Musculoskeletal Radiology – New Developments

Two novel musculoskeletal radiology applications came to my attention at a recent conference.  The first related to MRI and the second to Ultrasound scanning using Doppler blood flow measurement.

MRI and Subtle Shoulder Pathology

The focus of this discussion was from the perspective of the radiologist diagnosing pathology with imaging and correlating radiological diagnosis with surgical findings.

Discussion was largely focused on differential diagnosis rather than easily definable pathologies such as gross instability, tendon rupture or gross degenerative change.

The first issue of discussion was quantifying the site of a glenoid labral lesion in relation to its position on the glenoid.  It appears from a surgical perspective that the reconstructive techniques can vary quite considerably depending on the site of the labral lesion and therefore it is of significant benefit to the surgeon to know in advance of surgical exploration to plan appointment times and surgical lists.  What struck me most was a series of five images of subtle shoulder pathology displayed to an audience of 100 sports medicine doctors, physicians, physiotherapists and strength and conditioning coaches. None could identify the subtle image changes at specific sites along the labrum, which correlated with labral pathology involving partial tearing and inflammation at the site.  In comparison to more obvious ‘SLAP’ lesions (superior labral antero-posterior) there was obviously a significant visual difference and reliance on a high level of skill in determining radiological abnormality.

We then switched our attention to evaluating rotator cuff tendonopathy where some extremely exciting developments are emerging.  It appears that radiologists are now capable of determining whether rotator cuff tendonopathy is evident on the sub-acromial side or the tendon under surface at the humeral head.  I had never seen this commented on before clinically, but from a rehabilitation perspective it is extremely exciting, because it help’s to sub-classify patients into primary or secondary impingements and therefore streamline for specific shoulder rehabilitation protocols (we have discussed in the shoulder course on this blog).  If this turns out to be incorporated into routine practice I think it will become very beneficial to physiotherapy and provide an excellent opportunity for research into shoulder rehabilitation protocols.

Doppler Ultrasound Imaging

The other interesting radiological investigation discussed was ultrasound scanning of achilles tendonopathies.  The cost effectiveness and ease of use of ultrasound coupled with the major improvements in image quality have widely increased its application in musculoskeletal medicine.  Most typically in achilles tendonopathy the purpose of the scan is to quantify the integrity of the tendon, but also to investigate more subtle processes where there are visible changes of degenerative change within the tendon, indicated by partial fibre disruption or cysts within the tendon substance – associated with tendonosis.  Whilst these applications are relatively well established, the new application of ultrasound scanning is to use the Doppler blood flow measurement to investigate blood flow within the target structure.  As we know, tendons have a notoriously poor blood supply and it appears that one marker of an inflammatory response is an increase in vascular proliferation and together with chemical

substraits which precipitate vascular infiltration of the tendon.  The colour image quantification of Doppler ultrasound allows what essentially is a “heat map” of a tendon to be reproduced, giving more detailed evaluation of the state of pathophysiology in cases where we were not looking at gross tendon disruption.

An interesting reference to a study of elite marathon runners was made where biochemical markers for vascular proliferation were monitored in achilles tendon’s up to one month post event.  It appears that it took this length of time for the vascular proliferation markers to return to pre-running base line levels, which the researchers classified as normal.   As one of the current concepts of perpetuating factors in chronic tendonopathy and enthesopathies is vascular proliferation distorting a normal repair process, this now gives us another level of insight into the pathophysiology..

Interestingly sports physiotherapists in elite professional soccer are using Doppler blood flow assessment of low grade tendon strain as a marker of when to increase training load rather than relying on clinical observation and functional loading capacity.  This raises some very interesting questions and needs to be subjected to more rigorous research analysis in the future.

The two exciting thoughts to start us off for 2010!

Enjoy the clinical challenge.

David