Imaging Techniques

Imaging Techniques are used in our office on a daily basis. Often times patients are being confronted with terms like Bone Scan, CT, MRI without really knowing what these Imaging Techniques really entail. This blog explains the different techniques, and what they are used for.

1. X-Rays

X-Rays use radiation to create a simple black-and-white image that looks like a film negative. It is useful for imaging bones, but not ligaments and tendons. These Imaging Techniques are probably the most common.

X-rays are made by using external radiation to produce images of the body, its organs, and other internal structures for diagnostic purposes. X-rays pass through body structures onto specially-treated plates (similar to camera film) or digital media and a “negative” type picture is made (the more solid a structure is, the whiter it appears on the film).

When the body undergoes X-rays, different parts of the body allow varying amounts of the X-ray beams to pass through. The soft tissues in the body (such as blood, skin, fat, and muscle) allow most of the X-ray to pass through and appear dark gray on the film or digital media.

A bone or a tumor, which is more dense than soft tissue, allows few of the X-rays to pass through and appears white on the X-ray. When a break in a bone has occurred, the X-ray beam passes through the broken area and appears as a dark line in the white bone.

2. Bone Scan

A Bone Scan is a nuclear scanning test that finds abnormalities in bones, such as fractures. These Imaging Techniques can help diagnose fractures that are hard to see on an x-ray, such as a stress fracture. An injection into a vein, of a small amount of radioactive material is required to obtain the image.

Why it’s done

If you have unexplained bone pain, a bone scan might help determine the cause. The test is very sensitive to any difference in bone metabolism. The ability to scan the entire skeleton makes a bone scan very helpful in diagnosing a wide range of bone disorders, including:

Paget’s disease of bone
Cancer originating in bone
Cancer that has metastasized to bone from a different site
Infection of the joints, joint replacements or bones (osteomyelitis)
Impaired blood supply to bones or death of bone tissue (avascular necrosis)

3. MRI

The MRI is the tunnel-like machine you often see on TV. These Imaging Techniques are used to show the internal structures of the body. MRI uses nuclear magnetic resonance to show the inside of the body.

The patient lies in a large powerful magnet, and the magnetic field helps create the image by aligning the nuclei of the atoms in a certain way. We use it for imaging ligaments and tendons, for example.
The development of the MRI scan represents a huge milestone for the medical world.

Doctors, scientists, and researchers are now able to examine the inside of the human body in high detail using a non-invasive tool.

The following are examples in which an MRI scanner would be used:

anomalies of the brain and spinal cord
tumors, cysts, and other anomalies in various parts of the body
breast cancer screening for women who face a high risk of breast cancer
injuries or abnormalities of the joints, such as the back and knee
certain types of heart problems
diseases of the liver and other abdominal organs
the evaluation of pelvic pain in women, with causes including fibroids and endometriosis
suspected uterine anomalies in women undergoing evaluation for infertility
This list is by no means exhaustive. The use of MRI technology is always expanding in scope and use.

4. CT

The CT or computed tomagrophy scan (also called a CAT-scan) is a medical image using radiation that employs computer-processed x-rays to produce the three-dimensional images or “slices”. This test gives us excellent visuals of the bones of the body. However, the exposure to radiation with a CT scan is about ten to a hundred times more than a chest x-ray.

A CT scanner emits a series of narrow beams through the human body as it moves through an arc.

This is different from an X-ray machine, which sends just one radiation beam. The CT scan produces a more detailed final picture than an X-ray image.

The CT scanner’s X-ray detector can see hundreds of different levels of density. It can see tissues within a solid organ. This data is transmitted to a computer, which builds up a 3-D cross-sectional picture of the part of the body and displays it on the screen.

Sometimes, a contrast dye is used because it can help show certain structures more clearly.

For instance, if a 3-D image of the abdomen is required, the patient may have to drink a barium meal. The barium appears white on the scan as it travels through the digestive system.

If images lower down the body are required, such as the rectum, the patient may be given a barium enema. If blood vessel images are the target, a contrast agent will be injected into the veins.

The accuracy and speed of CT scans may be improved with the application of spiral CT, a relatively new technology. The beam takes a spiral path during the scanning, so it gathers continuous data with no gaps between images.

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