What is MRI useful for?

Back pain: when do MRIs and X-rays make sense?

Status: 02/24/2020 5:05 p.m. | archive
An MRI scan of the spine is not useful for all back problems.

Nowhere in the world are so many outpatient magnetic resonance imaging (MRI) performed as in Germany. And X-ray examinations are even more common: According to statistics from the Federal Office for Radiation Protection, every person in this country is X-rayed an average of 1.7 times a year. Diseases of the back make up a large part of the so-called imaging examinations.

When it comes to back pain, it is often not about making a diagnosis, but about ruling out serious illnesses for safety. But only in 15 percent of the cases is a possibly serious disease such as a slipped disc, slipped vertebrae or a tumor hidden behind the symptoms. 85 percent of back pain is non-specific and medically harmless. This back pain usually comes from the muscles and disappears again after a few weeks - for example through manual therapy or targeted muscle training.

Warning signs require an MRI or X-ray

For about every fourth person affected, MRI images are ordered right at the start of the examinations. However, in order to avoid unnecessary MRI or X-ray recordings, the doctor should first thoroughly ask each person affected about their symptoms and examine them physically. If there are misalignments or certain warning signs ("red flags"), imaging is justified. These include:

  • Numbness
  • pain radiating to the legs
  • Muscle weakness
  • Paralysis
  • Suspicion of inflammation or rupture.

Only in these cases should an MRI or X-ray be taken within six weeks. This is also the case in the German guideline for unspecific back pain, which is a nationwide recommendation for doctors.

Sufferers often ask their doctor to order imaging tests such as an MRI or X-ray - and it is not uncommon for the doctor to comply with the request instead of explaining why a physical examination is usually more useful than an MRI or an X-ray.

MRI: exposure to contrast media

Some doctors send their patients for an MRI scan even though the x-ray does not show any abnormal findings - just to "take a closer look". For those affected, after the X-rays, there is also the exposure to the MRI contrast agent. Such an MRI is rarely useful. With the method, areas of the body can be examined with millimeter precision using specific questions. But only with a clear suspected diagnosis does the radiologist know how to set the device for the examination.

MRI: risk of misdiagnosis

A general question such as "back pain" can even have negative consequences for those affected: Incidental findings can be misinterpreted and lead to unnecessary therapies. An example: about a quarter of the population shows herniated discs on MRI after a certain age. These are age-related changes that usually have nothing to do with the symptoms and that do not need to be treated.

MRI diagnosis: mixed results

According to a US study, the result of an MRT examination does not only depend on the setting of the device and the position of the person being examined. It is therefore crucial what the radiologist is looking for and how he interprets the recordings.

After two experienced spinal radiologists had found 25 abnormal changes in a patient on the MRI after a detailed and careful assessment, they sent her to ten different MRIs. A total of 49 alleged changes were found - so many more than were actually present. But of the 25 changes relevant to the symptoms, not even half were recognized.

Experts on the subject

Dr. Christian Sturm, senior physician
Clinic for Rehabilitation Medicine
Hannover Medical School
Carl-Neuberg-Strasse 1
30625 Hanover
www.mhh.de

PD Dr. Christian von Falck, senior physician
Institute for Diagnostic and Interventional Radiology
Radiology Center
Hannover Medical School
Carl-Neuberg-Strasse 1
30625 Hanover
www.mhh.de

Dr. Sabine Bleuel, specialist in orthopedics and trauma surgery
Focus on hand and foot surgery
Orthopedics and surgery Elbchaussee
London 567
22587 Hamburg
(040) 86 23 21
www.orthopaedie-elbchaussee.de

additional Information
Low back pain patient guideline
www.patienten-information.de/

National Health Care Guideline (NVL) Non-specific low back pain
www.leitlinien.de/nvl/kreuzschmerz

German Radiologieetz AG
Information portal for patients on the various examination techniques
www.radiologie.de

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Visit | 02/25/2020 | 8:15 pm