Medical Imaging in Diagnosis of Back Pain

Medizinische Bildgebung bei Rückenschmerzen: Röntgen, MRT oder CT sinnvoll?

Back pain is a common problem and affects many people. It is no wonder that back pain is one of the most common reasons for visiting a doctor. 1

Many of those affected ask themselves during a visit to the doctor whether further examinations are necessary for back pain. According to the survey, more than half of the patients with back pain believe that further examinations such as an X-ray are automatically necessary. 2

Experts take a completely different view on this point and are much more cautious when it comes to the use of medical imaging such as X-rays for back pain. 3

Independent reports (such as the Bertelsmann Foundation’s 2016 report) also criticize the fact that too often imaging of the spine is requested in the case of back pain including unnecessary radiation exposure in the process. 4

In the following article we would like to explain the reasons experts give for their attitude. We would also like to try to answer further questions: Which images of the back are recommended by experts and when. Which different advantages do the different recording techniques have and further questions.

When do experts recommend at all to arrange for an imaging of the back?

Back pain is a very common condition and affects millions of people every year in Germany alone. Patients and, above all, doctors face a great challenge: Among the very large number of people suffering from back pain, there are a few who actually suffer from a change that requires treatment, such as the spinal column. Fortunately, however, these can usually be identified by means of warning signs in the physical examination or the doctor-patient consultation. 5

In order to be on the safe side, one could, of course, simply perform an imaging such as an x-ray on all patients in order not to overlook a diagnosis in any patient. But when patients with back pain routinely get imaging, studies don’t show an improvement of the symptoms of these patients. 6

Instead, changes are often found which have nothing to do with the symptoms and often only unsettle the affected person additionally without having any influence on the treatment. 7 The further development of complaints and possible further back pain episodes cannot be reasonably predicted with routine imaging either. 8

This even means that more (and probably often unnecessary) follow-up treatments are often initiated in the case of unnecessarily performed examinations. 9

Not least for this reason, experts internationally recommend that medical images such as x-rays of the back should only be taken if the doctor-patient consultation and the physical examination reveal indications of a cause requiring treatment. 10,11

These recommendations also apply to neck pain because medically remarkable changes in the spine are very rare here as well and these are usually indicated by typical findings in the medical examination. 12

Therefore, experts agree: Imaging examinations such as x-rays or magnetic resonance imaging (MRI) should be used with restraint for back pain and only if there is a suspicion that a specific cause may exist.

X-rays of back pain are quickly available, but usually not necessary

X-rays of the spine are easily available because not only radiologists, but also many orthopaedic surgeons can arrange and analyze these images. 4 But what knowledge gain and what risks do they bring for patient and physician?

The biggest limitation of X-rays of the spine is that these can primarily only show bony changes. 13 This means that important other changes, such as the intervertebral discs, ligaments and muscles, cannot be visualized at all. X-ray examinations of the spine can therefore be of particular help if there has been an accident and a fracture of the spine is to be ruled out or if there is suspicion of another change in the bones.

Another disadvantage of X-ray examinations is the radiation exposure of X-rays, which represents a proven health risk depending on the level of exposure, especially among young people. 14.15 This disadvantage is very important, especially for X-ray examinations of the lumbar spine, as the X-rays also reach the vicinity of the genital organs.

Overall, it is therefore advised to be cautious when taking X-rays of the spine, as only a few of the possible changes can be seen and still create a great deal of uncertainty due to accidental findings. Radiation exposure also suggests that X-rays of the spine should only be taken in selected cases, such as in the event of suspected injury to the bony parts of the spine, for example after an accident.

Magnetic resonance imaging (MRI) examinations of the spine

Just a few years ago, magnetic resonance imaging (MRI) was only available at a few centres. Today that’s different: Magnetic resonance imaging is now performed almost as often as X-rays of the spine and is therefore one of the most frequently performed diagnostic examinations of the spine. 4

Compared to X-rays, magnetic resonance imaging has two decisive advantages: On the one hand, it has no radiation exposure, since the images are not generated with the aid of X-rays but by magnetic fields. On the other hand, MRIs can also display changes in the intervertebral discs or other parts that do not consist of bones in high resolution – and in contrast to conventional X-rays also in three dimensions. 16

If warning signs appear in the doctor-patient consultation that may indicate a course requiring treatment (so-called red flags), experts therefore generally recommend magnetic resonance imaging as the first choice for further clarification. 17

But also with magnetic resonance imaging it must always be considered: Often the pictures show changes that have nothing to do with the complaints. For example, more than a third of completely symptom-free people have herniated discs, which can be seen in the magnetic resonance image but obviously do not cause any discomfort! 18, 19

Although, in principle, magnetic resonance imaging has only a few “side effects”, it should only be used very carefully for back pain, since some changes that would otherwise be random findings and do not explain the pain are discovered. These findings are sometimes even (wrongly) operated on – often without success, of course. 20

Computed tomography for back pain is rarely necessary

As with X-ray examinations, computer tomography (CT) uses X-rays to take medical images, which, as with conventional X-ray images, means that the bones in particular can be seen well in the spinal region. 21

In contrast to “normal” X-ray examinations, however, three-dimensional images are created in computer tomography – which in principle represents a tremendous advantage. However, this advantage is only possible because the radiation exposure is significantly higher than with conventional X-rays. 22

Because magnetic resonance imaging is better able to visualize the non-bone parts of the spine than computer tomography and does not show any radiation exposure, MRI of the spine is used more often for back pain. 4

CT examinations of the spine are thus usually only rarely reserved for cases in which, for example, an MRI examination would be indicated but cannot be performed or the bones are to be depicted particularly precisely, which is often successful with CT examinations.

Summary: Usually no medical images are necessary for back pain

Very few patients with back pain have changes to the spine that require treatment. If there are no warning signs in the physical examination or the doctor-patient consultation, changes requiring urgent treatment can be expected so rarely (less than one percent of those affected) that experts initially recommend no medical images. 23

However, because accidentally discovered findings often unsettle patients, it is all the more important to exercise restraint in imaging diagnostics! 24

If there is a well-founded suspicion that changes in the spine that require treatment cause the symptoms, medical imaging should of course be arranged.

In the majority of cases, magnetic resonance imaging of the spine is the first choice for further clarification. The reason for this is, on the one hand, the comparatively good presentation of non-bony changes and the lack of radiation exposure of the examination.