People often rely quite heavily on the results of imaging to determine what might be causing their symptoms, yet it is important to realise that imaging techniques are only part of the bigger clinical picture. Imaging techniques can have a high amount of false positives, in which degenerative changes in a structure are assumed to cause pain and symptoms. The identification of an imaging abnormality does not always correlate with pain.
Interestingly recent research into back pain and imaging shows that in up to 50% of cases the pain is unrelated to the imaging findings. The back is a complex area and diagnosis is made even more difficult by the fact that the nerves in the area supply multiple structures and spinal levels. This can help to explain the reason why back surgery is successful for some individuals and not for others.
The back is not the only area in which this problem exists. Research into imaging of the rotator cuff region has also demonstrated a high amount of false positives. This is increasingly common as we age, with at least 50% of people in their middle years or beyond having rotator cuff tears that are not necessarily symptomatic. As with the lower back, a thorough clinical assessment of movement and function is necessary to present the complete picture.
The big take home message is that like most testing, imaging only forms one piece of what is often a complex puzzle. While it can be very helpful to confirm a diagnosis in some situations, it can also be quite misleading when there is an incidental abnormality present.