CT Scan vs. Ultrasound: What Is the Difference? 10 Facts

Different tools are used to treat and figure out what’s wrong with people. Ultrasound and CT scans are two common imaging methods used in medicine.

When you compare CT scans and ultrasounds, the main difference is in how much radiation they use. With a CT scan, the patient has to go through the machine and be exposed to radiation.

With an ultrasound, on the other hand, the patient doesn’t have to go through the machine and is only exposed to sound waves and echoes.

What is an ultrasound?

An ultrasound is a way to see inside the body by using high-frequency sound waves that can’t be heard.

Sonar technology is used to send these sound waves into your body. It can also “hear” the echoes sound waves make when they hit structures or tissues in your body (NIBIB-a, 2016).

A hand-held tool called a transducer is used by doctors and nurses to do ultrasounds.

The transducer sends out sound waves and turns echoes into electrical impulses at the same time. An ultrasound scanner takes these impulses and turns them into an image.

CT Scan vs. Ultrasound

This picture of the ultrasound is also called a sonogram. In some cases, you may need specialized ultrasound transducers, which are often called “probes.”

For example, transducers are sometimes put in the vagina, the GI tract, or the blood vessels. This, on the other hand, doesn’t happen as often as a normal ultrasound.

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There are two different kinds of ultrasound. Here’s what they are:

  • Diagnostic ultrasound is by far the most common type. It’s used to make images of your body so that doctors can diagnose and rule out health problems.
  • The purpose of an ultrasound: This less common type measures or takes pictures of how things work inside the body. Functional ultrasounds, for instance, can show how your heart or veins move blood. They can also look at how your tissues are doing.

What is a CT scan?

“CT” stands for “computed tomography.” Tomography is another word for a picture that is made up of different pieces or slices.

X-ray technology is used to take a series of pictures of your body as a CT scanner spins around it.

The CT machine saves each of these pictures. It can then put them together to make a more accurate 3D picture than a regular X-ray.

Doctors can get a better idea of what is going on inside you by looking at both the individual images and the combined 3D image.

How Ultrasounds and CT Scans Work

Ultrasounds and CT scans look at the body in different ways. So, the process of scanning is also different.


A CT scan makes a three-dimensional picture of an organ or the inside of the body. It does this by putting together several X-ray pictures made by low-powered beams that go over the same part of the body more than once from different angles.

A computer combines all of the photos to produce a final result that improves clarity and definition.

An ultrasound sends out short pulses of sound at the desired frequency and focuses them on the part of the body that is being looked at.

Some of these sound waves bounce back from the body and are picked up by a transducer. They are then sent to an ultrasonic scanner, where they are processed and turned into a digital image.

The time and strength of the echo are used to create the image, which is then shown on the computer screen for study.

CT Scan Procedure

During a CT scan, the patient is moved through the scanning system. Both the X-ray source and the detector rotate at the same speed.

This makes it possible for the X-rays that pass through the area of interest to create separate image slices in axial or helical mode. The many pictures are then put together to make a view of an organ.

The CT image that is made can be seen right away on a TV screen or recorded so that it can be looked at later.

Ultrasound Procedure

During a medical ultrasonography, sound waves are sent into the area of interest by moving a probe over it. First, a gel is put on the area to keep air from getting between the probe and the skin.

The patient may be asked to change positions so that they can see the target area better. The measurements that can be taken from the photos can be looked at or saved for later.

Key Differences Between CT Scan and Ultrasound

ComponentsCT ScanUltrasound
HistoryCT scan was first invented in 1972 by an engineer Godfrey Hounsfield and Allan Cormack. At first, it can only provide images of the head.The ultrasound technique was first used by Dr. George Ludwig to detect gallstones, and later in 1957, Dr. Ian Donald used it for fetal images.
FunctionalityCT scan uses an X-ray, which enters the body to produce images of internal organs.In ultrasound sound, sound waves enter the patient body and produce an image when bounced back.
Details of Soft TissuesCt scan can provide a detailed image of the bones, soft tissue, and blood vessels simultaneously.Some ultrasounds with advanced technology may be able to show the images of soft tissues.
Detail of Bony StructureCT scan can provide excellent detail about the bony structureUltrasound can not show a clearer image of a bony structure; it is used for internal organs mostly
Price RangeCT scan may cost $1200, or $2300, depending upon a patient’s condition.Ultrasound costs half if we compare ultrasound Vs. CT scan, it costs $100-$1000
AdvantagesCT scan can provide detailed visual information about the interior of a patient body. It can be beneficial in detecting internal injuries.Ultrasound can be very effective in detecting stones in the kidney or gallbladder; it also provides information about the fetus during pregnancy.

Abdominal Ultrasound vs. CT Scan

A CT scan and an ultrasound can both be used to find out what’s wrong with an abdomen that hurts right now.

But when comparing a CT scan to an ultrasound of the abdomen, an ultrasound can tell you more about the abdomen, while a CT scan may miss fewer cases. CT scans and ultrasounds can also be used to look for cancer.

But when it comes to cancer, a CT scan can give more information than an ultrasound because it shows a picture of the bones, tissue, and blood vessels.

CT Scan vs Ultrasound

Ultrasound uses vs. CT scan uses

Ultrasound and CT scans are used for different things.

Most of the time, ultrasound imaging is used for the following (NIBIB-a, 2016):

  • During pregnancy, fetal imaging
  • Images of the heart and other organs
  • Imaging of blood vessels
  • Seeing with the eyes
  • The study of the brain
  • Mammography or imaging of the testicles
  • Imaging of organs
  • The study of tumours
  • Identifying the Sources of Stomach Pain
  • Gallstones: Where to Look in 2011 (Benarroch-Gampel)

Most of the time, CT scans are used for the following (NIBIB-b, n.d.):

  • Complex imaging of bone fractures
  • Images can be made of the skeleton and other parts of the body.
  • Checking out worn-out joints or bone cancers
  • Imaging of the abdomen to look for cancers or lesions
  • Imaging the heart to find problems
  • The head is scanned to look for cancer or other problems.
  • Imaging the lungs or blood vessels to look for blood clots, fluid buildup, or other problems

Even though ultrasounds and CT scans are often used for different things, doctors usually schedule an ultrasound before a CT scan.

For example, a CT scan can help look at the pelvis of a woman when an ultrasound doesn’t give a clear picture or diagnosis (Patel, 2021; Benacerraf, 2015).

Cost Comparison

CT scans cost between $1,200 and $3,200, which is more than what an ultrasound costs. Ultrasonography can cost anywhere from $100 to $1000, depending on what is being looked at. The price may vary from country to country.

Applications of Ultrasound vs CT Scan

CT scans are most helpful when they are used to check for cancer (tumours), injuries, or problems inside the body.

Scans can be combined with other methods, like ultrasound or magnetic resonance imaging (MRI), to get better detail and accuracy.

Ultrasound is used to diagnose problems. For example, it can be used to look at muscles, tendons, and internal organs to see how big they are, how they are put together, and if there are any sores or other problems.

Obstetric sonography is used to look at fetuses while a woman is pregnant. Ultrasound is also used to remove kidney and gallstones, as well as for liposuction and other procedures.

Advantages and Risks

CT scans are better than X-rays because they show differences between types of tissue better.

Also, a CT scan can focus on a specific structure or area of the body by getting rid of obstacles like other organs, bones, or tissue. With a single scan, a doctor can look at the patient from different angles and planes.

This makes it easier to make a diagnosis. This level of accuracy can help people avoid unnecessary procedures like colonoscopies and exploratory surgery.

But using X-rays in CT scans is often linked to a higher risk of cancer, especially lung cancer, colon cancer, and leukemia.

To help with this problem, newer CT scanners use fewer X-rays and take less time to scan. Another worry is that the different chemicals used to make things more visible may have long-term effects.

CT scans cost more and are more dangerous than ultrasounds. It can be used in a lot of different ways in biology, industry, and other fields.

CT Scan vs. Ultrasound

The benefits of ultrasonography are much greater than any risks it might have. But multiple studies have shown that ultrasound is bad for pregnant mammals like mice, but this hasn’t been shown to be true for people yet.

Also, more ultrasonic waves cause the tissue to heat up, the pressure to change, and other mechanical problems.

Preventative value

A study paid for by the government found that heavy smokers, both now and in the past, can cut their risk of dying from lung cancer by up to 20% with annual CT scans. This is because early detection of diseases greatly increases the chance of survival.

Advantages and drawbacks of ultrasound

Like any other imaging test, ultrasounds have their pros and cons.

Advantages of ultrasound

Ultrasounds cost less than CT scans and other types of imaging. Most of the time, they are quick and easy. Most of the time, you don’t need to do anything to get ready for an ultrasound.

It makes useful and detailed photos right away. When used according to safety rules, standard ultrasounds don’t pose nearly any health risks (Levine, 2001; NIBIB-a, 2016).

Drawbacks or risks of ultrasound

The pictures that ultrasound makes are not as clear as the pictures that other imaging methods make.

Some researchers have found that if doctors only use ultrasonography, they might miss out on important information. So, your doctor may tell you to get more imaging using a different method (Levine, 2001; Sotiriadis, 2019).

Also, the skill and experience of the medical professional who uses ultrasound determine the quality of the images that are made. This could leave room for people to make mistakes (Reddy, 2008).

Advantages and drawbacks of CT scan

CT scans have some good points and some bad points.

Advantages of CT scans

CT scans make detailed pictures that can tell doctors important things. CT scans can help find major health problems like cancer, bleeding in the brain, and blood clots.

Drawbacks or risks of CT scans

All X-ray imaging, including CT scans, sends out radiation that can damage cells. Because radiation can hurt your cells and cause changes in your DNA, it can make you more likely to get cancer.

Most of the time, the risk is low, but each dose of radiation adds up and makes the risk go up (Patel, 2021; NIBIB-b, n.d.).

Because of this, women who are pregnant aren’t likely to get pelvic or abdominal CT scans unless they are absolutely necessary.

Also, because children are more sensitive to ionizing radiation, doctors rarely order CT scans for them unless they have no other choice (Patel, 2021; NIBIB-b, n.d.).

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In addition to the dangers of radiation, some CT scans need contrast agents. These are liquids that you either drink or have injected into your body to help the CT scan make more accurate pictures.

Some people have allergic reactions to contrast agents. People with kidney problems can also be hurt by them (NIBIB-b, n.d.).

Lastly, CT scans cost more and take more time than ultrasounds (Benacerraf, 2015).

Both ultrasounds and CT scans are useful imaging tools that are often used in medicine. Each has its own pros and cons. Either one of them could save your life; that’s the simple truth.


How Does Ultrasonography Differ From Radiology and CT Scan?

Ultrasonography can’t be used to get a picture of a bone’s structure. Radiography and CT scans are two tools that can be used for this.

Which Is More Accurate, CT scan or Ultrasound?

A CT scan is a good way to check for diseases like tumours, internal injuries, and other problems inside the body.

Is A CT Scan More Accurate Than An Ultrasound?

When it comes to finding diseases like tumours, CT scans can be very accurate. However, when comparing an ultrasound to a CT scan of the abdomen, an ultrasound can show real pictures of the belly.

Which Is Better, CT Scan or Ultrasound?

Both can help find diseases, but CT scans are better at finding cancer and other problems inside the body.

Ultrasound, on the other hand, is better at finding fetal development and medical problems like gallstones or kidney stones.

CT Scan vs. Ultrasound

What Is the Difference Between an Ultrasound and A Sonogram?

A sonogram is a picture of the outside of the body, while an ultrasound is a tool that uses sound waves to make a picture of the inside of the body. is a picture made by ultrasound.


As the number of diseases increases every day, so do the tools and technologies that can be used to diagnose and treat them. Doctors use many different kinds of tools and methods, such as MRI, ultrasound, and CT scans.

when CT scans, MRIs, and ultrasounds are compared. All of them are different ways to find out what’s going on inside a person.

CT scans and ultrasounds can both show pictures of organs inside the body, but they do so in different ways. In CT scans, X-rays are used.

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