How to Read a CT Scan Report: Decoding Common Terminology

How to Read a CT Scan Report

Your guide to understanding common terminology in your CT scan report.

A CT scan creates detailed images of the internal structures and workings of your body. A doctor might refer you for a CT scan to diagnose, identify or monitor the treatment of illnesses or soft tissue, organ or bone injuries.

Having access to your medical records, including CT scan results, allows you to advocate for your own health and treatment, while also relieving ‘scanxiety’, the stress of waiting for medical results. A 2023 Leger study revealed more than half of patients experience scanxiety when waiting on medical results.

Additionally, having access to your own medical records is the law under the Health Insurance Portability and Accountability Act (HIPAA) in the U.S. and the Privacy Act in Canada, which is enacted at the provincial level and governed by the Personal Health Information Protection Act (PHIPA) in Ontario.

But even when you have access to your health records, that doesn’t mean they are simple to read or understand. Medical reports are still full of complex terminology. This article will clarify some of the medical terms and abbreviations you might encounter in your CT scan report so you’ll know where you stand and can be more prepared for conversations with your healthcare team.

What does CT stand for?

CT is short for computed tomography. Also known as a CAT scan, a CT scan uses a donut-shaped array to take multiple X-rays from many different angles. Those angles, or slices, are then combined digitally into a highly detailed 3D image. A radiologist will interpret the image and create a detailed report. Your referring physician will receive the images and radiology report and discuss them with you at a follow-up appointment.

A CT scan provides much more detail than a single X-ray and can be used to locate clots and tumors, identify bone or muscle issues, examine organs, diagnose specific illnesses and monitor treatment.

What does dual-energy CT mean

A dual-energy CT scan uses two different kinds of X-ray to capture internal images. In addition to the normal X-rays used in regular CT scans, a dual-energy CT scan also uses a lower-energy X-ray at the same time.

Having the two types of X-ray energy can increase the clarity of the images, especially if a contrast ingredient is used. Instead of scanning twice, once with the contrast and once without, a dual-energy CT scan allows the radiologist to heighten or lower the effect of the contrast.

What are the coronal, sagittal and axial planes?

CT scan images are taken along 3 different planes or orientations to provide the radiologist with a 360° view of your body’s internal structures and organs:

  • Coronal: the frontal view, which presents images of the front and back halves of your body.
  • Sagittal: a cross-sectional side view through the middle, which provides lateral images of the left and right sides of the body.
  • Axial: also called the transverse view, this horizontal view creates images of the top and bottom halves of your body.

What does density mean?

Density refers to how much contrast appears on the CT image after processing. As X-rays pass through a patient they are absorbed in varying degrees (depending on the density of the objects they encounter) before being captured on film or digital media on the other side. Dense structures appear lighter on CT scans. Bone, muscle and calcifications (like bladder or kidney stones) are all considered dense. Conversely, non-dense tissues with water or air (e.g., lungs) appear darker on a CT scan. Density is broken down into 2 categories:

  • Hypodense means an area is darker or less dense than the tissue or structure around it.
  • Hyperdense means an area is brighter or more dense than the tissue or structure surrounding it.

CT scans can also measure bone density. Densitometry is the process that measures the mineral content and mass of your bones, and it can be performed with a CT scan or a dual-energy X-ray absorptiometry (DXA) scan. Regular bone density screening is important to evaluate for decreased bone mass (known as osteopenia and osteoporosis) and to help determine fracture risk.

What does lucency mean?

Lucency is the opposite of density and describes how dark different parts of your body appear on a CT scan. Air and fat are lucent, which is why areas like your lungs show up darker in a CT image.

What’s the Hounsfield Scale?

Wondering what all those numbers mean in your CT scan? The Hounsfield scale measures tissue density and assigns a common scale to express how the radiation from the CT scan is transmitted and absorbed by your body. This process of absorption is called attenuation. Hounsfield units (HU) are standard numbers expressing the radiodensity of different parts of the body. Your CT scan images and report will contain HU numbers.

The lower the number on the Hounsfield scale, the less dense the tissue is. The higher the number, the more dense the tissue is. For example:

  • Air: –1000 HU
  • Fat: –100 HU
  • Water: 0 HU
  • Soft tissue: 30 to 45 HU
  • Blood: 60 to 90 HU
  • Bone: 300 to 1000+ HU

What’s intravenous versus oral contrast?

Some CT scans require a contrast agent, a liquid chemical compound that works like a dye to improve the clarity of your images. In a CT scan with contrast, the dye shows up very bright in your images, making it easier for radiologists to pinpoint any abnormalities.

  • An intravenous (IV) contrast is injected into your body to highlight areas of increased blood flow, like tumors or blood clots.
  • An oral contrast is swallowed and helps internal CT scans provide more details about the esophagus, stomach and intestines.
  • A rectal contrast is inserted in the rectum to improve CT images in the large intestines and pelvic organs.

A CT scan with contrast might make use of the multiphase imaging technique, which takes images at specific points in time, for instance as the contrast reaches specific blood vessels or moves through them.

What’s a lesion?

A lesion is an area of damaged bone, organ or tissue that can appear anywhere in your body. Lesions can be the result of injury or disease and might present in different ways, such as:

  • Calcifications: small sections of hardened tissue
  • Cysts: fluid-filled sacs
  • Masses: unexpected clusters of tissue
  • Nodules: swellings or lumps of tissue distinct from their surroundings
  • Tumors: areas of abnormal cell growth

Depending on their source and composition, lesions can be benign (non-cancerous), or malignant (cancerous).

Is unremarkable good or bad?

When it comes to medical terminology the term “unremarkable” is actually a good thing. It means your CT scan has revealed no abnormal findings.

How PocketHealth can help you understand your CT scan report

With PocketHealth, you get fast and easy access to view, share and store your CT scan results, often before your follow-up appointment with your doctor.

If you are unfamiliar with certain medical terms, Report Reader will provide definitions to help make your report easier to understand. Report Reader also spotlights any follow-up recommendations, so you can keep tabs on your own health and always know what’s coming next. Access your records here.

“With Report Reader, I get explanations for words [in my report] that I don’t understand. I can now discuss my health with my family doctor with more confidence and have a better understanding of what is going on.”
– PocketHealth Patient

The importance of understanding your CT scan results

The more you know about what’s going on in your body, the more informed your conversations will be about any potential diagnosis and ongoing health concerns. Having access to your health records, like your CT scan images and report, puts you in the driver’s seat.

PocketHealth makes that access easy and secure, so you can be confident and in control along every step of your healthcare journey.

How PocketHealth works

Learn more about how to use PocketHealth to securely access and share your CT scan results.

    Get The Knowledge And Tools To Take Control Of Your Health

      Get The Knowledge And Tools To Take Control Of Your Health

      Access My Records