Radiological testing: CT Scan (Computerized Axial Tomography)

Diagnostic tests Medical history and physical examination Radiological texting Plain X-rays CT Scan (Computed Axial Tomography) Magnetic Resonance Imaging (MRI) Radionuclide imaging Discography Myelography Neurophysiological testing Blood tests Other diagnostic tests

What it is:

Basically it consists of many radiographs shot at the same time from different angles. Later, a computer gathers all the images and reconstructs them in only one image, summing up the images obtained from the different angles.

What it allows:

It allows the visualization of "soft" tissues (that is, different from bone) that are easily crossed by X-rays due to their low consistency, and that have poor imaging through conventional radiography. CT scan was a very important development, since it was the first painless diagnostic test that allowed the viewing of intervertebral disc images.

Risks

CT scan is painless but is potentially harmful; it exposes patients to a considerable radiation dose, equivalent to several X-rays at the same time.

Indications:

The CT scan permits visualization of the bone more clearly than the MRI. However, the MRI allows a better visualization of soft tissue, including the intervertebral disc. Due to this and to the fact that the CT scan emits a strong dose of radiation, it is presently only recommended in those cases in which it is necessary to visualize the bone (i.e., when a tumor in its interior is suspected). It is also recommended when it is necessary to visualize soft tissue but there is no MRI available.

Some of the existing recommendations based on scientific evidence suggest waiting 6 weeks before ordering a CT scan or MRI for patients suffering acute back pain.