Diagnostic Imaging of the Shoulder

Original Editor - Naomi O'Reilly

Top Contributors - Naomi O'Reilly, Kim Jackson, Rucha Gadgil, Admin, Wanda van Niekerk and Lucinda hampton  

Introduction

Diagnostic Imaging can be a useful resource for musculoskeletal conditions and where used appropriately can be an invaluable tool for physiotherapists. Imaging such as MRI, X-ray, CT Scans, and Bone Scans are prime examples of practical diagnostic imaging that facilitates accurate diagnosis, prognosis, intervention, and assessment of injuries and dysfunction that physiotherapists' address daily. Unnecessary imaging will not only potentially squander financial resources and increase potential for premature surgery, but may also lead to increase failure of conservative physiotherapy treatment as a result of patient expectations following diagnostic imaging e.g. perception that if a tear is there then physiotherapy has no role to play, so it is key to understand and recognise when imaging is appropriate. While there are a number of studies which indicate diagnostic imaging is underutilized such as x-rays identifying fractures or bone scans identifying osteoporosis, there are also many more studies which suggest over utilization of imaging, such as X-rays or MRI for acute and uncomplicated shoulder pain. While a thorough history and physical examination are the most important instruments in evaluating shoulder pain, musculoskeletal imaging can be an important adjunct.

There may also be an expectation from patients in relation to the needs for imaging studies, many who often demand investigations believing it is necessary for adequate diagnosis and management of shoulder pathology, which can present a multitude of problems for the physiotherapist in managing these expectations and advising or educating patients around the diagnostic imaging and its role. Cuff and Littlewood highlight a wide range of factors which influence patient beliefs about the cause of their shoulder pain, but suggests the information they receive from healthcare professionals has the strongest influence, hence, the language and terminology we use is key to achieving good clinical outcomes. Successful physiotherapy management of shoulder pain is often impacted by the patients expectations about how effective they believe physiotherapy to be and has been shown to be the strongest predictor of future surgical intervention in people with shoulder pain and associated rotator cuff tear.

If the patient perceives their problem as one not amenable to physiotherapy following diagnostic imaging, for example an osteophyte (bone spur) impinging on their rotator cuff, the opportunity to achieve a satisfactory outcome might be compromised."

Where a thorough and detailed subjective and objective physical assessment has been completed, imaging in some cases may aid in confirming diagnosis, but remember that diagnostic imaging findings can lead to misdiagnosis if not reviewed in the overall context of the patients symptoms and physical exam findings. As such shoulder examination and development of adequate differential diagnosis is therefore key to establish if advanced imaging is required.

Traditionally it was assumed that the utilisation of advanced imaging modalities would provide additional benefits and increase diagnostic accuracy, however as highlighted by Jarvie et al there are many studies which now refute this and suggest the use of additional advanced imaging has minimal impact on the care patients receive. We will review the options and principles of shoulder investigations as they can play a role in the effective management in some shoulder conditions. There are many different types of imaging and each type is used for a specific purpose. For shoulder related problems the main forms of imaging include X-rays (Plain Radiography), Ultrasound, CT and MRI Scans although direct access to these types of testing vary dramatically worldwide, and even within countries

Imaging Options

X-Ray (Pain Radiography)

Plain X-rays can be important in the diagnosis of some shoulder conditions, with a good overview provided by routine views which include AP with Internal and External Rotation and Axillary Lateral.

In the context of sporting injuries, X-rays are primarily indicated for detecting any bony fractures or dislocations / subluxations and patients should be referred for immediate X-ray if there is any suspicion of these injuries.

The conditions that can be identified on Plain Films include;

• Calcific Teninopathy
• Glenohumeral Joint ARthritis
• Scelrosis of Anterior ad Lateral Acromion
• Sclerosis of the Greater Tuberosity
• Proximal Humeral Head Translation
• Fractures

"X-ray is currently considered an indicated imaging modality for diagnosing adhesive capsulitis and ruling out an intrinsic cause for motion loss (e.g., glenohumeral arthritis)."

"X-ray studies are also considered indicated for suspected instability to identify concentric reduction and the absence of fracture or bone loss."

Indications for X-ray

To detect or exclude pathology when diagnosis is obscure and thus contribute to decisions regarding further management

Consider an x-ray and further discussion with GP if patient has;

• Exquisite Pain - Exclude Acute Calcific Tendonitis;
• Subacromial Pain (ONLY if suspect a structural deformity or is unresponsive to treatment);
• History of Trauma - Exclude Fracture and / or Dislocation / Subluxation;
• Possibility of Metastases, particularly in patients with a previous history of Cancer (Breast or Lung)
• AC Joint Pain - Persistent pain with continued functional impairment;
• Older Person with a stiff, painful shoulder +/- crepitus.

Arthrography

Arthrography is when the joint is injected with a dye and is generally combined with CT or MR to provide detailed anatomical information of the Shoulder Joint including strong detail of the Capsular attachments and Labrum and can very clear highlight small avulsion fractures of the Glenoid Rim (Bankart Lesions) and Humeral Head (Hills-Each Lesion).

Ultrasound

Musculoskeletal ultrasound has evolved as a useful and powerful tool for both diagnosis and treatment of shoulder pain, as it provides both static and dynamic visualization of structures surrounding the shoulder including the lateral third of the acromion, the subacromial/subdeltoid bursa, supraspinatus tendon, and the head of the humerus.and their biomechanical relationships,

A sensitivity level of 79% and a specificity of 94% was found in a meta-analysis of five studies (311 Shoulders) which used ultrasound to diagnose Rotator Cuff related disorders, so can be considered a valuable investigation for rotator cuff related shoulder pain where indicated.

"High resolution ultrasound, in the hands of an experienced operator, is a reliable non-invasive technique for imaging the rotator cuff and adjacent muscles, the bursar, and the long head of biceps muscle."

MRI

MRI allows for multiplaner, non-invasive examination of the shoulder. Currently there are many debates surrounding the use of MRI with many studies questioning the clinical relevance of the findings seen on MRI, which have been shown to not always correlate well with surgical findings. These studies suggest that the findings on shoulder MRI may not always be clinically relevant. MRI can be used to evaluate both soft tissue and bony injuries in detail, as yet it is still unclear whether MRI is more accurate at detecting shoulder related disorders compared with Ultrasound, specifically in relation to Rotator Cuff or Subacromial Related Shoulder Pain, but both have been shown to be equally effective in the detection of partial or full thickness rotator cuff tears . Onward referral to a specialist rather than requesting a MRI may often be a much better management strategy due to the cost implications for shoulder MRI.

Summary

Imaging findings such as tendon tears and bursal thickening, often diagnosed as bursitis, are as common in individuals with no shoulder pain, as they are in those with shoulder pain. One study suggest as much as 96% of individuals without any shoulder pain or loss of function were found to have imaging changes, such as tears, and bursal thickening. This suggests that what can be seen in imaging is not always the cause of the problem, and in many cases imaging findings do not tell you what structure is specifically causing the pain. It is important to consider that diagnostic imaging findings in the acute setting in many cases will not actually change the management of the injury, so knowing and recognising when diagnostic imaging is required is key. Keeping that in mind, current research suggests that Ultrasound is a valuable for rotator cuff related and subacromial related shoulder pain, in particular complete or incomplete ruptures of the Rotator Cuff, and is more cost effective than use of MRI. MRI on the other hand is moe accurate when evaluating for Hill-Sachs Lesions or bony Bankart Lesions, while MR Arthrography is far superior when looking for labral capsular ligamentous complex lesions.

Currently in many cases MRI often represents a more universally accepted imaging modality, which may be due to ease of use with the ability for imaging to be evaluated by more than one radiologist. Ultrasound on etc other hand, can be slightly more challenging

References