Diagnostic Tests: Pictures That Are Worth More Than a Thousand Words
By Dr. Molly Casey
There are times in life and healthcare when diagnostic testing is required as a means of ruling out certain diagnoses, and to determine the best path of treatment for a patient.
Diagnostic tests illustrate the condition of different tissues in the body to a greater or lesser degree. The type of test is dependent on the type of structure, tissue, or organ that needs to be examined.
Three common tests that one may encounter in their healthcare journey are X-rays, MRIs, and CT scans. Below is a basic primer for these tests to provide more information as to why these are sometimes ordered. My experience is that patients often participate in tests and procedures without knowing the basics and blindly follow orders. When you have a foundational understanding you can converse more clearly with your healthcare provider, and understand a bit better why you’re being asked to participate.
X-rays are a form of electromagnetic radiation, similar to visible light. X-rays pass through most structures and they have higher energy frequency than visible light. Medical X-rays generate images of tissues and structures within the body. While X-rays highlight and make visible different structures, bones are visualized best on this diagnostic tool. There are also shadows of organs and other tissues that can be seen on X-rays. Those shadows can be looked at and identified by the doctor reading the X-ray.
For most tissues other than bone, the X-ray is not the primary diagnostic tool. X-rays are most commonly used to seek out and assess the presence of bone fractures, certain tumors, and other abnormal masses. Pneumonia can be visualized well on X-rays, as well as calcifications, foreign objects, or dental problems.
MRI stands for Magnetic Resonance Imaging, which produces three-dimensional detailed images. It is a technology that uses powerful magnets to produce strong magnetic fields, forcing protons (subatomic particles) in the body to align with the field of the machine. The way in which these protons align, and the time it takes to do so (along with a whole host of reactions involving energy release, chemical changes, and more), produce an image with different shades of light and dark, density, and lucidity that creates the end picture. Different types of tissue appear in different ways. For instance, spinal fluid always shows up differently than ligamentous or tendon tissues.
MRIs are used for tissues such as the brain, spinal cord, nerves, muscles, and ligaments, as well as the meniscus or labrum/cartilage in extremity joints. Diseases or injuries to these types of tissues are visualized well with an MRI. MRIs do not contain or use radiation and are more expensive than both X-rays and CT scans.
CT Scans are computed tomography scans. These are computerized X-ray images in which the beam of the X-ray is narrowed/focused and rotated around the patient’s body. This technique produces cross-sectional images of certain areas of the body and organs. These images are referred to as slices. When several layers are stacked together, a three-dimensional image is the result.
This procedure offers more detail than conventional X-rays. Very specific identification of basic structures becomes exponentially clearer. CT scans are used as a diagnostic tool for a variety of clinical suspicions. Because it is an X-ray, it is very good with clarity in bone, though it would normally only be used with more complex bone issues or severely eroded joints, or more detailed information with tumors within the bone. However, CT scans are also good with locating injuries in tissue, locating damage from strokes in tissue, pulmonary embolisms, and heart vessel issues, among other things.
It’s Good to Know
More information is sometimes required to better serve the patient. Patients shouldn’t fear asking for more testing and imaging. There is a time and a place for everything, and a patient’s gut feeling can be indicative that something else is going on inside. Knowing the basics can help you understand more of your health journey.
If there comes a time when you need one of these tests, do yourself a favor and ask for a copy of the digital image, as well as a written report from the provider reading the images. Keep these for your records. This is helpful to have for your own health information, but also to give other providers; it may also decrease the need to have the test done in the future.
Technology has given us some great tools to help assess and evaluate the body and potential issues. Understanding these tools may make our health journey a little easier.
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