Doppler sonography in rheumatology

The role of ultrasound in the diagnosis of temporal arteritis

Temporal arteritis (TA), also known as giant cell arteritis, is a chronic vasculitis of medium and large-sized blood vessels, in particular the main cervical branches of the aorta, with particular affinity to the temporal arteries and eye-supplying arteries. Temporal artery biopsy is still a gold standard for diagnosis, however in recent years colour duplex ultrasound examination has been proposed as a useful diagnostic screening tool in cases of TA suspicion. We report three cases of TA in which the ultrasonographical examination of the temporal arteries had a decisive role in the diagnosis.

Is there subclinical synovitis in early psoriatic arthritis? A clinical comparison with gray-scale and power Doppler ultrasound

OBJECTIVE

Arthritis activity assessments in psoriatic arthritis (PsA) have traditionally relied on tender and swollen joint counts, but in rheumatoid arthritis, multiple studies have demonstrated subclinical inflammation using modern imaging. The aim of this study was to compare clinical examination and ultrasound (US) findings in an early PsA cohort.

METHODS

Forty-nine disease-modifying antirheumatic drug-naive patients with recent-onset PsA (median disease duration 10 months) underwent gray-scale (GS) and power Doppler (PD) US of 40 joints plus tender and swollen joint counts of 68/66 joints. GS and PD were scored on a 0-3 semiquantitative scale for each joint. Clinically active joints were defined as tender and/or swollen and US active joints were defined as a GS score ≥2 and/or a PD score ≥1.

RESULTS

The most common sites for subclinical synovitis were the wrist (30.6%), knee (21.4%), metatarsophalangeal (MTP) joints (26.5-33.7%), and metacarpophalangeal joints (10.2-19.4%). Excluding MTP joints and ankles, 37 (75.5%) of 49 patients had subclinical synovitis with a median of 3 (interquartile range [IQR] 1-4) joints involved. In contrast, clinical overestimation of synovitis occurred most commonly at the shoulder (38%) and ankle (28.6%). Twelve of 49 patients were classified clinically as having oligoarthritis; of these, subclinical synovitis identified 8 (75%) as having polyarthritis with an increase in their median joint count from 3 (IQR 1-4) to 6 (IQR 5-7).

CONCLUSION

This study has demonstrated that subclinical synovitis, as identified by US, is very common in early PsA and led to the majority of oligoarthritis patients being reclassified as having polyarthritis. Further research is required into the relationship of such subclinical synovitis to structural progression.

Scanning of the Sacroiliac Joint and Entheses by Color Doppler Ultrasonography in Patients with Ankylosing Spondylitis

Objective.

To assess Doppler ultrasonography by comparing its detection of sacroiliitis with detection of enthesitis in patients with ankylosing spondylitis (AS).

Methods.

One hundred sixty-one patients with AS (according to modified New York criteria or Spondyloarthritis International Society classification criteria for axial spondyloarthritis) underwent ultrasonography (US) of the sacroiliac joint (SIJ) and major entheses of the lower limbs. Vascularization of the SIJ and morphologic changes and vascularization of entheses were observed. The resistive index of the SIJ was measured. Doppler ultrasonography examination was repeated in 20 patients by another ultrasonographer.

Results.

In the AS active group [Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) ≥ 4], 90.7% of SIJ showed vascularization; this was significantly more than in the inactive group (38.5%). The resistive index of the active group in the SIJ area was significantly lower than that of the inactive group. Doppler US scanning of the SIJ was more sensitive (92.0%) than that of the entheses (52.2%). Agreement of Doppler US scanning of the SIJ and BASDAI was good, while agreement of the entheses and BASDAI was poor.

Conclusion.

Lower resistive index value and vascularization in the SIJ had good agreement with AS activity. Doppler US is more sensitive in detecting sacroiliitis than in detecting enthesitis.

Comparison of clinical and ultrasonographic evaluations for peripheral synovitis in juvenile idiopathic arthritis

OBJECTIVES

The characteristics of synovitis in juvenile idiopathic arthritis (JIA) are important to evaluate, as they define several clinical categories. The metacarpophalangeal (MCP) and metatarsophalangeal (MTP) joints are frequently involved. Few studies have investigated peripheral joint evaluation using ultrasonography, a sensitive tool for detecting subclinical synovitis. Our objectives here were to compare clinical and ultrasound evaluations of MCP and MTP joint synovitis and to determine the prevalence of predefined ultrasound abnormalities in JIA patients and healthy controls.

METHODS

Standardized physical and ultrasound assessments of the same joints were done in 31 consecutive patients with JIA and 41 healthy volunteers. Joint pain, motion limitation, and swelling were recorded. Ultrasonography was performed on the same joints by 2 trained sonographers who recorded synovial fluid, synovial hypertrophy, erosion, and power Doppler signal. Intraobserver reproducibility of ultrasonography was assessed.

RESULTS

Of 558 peripheral joints examined in JIA patients, 69 (12.5%) had ultrasonographic synovitis and 83 (15%) had abnormal physical findings. All the physical abnormalities were significantly associated with ultrasonographic synovitis (P < 0.0001) but agreement was low between ultrasonographic and physical findings. Ultrasonographic synovitis was most common at the feet (59.4%), where it was detected clinically in only 25% of cases. Ultrasonographic synovitis was associated with the presence of synovial fluid. Cartilage vascularization was found in 2 (4.2%) healthy controls.

CONCLUSION

Ultrasonography is useful for monitoring synovitis in JIA. Subclinical involvement of the MTP joints is common. Clinicians should be aware of the specific ultrasonographic findings in children.

Temporal arteritis: an approach to suspected vasculitides

Temporal arteritis, also known as giant cell arteritis, is the most common vasculitis in adults. Classic symptoms include polymyalgia rheumatica, new-onset headache, jaw claudication, and visual symptoms such as diplopia and amaurosis fugax. Elevated erythrocyte sedimentation rate is a common laboratory finding in temporal arteritis, and abnormalities on temporal artery biopsy are the gold standard for diagnosis. Rapid treatment with steroids can prevent permanent vision loss, which is the worst ischemic complication of the disease. It is important for primary care physicians to be able to recognize the signs and symptoms of this disease and begin treatment rapidly.

Imaging of giant cell tumour of the tendon sheath

Giant cell tumours of the tendon sheath (GCTTS) and pigmented villonodular synovitis (PVNS) are part of a spectrum of benign proliferative lesions of synovial origin that may affect the joints, bursae and tendon sheaths. This review article describes the clinicopathological features and imaging findings in patients with GCTTS. GCTTS usually presents as a soft tissue mass with pressure erosion of the underlying bone. Magnetic resonance (MR) imaging of GCTTS typically shows low to intermediate signal on T1- and T2-weighted spin-echo sequences due to the presence of haemosiderin, which exerts a paramagnetic effect. On gradient-echo sequences, the paramagnetic effect of haemosiderin is further exaggerated, resulting in areas of very low signal due to the blooming artefact. Ultrasonography shows a soft mass related to the tendon sheath that is hypervascular on colour or power Doppler imaging.

[Color Doppler sonography for investigation of peripheral joints and ligaments]

Doppler ultrasound is able to visualize blood flow by the change in frequency (Doppler shift) of sound waves which are reflected by moving blood cells inside the vessels (Doppler effect). As hyperemia caused by vasodilatation and angiogenesis is the earliest detectable pathologic change in the beginning of synovitis, Doppler ultrasonography can be used to assess inflammatory activity. Several studies could show a strong correlation between magnetic resonance imaging (MRI) as well as histological findings (blood vessel density) and Doppler sonographic determination of synovial perfusion. Equipment settings must be adapted to slow blood flow in very small blood vessels to reach an appropriate imaging quality. Color and power Doppler ultrasound can depict different grades of intra-articular and peritendinous blood flow, which allows an estimation of inflammatory activity and facilitates the differentiation and monitoring of rheumatic diseases during follow up.

MRI in juvenile idiopathic arthritis and juvenile dermatomyositis

The use of MRI in the assessment of the musculoskeletal system in children has important differences from its use in adults. Growth in children has significant impact on the epiphysis and growth plate, which are important structures in the growing child, and there are radiological features that differ from those in adults: disease may alter structures during a period of growth; the pathologies themselves are a distinct group of diseases at variance with adult arthritis and myositis, with a different spectrum of differential diagnoses; and many technical issues are different when imaging a child. These are important considerations in choosing the appropriate imaging. MRI is a powerful and valuable imaging technique in pediatric musculoskeletal pathologies, with considerable potential for future developments to enhance its role in diagnosis, management, and therapeutic intervention for these children.

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.

[Imaging procedures in rheumatology: imaging in vasculitis]

In small vessel vasculitides, imaging studies aid in determining disease extent and activity, localization for biopsy, and for disease monitoring. They do not directly delineate the vasculitic lesion. Imaging studies focus on the upper and lower respiratory tract. Cranial magnetic resonance imaging (MRI) shows upper respiratory and retrobulbar granuloma in Wegener's granulomatosis. Furthermore, MRI depicts both mastoiditis and mucosal inflammation of the ear, nose, and throat. It is sensitive but not specific for the detection of cerebral vasculitis. Computed tomography (CT) reliably detects osseous facial lesions. Chest radiography in two planes remains the standard method of investigation for the lower respiratory tract. High-resolution CT aids in detecting further interstitial pathologies. Medium-sized vasculitides frequently occur with aneurysms. The classification criteria for polyarteritis nodosa involve the angiographic detection of visceral aneurysms. Patients with Kawasaki disease may develop coronary aneurysms that may be described by echocardiography or angiography according to diagnostic criteria. In large-vessel vasculitides such as temporal arteritis (giant cell arteritis) and Takayasu arteritis, MRI, MR-angiography, CT, CT-angiography, and duplex sonography delineate characteristic homogenous wall thickening with or without stenoses in the aorta and other arteries. There is a high correlation with angiography and positron emission tomography. Duplex sonography of the temporal arteries has a high sensitivity and specificity for the diagnosis. Data on temporal artery MRI in giant cell arteritis have recently been published.

Are bone erosions detected by magnetic resonance imaging and ultrasonography true erosions? A comparison with computed tomography in rheumatoid arthritis metacarpophalangeal joints

The objective of the study was, with multidetector computed tomography (CT) as the reference method, to determine whether bone erosions in rheumatoid arthritis (RA) metacarpophalangeal (MCP) joints detected with magnetic resonance imaging (MRI) and ultrasonography (US), but not with radiography, represent true erosive changes. We included 17 RA patients with at least one, previously detected, radiographically invisible MCP joint MRI erosion, and four healthy control individuals. They all underwent CT, MRI, US and radiography of the 2nd to 5th MCP joints of one hand on the same day. Each imaging modality was evaluated for the presence of bone erosions in each MCP joint quadrant. In total, 336 quadrants were examined. The sensitivity, specificity and accuracy, respectively, for detecting bone erosions (with CT as the reference method) were 19%, 100% and 81% for radiography; 68%, 96% and 89% for MRI; and 42%, 91% and 80% for US. When the 16 quadrants with radiographic erosions were excluded from the analysis, similar values for MRI (65%, 96% and 90%) and US (30%, 92% and 80%) were obtained. CT and MRI detected at least one erosion in all patients but none in control individuals. US detected at least one erosion in 15 patients, however, erosion-like changes were seen on US in all control individuals. Nine patients had no erosions on radiography. In conclusion, with CT as the reference method, MRI and US exhibited high specificities (96% and 91%, respectively) in detecting bone erosions in RA MCP joints, even in the radiographically non-erosive joints (96% and 92%). The moderate sensitivities indicate that even more erosions than are seen on MRI and, particularly, US are present. Radiography exhibited high specificity (100%) but low sensitivity (19%). The present study strongly indicates that bone erosions, detected with MRI and US in RA patients, represent a loss of calcified tissue with cortical destruction, and therefore can be considered true bone erosions.

Technology Insight: the role of color and power Doppler ultrasonography in rheumatology

An increasing number of rheumatologists have access to ultrasound equipment that provide both color and power Doppler modes, which can be used to investigate musculoskeletal and vascular pathologies. Musculoskeletal Doppler ultrasonography can be used to estimate levels of inflammation, to document the anti-inflammatory effect of agents such as corticosteroids and tumor necrosis factor inhibitors, to differentiate between inflammatory and degenerative disease, and to distinguish between normal and inflamed joints in cases of minor synovial swelling. Vascular Doppler ultrasonography can be used to determine organ involvement in small-vessel vasculitides, to delineate aneurysms in vasculitides of medium-sized arteries, and to assess the characteristic findings in large-vessel vasculitis. Numerous studies, including a meta-analysis, have been published on the use of temporal-artery ultrasonography for the diagnosis of giant cell arteritis. Duplex ultrasonography is a sensitive approach for detecting characteristic edematous wall swellings in active temporal arteritis and for assessing vasculitis of the axillary arteries (large-vessel giant cell arteritis) in patients with suspected temporal arteritis, polymyalgia rheumatica, or fever of unknown origin. Duplex ultrasonography can also be used to assess vasculitis of subclavian and carotid arteries in younger patients with Takayasu's arteritis and acute finger artery occlusions in patients with small-vessel vasculitides.

Assessment of enthesitis in ankylosing spondylitis by power Doppler ultrasonography

OBJECTIVE

To evaluate the relationship between power Doppler ultrasonography (PDUS) assessment and clinical variables including enthesitis index, pain threshold and disease activity parameters, and to document grey-scale US findings of the 13 entheses examined.

DESIGN AND PATIENTS

A total of 390 entheses were examined in thirty patients with AS, and clinical variables of the Maastricht Ankylosing Spondylitis Enthesitis Index (MASES), anthropometric measurements, disease activity and functional parameters were documented. A total MASES score by palpation (t-PS) and algometric pressure pain threshold (t-PPT) was obtained. Grey scale and PDUS examination of 13 entheses were performed. Grey-scale changes such as altered tendon echogenity, calcification, cortical reactive changes and bursitis were noted, and flow on PDUS was graded semi-quantitatively.

RESULTS

Cumulative power Doppler (t-PDS) score significantly correlated with t-PS and t-PPT. Ultimate correlations were found between power Doppler scores and pain, disease activity and disability parameters. Changes in grey scale combined with PDUS were more prevalent in lower-extremity entheses. The intraobserver agreement of flow signal grading was excellent (kappa = 0.82). Clinical and sonographic results were concordant for three regions, but were discordant for four regions where tenderness was accepted as the sole clinical manifestation of enthesis.

CONCLUSION

Pain or tenderness is associated with increased vascularity of entheses. Power Doppler US examination of the entheses may be useful and complementary to the clinical evaluation, and further research is needed to assess its role in diagnosis and follow-up of disease course.

Colour duplex sonography of finger arteries in vasculitis and in systemic sclerosis

CASE REPORTS

Three patients-two with Wegener's granulomatosis and one with an overlap syndrome of rheumatoid vasculitis, systemic lupus erythematosus, and antiphospholipid syndrome-are described. All patients experienced a sudden onset of Raynaud's phenomenon or acrocyanosis when they had a flare of their disease.

DISCUSSION

Ultrasonography (US) showed dark (hypoechoic) arteries without colour signals, resembling the US pattern of embolism. In contrast, US in patients with systemic sclerosis is entirely different, delineating a smaller artery lumen, reduced pulsation, and thickened, slightly hyperechoic artery walls.

MRI and musculoskeletal ultrasonography as diagnostic tools in early arthritis

Rheumatoid arthritis (RA) is a chronic and progressive inflammatory disorder primarily affecting the synovium and is characterized by destruction of bone and cartilage. Early diagnosis and treatment of RA can improve disease outcomes substantially. Magnetic resonance imaging and musculoskeletal ultrasonography may facilitate early diagnosis and aid the targeting of intensive therapy. Magnetic resonance imaging and musculoskeletal ultrasonography also are able to monitor temporal changes in disease activity (ie, synovitis) and damage (ie, erosions). These imaging modalities are likely to be increasingly used in the management of early rheumatoid arthritis to ensure the best patient outcomes, although more work is required to determine their optimal roles.

What is the best approach to diagnosing large-vessel vasculitis?

Temporal arteritis, including large-vessel giant cell arteritis, and Takayasu's arteritis are the two primary large-vessel vasculitides. Patients with temporal arteritis often present with headache, swollen temporal arteries, impairment of vision or symptoms of polymyalgia rheumatica. Clinical examination includes palpation of the temporal arteries and radial pulses, auscultation of the subclavian and axillary region, and fundoscopy. The presence of jaw claudication, diplopia and temporal artery abnormalities correlates with a high probability of positive histology. Duplex ultrasonography of the temporal arteries delineates a characteristic hypoechoic, oedematous wall swelling, stenoses and occlusions. It detects the same pathologies in the axillary arteries and other arteries in large-vessel giant cell arteritis. Angiography, magnetic resonance imaging, magnetic resonance angiography, electron beam computed tomography, computed tomography angiography and positron emission tomography show characteristic changes in the aorta and its primary branches in large-vessel giant cell arteritis and Takayasu's arteritis. Takayasu's arteritis often begins with diffuse symptoms such as low-grade fever, arthralgia, fatigue and weight loss. Clinical examination is important to detect bruits, pulse reduction and blood pressure differences. Profound experience exists with angiography. Other imaging methods are interesting alternatives as they are less invasive and may depict the inflammatory wall swelling.

Use of ultrasonography and positron emission tomography in the diagnosis and assessment of large-vessel vasculitis

PURPOSE OF REVIEW

Ultrasonography and positron emission tomography have been increasingly studied and, in part, introduced in clinical practice to diagnose large-vessel vasculitides, such as temporal arteritis, Takayasu arteritis, large-vessel giant cell arteritis, and isolated aortitis.

RECENT FINDINGS

Ultrasonography reveals characteristic homogenous, concentric wall thickening in vasculitis, often combined with stenoses and, less frequently, with acute occlusions. Thirteen studies describe sensitivities of 40 to 100% (median, 86%) for temporal artery vessel wall edema compared with histology, and of 35 to 86% (median, 70%) compared with clinical diagnosis. If wall edema, stenoses, and occlusions are included, sensitivities increase to 91 to 100% (median, 95%) compared with histology, and to 83 to 100% (median, 88%) compared with clinical diagnosis. Specificities for wall edema are 68 to 100% (median, 93%) compared with histology, and 78 to 100% (median, 97%) compared with clinical diagnosis. One should be aware of large-vessel giant cell arteritis in all patients with temporal arteritis and polymyalgia rheumatica. Ultrasonography reveals characteristic wall thickening, particularly of the distal subclavian, axillary, and proximal brachial arteries. Findings in Takayasu arteritis are similar, but the vessel wall swelling is usually brighter. Positron emission tomography reveals vasculitis in arteries with a diameter of more than 4 mm. Ultrasonography and positron emission tomography agreed completely in the anatomic distribution of changes in patients with large-vessel giant cell arteritis. It reveals asymptomatic large-vessel vasculitis in giant cell arteritis and Takayasu arteritis. Positron emission tomography is not suitable for the assessment of temporal arteries.

SUMMARY

Ultrasonography and positron emission tomography are new, promising techniques to assess large-vessel vasculitides.