It is important to understand that xrays are a very basic form of imaging that has been around for a long time and is not as detailed nor as effective as other forms of imaging. This is important to remember when the xray right after your collision doesn’t show any fracture. That doesn’t mean that you don’t have a fracture – it just means that the xray didn’t show a fracture. The difference between xrays, CT scans and MRIs is explained in the following quotation from the Associated Physicians Group:
X-rays are a type of radiation, and when they pass through the body, dense objects such as bone block the radiation and appear white on the x-ray film, while less dense tissues appear gray and are difficult to see. X-rays are typically used to diagnose and assess bone degeneration or disease, fractures and dislocations, infections, or tumors.
Organs and tissues within the body contain magnetic properties. MRI, or magnetic resonance imaging, combines a powerful magnet with radio waves (instead of x-rays) and a computer to manipulate these magnetic elements and create highly detailed images of structures in the body. Images are viewed as cross sections or “slices” of the body part being scanned. There is no radiation involved as with x-rays. MRI scans are frequently used to diagnose bone and joint problems.
A computed tomography (CT) scan (also known as CAT scan) is similar to an MRI in the detail and quality of image it produces, yet the CT scan is actually a sophisticated, powerful x-ray that takes 360-degree pictures of internal organs, the spine, and vertebrae. By combining x-rays and a computer, a CT scan, like an MRI, produces cross-sectional views of the body part being scanned. In many cases, a contrast dye is injected into the blood to make the structures more visible. CT scans show the bones of the spine much better than MRI, so they are more useful in diagnosing conditions affecting the vertebrae and other bones of the spine.
These three types of imaging will produce different results. Generally the CT scan will provide the most detailed imaging of fractures of the spine. I had a client many years ago who had an xray taken immediately following her car accident and the xray didn’t show any problems. She had significant neck complaints for the next two and a half years. She finally had a CT scan arranged and it showed that she had a broken neck (i.e. a fracture in her c-spine) and the orthopaedic surgeon was of the view that this fracture had been caused by the car accident (as the client had not had any other trauma to her neck that could have caused the fracture).
The ‘moral’ of the story is don’t accept an xray as the ‘truth’ about your injury if it is ‘negative’ on identifying an injury – better imaging (e.g. CT or MRI) may show why you are having ongoing problems.