December 4, 2023Read More
A computed tomography or CT scan is a procedure that uses a computerized X-ray to create cross-sectional images or “slices”. Multiple slices are collected during one CT scan, creating a detailed three-dimensional image that can give the radiologist and your referring doctor more information than a regular X-ray.
CT scans, previously known as CAT scans, are used to help detect and diagnose disease or to understand how well treatment is working.
If your doctor sends you for a CT scan, you may have some questions about the imaging procedure itself and any next steps. To help you prepare, this article breaks down:
Your doctor may refer you for a CT scan if you’ve been in a car accident or involved in other serious physical trauma, have unexplained chronic pain, dizziness and severe headaches with or without a head injury, abdominal pain and certain digestive system concerns.
CT scans are effective at detecting possible life-threatening conditions, such as:
CT scans can be used in conjunction with positron emission tomography or PET scans to explore inside the body in more detail. PET scans are able to provide information about the specific location of a disease within the body and are a valuable diagnostic tool.
CT scans are used to diagnose:
There are different types of CT scans, including head, lung, abdomen or whole-body scans. Your doctor may order a CT scan with or without contrast fluid. Double-contrast studies are CT scans where you are required to ingest contrast fluid orally before the CT scan because it allows the tissue or organ studied to be more visible on the scan images. In some cases, contrast fluid may be given intravenously, depending on the parts of the body being examined.
CT Scans and MRIs both provide a comprehensive look inside the body to support the diagnosis of a disease or treatment, but they use different technology. CT scans use low-dose X-rays to create images, while MRIs use magnets and radio waves, and each can provide different insights into the various tissues and structures of the body.
Softer parts of the body like ligaments, muscles and tendons show up more clearly on MRI scans. CT scans are better able to detect anomalies in bones and skeletal structures. CT scans also take less time, as little as 10 minutes for simple procedures, while an MRI can last an hour or more. This makes CT scans a more common and less expensive procedure than MRI scans.
Your doctor will decide which test is appropriate for you based on its effectiveness at providing diagnostic detail for your particular concern.
Unlike booking an ultrasound or blood work appointment, you won’t book your CT scan appointment yourself. Typically, your referring physician will send your requisition directly to the imaging department of a nearby hospital or clinic. The hospital will contact you with the date and time of your CT scan appointment. CT scans are not a walk-in service, and you will require an appointment prior to your scan.
Most Toronto hospitals conduct CT scans, including:
In Toronto, you can also book a CT scan with a private imaging clinic. Doing so may speed up the process, but keep in mind that it can be costly. A private imaging clinic will require an appointment, but they do not need a requisition from your doctor.
The amount of time it takes to wait for a CT scan appointment in Toronto depends on the location and timing of your appointment, but also on your priority as a patient. Patients requiring a CT scan are prioritized based on symptoms and medical history.
To promote the best overall health outcomes, healthcare providers divide CT scan patients into 4 categories depending on symptoms and medical history:
Depending on your level of priority, you may wait longer than the times listed above for your scan. In Toronto, many priority 4 patients wait longer than 80 days for their CT scan, although priority 2 patients typically wait no longer than 2 days.
Wait times can vary quite a bit, but you may be able to get an appointment faster by telling your doctor you are willing to travel to a hospital if it is less busy, are available overnight for a scan or that you’d like to be on last-minute cancellation lists for nearby hospitals. Ontario Health tracks CT scan wait times. Use this tool to determine which region and hospitals have quicker times between your referral and appointment.
In Ontario, OHIP will cover your CT scan appointment if:
Private clinics offer CT scans, as well, and you can make an appointment for a scan without a doctor’s referral. Private CT scans can be helpful for monitoring ongoing brain trauma, managing chronic conditions or getting a second opinion. You typically get your results quickly (often within 24 hours), but you will have to pay for the scan.
Private CT scan costs can vary depending on the clinic and type of CT scan but range from $400 to thousands of dollars depending on the area of the body scanned. If contrasting fluid is required there is an additional cost.
Depending on the type of CT scan you’re booked for, you may be asked to drink a contrasting liquid dye beforehand. This contrasting fluid may be given to you just prior to your appointment or you may pick it up earlier, depending on the instructions for your scan. If you have an allergy to the contrasting liquid, your doctor will advise you to take a steroid and an antihistamine prior to ingesting.
CT scans do not usually cause patients to feel claustrophobic like MRI scans can. CT scans use an open, donut-shaped scanner that isn’t enclosed like the scanner used during an MRI. If you are concerned you may feel anxious or significantly claustrophobic during your CT scan, speak with your doctor about using a short-acting anti-anxiety medication during your appointment.
You may have questions before or during your CT scan appointment, such as:
The technician giving you the scan will be able to answer these questions during your appointment but during your scan you’ll be required to stay still, so be sure to speak with the technician before your scan starts.
Your referring physician will typically receive the results of your CT scan within a week of your appointment and will book a follow-up appointment with you to discuss your results. If you attended a private CT scan clinic for your appointment, you must contact your physician to set up a follow-up.
You can easily access your CT scan images and report with PocketHealth, often before your follow-up appointment. PocketHealth allows you to securely access, share and store your medical images and information in one place. If you had your CT scan at a private clinic, you can share your records with your doctor directly through PocketHealth. Access your records here.
The terminology on your CT scan report may be complicated and you may not understand all of the medical terms, but PocketHealth Report Reader can help. Report Reader makes it easy to understand terms in your CT scan and highlights any follow-up recommendations, so you can feel informed and confident when speaking to your doctor at your CT scan follow-up appointment.
The images generated during your CT scan will show the radiologist whether any irregularities were detected. The radiologist will review these images and create a report, sending both to your referring physician.
Your CT scan images may be taken in 3 different ways capture a complete 360-degree picture for interpretation:
CT scan images are reviewed using a numbering scale called the Hounsfield scale. Denser areas of the body—such as bone—appear white, whereas areas that are less dense appear darker. Hounsfield numbers are applied to the scan images depending on the density of the structures or tissue captured. For example, dense structures like bone may be given a number of 700, while lung tissue may be given a number of -500, depending on how dense each area appears.
CT scans use X-ray technology to create multiple images that can be combined into a comprehensive 3D view of your body. The images produced by a CT scan, and the accompanying radiologist’s report, help physicians diagnose and treat disease and injuries, and allow them to track how well a patient is responding to treatment.
Being able to see and understand your CT scan results allows you to confidently advocate for your health. With PocketHealth, you can securely access your CT scan images and reports so you can be a more informed participant in your health journey.