Sonogram vs. Ultrasound: What's the Difference?

In medical imaging, the terms "ultrasound" and "sonogram" are sometimes used interchangeably — but in fact, there are key distinctions between the two. If you're thinking of studying to become an ultrasound technician, understanding the difference between sonogram and ultrasound is important.

Understanding Ultrasound Technology

Before diving into the differences between ultrasound and sonogram, let’s discuss exactly what an ultrasound is and what this unique type of medical imaging entails.

What Is Ultrasound?

According to MedlinePlus, an official website of the United States government, "an ultrasound is an imaging test that uses sound waves to make pictures of organs, tissues, and other structures inside your body." This imaging method allows healthcare providers to see inside the body without invasive procedures, which can aid in diagnosis and treatment.

How Ultrasound Works

Ultrasounds rely on high-frequency sound waves that are emitted from an ultrasound wand. When these waves pass through a thin layer of gel that is applied to the skin prior to imaging, sound waves can travel safely into the body. As the waves bounce off different parts of the body (including soft tissue and organs), the resulting echoes are picked up by a transducer and displayed in the form of a moving image on a monitor.

Because ultrasounds don't use radiation like X-rays do, they're a popular diagnostic imaging option for numerous applications.

What Is a Sonogram?

So, why are the words "sonogram" and "ultrasound" so commonly used interchangeably? There’s actually a pretty good reason.

While the term "ultrasound" refers to the imaging procedure itself, a "sonogram" is the resulting image that appears on the screen (and may even be printed on thermal paper).

The Product of Ultrasound Imaging

In other words, a sonogram is simply the product of ultrasound imaging. Sonography, on the other hand, is another word for ultrasound. With these similar definitions, it's easy to see why so many people (especially those not working in the medical field) use the terms interchangeably despite their slightly different meanings.

Types of Sonograms

It is also worth noting that there are different types of sonograms that can result from an ultrasound imaging procedure, depending on the specific type of equipment used and the reason for the imaging. These types include 2D, 3D, and even 4D sonograms.

2D Sonogram

The most basic type of sonogram is the 2D sonogram: a two-dimensional image that is flat and appears in simple black-and-white. Typically, 2D sonograms show a small, cross-sectional view of the inside of the body. This sonogram shows the least amount of detail of the three types but is a suitable option for a range of applications.

3D Sonogram

When a clearer picture is needed of the inside of the body, a 3D ultrasound may be ordered in addition to a 2D ultrasound. This type of ultrasound offers a three-dimensional image of the inside of the body, allowing for a more detailed view that can be useful for diagnostic purposes. Usually, 3D ultrasounds are ordered when additional details are needed to make an accurate diagnosis or rule out certain medical issues.

4D Sonogram

Finally, there's the 4D ultrasound or sonogram, which is similar to a 3D ultrasound with the added benefit of providing video footage of the procedure itself. Most frequently used in pregnancy ultrasound, a 4D sonogram can be a great way for parents-to-be to bond with their babies by seeing facial expressions and features that may not be possible in a static sonogram.

Key Differences Between Sonogram and Ultrasound

Not completely clear on the distinction between a sonogram and an ultrasound? Explore in a bit more detail its terminology/usage and communication in healthcare specifically.

Terminology and Usage

In general, when you hear a medical professional talking about an ultrasound, they're referring to the imaging procedure itself. This includes the process of preparing the patient, applying the gel, and using a transducer to capture still images.

On the other hand, a sonogram refers to the actual images that have been captured during the imaging procedure. These images may be displayed and stored on computers — but they may also be printed on thermal paper for patients. This is most common in the case of pregnancy ultrasound, where medical professionals may print sonograms for expecting parents to take home as a keepsake.

Communication in Healthcare

In the healthcare field, ultrasound or sonography may be used to refer to this specific type of medical imaging. However, when a radiologist is reviewing images to make a diagnosis or rule out certain medical issues, they are looking specifically at a sonogram.

Common Applications of Ultrasound and Sonograms

There are various potential applications of ultrasound imaging in the medical field — ranging from those in obstetrics and gynecology to cardiovascular and musculoskeletal imaging.

Obstetrics and Gynecology

Most often, an ultrasound exam is used in OB/GYN offices to confirm pregnancies and measure the estimated fetal age of an unborn child. A pregnancy ultrasound can also be useful for measuring amniotic fluid and checking for signs of potential abnormalities with the placenta or fetus.

In addition to pregnancy ultrasound, imaging can be used in OB/GYN settings to diagnose such conditions as polycystic ovary syndrome (PCOS), uterine fibroids, and endometriosis.

Cardiovascular Diagnostics

In the field of cardiology, it is also common for medical professionals to use ultrasounds to assess the overall health and function of the heart while checking for signs of heart conditions. For example, an echocardiogram (or heart ultrasound) may check blood flow between different arteries and blood vessels. Likewise, this ultrasound procedure can check for valve problems, signs of congenital heart disease, and potential heart failure.

Musculoskeletal Imaging

In musculoskeletal medicine, ultrasounds can serve as a non-invasive means of assessing muscles, tendons, joints, and other soft tissues for signs of injury or damage. With this type of ultrasound, professionals may review sonograms to check for signs of such conditions as joint inflammation, sprains, tears, and collections of fluid. This information can then be used to provide the best possible treatment. In some cases, musculoskeletal ultrasound may even help guide surgical procedures.

Advantages of Ultrasound Imaging

Ultrasounds are a popular form of diagnostic imaging — and for good reason. Not only are they generally non-invasive, but they also provide the added benefit of real-time imaging.

Safety and Non-Invasiveness

Unlike some other forms of imaging (such as X-ray), ultrasounds don't use any radiation to capture images of the inside of the body. Additionally, most ultrasound procedures (such as transabdominal ultrasound) are completely non-invasive. In certain scenarios, a transrectal or transvaginal ultrasound may be needed to obtain the proper images — but these are still less invasive than many other options.

Real-Time Imaging

Meanwhile, ultrasounds offer the benefit of real-time imaging. Ultrasound technicians can see on the screen exactly what they're capturing at any given time and can make adjustments as needed to get the image they need.

Limitations and Considerations

As with any medical imaging, of course, there are some potential limitations to keep in mind when it comes to ultrasounds.

Dependence on Operator Skill

For starters, the quality of an ultrasound image relies heavily on the skill and expertise of the ultrasound technician. Without the proper technique and a skilled hand, images may be blurry or may not capture exactly what is needed for a physician to make an accurate diagnosis.

Limited Depth and Resolution

Ultrasounds are also limited in the level of detail and depth they're able to capture. In instances where a clear image cannot be captured, more invasive imaging may be required.

Knowing the Difference Matters

Although everyday patients may not need to know the difference between an ultrasound and sonogram, the medical professionals performing this type of imaging should understand the distinctions between the two and why they matter. In doing so, they can provide the highest standard of care while answering any questions their patients may have.

Earn Your Degree in Sonography

Interested in becoming a medical imaging professional? The right education can make all the difference.

At Nebraska Methodist College (NMC), we're proud to offer an Associate of Science in Sonography program that can be completed in as little as 21 months. This degree program, which is accredited by the Commission on Accreditation of Allied Health Education Programs (CAAHEP), delivers a combination of student-focused instruction and hands-on learning experiences in a laboratory setting. To learn more, get in touch today or take the next step by completing your online application for admission.