Imaging can be indicated in your treatment to confirm or go further in the diagnosis. Depending on the clinical examination, different types of imaging are required. X-ray and MRI are among the most common imaging methods used in practice, but both are indicated explicitly by specific diagnostics.

The technical difference between X-rays and MRIs is the length of the electromagnetic wave. MRI waves are very long compared to X-ray, which has short waves. The X-ray is ionizing because the waves are shorter, and MRI is not. Both are complementary and work with contrast to give a picture of the body.

X-rays are widely used, less expensive than MRI, and excellent for bone, but not for non-bone tissue named soft tissue such as muscle, ligaments, or tendons. X-rays are electromagnetic radiation, like light, but with higher energy. Basically, X-rays are produced in the X-ray tube, and the X-ray beam is projected to the patient and then to the image receptor. The X-ray beam can pass through the body. The tissues will absorb or not the X-ray beam, depending on its density. One major limitation of X-rays is a picture of the body in 2 dimensions.

Tissues or structures with high density will appear white, and tissues with low density will appear black. In the X-ray, the air with the lowest density is black, fat is denser and dark gray, water is mid-gray, bone is light gray, and metal is white. The Bones and metal appear very light because the beam cannot penetrate the structure. On the other hand, the beam can pass through fat and even more air.

The differences between the radiographs can be due to several factors. Motion is the primary factor for blur and unsharpness in radiography. Another factor that could affect detail in X-rays is how close the receptor is. The closer you and the studied joint are to the receptor, the sharper the image is. Last, the radiologist might change the radiographic contrast between the two pictures; the one with more clarity can have a high contrast setting to see the bone details perfectly.

Compared to X-ray, MRI creates a perfect contrast between every tissue in the body; therefore, MRI is excellent for soft tissues like muscles, ligaments, Tendons, and bones. We can see every tissue with an MRI. It is non-invasive imaging that creates 3-dimensional pictures of our body. It is a sophisticated and powerful magnet that produces magnetic fields. Compared to X-ray, there is no radiation risk, but because of the strong magnetic field, we must be careful with iron and steel objects, especially with medical devices such as pacemakers or implants.

Dr. Benjamin Petrolati

PT, DPT, French Osteopath