8Ultrasound in rheumatology
Section snippets
Equipment and methods
The quality of the US documentation that can be obtained by a skilled operator is directly linked to the quality of the US machine used. Top quality equipment for musculosketal US should include: a set of probes that cover a vast frequency range (ideally from 5 to more than 20 MHz), a very sensitive power and colour Doppler, extended view and three-dimensional US facilities (Figure 1). All these requirements are met by several types of equipment that are now available. Obviously the quality and
Acquisition techniques
Proper US scanning depends on the operator's ability to correctly place the probe and set the equipment. The US beam must be perpendicular with respect to the structures that are to be examined so as to avoid artefacts. Even minimal transducer inclination changes can strongly influence the characteristics of the US images. The best angle of insonation is determined by the operator, with minimal adaptive movements of the probe and/or the anatomical region. Each anatomical structure should be
Sonographic image interpretation
A correct interpretation of US images depends on several elements, such as a detailed knowledge of US anatomy and of the main pathological signs and pitfalls. At present, the US diagnosis is based on the examiner's comments, rather than on an off-line evaluation of the images appended to the report. This is due to the fact that sonographers tend not to print a full and detailed series of images and rheumatologists are not very prone to analysing and understanding them. A rapid and decisive
Indications and limits
There are five main indications for the use of US in rheumatology.
- 1.
Initial evaluation of patients with regional pain syndromes. In these patients, information obtained using US can be integrated with clinical data. This leads to a more precise diagnosis based on the identification of the specific anatomical targets of the disease.41, 42
- 2.
Identification of the anatomical changes associated with early arthritis. With the introduction of early aggressive therapy, it is advisable to use a very
Who should carry out US examinations?
It is a known fact that most US examinations on the musculoskeletal system are carried out by radiologists. This leads to a series of problems. First and foremost is the considerable time lapse that occurs between the request for an US examination, its execution and the evaluation, by the rheumatologists, of the information acquired. Moreover, many radiologists have a very limited knowledge of rheumatic diseases. This greatly limits the potential utility of the examination, since many important
Training
US is considered to be the most operator-dependent imaging modality. The relatively long learning curve and the lack of standardised training criteria are the main obstacles that hinder its widespread use.
The learning process for most rheumatologists is based on the participation in short (2–3 days) national or international courses and on informal training acquired under the guidance of a tutor.
Sonography courses and workshops are now included in the program of the most important rheumatology
Shoulder
The shoulder is a complex joint and is frequently involved in a wide range of pathological processes. A precise diagnosis and the identification of the anatomical damage to the different structures (joint, tendons, bursae) cannot be solely defined on the basis of history and clinical evaluation. US offers a quick and highly effective assessment of the most frequent pathological changes involving the shoulder.47, 48 These include biceps tenosynovitis, subdeltoid bursitis, rotator cuff pathology
Summary
US can provide a great contribution to the early diagnosis of various rheumatic disorders and offers a clearer view of the anatomical damage induced by inflammatory or degenerative processes. Most of the studies published up until now have been carried out in a relatively small number of pilot centres. Notwithstanding this, one can legitimately affirm that an US revolution has taken place in the field of rheumatology.
The main indications for US in rheumatology include the evaluation of patients
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