Scoliosis and EOS Imaging

High-tech, low risk alternative to traditional spinal x-rays.

The EOS® Imaging System is a safe and effective way to image the spine, pelvis and lower limbs, such as in cases of scoliosis and sagittal imbalance. EOS technology is based on Professor Georges Charpak’s Nobel Prize-winning advance in physics covering particle detection (eg, radiation detector). EOS imaging allows the patient to stand while simultaneous anteroposterior (front to back, AP) and lateral (side) 2D images are quickly taken in seconds and reconstructed into 3D true-to-size pictures.1,2
Man standing inside ultra low dose 2D,3D EOS machine.The EOS Imaging System allows the patient to stand while spinal images are captured. Copyrighted photo provided courtesy of EOS Imaging, Inc.

What is scoliosis and sagittal imbalance?

Scoliosis is a side-to-side curvature of the spine that can cause sagittal imbalance. The term sagittal imbalance refers to the front to back view of the body. Imbalance simply refers to being out of balance or lack of harmony. In spinal deformity, sagittal imbalance may refer to abnormal spinal curvature that causes the spine to be too far forward, backward or to one side.

Abnormal kyphosis (hyperkyphosis, hunched back) and flatback syndrome are other spinal disorders that cause sagittal imbalance. Flatback syndrome affects the lumbar spine normal lordosis (low back’s inward curve) flattens.
Body posture defectScoliosis, flatback syndrome, and abnormal lordosis and kyphosis are types of spinal curvature disorders. Photo Source:

Why do spine specialists choose EOS imaging?

Doctors have several imaging choices—such as x-rays, CT scans and MRIs. The doctor’s imaging test choice may depend on his patient’s age, spinal deformity and its severity, or how the imaging results will be used. Images are used for different purposes including confirming a diagnosis, as part of monitoring scoliosis curve progression, and/or surgical planning. Many spine specialists select EOS because of its (1) safety profile, (2) image quality and (3) time-saving image delivery.

#1. Imaging Safety Profile

EOS utilizes ultra-low dose radiation to capture 2D and 3D images of the patient’s entire body in natural, load-bearing positions while standing. The EOS software renders images into exceptional high-quality in a 1:1 scale removing the need for magnification and eliminating image distortion.

Ultra-low radiation dose is particularly advantageous for children and adolescents being treated for scoliosis. Young people with scoliosis typically need standing spinal x-rays every three to six months, often for several years. This can mean up to 20 spinal scans for their total treatment (eg, scoliotic curve observation). In standard x-rays, the amount of radiation is kept as low as possible, and lead shields are placed over the breast and abdominal/genital areas for additional protection. Even so, the radiation exposure is troubling, leading to a small but not insignificant increase in the risk of breast and thyroid cancer. Lead shields certainly help, but they aren’t totally protective and can interfere with imaging views of the spine and pelvis. EOS greatly reduces this risk by delivering only one tenth the radiation dose of conventional x-rays with no need for shielding.

EOS is undoubtedly a game-changer for imaging children, but many adult patients benefit from this technology too. In adults, the technology is useful for monitoring degenerative scoliosis and progressive kyphosis. EOS can also be used to monitor postural and balance changes in elderly patients, perhaps helping to reduce falls and related injuries in older patients.

#2. Superior Image Quality

EOS delivers superior images of the skeleton, spine, pelvis and lower limbs as well. The system is highly sensitive, up to the level of a single photon (a particle of light), but insensitive to diffuse scattered radiation. EOS images have gray shades ranging up to 30-50 thousand, whereas traditional x-rays are limited to only a few hundred. This allows EOS technology to create much sharper, higher-quality images, thus making for easier interpretation and diagnostic decisions.

With EOS—depending on the patient’s health and the particular spine views required—the patient can stand, sit, or even squat while being imaged. This allows the doctor to see the skeleton/spine under natural stresses in weight-bearing positions, giving them not only a better image, but also making it possible to analyze a spinal joint in relation to other joints or to the entire skeleton.

Unlike traditional x-rays, which must combine a number of images to present a full view of the spine or long bones, such as in the legs, EOS provides the images in a 1:1 scale. This allows the doctor to see the entire image at once, rather than having to stitch several images together to get a full view. This is particularly useful in planning scoliosis surgery.
Eos Scoliosis 3-D frontal imageEOS Imaging is used by spine specialists to diagnose spinal conditions including surgical planning, monitoring treatment and postoperative follow-up. Copyrighted photo provided courtesy of EOS Imaging, Inc.

#3. Time-saving Image Delivery

Another advantage of EOS is the images can be reviewed immediately. Saving time is always great, but this can be especially helpful when planning surgery or making post-operative decisions. Immediate access to the images is also very helpful when teams—orthopaedic spine surgeon, physical therapist, physiatrist, orthotist—need to consult about treatment options.

What do patients experience during EOS imaging?

This high-tech nature of EOS is not lost on patients. When they step into the scanning both, patients are often reminded of the transporter in the Star Trek movies. They can safely watch the light as it quickly scans down their bodies, front and back. The entire process takes from 10 to 25 seconds—compared with 15-20 minutes for traditional imaging. (And, of course, they step out of the scanner into the same room they left, not on a distant planet.)

Does EOS imaging technology replace x-rays?

EOS does not replace traditional x-rays. Traditional x-rays are still used for injuries such as fractures, and whenever when a close view of a small section of the skeleton is required. EOS is most useful for spine, pelvis/hip, and leg disorders.

Though the technology is still relatively new, hospitals, orthopaedic practices, and imaging centers are increasingly adopting this new tool for the evaluation and monitoring of orthopaedic disease and giving patients a safer and more comfortable option for images.

Dr. Alan H. Daniels is consultant to EOS Imaging, Inc.

Updated on: 09/20/19
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