Ultrasound imaging for the rheumatologist XXX. Sonographic assessment of the painful knee

The knee joint is a frequent focus of attention for rheumatologists when assessing patients presenting to a clinic and may represent underlying intra-articular inflammatory pathology or involvement of the surrounding soft tissues. This study describes the correlation between clinical and ultrasound findings in patients presenting with a variety of rheumatic disorders and knee pain. US imaging provides for a sensitive and detailed identification of different intra- and peri-articular pathology responsible for knee pain.

Musculoskeletal ultrasound in the diagnosis of rheumatic disease

The use of musculoskeletal ultrasound (MSKUS) in rheumatology practice and research has increased steadily over the last decade. An ever-growing body of literature shows parity and even superiority of MSKUS when compared to physical examination, plain radiography, and more expensive and static imaging modalities such as MRI. While many use the modality for procedure guidance, investigators continue to demonstrate its ability to impact diagnoses in a variety of rheumatic diseases. Initial efforts focused on establishing MSKUS as a helpful tool for rheumatoid arthritis (RA), especially in the detection of synovitis and joint erosions, but numerous studies are validating the use of MSKUS as a helpful diagnostic tool for the spondyloarthropathies, crystal diseases, osteoarthritis, and other rheumatic diseases. Advances in ultrasound technology are translating into more sensitive and accurate studies. Within the research community, current efforts aim at maximizing the direct clinical impact of MSKUS by developing global or patient level assessments and simplified joint scoring systems, with improvements in intra- and inter-reader reproducibility.

[Modern ultrasonographic techniques for the study of the synovial membrane in rheumatic diseases]

In recent years ultrasonography has become one of basic imaging techniques used by radiologists, orthopedists, and rheumatologists for the study of the musculoskeletal system, particularly in patients with rheumatic diseases. This position of ultrasonography is the result of rapid technical advances. Contemporary ultrasound scanners have little in common with those used when ultrasonography was introduced into medicine. Modern ultrasound scanners offer additional options like tissue harmonic imaging, power color Doppler, volumetric ultrasonography (3D/4D imaging), and contrast-enhanced ultrasonography. Moreover, image resolution during examination has significantly been improved thanks to high-resolution transducers and software for image analysis. This article discusses modern ultrasonographic techniques and their use.

[Imaging techniques in rheumatology: PET in rheumatology]

Positron emission tomography (PET) using F-18-fluoro-deoxyglucose (FDG) is suitable for many indications in oncology and can also be used in rheumatology to search for inflammatory foci and benign lesions with increased glucose metabolism in, for example soft tissue and joints (arthritis, vasculitis etc.) and fever of unknown origin. Usually a whole-body scanning technique is used for data acquisition in the search for foci of unknown localization or for the characterization of glucose metabolism of one or more known lesions - also for observation of the effect of, for example pharmacotherapy. Patients are admitted under fasting conditions and acquisition starts 1 h after i.v. injection of FDG with an acquisition time of 30-60 min. The method is sensitive and can measure glucose metabolism in an objective manner, but is not specific for inflammatory diseases (FDG also accumulates in malignant diseases).

Association of ultrasonographic findings of synovitis with anti-cyclic citrullinated Peptide antibodies and rheumatoid factor in patients with palindromic rheumatism during active episodes

OBJECTIVE

The purpose of this study was to investigate whether the presence of ultrasonographic findings of synovitis is associated with the presence of anti-cyclic citrullinated peptide (CCP) antibodies and rheumatoid factor (RF) in patients with palindromic rheumatism (PR) during active episodes.

METHODS

Clinically involved regions of 84 patients with PR during active episodes were examined with high-resolution ultrasonography. Serum levels of anti-CCP antibodies were determined by an enzyme-linked immunosorbent assay, and RF levels were measured by nephelometry.

RESULTS

Thirty patients (36%) had ultrasonographic findings of synovitis during active episodes. Significantly higher positive rates of anti-CCP antibodies and RF were observed in patients with PR who had ultrasonographic findings of synovitis compared with those who had no ultrasonographic findings of synovitis (26.7% versus 5.6%; odds ratio, 6.18; P < .05; and 30.0% versus 5.6%; odds ratio, 7.29; P < .01, respectively). The intraobserver and interobserver agreement for the detection of synovitis and Doppler signals by ultrasonographic assessment was excellent.

CONCLUSIONS

Ultrasonography is a reliable method for assessing the presence of synovitis in patients with PR during active episodes. The ultrasonographic findings of synovitis are associated with the presence of anti-CCP antibodies and RF in patients with PR.

Survey of the enthesopathy of X-linked hypophosphatemia and its characterization in Hyp mice

X-linked hypophosphatemia (XLH) is characterized by rickets and osteomalacia as a result of an inactivating mutation of the PHEX (phosphate-regulating gene with homology to endopeptidases on the X chromosome) gene. PHEX encodes an endopeptidase that, when inactivated, results in elevated circulating levels of FGF-23, a novel phosphate-regulating hormone (a phosphatonin), thereby resulting in increased phosphate excretion and impaired bone mineralization. A generalized and severe mineralizing enthesopathy in patients with XLH was first reported in 1985; we likewise report a survey in which we found evidence of enthesopathy in fibrocartilaginous insertion sites, as well as osteophyte formation, in the majority of patients. Nonetheless, there has been very little focus on the progression and pathogenesis underlying the paradoxical heterotopic calcification of tendon and ligament insertion sites. Such studies have been hampered by lack of a model of mineralizing enthesopathy. We therefore characterized the involvement of the most frequently targeted fibrocartilaginous tendon insertion sites in Hyp mice, a murine model of the XLH mutation that phenocopies the human syndrome in every detail including hypophosphatemia and elevated FGF-23. Histological examination of the affected entheses revealed that mineralizing insertion sites, while thought to involve bone spur formation, were not due to bone-forming osteoblasts but instead to a significant expansion of mineralizing fibrocartilage. Our finding that enthesis fibrocartilage cells specifically express fibroblast growth factor receptor 3 (FGFR3)/Klotho suggests that the high circulating levels of FGF-23, characteristic of XLH and Hyp mice, may be part of the biochemical milieu that underlies the expansion of mineralizing enthesis fibrocartilage.

Dactylitis, a term for different digit diseases

Dorland's Illustrated Medical Dictionary gives the following definition of dactylitis (deltaalphachitauupsilonlambdaomicronsigma = digit): 'inflammation of a finger or toe'. Although any inflammatory process involving the fingers or toes may be called dactylitis, the term has entered in current use only in some well-defined entities. These differ in the involved tissue of the digit and in the type of involvement. Tuberculous dactylitis is the variant of tuberculous osteomyelitis affecting the short tubular bone of the hands and feet. Radiographs typically show a central, lytic, cystic, and expansive lesion known as spina ventosa. Syphilitic dactylitis is a manifestation of congenital syphilis. Radiological findings mimic those of tuberculous dactylitis but the involvement is bilateral and symmetric. Sarcoid dactylitis is due to typical non-caseating granulomas invading the phalanges and the adjacent soft tissue. Blistering distal dactylitis is an infection of the anterior fat pad on the volar surface of the distal portion of a single finger or more rarely a toe, mostly caused by group A beta-haemolytic streptococci. Sickle cell dactylitis, also known as 'hand-foot syndrome', is due to localized bone marrow infarction of the carpal and tarsal bones and phalanges. Spondyloarthritis dactylitis, also called 'sausage-like' digit, is a diffuse painful swelling of the fingers and toes. Recent ultrasonography (US) and magnetic resonance imaging (MRI) studies on both finger and toe dactylitis have established that dactylitis is due to flexor tenosynovitis and that the enlargement of the joint capsule is not an indispensable condition for the 'sausage-like' feature. There is no evidence of enthesitis of flexor digitorum tendons and joint capsule.

Inflammation of unknown origin versus fever of unknown origin: two of a kind

OBJECTIVES

A vast literature exists on fever of unknown origin (FUO), characterized by prolonged and perplexing fevers >38.3 degrees C. In contrast, no studies are available to guide the approach to inflammation of unknown origin (IUO), defined as prolonged and perplexing inflammation with temperatures <38.3 degrees C. We aimed to determine the diagnostic yield, the case-mix, and the outcome of patients with IUO, relative to patients with FUO.

METHODS

We matched 57 patients with IUO to 57 patients with FUO of the same gender (54% male) and a similar age (median: 67 years).

RESULTS

A diagnosis was established in 35 patients with IUO (61%) and in 33 patients with FUO (58%) (p=.70). The case-mix did not differ significantly (p=.43). Non-infectious inflammatory disorders were the dominant diagnostic category in the IUO group (16 patients), while in the FUO group, similar numbers of malignancies [10], infections [9], and non-infectious inflammatory diseases [9] were diagnosed. (18)F-fluorodeoxyglucose-positron emission tomography (FDG-PET) scan contributed comparably to the diagnosis in both groups (in 18 of 50, 36%, patients with IUO and in 13 of 40, 33%, patients with FUO) (p=.83). In both groups, 7 patients (12%) died during an average follow-up of 1 year.

CONCLUSION

Diagnostic yield, case-mix, contribution of FDG-PET scan and vital outcome were similar in patients with IUO and FUO. These data suggest that the 38.3 degrees C boundary may be arbitrary and that the diagnostic approaches used in FUO can be applied to IUO.

Imaging of sternocostoclavicular joint in spondyloarthropaties and other rheumatic conditions

OBJECTIVE

To retrospectively evaluate the role of the various imaging techniques in the study of the sternocostoclavicular joint, in patients with spondyloarthropathies and other rheumatic conditions and to assess potential pitfalls in the radiological diagnosis.

SUBJECTS AND METHODS

Thirty patients, 11 male and 19 female, mean age 45 years, with involvement of the sternocostoclavicular joint as part of rheumatologic disorders (psoriatic arthritis, ankylosing spondylitis, Tietze syndrome, SAPHO syndrome, and condensing osteitis of the clavicle) were studied. Conventional radiography, CT, MRI and bone scintigraphy were performed. The following imaging findings were evaluated: soft tissue swelling, bone sclerosis, cortical bone erosions, joint space narrowing, subchondral sclerosis, periosteal new bone formation, synovial reaction and intrarticular effusion. All the images were independently reviewed by two musculoskeletal radiologists.

RESULTS

Conventional radiography demonstrated only sclerosis of the clavicula in 8 pts (26%) and the sternum in 3 pts (10%), cortical bone erosions in 7 pts (23%), joint space narrowing in 6 pts (23%) and periosteal bone formation in 2 pts (10%). At the CT examination sclerosis of the clavicula and the sternum was observed in 13 pts (44%), cortical bone erosions in 22 pts (76%), joint space narrowing in 10 pts (34%), ligament ossification in 12 pts (41%), subchondral sclerosis in 9 pts (34%) and periosteal bone formation in 10 pts (34%). The MRI was the most sensitive technique in the evaluation of the soft tissue swelling in 9 pts (56%), intrarticular effusion in 13 pts (81%) and synovial reaction in 13 pts (81%). Finally, bone scintigraphy showed an increased uptake at the sterno-costoclavicular joint in all patients who underwent the examination.

CONCLUSION

The radiological evaluation of the anterior chest wall in patients with different rheumatic disorders represents a problem of difficult diagnostic evaluation both for the anatomic region complexity and for the variability of the radiographic findings. The integrated use of X-ray, CT, MRI and nuclear medicine is suggested to avoid misdiagnosis.

[Musculoskeletal ultrasonography in rheumatology]

AIMS

To evaluate the evolution of musculoskeletal ultrasonography and its role in rheumatological practice by comparing recent casuistics of the ultrasonography exams performed at the Rheumatology Department of University Hospital La Paz -Madrid with the exams performed before 2003.

MATERIAL AND METHODS

Revision of the ultrasonographies made between January 2007 and June 2008 and comparison with the exams performed between 1998 and 2003.

RESULTS

In the recent casuistics, that included 1,000 exams, anatomic ultrasonography represents 45.9% in contrast to 100% of the ultrasonographies preformed before 2003. The indication for the remaining 54.1% were: diagnosis of arthritis 16.3%, evaluation of inflammatory activity 6.8%, evaluation of enthesis 6.3%, study of temporal arteries 12.5% (9.7% for suspected temporal arteritis and 2.8% for disease monitoring); differential diagnosis of gout or chondrocalcinosis 2.2%, diagnosis of sacroiliitis 1.2%, diagnosis of carpal tunnel syndrome 1.5% and sonographic-guided procedures 7,3%.

CONCLUSIONS

At the present time, the anatomic ultrasonography represents 45.9% of all ultrasonographies in contrast to what happened before 2003. Technological advances and the progress in science promote the evolution of ultrasonography from an anatomical imaging tool to a more clinical, diagnostic, monitoring and therapeutic profile.

What the practising rheumatologist needs to know about the technical fundamentals of ultrasonography

A transducer generates ultrasound waves and emits them into the body. Boundaries in or between tissues reflect the waves, and the transducer receives the reflected waves. A computer converts the information into images that are displayed on a monitor. Image resolution is greater with higher frequencies, and penetration is greater with lower frequencies. Linear probes with frequencies between 5 and 20 MHz are mainly used for musculoskeletal ultrasound. Image quality and resolution have improved significantly. Tissue harmonic imaging and cross-beam technology aid in differentiating between anatomical structures, although borders appear artificially thickened. Three-dimensional ultrasound provides additional coronary planes, and contrast agents increase the sensitivity for synovial blood flow in inflamed joints. This chapter provides further information regarding which ultrasound technology is the best for purchase by a rheumatology unit, how to organize ultrasound clinics, and how best to perform ultrasonography in daily practice, including the most important indications for ultrasound in rheumatology.

[Diagnostic imaging in assessment of rheumatic diseases]

Rheumatic diseases represent one of the most common health problems for which patients visit the doctor. This fact imposes the need for verification of clinical symptoms and clear presentation ofpathomorphyology changes primarily because of the best methods of treatment selection. A wide range of diagnostic imaging modalities are available today: conventional radiography, conventional myelography, computed tomography (CT), CT myelography, magnetic resonance imaging (MRI), MR or CT artrography, spinal cord angiography, ultrasound and scintigraphy, and combined radiological methods and scintigraphy (PET-CT). Each of the above methods has its own importance, advantages and limitations. Sometimes a method excludes the other, and often support each another in setting the final diagnosis. For the proper choice of radiological imaging methods that will give us insight into the problem, a good knowledge of their capabilities, and a clear clinical inquiry are necessary. But most of all, good cooperation of clinicians and radiologists who should be diagnostic team responsible for that sets the indication for radiological examination is essential.

Ultrasound in rheumatology. The Mexican experience

Over the last few years, a growing number of rheumatologists has taken great interest in ultrasonography for its well known advantages and wide spectrum of validated applications in daily rheumatological practice. Most rheumatologists actively performing ultrasonography have had a training experience mainly based on attendance in sonographic courses and/or in radiological or rheumatological units. At present, in Mexico ultrasonography has a still limited diffusion among rheumatologists even if it may play a key role as a first line imaging technique also because of the restricted availability for rheumatic patients for other imaging modalities. This report describes the Mexican experience in education and training on musculoskeletal ultrasound. In 2003, the Mexican School of Musculoskeletal Ultrasound of the Mexican College of Rheumatology (ECOMER) was founded with the intention of joining efforts to launch musculoskeletal ultrasound in Mexico. Essential requirements shared by all the members of ECOMER include: to own an ultrasound machine, to incorporate ultrasonography into clinical daily practice and to keep up-to-date in musculoskeletal ultrasound. The motto of ECOMER is una clara imagen de la reumatologia which means a clear picture of rheumatology. The statute of ECOMER can be read in its web site: www.ecomer.org.mx. This web site also provides a forum for case discussion, consultation and image review.

Ultrasound imaging for the rheumatologist. XVII. Role of colour Doppler and power Doppler

The use of Doppler ultrasound in rheumatology has grown in recent years. This is partly due to the increasing number of rheumatologists who perform US in their daily clinical practise and also to the technological advances of US systems. Both colour Doppler and power Doppler are used to evaluate the degree of intra- and peri-articular soft tissue inflammation. Moreover, Doppler US has been found to be of help in the assessment of vascular pathologies such as the vasculitides. In this review we provide an update of the data regarding the use of colour Doppler and power Doppler in rheumatology.

Ultrasound of target joints for the evaluation of possible inflammatory arthropathy: associated clinical factors and diagnostic accuracy

OBJECTIVE

To examine the clinical features associated with an ultrasound (US) diagnosis of synovitis and/or erosions in patients suspected of inflammatory arthritis, and the factors associated with this evolution in patients with a normal initial US.

PATIENTS AND METHODS

Cross-sectional: the records of 144 patients who underwent US for suspected inflammatory arthropathy were categorized into synovitis and/or erosions present or not. Longitudinal: of 58 patients without synovitis and/or erosions, 30 could be located and 19 agreed to be studied (two were asymptomatic and refused, nine could not be reached).

ANALYSES

univariable descriptive analyses were performed. Age, gender, variables significant (p<0.05) in the univariable analyses, and those clinically relevant were examined by logistic regression for the cross-sectional study. The metric properties of US compared to overall clinical assessment were also examined.

RESULTS

Age, gender, ethnicity and symptoms' duration were comparable in patients with and without synovitis and/or erosions. Wrist swelling (history) and the number of swollen wrist/hand joints were associated with synovitis and/or erosions by US; morning stiffness, sicca symptoms and low back pain were negatively associated with synovitis and/or erosions. Four patients evolved into an inflammatory arthropathy but no features distinguished them from those who did not evolve into an inflammatory arthropathy. The sensitivity, specificity, and overall accuracy of US, compared to the clinical assessment were 98.9%, 94.1% and 98.1%, respectively.

CONCLUSIONS

US is an adequate tool for the assessment of inflammatory arthropathy; however, patients with a single negative US at initial clinical presentation still need to be followed for the eventual development of an overt arthropathy.

Ultrasound imaging for the rheumatologist. XVI. Ultrasound-guided procedures

Ultrasonography (US) has proved to be a useful tool for the clinical evaluation of patients with rheumatic diseases. It is also recognised as a useful imaging technique in interventional radiology. In the last few years, a number of rheumatologists have also described and advocated the use of US guidance in joint and soft tissue aspiration and injection technique in clinical practice. Moreover, US-guided synovial biopsy methods have been proposed as an interesting and reliable method for the histopathological assessment of small and large joint sinovium. The present review provides an update of the available data regarding the use of US in interventional procedures in clinical rheumatology.

Ultrasound imaging for the rheumatologist. XV. Ultrasound imaging in vasculitis

Over the last few years, a large number of studies have emphasized the fundamental role of ultrasonography (US) in the clinical evaluation of patients affected by rheumatic disorders. However, not all rheumatic diseases have been studied by US. To date, very few reports exist on the use of US in the assessment of articular, periarticular structures and blood vessels in vasculitis. In this review we provide an overview of the current data regarding the role of US in vasculitis. Sonographic evaluation of cardiac or renal involvement in these disorders will not be covered.

Ultrasound imaging for the rheumatologist XIV. Ultrasound imaging in connective tissue diseases

Ultrasound (US) role is becoming more and more relevant in the assessment of rheumatic diseases but there are still some almost unexplored fields and, surely, one of these is represented by the great family of connective tissue diseases (CTD). In this review we provide an update of the available data regarding some applications of US in CTD. Besides an overview of the role of US in their musculoskeletal involvement, we will report data on the use of US in the evaluation of skin and lung in systemic sclerosis and of salivary glands in Sjögren's syndrome. US assessment of heart, kidney or vascular involvement in CTD will not be the subjects of this paper.

Diagnostic sensitivity and specificity of Doppler ultrasound in rheumatoid arthritis

OBJECTIVE

To evaluate the sensitivity and specificity of Doppler ultrasound (DUS) in diagnosing arthritis in the wrist and hands, and, if possible, to define a cutoff level for our ultrasound measures for inflammation, resistive index (RI), and color fraction.

METHODS

Using DUS, 88 patients with active RA were selected for study and 27 healthy controls. A total of 419 joints were examined. The synovial vascularization was determined by color Doppler and spectral Doppler estimating the color fraction (the percentage of color pixels inside the synovium was the region of interest) and RI in wrist, metacarpophalangeal (MCP), and proximal interphalangeal (PIP) joints. Receiver-operator characteristic (ROC) curves were made for both US measures. Cutoff levels were selected from the ROC curves as the values with the optimum sensitivity and specificity.

RESULTS

Analyses were carried out for small joints (MCP and PIP), wrists, and for all joints (pooled). Pooled joint analysis showed the area under the curve for both RI and color fraction was 0.84. The cutoff level for the color fraction was 0.01 and for RI 0.83. With these cutoff levels, the sensitivity and specificity for the color fraction were 0.92 and 0.73, respectively. For RI a sensitivity of 0.72 and specificity of 0.70 were found. Analysis of small joints and wrist gave very similar results.

CONCLUSION

DUS may detect vascularization of the inflamed synovium with a high sensitivity and a moderate specificity with selected cutoff levels.

Lower limb enthesopathy in patients with psoriasis without clinical signs of arthropathy: a hospital-based case-control study

BACKGROUND

Psoriasis is associated with a form of spondyloarthropathy in 10-30% of cases. A major feature of psoriatic arthritis is enthesitis. In some patients with psoriasis the presence of enthesitis could be underdiagnosed.

OBJECTIVE

To investigate the presence of lower limbs entheseal abnormalities in patients with chronic plaque psoriasis without signs and symptoms of psoriatic arthritis.

METHODS

Thirty patients with psoriasis and 30 controls underwent ultrasonographic evaluation of Achilles, quadriceps, patellar entheses and plantar aponeurosis. Ultrasonographic findings were scored according to the Glasgow Ultrasound Enthesitis Scoring System (GUESS).

RESULTS

Mean GUESS score was significantly higher in patients with psoriasis as compared with controls: 7.9 (0.6) vs 2.9 (0.3); p<0.0001. In particular, the thickness of all tendons examined was significant higher in cases than in controls (p<0.0001), as well as the number of enthesophytes in all sites examined. In both cases and controls, the GUESS score was directly correlated with age (r = 0.22; p = 0.008), body mass index (r = 0.23, p = 0.0067) and waist circumference (r = 0.17; p = 0.02). In contrast, the GUESS score was not correlated with the duration and severity of psoriasis according to the Psoriasis Area and Severity Index (r = 0.03; p = 0.8) and body surface area involvement (r = 0.07; p = 0.6).

CONCLUSIONS

Entheseal abnormalities can be documented by ultrasonography in clinically asymptomatic patients with psoriasis. These findings could be related to a subclinical entheseal psoriatic inflammation. We suggest close follow-up of patients with psoriasis with entheseal abnormalities for early diagnosis of psoriatic arthritis.

Quantitative measures of rheumatic diseases for clinical research versus standard clinical care: differences, advantages and limitations

No single measure can serve as a 'gold standard' for the diagnosis, prognosis, and monitoring of patients with rheumatic diseases. Therefore, pooled indices of several measures have been developed for patient assessment. Quantitative measures and indices in rheumatology have been used primarily in clinical trials and other clinical research, but not in standard clinical care. Indeed, most standard rheumatology care is conducted without quantitative data other than laboratory tests, which often are uninformative. Some measures used in research have been adapted for standard care. The classical 66/68-joint count with graded scoring for swelling, tenderness, pain on motion, limited motion, and deformity has been shortened for clinical care to a 28-joint count, scored only as 'Yes' or 'No' for swelling or tenderness. Patient questionnaires designed for clinical research can be lengthy, with complex scoring, so that information is not available to help guide clinical decisions. By contrast, patient questionnaires designed for standard care, such as a simple one-page, multi-dimensional health assessment questionnaire (MDHAQ), are short, save time, are easily scored, and are useful in all rheumatic diseases to monitor patient status at each visit and document changes over long periods. More attention to measures for use in standard care could improve care and outcomes for patients with rheumatic diseases.