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Spine Tests

What tests do Spine Specialists use to diagnose a spine problem?

  1. The most commonly used tests are called ‘spine images’. These are radiology tests which take pictures (images) of a specific part of the spine.

Here are the most commonly ordered radiology tests:

  1. X-Rays
  2. CT Scans
  3. MRI’s
  4. Bone Scans


Other tests get information about the spinal nerves:

  1. Electromyogram (EMG)
  2. Nerve Conduction Study (NCS)


Sometimes Laboratory Studies are used:

  1. Complete Blood Count (CBC)
  2. Sedimentation Rate (Sed Rate)
  3. C-Reactive Protein (C-RP)


A. X-Rays

What are Spine X-Rays?

A Spine X-Ray is the simplest imaging procedure and a good screening tool. It takes usually just minutes to have these X-Rays taken and the radiation exposure is very low.

How long does it take to see an X-Ray after it is taken?

Depending on the facility, the processing of these X-Rays may differ. Some facilities such as many hospitals still have to process these films like pictures of older cameras. Some of the newer facilities have digital processing where the images are almost immediately available to be viewed by the Radiologist.

What information can Spine X-Rays show?

Spine X-Rays tell the doctor mainly about the bone anatomy, such as the vertebrae and joints of the spine. The alignment between the Vertebrae can be seen. The discs cannot be seen directly, but the space between the vertebrae can be examined to see how tall a disc is. Soft structures such as nerves, muscles, and the spinal cord cannot be seen on an X-Ray. An X-Ray can only show the parts of the anatomy which are very dense, such as bone. Here again are some of the spine structures seen on Spine X-Rays:

  1. Vertebrae
  2. Spine Joints
  3. Spinal Curves

What type of X-Ray views are there?

Depending on how these X-Rays are ordered, different X-Ray views can be taken:

  1. AP and Lateral Spine Views: These are front and side views of the spine
  2. 5 Views of the Spine: These include AP (front), Lateral (side), Oblique (from a 45 degree angle), and a Spot film (magnified view of the lowest part of the spine).
  3. Flexion/Extension Spine Views: These are also called ‘bending films’ where the spine is X-Rayed in the forward and backward bent position.

B. MRI Scans

What are Spine MRIs?

Spine MRI’s offer much more comprehensive information about the spine than X-Rays. Both ‘hard’ (bone or dense structures) and ‘softer’ structures can be seen, unlike on X-Rays which can only show harder, denser structures. Here are some of the important ‘softer’ structures which can be seen on an MRI:

  1. Spinal Disc
  2. Spinal Cord
  3. Spinal Nerves

Does an MRI scan have radiation?

An MRI does not expose patients to radiation.

How do MRI Scans work?

MRI technology uses powerful magnets which align our hydrogen atoms. Hydrogen atoms are very common in the human body since we consist of large quantities of water. When the magnet lines up the hydrogen atoms, it can get precise information about the tissue where the hydrogen atoms reside.

Do all MRI scanners have the same strength and quality?

MRI scanners are graded in their quality by something called a ‘Tesla’. Tesla is a measure of how powerful the magnet is. The higher the Tesla number, the more powerful the MRI scanner is. This often means better images. Typical ranges of MRI scanners are 0.5 to 3.0 Tesla.

What about claustrophobia in MRI scanners?

MRI scanners often look like a narrow, long tube, not allowing much space around the patient. This can make patients feel claustrophobic. Medication can be given by mouth or IV to relax patients with claustrophobia. For those patients who still have difficulty with claustrophobia, ‘open’ MRI scanners can be used. While they are far easier to tolerate for claustrophobic patients, their image quality is often lower than that of the conventional ‘closed’ MRI scanners.

Why are MRI scanners noisy?

MRI scans are often noisy with a loud clacking sound at certain intervals. This noise is produced by the powerful magnets as they interact with coils in the system. Usually patients get hearing protection. Patients must avoid movement as it degrades the quality of the MRI images.

Can patients with metal in the body have MRI scans?

The powerful magnets can be dangerous if patients have certain types of metals implanted in the body. They can be strong enough to make some of these metals move within the body. Some of the potentially dangerous metal implants are Pacemakers and Spinal Cord Stimulators. Before taking an MRI, patients are given a form to fill out which screens for metal implants in the body. Not all metal implants are dangerous for MRIs. An example of metals which are not problematic is titanium. Spine surgeries such as fusions use titanium implants.

What is an MRI with Contrast?

Sometimes MRI images are enhanced by giving contrast material through an IV (intravenous catheter). Usually a chemical called Gadolinium is used. Contrast is delivered through a vein and travels to parts of the spine where more blood flow is present, such as areas of infection or scarring. Spine MRI’s often uses contrast when patients had previous spinal surgery. This allows the doctor to see scar tissue.

Is the MRI Contrast material safe?

Gadolinium is generally safe. It does not contain Iodine, which is a contrast chemical used for some other Radiology imaging procedures. It is not uncommon to have an allergic reaction to Iodine containing chemicals.

Gadolinium should not be used in patients with kidney disease.

Are MRI Scans safe in Pregnancy?

MRI scans appear to be safe in pregnancy, but are still only recommended if absolutely necessary during pregnancy.


C. Spine CT Scans

What is a CT Scan?

Computerized tomography (CT) is basically a ‘super X-Ray’. However the images a CT delivers are of much higher quality and detail. For the spine, a CT is the best way to analyze bone structures. However it is not nearly as good about showing softer tissues such as the spinal cord which are better seen with an MRI scan.

A CT scan takes one slice (picture) at a time, like cutting pieces of pie. The slices come in various thickness and orientation.

Do CT Scans have radiation?

While CT scans can offer important information about the spine, CT scans do have significant radiation exposure for patients. They are usually taken when other radiology tests such as an MRI scan cannot provide the information the spine specialist needs. It is important to keep track of how many CT Scans a patient has been exposed to over time.

Is there such thing as a 3-D CT Scan?

Newer CT scans have the capability to produce a 3-dimensional (3-D) reconstruction of the bones in the spine. This is a 3-D model which can be seen from all different directions.

Are contrast materials used in Spine CT Scans?

CT scans can be obtained with IV contrast, but contrary to MRI scans, the contrast typically does not help viewing spine CT images. It is mostly used for other parts of the body such as in the abdomen and head.

What is a CT Myelogram?

A CT myelogram is a specialized study which can show the spinal cord and spinal nerves which are otherwise difficult to see on a regular CT scan. A myelogram involves an injection of contrast material (dye) into the spinal fluid. The injection is done by the Radiologist in the back of the spine between the vertebrae. Patients can be given relaxing medicine for this.

After the contrast injection, a Spine CT Scan is taken. The CT images obtained by the myelogram can show if the spinal cord or spinal nerves are compressed.

Can CT Scans cause claustrophobia?

A CT machine looks like a donut. It is not a long tube like an MRI scanner and therefore not as claustrophobic.

Are there new types of CT Scans?

CT technology has become better with faster machines and more slices (images). The most advanced CT scanners are called ‘64-slice CT’. They can take more pictures in a shorter amount of time than older styles of CTs. There are even mobile CT scanners which can take a CT scan in the operating room during spine surgery (O-Arm).

Are CT Scans safe in pregnancy?

CT scans emit quite a bit of radiation and are therefore not recommended in pregnant patients unless absolutely necessary.


D. Nuclear Bone Scan

What is a Nuclear Bone Scan?

A nuclear bone scan is a nuclear medicine scan which evaluates the activity within bone. The word ‘nuclear’ comes from the radioactive dye which is injected through a vein prior to the procedure. The nuclear bone scan is not a ‘bone density scan’ (DEXA scan) which evaluates the bone density to look for osteoporosis (bone thinning).

What does a Nuclear Bone Scan look for?

Spine specialists often order nuclear bone scans to look for fractures due to osteoporosis (bone thinning) or to see if the bone from a spine fusion surgery has healed. Sometimes it is ordered to exclude cancer or a bone infection. Specifically, a nuclear bone scan looks at areas of unusual activity within bone, such as bone cells which are trying to stimulate healing (osteoblasts) to build new bone after a fracture. Here are some examples of what a Nuclear Bone scan can show in the Spine:

  1. Fractured Vertebrae
  2. Spine Infection
  3. Spine Cancer
  4. Failed Spine Fusion

What is the dye used in Nuclear Bone Scans?

The most common dye is technetium-99 which is radioactive, but does not carry enough radiation to harm the body. This dye can be seen by a specialized camera (gamma camera) which records its location. The dye typically accumulates in areas of the bone where there is more than normal activity, which the gamma camera records.

Roughly half the injected dye is taken up by bone, while the other half quickly travels to the kidneys and bladder to be excreted. The dye from the bones is also eventually excreted, but this may take days.

Why are Nuclear Bone Scan pictures taken at different times?

Nuclear bone scan pictures are taken after the dye is injected and then several hours later to evaluate where the dye has traveled to. Sometimes more pictures are needed at different times depending on what disease the radiologist is looking for.

What is a SPECT Nuclear Bone Scan?

If the Spine Specialist is looking for a very small area within bone which may be diseased, then the basic nuclear bone scan is combined with another specialized test, called a Single Photon Emission Computerized Tomography scan (SPECT scan). The SPECT scan can show much more detail of the anatomy than a regular Nuclear Bone Scan.


E. Electromyogram (EMG) and Nerve Conduction Study (NCS)

What is an Electromyogram (EMG)?

The EMG is a test which records the electrical activity produced by a muscle when it is stimulated. There are two types of EMGs:

  1. Surface EMG: For this study small electrodes are attached to the skin to measure the electrical activity of the muscle
  2. Intramuscular EMG: For this study the doctor who performs it inserts small needles through the skin directly into the muscle to measure the electrical activity. This activity is measured at rest, and then when the patient contracts the muscle.


What is a Nerve Conduction Study?

A Nerve Conduction Study (NCS) evaluates specific nerves and their function. A certain nerve is stimulated with electricity and the response of the muscle measured. This tells the doctor how fast and how complete the information was relayed from the nerve to the muscle.

Why do Spine Specialists order EMG and NCS tests?

An Electromyogram (EMG) and a Nerve Conduction Study (NCS) are usually ordered by a Spine Specialist to get more information about which nerve in the spine might be compressed or diseased.It can also rule out if the problem is with a particular muscle rather than a nerve, or if the patient is suffering from a nerve disease.

Why are Electromyograms (EMG) and Nerve Conduction Studies (NCS) often used together?

EMG and NCS studies are usually done together (EMG/NCS) so the doctor can get information about both the nerves and the muscles to get a more complete picture of what disease could be present.


F.Laboratory Studies

Here are some Laboratory Studies Spine Specialists sometimes order. Typically these are done to look for the presence of an infection.

A. Complete Blood Count (CBC)

What is a Complete Blood Count (CBC)?

This test looks at the cells in the blood stream. These cells are counted.

What types of Blood Cells are counted?

There are three types of cells:

  1. White Blood Cells (leukocytes)

Often fight infection

      2. Red Blood Cells (erythrocytes)

Carry oxygen

      3. Platelets (thrombocytes)

Help make blood clots

Why is the White Blood Cell Count important?

The White Blood Cell count is important when looking for an infection. The more White Blood Cells are found on the CBC, the higher the likelihood that an infection is present.

What type of White Blood Cells are there?

The White Blood Cell count is divided into what types of White Blood Cells are found. They are:

  1. Neutrophils
  2. Basophils
  3. Monocytes
  4. Eosinophils
  5. Lymphocytes


A high count in the Neutrophils can signal the presence of an infection.

B. Erythrocyte Sedimentation Rate (ESR)

What is an Erythrocyte Sedimentation Rate (ESR)?

Erythrocytes are Red Blood Cells. An ESR is a measure of how much these Red Blood Cells ‘sediment’ (sink to the bottom of a tube of blood) in 1 hour. The more the Red Blood Cells sink (sediment), the more likely it is that severe inflammation is present.

Why is an Erythrocyte Sedimentation Rate (ESR) test ordered?

Spine specialists may order this test if they are not sure if a patient has an infection or a severe inflammation of the spine. When an ESR test is combined with a CBC and a C-RP test, the combination of the information gathered from the test results can help determine if it is an infection or a severe case of inflammation of the spine.

C. C-Reactive Protein (C-RP)

What is a C-Reactive Protein (C-RP) test?

A C-RP test is blood test which measures a specific protein which is a marker for inflammation in the body.

Why is a C-Reactive Protein test ordered?

Spine specialists may order this test if they are not sure if a patient has an infection or a severe inflammation of the spine. When a C-RP test is combined with a CBC and an ESR test, the combination of the information gathered from the test results can help determine if it is an infection or a severe case of inflammation of the spine.