Spine Computed Tomography (CT)

Computed tomography (CT) was introduced in the 1970s and provides radiologists with higher-resolution images compared to X-ray.  CT scanners contain an ionizing radiation source and detectors, similar to X-ray machines, however; in CT, the source and detectors rotate around the patient. This rotation allows for the creation of 3D images that can be viewed in axial, sagittal, and coronal planes (examples below) after being processed by a computer program.  Similar to X-ray, the radiation emitted from the CT scanner is absorbed or reflected differently depending on the density of the tissue it passes through. This results in the creation of images where bone appears white (increased attenuation), air appears black (decreased attenuation), and everything in between (water, fat, organs) is a different shade of gray.

Indications: evaluating spine trauma, detecting malignancy or metastasis, identifying infection or abscesses around the spine, and providing procedural guidance in the operating room.

Advantages: higher resolution compared to X-ray (wider range of densities), fast (a head CT can be performed in less than a minute, which is crucial for timely stroke detection), widely available, and provides detailed 3D images.

Disadvantages: more radiation than X-rays, poor soft tissue contrast compared to MRI, imaging artifacts may make interpretation difficult or impossible in some cases, large machines are not portable, and contrast reactions are possible in patients receiving contrast-enhanced CT scans.