of Ultrasound Imaging

There are four types of ultrasound imaging, such as two-dimensional, three-dimensional, four-dimensional, and Doppler ultrasound.

Two-Dimensional (2D)

It is a common type of ultrasound technique that produces a series of flat, 2D cross-section images of the internal structures. 2D ultrasound is a standard procedure used for diagnostic and obstetric situations in hospitals and clinics.

Three-Dimensional (3D)

t is an advanced ultrasound technique that involves scanning the cross-sections of tissues at various angles. The data is reconstructed to produce a 3D image, which provides a more accurate image of the developing embryo or fetus.

Four-Dimensional (4D)

Today, it has become easy to transform 3D images into 4D images. The 4D ultrasound is a great way to add factors like time and movement, which provide a more realistic representation of the internal body structure. The 3D and 4D ultrasound images can accurately reveal abnormalities, which are usually not detected by the 2D ultrasound.

Doppler Ultrasound

Generally, an ultrasound evaluates blood flow as the sound waves travel through blood vessels. Although 2D and 3D ultrasound can show internal structures and tissues, Doppler ultrasound is intended for blood flow and pressure within the vessels.

The procedures involve sending high-frequency sound waves through blood cells in motion. The sound waves reach the vessels and bounce back to the transducer probe. The data is converted into a visual representation that helps a doctor determine the speed and direction of the blood flow.

Doppler is a crucial diagnostic tool in all domains of ultrasound testing. Currently, health professionals use three types of Doppler ultrasound. Among them, colour Doppler uses a wide range of colours to visualize the flow of blood and embed data with a 2D ultrasound to produce images of structures and tissues.

As a result, the health professional gets a more pronounced and detailed representation of blood flow. The aim is to determine the direction and speed of the blood flow, which can’t be achieved through the conventional grayscale images.

Moreover, the power Doppler ultrasound offers more detailed and sensitive images of blood flow measurements than the colour Doppler. It is used to get images of the structures that can’t be achieved with the colour Doppler ultrasound.

However, power Doppler does not indicate the direction of the blood flow. That’s why doctors use spectral Doppler to scan the internal structure of the blood vessels because it can indicate both direction and speed of blood flow. Spectral Doppler ultrasound shows a graphical representation of data.

Applications or Uses

Health professionals use ultrasound technology to diagnose a wide range of diseases. Physicians use ultrasound to evaluate symptoms like inflammation, pain, and infection. Ultrasound is an excellent imaging tool to examine the internal organs of the body.

Doctors use it to examine blood vessels, gallbladder, liver, pancreas, spleen, bladder, ovaries, uterus, fetus, scrotum, thyroid gland, infant’s brain, hips, and spine, etc. Ultrasound is a useful device that helps guide procedures like needle biopsies, which involve the use of needles to sample cells from an abnormal part of the body for lab testing.

Doctors use ultrasound to produce images of breasts. The tool assists in breast cancer biopsy. It is also useful in diagnosing different cardiovascular conditions, including congestive heart failure and valve problems.

A health professional also uses it to assess damage after angina and heart attack. An echocardiogram, in general, refers to the ultrasound of the heart. Moreover, physicians use Doppler ultrasound images to view and assess the narrowing of vessels, clots, tumours, increased blood flow, infections, congenital vascular malformations, and more.

A Doppler ultrasound image provides significant data about the volume and speed of blood flow that helps the physician to determine whether or not angioplasty is suitable for the patient.

Ultrasound and Pregnancy

Ultrasound is a prenatal test performed by doctors on most pregnant women. The device uses sound waves to produce an image of the baby in the womb. Ultrasound helps a health professional to check the baby’s health and development.

It is no surprise to tell you that ultrasound is an essential part of pregnancy. It allows a pregnant woman to see her baby for the first time. Depending on the baby’s position and when the doctor performs it, a pregnant woman can see her baby’s hands, legs, and other parts of the body.

Most pregnant women undergo an ultrasound procedure in the second trimester. Some women also get an early ultrasound in the first trimester, and this is usually before 14 weeks of pregnancy. Women with certain conditions like obesity and asthma more often undergo ultrasound procedures.

There are different uses of ultrasound in pregnancy. Doctors use it to confirm pregnancy, check the baby’s health, age, and growth, as well as the baby’s heartbeat, movement, muscle tone, and overall development.

Moreover, ultrasound during pregnancy is also useful in determining if a woman is pregnant with twins, triplets, or multiples. Ultrasound is a helpful tool that allows a doctor to check the position of the baby before birth. It also helps the doctor examine ovaries and uterus.

Advantages and Disadvantages of Ultrasound

Ultrasound is an effective tool or procedure to streamline certain medical practices. An ultrasound, in general, is painless and does not require cuts, shots, and needles. Because the patient is exposed to ionizing radiation, ultrasound is much safer than CT scans and X-rays.

Ultrasound can capture images of soft tissues, which don’t show up on X-rays. It is an affordable and widely accessible tool than many others. There is no or little research evidence that highlights the harmful effects of ultrasound on human health.

  • Detects lesions in breasts.
  • Identifies the nature of a lesion.
  • Less expensive than other tools like a mammogram.
  • Detects the direction and speed of blood flow.
  • Quick and painless exams.

The downside of an ultrasound procedure is that it does do produce detailed images compared to MRI and CT scans. Ultrasound can’t determine whether a tumour is a cancer. The use of ultrasound is limited to a few body parts because sound waves can’t travel through the air, such as in lungs and bones.

Final Words

Ultrasound, also known as sonography, is a sophisticated imaging method used by doctors, physicians, radiologists, and nurses to identify the causing of different health conditions. It uses high-frequency sound waves that go through the body and bounce back to the machine, which transforms them into high-quality images.

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