Imaging Referral Criteria: What Can and Cannot Be Scanned at ScanAlign?
ScanAlign offers standing, weight-bearing EOS imaging for adults who can stand still for about 20 seconds. The scan is suitable for questions about the alignment of the spine, hips, knees and whole body. It is not right for pregnant patients, for a serious injury that needs emergency care, or for medical questions that need the soft-tissue detail of an MRI.
Key points
- Adults who can stand without support for around 20 seconds are generally suitable.
- Pregnancy is an absolute exclusion. No ionising imaging is done on pregnant patients.
- EOS uses about 90% less radiation than a standard X-ray, around ten times less.
- For questions about soft tissue, discs or nerves, MRI is the better choice, not EOS.
- You do not need a referral from your doctor. We accept patients who refer themselves and patients referred by a clinician.
Who is suitable for a standing EOS scan?
Most adults with a question about the alignment of their bones and joints are suitable. The scan captures the full skeleton, from head to foot, while you stand in your natural posture. This makes it especially useful when a clinician needs to see how the whole chain of bones and joints lines up under gravity.
- Long-term back, hip or knee pain without a clear diagnosis
- Planning before joint replacement or spinal surgery
- Follow-up of implants or spinal fusion after surgery
- Monitoring scoliosis or kyphosis in adults
- Checking for a difference in leg length
- Posture or walking problems with no clear cause
- Alignment imaging for a second opinion
- Pregnant patients (absolute exclusion)
- Patients who cannot stand still for about 20 seconds
- A serious, recent injury that needs emergency imaging
- Questions about discs, nerves or soft tissue (MRI is better)
- Patients under 18 (ScanAlign sees adults only)
You can check who our scan is suitable for on our eligibility page. It covers the same criteria from a patient's point of view.
What are the exclusion criteria for an EOS scan?
The main exclusions relate to pregnancy, the ability to stand, and whether the medical question really needs weight-bearing imaging of the bones rather than another type of scan.
Absolute exclusion. Even though EOS gives a very low dose of radiation, no ionising imaging is done on a pregnant patient. If pregnancy is possible, it must be ruled out before the scan.
For the scan, the patient must stand without support for about 20 seconds. If severe pain, poor balance or a neurological condition makes this impossible, EOS is not right.
If the patient has a recent fracture or sudden injury, emergency imaging at a hospital emergency department is the right route. ScanAlign is a planned imaging service, booked in advance.
EOS shows bones, joints and alignment. If the medical question is about discs, ligaments, tendons or nerves, MRI is usually the better tool.
A note on MRI. EOS is excellent at showing the skeleton under load. It shows how bones, joints and the whole kinetic chain line up when you stand. For soft-tissue detail, disc herniations, nerve compression or inflammatory conditions, MRI is still the right test. The two scans work together. They do not compete.
Why does standing imaging change the referral decision?
Standard X-ray, CT and MRI are done lying down. In that position, gravity is taken away, muscles relax, and the skeleton settles into a shape that may look quite different from the patient's upright posture. Alignment problems, a tilted pelvis, differences in leg length and compensating curves can be invisible on scans taken lying down.
When you refer a patient for standing EOS imaging, you are asking a very different medical question: "How does this person's skeleton actually behave under load?" This is why the referral criteria differ from those for standard radiology. The patient must be able to stand, and the question must be about bone alignment or the shape of the joints rather than soft tissue.
The body works as a connected chain. A small tilt in the pelvis can make the spine compensate, which can then cause symptoms in the neck or shoulder. Pain often shows up away from its cause. Whole-body standing imaging captures the entire chain in a single exposure. This gives clinicians a far more complete picture than imaging one area on its own.
For more on radiation levels and scan safety, see EOS scan safety and radiation.
When should you refer for MRI instead of EOS?
MRI is the better choice when the medical question involves soft tissue. Disc bulges, nerve root compression, ligament tears, cartilage damage, inflammatory arthropathy and assessing a tumour all need the soft-tissue contrast that MRI gives. EOS does not image soft tissue.
In many cases, the two tests work together. A patient with back pain might benefit from MRI to look at the discs and EOS to look at overall spinal alignment and pelvic balance. One does not replace the other.
How do I refer a patient to ScanAlign?
Referral is simple. Patients who pay for themselves do not need a letter from their doctor, and referrals from clinicians are also welcome. Here is how it works.
The patient, or the referring clinician, books a short video call. This confirms that the medical question is right for standing EOS imaging and checks that the patient is suitable.
Every scan must have a clear medical reason. If EOS is not the right test, we will say so and, where possible, suggest another route.
The appointment takes place at ScanAlign, standing EOS imaging, inside The Harley Street Hospital. Read about what to expect at an alignment assessment.
A specialist radiologist reports on the images. The report and images are shared with the patient and, if asked, with the referring clinician.
Not sure whether EOS is the right test for your patient? You can discuss a referral with our team before booking.
What about red-flag symptoms?
If a patient has sudden severe pain, numbness, weakness, or loss of bladder or bowel control, this is not a question for planned imaging. Please tell them to get urgent medical help from their doctor or the nearest hospital emergency department. ScanAlign is a planned diagnostic service and is not set up for emergencies.
Before starting treatment, or changing the treatment you are already on, it is worth getting a detailed diagnosis. Knowing whether the cause lies in the pelvis, the legs or the spine changes what will actually help.
Frequently asked questions about imaging referral criteria
No. ScanAlign accepts adults who refer themselves, as well as referrals from consultants, family doctors, physiotherapists and other clinicians. Every scan still needs a clear medical reason, which is confirmed during the free video consultation.
No. Pregnancy is an absolute exclusion for any ionising imaging at ScanAlign, at any stage of pregnancy. If there is any chance of pregnancy, it must be ruled out before the scan.
EOS uses about 90% less radiation than a standard X-ray, around ten times less. This makes it one of the lowest-dose options for full-body imaging of the skeleton.
For the scan, the patient must stand without support and fairly still for about 20 seconds. If pain, balance problems or a neurological condition prevents this, EOS is not the right test. We will discuss this at the video consultation.
No. EOS images bones and joints. For disc herniations, nerve compression or other soft-tissue questions, MRI is the right scan. The two scans work well together when both bone alignment and soft-tissue detail are needed.
No. ScanAlign sees adults only. We do not scan patients under 18.
The EOS system has a weight limit, which we confirm during the video consultation. If there is any doubt, we check before booking a scan appointment.
Yes. Unlike MRI, EOS uses X-ray technology, so metal implants, joint replacements and spinal hardware do not rule out the scan. In fact, checking implant alignment after surgery is one of the most common reasons for referral.
ScanAlign is a self-pay service. The price for patients travelling from abroad is confirmed during the free video consultation.
We will tell you. If the medical question is better answered by MRI, CT or another type of scan, we will say so at the video consultation and, where possible, suggest another route. We do not scan patients when EOS is not the right tool.
Unsure whether EOS is right for your patient?
Book a free video consultation. We will confirm suitability, explain the process and answer any medical questions.
Book a free video consultationSources
- Deschênes S, Charron G, Beaudoin G, et al. "Diagnostic imaging of spinal deformities: reducing patients' radiation dose with a new slot-scanning X-ray imager." Spine, 2010;35(9):989-994.
- The Royal College of Radiologists. iRefer: Making the best use of clinical radiology. RCR guidelines on appropriate imaging referral criteria.
- Ionising Radiation (Medical Exposure) Regulations 2017 (IR(ME)R). UK law governing the clinical justification of medical exposures in the UK.
Written by Abbas Dhami (Specialist Diagnostic Radiographer).
This page is general information and not a diagnosis.
ScanAlign is the trading name of CoreMed Solutions Ltd and operates under The Harley Street Hospital's CQC licence.