This is a question often asked either before or during physiotherapy assessment and/or treatment . The short answer is no but let me explain.

It is natural to think that a scan (this can be anything from an x-ray, MRI or ultrasound) is useful to determine the exact structure or group of structures that might be at fault or might be the source of your symptoms. In physiotherapy we use a two way system when assessing and treating people. During the course of an assessment or treatment we perform a subjective (we ask questions) and objective assessment (perform physical tests) to decide on what the problem is and what treatment might work. Scans fall into the objective assessment side of the assessment and therefore does not give us a complete understanding of the problem on its own but just adds more information which can be useful.

But surely more information can only be a good thing?

Yes and no. It depends. Let me explain with an example. If you were to MRI 100 people knees over the age of 55 you would find cartilage tears in at least 35% of people will have tears and 75% of these will be asymptomatic or not painful. Therefore, as we age there are changes that we expect to see and are reported on MRI but is not always significant depending on symptoms and what the persons main complaint are.

This is never seen more so than in spinal MRIs. Many people attend the clinic and feel justifiably concerned that they have multiple disc bulges and that this a disease that is age related and can not be reversed. The reality is however that the changes seen on MRI are likely to have happened very slowly and may not be the full cause of their symptoms. In fact, due to the huge increases in requests for MRI some healthcare providers are now questioning if MRI are appropriate for certain back pain types as the evidence is suggesting that some people do worse off in terms of their recovery if MRI is requested unnecessarily.

In summary

In some circumstances a scan may not be useful in progressing somebodies recovery or helping diagnose a problem. Good old questioning and application of physical tests are really as useful for some problems. This is not to say either that scans do not help either. Depending on that problem, lack of response to usual rehabilitation for a certain condition or just sometimes difficulty in coming up with a definitive diagnosis scans have become a very useful tool in modern medicine. In fact in my practice ultrasound scanning has revolutionised my practice in terms of helping me understand soft tissues response to healing and loading, when to start changing exercises and also when more detailed investigations might be required. In this respects scan are really useful but assessment and treatment can happen without it too.

References:

Use of Knee Magnetic Resonance Imaging by Primary Care Physicians in Patients Aged 40 Years and Older

Sports Health. 2010 Sep; 2(5): 385–390. doi: 10.1177/1941738110377420

The association between early MRI and length of disability in acute lower back pain: a systematic review and narrative synthesis BMC Musculoskelet Disord. 2021; 22: 983. Published online 2021 Nov 24. doi: 10.1186/s12891-021-04863-9