Review: The Role of Dual-Energy Computed Tomography in Detecting Monosodium Urate Deposits in Vascular Tissues

PURPOSE OF REVIEW

To highlight novel findings in the detection of monosodium urate deposits in vessels using dual energy computed tomography, and to discuss the potential clinical implications for gout and hyperuricemia patients.

RECENT FINDINGS

Gout is an independent risk factor for cardiovascular disease. However, classical risk calculators do not take into account these hazards, and parameters to identify patients at risk are lacking. Monosodium urate measured by dual energy computed tomography is a well-established technology for the detection and quantification of monosodium urate deposits in peripheral joints and tendons. Recent findings also suggest its applicability to identify vascular urate deposits. Dual energy computed tomography is a promising tool for detection of cardiovascular monosodium urate deposits in gout patients, to better delineate individuals at increased risk for cardiovascular disease.

Prevalence of Monosodium Urate (MSU) Deposits in Cadavers Detected by Dual-Energy Computed Tomography (DECT)

Background: Dual-energy computed tomography (DECT) allows direct visualization of monosodium urate (MSU) deposits in joints and soft tissues. Purpose: To describe the distribution of MSU deposits in cadavers using DECT in the head, body trunk, and feet. Materials and Methods: A total of 49 cadavers (41 embalmed and 8 fresh cadavers; 20 male, 29 female; mean age, 79.5 years; SD ± 11.3; range 52–95) of unknown clinical history underwent DECT to assess MSU deposits in the head, body trunk, and feet. Lens, thoracic aorta, and foot tendon dissections of fresh cadavers were used to verify MSU deposits by polarizing light microscopy. Results: 33/41 embalmed cadavers (80.5%) showed MSU deposits within the thoracic aorta. 11/41 cadavers (26.8%) showed MSU deposits within the metatarsophalangeal (MTP) joints and 46.3% of cadavers demonstrated MSU deposits within foot tendons, larger than and equal to 5 mm. No MSU deposits were detected in the cranium/intracerebral vessels, or the coronary arteries. Microscopy used as a gold standard could verify the presence of MSU deposits within the lens, thoracic aorta, or foot tendons in eight fresh cadavers. Conclusions: Microscopy confirmed the presence of MSU deposits in fresh cadavers within the lens, thoracic aorta, and foot tendons, whereas no MSU deposits could be detected in cranium/intracerebral vessels or coronary arteries. DECT may offer great potential as a screening tool to detect MSU deposits and measure the total uric acid burden in the body. The clinical impact of this cadaver study in terms of assessment of MSU burden should be further proven.

Gouty Arthropathy: Review of Clinical Manifestations and Treatment, with Emphasis on Imaging

Gout, a crystalline arthropathy caused by the deposition of monosodium urate crystals in the articular and periarticular soft tissues, is a frequent cause of painful arthropathy. Imaging has an important role in the initial evaluation as well as the treatment and follow up of gouty arthropathy. The imaging findings of gouty arthropathy on radiography, ultrasonography, computed tomography, dual energy computed tomography, and magnetic resonance imaging are described to include findings of the early, acute and chronic phases of gout. These findings include early monosodium urate deposits, osseous erosions, and tophi, which may involve periarticular tissues, tendons, and bursae. Treatment of gout includes non-steroidal anti-inflammatories, colchicine, glucocorticoids, interleukin-1 inhibitors, xanthine oxidase inhibitors, uricosuric drugs, and recombinant uricase. Imaging is critical in monitoring response to therapy; clinical management can be modulated based on imaging findings. This review article describes the current standard of care in imaging and treatment of gouty arthropathy.

Ultrasound shear wave elastography of the anterior talofibular and calcaneofibular ligaments in healthy subjects

Aim of study

Most sprained lateral ankle ligaments heal uneventfully, but in some cases the ligament’s elastic function is not restored, leading to chronic ankle instability. Ultrasound shear wave elastography can be used to quantify the elasticity of musculoskeletal soft tissues; it may serve as a test of ankle ligament function during healing to potentially help differentiate normal from ineffective healing. The purpose of this study was to determine baseline shear wave velocity values for the lateral ankle ligaments in healthy male subjects, and to assess inter-observer reliability.

Material and methods

Forty-six ankles in 23 healthy male subjects aged 20–40 years underwent shear wave elastography of the lateral ankle ligaments performed by two musculoskeletal radiologists. Each ligament was evaluated three times with the ankle relaxed by both examiners, and under stress by a single examiner. Mean shear wave velocity values were compared for each ligament by each examiner. Inter-observer agreement was evaluated.

Results

The mean shear wave velocity at rest for the anterior talofibular ligament was 2.09 ± 0.3 (range 1.41–3.17); and for the calcaneofibular ligament 1.99 ± 0.36 (range 1.29–2.88). Good inter-observer agreement was found for the anterior talofibular ligament and calcaneofibular ligament shear wave velocity measurements with the ankle in resting position. There was a significant difference in mean shear wave velocities between rest and stressed conditions for both anterior talofibular ligament (2.09 m/s vs 3.21 m/s; p <0.001) and calcaneofibular ligament (1.99 m/s vs 3.42 m/s; p <0.0001).

Conclusion

Shear wave elastography shows promise as a reproducible method to quantify ankle ligament stiffness. This study reveals that shear waves velocities of the normal lateral ankle ligaments increased with applied stress compared to the resting state.

Ultrasonography and dual-energy computed tomography: impact for the detection of gouty deposits

Ultrasonography (US) and dual-energy computed tomography (DECT) are useful and sensitive diagnostic tools to identify monosodium urate deposits in joints and soft tissues. The purpose of this review is to overview the imaging findings obtained by US and DECT in patients with gout, to understand the strengths and weaknesses of each imaging modality, and to evaluate the added value of using both modalities in combination.

Imaging assessment of children presenting with suspected or known juvenile idiopathic arthritis: ESSR-ESPR points to consider

Juvenile idiopathic arthritis (JIA) is the most common paediatric rheumatic disease. It represents a group of heterogenous inflammatory disorders with unknown origin and is a diagnosis of exclusion in which imaging plays an important role. JIA is defined as arthritis of one or more joints that begins before the age of 16 years, persists for more than 6 weeks and is of unknown aetiology and pathophysiology. The clinical goal is early suppression of inflammation to prevent irreversible joint damage which has shifted the emphasis from detecting established joint damage to proactively detecting inflammatory change. This drives the need for imaging techniques that are more sensitive than conventional radiography in the evaluation of inflammatory processes as well as early osteochondral change. Physical examination has limited reliability, even if performed by an experienced clinician, emphasising the importance of imaging to aid in clinical decision-making. On behalf of the European Society of Musculoskeletal Radiology (ESSR) arthritis subcommittee and the European Society of Paediatric Radiology (ESPR) musculoskeletal imaging taskforce, based on literature review and/or expert opinion, we discuss paediatric-specific imaging characteristics of the most commonly involved, in literature best documented and clinically important joints in JIA, namely the temporomandibular joints (TMJs), spine, sacroiliac (SI) joints, wrists, hips and knees, followed by a clinically applicable point to consider for each joint. We will also touch upon controversies in the current literature that remain to be resolved with ongoing research. KEY POINTS: • Juvenile idiopathic arthritis (JIA) is the most common chronic paediatric rheumatic disease and, in JIA imaging, is increasingly important to aid in clinical decision-making. • Conventional radiographs have a lower sensitivity and specificity for detection of disease activity and early destructive change, as compared to MRI or ultrasound. Nonetheless, radiography remains important, particularly in narrowing the differential diagnosis and evaluating growth disturbances. • Mainly in peripheral joints, ultrasound can be helpful for assessment of inflammation and guiding joint injections. In JIA, MRI is the most validated technique. MRI should be considered as the modality of choice to assess the axial skeleton or where the clinical presentation overlaps with JIA.

Ultrasound Elastography in Musculoskeletal Radiology: Past, Present, and Future

Ultrasound elastography (USE) is becoming an important adjunct tool in the evaluation of various musculoskeletal (MSK) traumatic conditions and diseases, with an increasing number of applications and publications in recent years. This rapidly evolving technique enhances the conventional ultrasound (US) examination by providing information on the elastic properties of tissue alongside the morphological and vascular information obtained from B-mode US and Doppler imaging. Those performing USE must have basic knowledge of its proper imaging techniques and limitations. In this review article, we place the USE in historical perspective and discuss basic techniques and current applications of USE in the evaluation of various traumatic and pathologic conditions of fasciae, nerves, muscles, tendons, ligaments, and MSK soft tissue masses.

Clinical indications for image-guided interventional procedures in the musculoskeletal system: a Delphi-based consensus paper from the European Society of Musculoskeletal Radiology (ESSR)-Part II, elbow and wrist

BACKGROUND

Although image-guided interventional procedures of the elbow and wrist are routinely performed, there is poor evidence in the literature concerning such treatments. Our aim was to perform a Delphi-based consensus on published evidence on image-guided interventional procedures around the elbow and wrist and provide clinical indications on this topic.

METHODS

A board of 45 experts in image-guided interventional musculoskeletal procedures from the European Society of Musculoskeletal Radiology were involved in this Delphi-based consensus study. All panelists reviewed and scored published papers on image-guided interventional procedures around the elbow and wrist updated to September 2018 according to the Oxford Centre for Evidence-based Medicine levels of evidence. Consensus on statements drafted by the panelists about clinical indications was considered as "strong" when more than 95% of panelists agreed and as "broad" if more than 80% agreed.

RESULTS

Eighteen statements were drafted, 12 about tendon procedures and 6 about intra-articular procedures. Only statement #15 reached the highest level of evidence (ultrasound-guided steroid wrist injections result in greater pain reduction and greater likelihood of attaining clinically important improvement). Seventeen statements received strong consensus (94%), while one received broad consensus (6%).

CONCLUSIONS

There is still poor evidence in published papers on image-guided interventional procedures around the elbow and wrist. A strong consensus has been achieved in 17/18 (94%) statements provided by the panel on clinical indications. Large prospective randomized trials are needed to better define the role of these procedures in clinical practice.

KEY POINTS

• The panel provided 18 evidence-based statements on clinical indications of image-guided interventional procedures around the elbow and wrist. • Only statement #15 reached the highest level of evidence: ultrasound-guided steroid wrist injections result in greater pain reduction and greater likelihood of attaining clinically important improvement. • Seventeen statements received strong consensus (94%), while broad consensus was obtained by 1 statement (6%).

Clinical indications for image guided interventional procedures in the musculoskeletal system: a Delphi-based consensus paper from the European Society of Musculoskeletal Radiology (ESSR)-part III, nerves of the upper limb

BACKGROUND

Image-guided interventional procedures of the nerves are commonly performed by physicians from different medical specialties, although there is a lack of clinical indications for these types of procedures. This Delphi-based consensus provided a list of indications on image-guided interventional procedures for nerves of the upper limb based on updated published evidence.

METHODS

An expert panel of 45 members of the Ultrasound and Interventional Subcommittees of the ESSR participated in this Delphi-based consensus study. After revision of the published papers on image-guided interventional procedures for nerves of the upper limb updated to September 2018, the experts drafted a list of statements according to the Oxford Centre for evidence-based medicine levels of evidence. Consensus on statements regarding clinical indications was considered as strong when more than 95% of experts agreed, and broad if more than 80% agreed.

RESULTS

Ten statements were drafted on procedures for nerves of the upper limb. Only two statements reached the highest level of evidence (ultrasound guidance is a safe and effective method for brachial plexus block; ultrasound-guided non-surgical approaches are safe and effective methods to treat carpal tunnel syndrome in the short term, but there is sparse evidence on the mid- and long-term effectiveness of these interventions). Strong consensus was obtained on 6/10 statements (60%), while 4/10 statements reached broad consensus (40%).

CONCLUSIONS

This Delphi-based consensus study reported poor evidence on image-guided interventional procedures for nerves of the upper limb. Sixty percent of statements on clinical indications provided by the expert board reached a strong consensus.

KEY POINTS

• An expert panel of the ESSR provided 10 evidence-based statements on clinical indications for image-guided interventional procedures for nerves of the upper limb • Two statements reached the highest level of evidence • Strong consensus was obtained on 6/10 statements (60%), while 4/10 statements reached broad consensus (40%).

The radial and ulnar collateral ligaments of the wrist are true ligaments

PURPOSE

Our hypothesis in this study is that the radial and ulnar collateral ligaments of the wrist exist and are true ligaments which can be visualized by high-resolution ultrasonography (US).

METHODS

High-resolution US examination of the radial and ulnar collateral ligaments of the wrist was performed on 56 fresh cadaveric wrists. The visibility of these ligaments was assessed by four observers who classified the ligaments in consensus as well seen, adequately seen, or not seen. Surgical dissections of 12 radial collateral ligaments and 12 ulnar collateral ligaments were then performed and the ligaments were classified as present or absent. The US and dissection results were then compared. To confirm that the dissected structures represent true ligaments a histologic examination of the ligaments was performed.

RESULTS

All examined radial and ulnar collateral ligaments were seen on the US examination. The radial collateral ligament was seen between the radial styloid and radial aspect of the scaphoid. The ulnar collateral ligament was seen between ulnar styloid process and the triquetrum. On all surgical dissections, the radial collateral ligament was present at the floor of the first extensor compartment and the ulnar collateral ligament was at the floor of the sixth extensor compartment. Both ligaments were proven to be true capsular ligaments on both dissection and histologic examinations.

CONCLUSION

The radial and ulnar collateral ligaments of the wrist are true ligaments and can be seen at the floor of the first and the sixth extensor compartments, respectively, using high-resolution US. Based on their anatomic location, they most likely provide static stability to the wrist joint.

Clinical indications for image-guided interventional procedures in the musculoskeletal system: a Delphi-based consensus paper from the European Society of Musculoskeletal Radiology (ESSR)-part I, shoulder

BACKGROUND

Image-guided interventional procedures around the shoulder are commonly performed in clinical practice, although evidence regarding their effectiveness is scarce. We report the results of a Delphi method review of evidence on literature published on image-guided interventional procedures around the shoulder with a list of clinical indications.

METHODS

Forty-five experts in image-guided musculoskeletal procedures from the ESSR participated in a consensus study using the Delphic method. Peer-reviewed papers regarding interventional procedures around the shoulder up to September 2018 were scored according to the Oxford Centre for Evidence-based Medicine levels of evidence. Statements on clinical indications were constructed. Consensus was considered as strong if more than 95% of experts agreed and as broad if more than 80% agreed.

RESULTS

A total of 20 statements were drafted, and 5 reached the highest level of evidence. There were 10 statements about tendon procedures, 6 about intra-articular procedures, and 4 about intrabursal injections. Strong consensus was obtained in 16 of them (80%), while 4 received broad consensus (20%).

CONCLUSIONS

Literature evidence on image-guided interventional procedures around the shoulder is limited. A strong consensus has been reached for 80% of statements. The ESSR recommends further research to potentially influence treatment options, patient outcomes, and social impact.

KEY POINTS

• Expert consensus produced a list of 20 evidence-based statements on clinical indications of image-guided interventional procedures around the shoulder. • The highest level of evidence was reached for five statements. • Strong consensus was obtained for 16 statements (80%), while 4 received broad consensus (20%).

Imaging of Postoperative Infection at the Knee Joint

Postoperative infections of the knee are uncommon but may occur with joint arthroplasties, fracture fixation, or after arthroscopic procedures. The ultimate diagnosis is made by joint aspiration or tissue sampling. Joint aspiration and tissue sampling can be performed under imaging guidance or intraoperatively. Imaging is an important adjunct to clinical and laboratory findings and should start with radiographs. Cross-sectional imaging including magnetic resonance (MR) imaging, computed tomography (CT), nuclear studies, and ultrasound (US) are frequently used if the diagnosis is in doubt and to evaluate the extent of disease. We discuss the current algorithm in the diagnosis of various postoperative infections of the knee joint. The article addresses the utility of radiography, MR imaging, CT, US, and the most commonly used nuclear studies in the diagnosis of various postoperative knee infections and the imaging appearances of these infections on each of these diagnostic modalities.

Gout of hand and wrist: the value of US as compared with DECT

Objectives

The purpose of this study was to compare findings of ultrasound (US) with dual-energy CT (DECT) in patients presenting with suspected gouty hand and wrist arthritis.

Methods

This prospective study included 180 patients (136 men and 44 women, age range, 31– 94 years; mean age, 65.9 years) with an initial clinical diagnosis of acute gouty arthritis who underwent DECT and US examination. Intra- and extra-articular findings of each modality were tabulated and calculated with DECT as gold standard.

Results

The final diagnosis of gout was positive in 97/180 patients (53.9%) by DECT, an alternative diagnosis confirmed in 83 patients. US showed a sensitivity of 70.1% (extra-articular: 42.5%, p < 0.0001; intra-articular: 80.3%, p = 0.14) and specificity of 51%. The double contour sign (DCS) was present in 58/61 patients with a positive US study for intra-articular gout (95.1%).

Conclusions

Sensitivity of US for diagnosis of gouty arthritis in hand and wrist is limited, particularly with respect to extra-articular urate deposition. The DCS is the most sensitive sign for the assessment of gouty hand and wrist arthritis by US.

Key points

• Sensitivity of US for diagnosis of gouty arthritis in hand and wrist is limited, particularly with respect to extra-articular gouty deposits.

• The double contour sign is the most sensitive finding for the assessment of gouty hand and wrist arthritis by US.

• Although the sensitivity of US for diagnosis of gouty hand and wrist arthritis is limited, it can be used as a first-line imaging modality in the presence of the DCS.

Shear-Wave Elastography: Basic Physics and Musculoskeletal Applications

In the past 2 decades, sonoelastography has been progressively used as a tool to help evaluate soft-tissue elasticity and add to information obtained with conventional gray-scale and Doppler ultrasonographic techniques. Recently introduced on clinical scanners, shear-wave elastography (SWE) is considered to be more objective, quantitative, and reproducible than compression sonoelastography with increasing applications to the musculoskeletal system. SWE uses an acoustic radiation force pulse sequence to generate shear waves, which propagate perpendicular to the ultrasound beam, causing transient displacements. The distribution of shear-wave velocities at each pixel is directly related to the shear modulus, an absolute measure of the tissue's elastic properties. Shear-wave images are automatically coregistered with standard B-mode images to provide quantitative color elastograms with anatomic specificity. Shear waves propagate faster through stiffer contracted tissue, as well as along the long axis of tendon and muscle. SWE has a promising role in determining the severity of disease and treatment follow-up of various musculoskeletal tissues including tendons, muscles, nerves, and ligaments. This article describes the basic ultrasound physics of SWE and its applications in the evaluation of various traumatic and pathologic conditions of the musculoskeletal system. ^©RSNA, 2017.

Carpal tunnel syndrome assessment with diffusion tensor imaging: Value of fractional anisotropy and apparent diffusion coefficient

OBJECTIVES

To quantitatively assess carpal tunnel syndrome (CTS) with DTI by evaluating two approaches to determine cut-off values.

METHODS

In forty patients with CTS diagnosis confirmed by nerve conduction studies (NCs) and 14 healthy subjects (mean age 58.54 and 57.8 years), cross-sectional area (CSA), apparent diffusion coefficient (ADC) and fractional anisotropy (FA) at single and multiple levels with intraobserver agreement were evaluated.

RESULTS

Maximum and mean CSA and FA showed significant differences between healthy subjects and patients (12.85 mm² vs. 28.18 mm², p < 0.001, and 0.613 vs. 0.524, p=0.007, respectively) (10.12 mm² vs. 19.9 mm², p<0.001 and 0.617 vs. 0.54, p=0.003, respectively), but not maximum and mean ADC (p > 0.05). For cut-off values, mean and maximum CSA showed the same sensitivity and specificity (93.3 %). However, mean FA showed better sensitivity than maximum FA (82.6 % vs. 73.9 %), but lower specificity (66.7 % vs. 80 %), and significant correlation for maximum CSA, 97 % (p < 0.01), with good correlation for maximum ADC and FA, 84.5 % (p < 0.01) and 62 % (p=0.056), respectively.

CONCLUSIONS

CSA and FA showed significant differences between healthy subjects and patients. Single measurement at maximum CSA is suitable for FA determination. Key Points • DTI showed that FA is stronger than ADC for CTS diagnosis. • Single- and multiple-level approaches were compared to determine FA and ADC. • Single-level evaluation at the thickest MN cross-sectional area is sufficient.

Sonoelastography of the Common Flexor Tendon of the Elbow with Histologic Agreement: A Cadaveric Study

Purpose To determine the correlation of the results of conventional B-mode ultrasonography (US) and compression sonoelastography with histologic results in common flexor tendons of the elbow in human cadavers. Materials and Methods Twenty-five common flexor tendons were evaluated in 16 fresh, unembalmed cadavers of 11 women with a median age of 85 years (range, 71-101 years) and five men with a median age of 78 years (range, 70-88 years). Informed consent was provided according to the last will of the donors. B-mode US results were classified as grade 1, normal tendon with homogeneous fibrillar pattern; grade 2, tendon thickening or hypoechoic areas and/or calcifications in less than 30% of the tendon; or grade 3, hypoechoic areas and/or calcifications greater than 30% of the tendon. Sonoelastographic results were grade 1, blue (hardest) to green (hard); grade 2, yellow (soft); and grade 3, red (softest). The intraclass correlation coefficient was calculated to determine agreement with histologic findings for each B-mode US, sonoelastographic, and combined B-mode US and sonoelastographic examination. Histologic results were grade 1, normal, with parallel fibrillar pattern; grade 2, mild tendinopathy, with cellular infiltration, angiogenesis, or fatty vacuoles; or grade 3, severe tendinopathy, with loss of parallel collagen structure and necrosis. Results Histologic alterations were detected in 44% (11 of 25) of biopsy specimens. Intraclass correlation with histologic results was 0.57 for B-mode US, 0.68 for sonoelastography, and 0.84 for the combination of the two approaches. Conclusion The addition of sonoelastography to B-mode US provided statistically significant improvement in correlation with histologic results compared with the use of B-mode US alone (P < .02). ^© RSNA, 2016 Online supplemental material is available for this article.

High-Resolution US of Rheumatologic Diseases

For the past 15 years, high-resolution ultrasonography (US) is being routinely and increasingly used for initial evaluation and treatment follow-up of rheumatologic diseases. This imaging technique is performed by using high-frequency linear transducers and has proved to be a powerful diagnostic tool in evaluation of articular erosions, simple and complex joint and bursal effusions, tendon sheath effusions, and synovitis, with results comparable to those of magnetic resonance imaging, excluding detection of bone marrow edema. Crystal deposition diseases including gouty arthropathy and calcium pyrophosphate deposition disease (CPPD) have characteristic appearances at US, enabling differentiation between these two diseases and from inflammatory arthropathies. Enthesopathy, which frequently accompanies psoriatic and reactive arthritis, also has a characteristic appearance at high-resolution US, distinguishing these two entities from other inflammatory and metabolic arthropathies. The presence of Doppler signal in examined joints, bursae, and tendon sheaths indicates active synovitis. Microbubble echo contrast agents augment detection of tissue vascularity and may act in the future as a drug delivery vehicle. Frequently, joint, tendon sheath, and bursal fluid aspirations and therapeutic injections are performed under US guidance. The authors describe the high-resolution US technique including gray-scale, color or power Doppler, and contrast agent-enhanced US that is used in evaluation of rheumatologic diseases of the wrist and hand and the ankle and foot in their routine clinical practice. This article demonstrates imaging findings of normal joints, rheumatoid arthritis, gouty arthritis, CPPD, psoriatic and reactive arthritis, and osteoarthritis.

Feasibility of Ultrasound-Guided Sacroiliac Joint Injections in Children Presenting with Sacroiliitis

PURPOSE

To evaluate the feasibility and effectiveness of US-guided sacroiliac joint injection in the treatment of sacroiliitis in children.

MATERIALS AND METHODS

This study was approved by the institutional review board and informed oral and written consent was obtained from the patients and their parents. In 13 patients (7 females and 6 males), 9 - 16 years (mean +/- std 11.39 +/-1.98), 18 sacroiliac joint (SI joint) injections were performed under US guidance. All patients suffered from severe sacroiliitis. US scanning was performed using a linear-array transducer operating at 5 - 18 MHz. Rating of the patients pain using a 0 - 10 dolorimetry scale on a visual analog score (VAS) was recorded before, immediately after and 3 months after injection to monitor severity and therapeutic response.

RESULTS

Injection could be performed in all patients without complication and showed good response immediately and 3 months after the injection with a decrease of the VAS (from mean +/- std 9.44 +/- 1.097 to 3.89 +/- 3.82, p < 0.001 and to 0.56 +/- 1.097, p < 0.05, respectively).

CONCLUSION

US-guided SI joint injection was feasible in all children, relatively quick and easy to perform and appeared effective in the treatment of children with sacroiliitis.

Sonoelastographic Findings of Carpal Tunnel Injection

PURPOSE

The objectives of this study were to compare sonoelastographic color findings of the perineural area between carpal tunnel syndrome patients and healthy volunteers, and to analyze elastographic findings in that area before and immediately after intracarpal tunnel injection in carpal tunnel syndrome patients.

MATERIALS AND METHODS

We studied both hands of 15 healthy volunteers (7 men, 8 women; mean age: 60.1 years, range: 41 - 88 years) and 72 hands from 70 patients with symptomatic carpal tunnel syndrome (24 men, 46 women; mean age: 54.2 years, range: 24 - 83 years). Sonoelastographic color distribution was assessed in the perineural area between the median nerve and adjacent flexor tendons. The color elastograms were graded using the following system: Grade 1 as red (softest), grade 2 as yellow (soft), grade 3 as green (hard), grade 4 as blue (hardest). The patients were treated with corticosteroid injection and were reassessed with sonoelastography immediately after the injection.

RESULTS

The median color grading in the perineural area of carpal tunnel syndrome patients was grade 3 (3.1 ± 0.3, mean ± 95 % Cl), which was stiffer than that of healthy volunteers (grade 1, 1.9 ± 0.4) (p < 0.0001). Immediately after injection, the diffusion of the injected fluid was observed as having a softer appearance (grade 1, 1.4 ± 0.2) (p < 0.0001).

CONCLUSION

The perineural area surrounding the median nerve in carpal tunnel syndrome patients was stiffer than that in healthy volunteers. Diffusion of the injected fluid in the carpal tunnel was seen as a softer finding after injection in real time using sonoelastography.

Meralgia paraesthetica: Ultrasound-guided injection at multiple levels with 12-month follow-up

OBJECTIVES

To evaluate the efficacy of ultrasound (US)-guided injections around the lateral femoral cutaneous nerve (LFCN) at different levels in meralgia paraesthetica (MP) patients.

METHODS

The study was approved by the university ethics committee and informed oral and written consent were obtained from all patients. Between June 2008 and August 2013, 20 patients with symptoms of MP, including nine men (mean age, 61.33 years) and 11 women (mean age 61.18 years), were treated with US-guided injection of steroids along the LFCN at three different levels in a mean of 2.25 sessions. A visual analogue scale (VAS) was used to measure symptoms before, immediately after and 12 months after treatment.

RESULTS

Complete resolution of symptoms was documented in 15/20 patients (mean VAS decreased from 82 to 0), and partial resolution in the remaining five (mean VAS decreased from 92 to 42), which was confirmed at 12-month follow-up. By using the different levels of injection approach overall significantly better symptom relief was obtained (p < 0.05).

CONCLUSION

The outcome of US-guided injection along the LFCN can be further improved by injections at different levels (p < 0.05), which was confirmed at 12-month long-term follow-up.

KEY POINTS

Meralgia paraesthetica is an entrapment neuropathy of the lateral femoral cutaneous nerve. Ultrasound proved effective in diagnosis and in guiding injection therapy. Injection at the anterior superior iliac spine has been used previously. Multiple injections along the nerve course were used in this study. Long-term follow-up (12 months) confirmed the results.

Sonoelastography: musculoskeletal applications

All participants for image samplings provided written informed consent. Conventional B-mode ultrasonography (US) has been widely utilized for musculoskeletal problems as a first-line approach because of the advantages of real-time access and the relatively low cost. The biomechanical properties of soft tissues reflect to some degree the pathophysiology of the musculoskeletal disorder. Sonoelastography is an in situ method that can be used to assess the mechanical properties of soft tissue qualitatively and quantitatively through US imaging techniques. Sonoelastography has demonstrated feasibility in the diagnosis of cancers of the breast and liver, and in some preliminary work, in several musculoskeletal disorders. The main types of sonoelastography are compression elastography, shear-wave elastography, and transient elastography. In this article, the current knowledge of sonoelastographic techniques and their use in musculoskeletal imaging will be reviewed.

Intracarpal tunnel contents: evaluation of the effects of corticosteroid injection with sonoelastography

PURPOSE

To define the stiffness of the intracarpal tunnel contents and to evaluate the effect of corticosteroid injection on the intracarpal tunnel contents by using sonoelastography.

MATERIALS AND METHODS

This study was conducted with the approval of the institutional review boards, and all participants provided written, informed consent. Both hands were studied in 20 healthy volunteers, including eight men (mean age, 59.6 years; range, 50-76 years) and 12 women (mean age, 61.0 years; range, 39-79 years) and 22 hands were studied in 20 patients with carpal tunnel syndrome (CTS) (five men [mean age, 49.0 years] and 15 women [mean age, 61.1 years]; range, 39-89 years) between April 2012 and August 2012. The stiffness of the intracarpal tunnel contents was estimated as the standardized acoustic coupler (AC)-to-intracarpal tunnel contents surrounding the nerve (AC/C) strain ratio, analyzed with the Mann-Whitney U test. The patients were treated with corticosteroid injections, and the strain ratio was reexamined 6 weeks later, analyzed with the Wilcoxon t test.

RESULTS

The mean AC/C strain ratio in the CTS patients was 12.6 ± 4.7 (standard deviation), which was higher (stiffer) than that in the healthy volunteers with a mean strain ratio of 8.2 ± 3.5 (P = .0013). Six weeks after the injection, the mean AC/C strain ratio had decreased to 8.5 ± 4.1 (P = .00069, compared with the preinjection value) in the CTS patients.

CONCLUSION

The stiffness of the intracarpal tunnel contents in untreated CTS patients is higher than that of healthy volunteers but decreases 6 weeks after corticosteroid injection.

Carpal tunnel syndrome: diagnosis by means of median nerve elasticity--improved diagnostic accuracy of US with sonoelastography

PURPOSE

To compare the elasticity of the median nerve (MN) between healthy volunteers and patients with carpal tunnel syndrome (CTS) and to evaluate the diagnostic utility of sonoelastographic measurements of the elasticity of the MN.

MATERIALS AND METHODS

This study was performed with institutional review board approval and written informed consent from all participants. Hands in 22 healthy volunteers and in 31 patients with symptomatic CTS were studied. The cross-sectional area (CSA) and the elasticity of the MN, which was measured as the acoustic coupler (AC)/MN strain ratio, were evaluated.

RESULTS

Both hands in 22 healthy volunteers (three men [mean age, 52.7 years; age range, 41-65 years]; 19 women [mean age, 62.2 years; age range, 40-88 years]) and 43 hands in 31 patients with symptomatic CTS (three men [mean age, 69.0 years; age range, 46-88 years]; 28 women [mean age, 61.2 years; age range, 39-92 years]) were studied. Both the AC/MN strain ratio and the CSA in the patients with CTS were significantly higher than those in the healthy volunteers (P < .001). The presence of CTS was predicted by means of AC/MN strain ratio and CSA cutoff values, respectively, of 4.3 and 11 mm(2), with areas under the receiver operating characteristic curves (AUCs) of 0.78 (95% confidence interval [CI]: 0.69, 0.88) and 0.85 (95% CI: 0.78, 0.93). A logistic model that combined the AC/MN strain ratio and the CSA improved diagnostic accuracy for CTS, with an AUC of 0.91 (95% CI: 0.85, 0.97; P < .001).

CONCLUSION

Sonoelastography provides significant improvement in the diagnostic accuracy of the ultrasonographic assessment of CTS.

EFSUMB guidelines and recommendations on the clinical use of ultrasound elastography. Part 2: Clinical applications

The clinical part of these Guidelines and Recommendations produced under the auspices of the European Federation of Societies for Ultrasound in Medicine and Biology EFSUMB assesses the clinically used applications of all forms of elastography, stressing the evidence from meta-analyses and giving practical advice for their uses and interpretation. Diffuse liver disease forms the largest section, reflecting the wide experience with transient and shear wave elastography . Then follow the breast, thyroid, gastro-intestinal tract, endoscopic elastography, the prostate and the musculo-skeletal system using strain and shear wave elastography as appropriate. The document is intended to form a reference and to guide clinical users in a practical way.

EFSUMB guidelines and recommendations on the clinical use of ultrasound elastography. Part 1: Basic principles and technology

The technical part of these Guidelines and Recommendations, produced under the auspices of EFSUMB, provides an introduction to the physical principles and technology on which all forms of current commercially available ultrasound elastography are based. A difference in shear modulus is the common underlying physical mechanism that provides tissue contrast in all elastograms. The relationship between the alternative technologies is considered in terms of the method used to take advantage of this. The practical advantages and disadvantages associated with each of the techniques are described, and guidance is provided on optimisation of scanning technique, image display, image interpretation and some of the known image artefacts.

Greater trochanteric pain syndrome

Pain around the greater trochanter is still a common clinical problem that may be secondary to a variety of either intra-articular or periarticular pathologies. Gluteal tendon pathologies are one of the primary causes of greater trochanteric pain, with attrition of the fasciae latae against the gluteus medius and minimus tendons, and the trochanteric bursa being possible causes. Key sonographic findings of gluteal tendinopathy, bursitis, and differential diagnosis are described in this overview. Clinical diagnosis and treatment of greater trochanteric pain syndrome is still challenging; therefore ultrasound is helpful to localize the origin of pain, determine underlying pathology, and, based on these findings, to guide local aspiration and/or injection in cases of tendinopathy and/or bursitis.

Clinical indications for musculoskeletal ultrasound: a Delphi-based consensus paper of the European Society of Musculoskeletal Radiology

OBJECTIVE

To develop clinical guidelines for musculoskeletal ultrasound (MSKUS) referral in Europe.

METHODS

Sixteen musculoskeletal radiologists from seven European countries participated in a consensus-based interactive process (Delphi method) using consecutive questionnaires and consensus procedure meetings at several European radiology meetings. The evaluation of musculoskeletal diseases was established by literature reviews, followed by consensus on clinical utility in three consensus meetings. This involved a thorough, transparent, iterative approach which including interview, questionnaire, Delphi and standard setting methodologies. European MSK radiologists with a special interest in MSKUS formed two different expert groups who worked on reaching a consensus in the first two meetings. The third meeting resolved questions that did not achieve a consensus level of 67% using the first two questionnaires.

RESULTS

On expert consensus, the use of MSKUS is indicated to detect joint synovitis, fluid and septic effusion for potential aspiration, and poorly indicated to detect loose bodies. Recommendations for most appropriate use of musculoskeletal ultrasound are reported in six areas relevant to musculoskeletal ultrasound: hand/wrist, elbow, shoulder, hip, knee and ankle/foot.

CONCLUSION

A comprehensive evidence-based, expert consensus-defined educational framework on clinical ultrsound is presented. This should facilitate referrals for this important imaging technique throughout Europe.

KEY POINTS

Musculoskeletal ultrasound is indicated for detecting joint synovitis, effusions and fluid collections. • Musculoskeletal ultrasound is poor at detecting loose bodies. • Musculoskeletal ultrasound is relevant for most joints.

Contrast-enhanced ultrasonography for the detection of joint vascularity in arthritis--subjective grading versus computer-aided objective quantification

PURPOSE

To compare joint inflammation assessment using subjective grading of power Doppler ultrasonography (PDUS) and contrast-enhanced ultrasonography (CEUS) versus computer-aided objective CEUS quantification.

MATERIALS AND METHODS

37 joints of 28 patients with arthritis of different etiologies underwent B-mode ultrasonography, PDUS, and CEUS using a second-generation contrast agent. Synovial thickness, extent of vascularized pannus and intensity of vascularization were included in a 4-point PDUS and CEUS grading system. Subjective CEUS and PDUS scores were compared to computer-aided objective CEUS quantification using Qontrast® software for the calculation of the signal intensity (SI) and the ratio of SI for contrast enhancement.

RESULTS

The interobserver agreement for subjective scoring was good to excellent (κ = 0.8 - 1.0; P < 0.0001). Computer-aided objective CEUS quantification correlated statistically significantly with subjective CEUS (P < 0.001) and PDUS grading (P < 0.05). The Qontrast® SI ratio correlated with subjective CEUS (P < 0.02) and PDUS grading (P < 0.03). Clinical activity did not correlate with vascularity or synovial thickening (P = N. S.) and no correlation between synovial thickening and vascularity extent could be found, neither using PDUS nor CEUS (P = N. S.).

CONCLUSION

Both subjective CEUS grading and objective CEUS quantification are valuable for assessing joint vascularity in arthritis and computer-aided CEUS quantification may be a suitable objective tool for therapy follow-up in arthritis.

US-guided therapy of calcific tendinopathy: clinical and radiological outcome assessment in shoulder and non-shoulder tendons

PURPOSE

To analyze the effectiveness and complication rate of ultrasound (US)-guided perforation and lavage using a two-needle technique with 16 - 18 G needles in the treatment of patients with calcific tendinopathy in the shoulder, elbow, hip, and knee by radiological and clinical follow-up.

MATERIALS AND METHODS

A retrospective chart review was performed and 40 patients (13 male, 27 female; mean age, 53.5 years; range 24 -74 years) were identified as having received US-guided perforation and lavage due to symptomatic calcific tendinopathy of the rotator cuff tendons, triceps, extensor and flexor tendons at the elbow, rectus femoris tendon and patellar tendons. The radiographic outcome was assessed by comparison of the size and quality of the calcification before and 6 weeks after the procedure. On US images, the quality of the acoustic shadow was assessed, together with other alterations of the tendon and surrounding tissue. Patients were interviewed by telephone to assess the clinical outcome regarding pre-treatment and post-treatment pain and tendon function.

RESULTS

34 shoulder tendons and 6 non-shoulder tendons were identified. The mean calcium reduction was 39.9 mm(2) (range, 0 - 215; p < 0.001), while 80 % of patient showed a resolution of more than 60 % resulting in good clinical improvement. A very low complication rate was found (1 partial tear).

CONCLUSION

The US-guided perforation and lavage technique is an effective and safe treatment for rotator cuff calcifications as well as for other body tendons. Although the two-needle technique and large needles were used in this study, a very low complication rate was detected.

Entrapment neuropathies II: carpal tunnel syndrome

Diagnostic tests in patients complaining of carpal tunnel syndrome (CTS) are based on physical examination, electrodiagnostic tests (EDTs), and diagnostic imaging. Timely diagnosis helps prevent permanent nerve damage and its sequelae in terms of functional impairment. Imaging provides additional information to that obtained from clinical tests and EDTs. By allowing direct visualization of the compressed median nerve (MN), ultrasound (US) and magnetic resonance imaging can depict the causes for secondary CTS and describe anatomical variants, such as a bifid MN or a persistent median artery of the forearm, as well as space-occupying lesions including tenosynovitis and ganglion cysts. In addition, diagnostic imaging is of value for postoperative patients presenting with persistent symptoms. Finally, US is able to add information for EDT-negative symptomatic patients. Over time, US has increased in its sensitivity and specificity so it can be used as the initial test in patients presenting with clinical symptoms of CTS because it is now equivalent to EDT. The use of US as a screening test may reduce the number of EDT examinations in patients with suspected CTS, providing additional valuable anatomical information.

Detection of vascularity in wrist tenosynovitis: power doppler ultrasound compared with contrast-enhanced grey-scale ultrasound

INTRODUCTION

We sought to assess vascularity in wrist tenosynovitis by using power Doppler ultrasound (PDUS) and to compare detection of intra- and peritendinous vascularity with that of contrast-enhanced grey-scale ultrasound (CEUS).

METHODS

Twenty-six tendons of 24 patients (nine men, 15 women; mean age ± SD, 54.4 ± 11.8 years) with a clinical diagnosis of tenosynovitis were examined with B-mode ultrasonography, PDUS, and CEUS by using a second-generation contrast agent, SonoVue (Bracco Diagnostics, Milan, Italy) and a low-mechanical-index ultrasound technique. Thickness of synovitis, extent of vascularized pannus, intensity of peritendinous vascularisation, and detection of intratendinous vessels was incorporated in a 3-score grading system (grade 0 to 2). Interobserver variability was calculated.

RESULTS

With CEUS, a significantly greater extent of vascularity could be detected than by using PDUS (P < 0.001). In terms of peri- and intratendinous vessels, CEUS was significantly more sensitive in the detection of vascularization compared with PDUS (P < 0.001). No significant correlation between synovial thickening and extent of vascularity could be found (P = 0.089 to 0.097). Interobserver reliability was calculated to be excellent when evaluating the grading score (κ = 0.811 to 1.00).

CONCLUSIONS

CEUS is a promising tool to detect tendon vascularity with higher sensitivity than PDUS by improved detection of intra- and peritendinous vascularity.

Developments in musculoskeletal ultrasound and clinical applications

OBJECTIVE

Ultrasound (US) technologies are rapidly advancing, offering several refined transducer technologies as well as soft and hardware facilities. The aim of this article is to outline US developments, from B-mode technologies over Doppler advances to more sophisticated technologies, and their potential clinical impact in the field of musculoskeletal (MSK) imaging.

NEW ADVANCES

When using B-mode ultrasound, compound imaging and beam-steering are of help to decrease anisotropy in tendons and ligaments, that are less well depicted due to their oblique course. Doppler imaging has become sensitive in the detection of flow in small vessels, which is of particular value in rheumatologic conditions, tumour and overuse assessment. The use of US microbubble contrast agents improves detection of low-volume blood flow in smaller vessels by increasing the signal-to-noise ratio and thereby facilitating detection of angiogenetic vessels in inflammatory conditions or tumours. The use of US blood pool contrast agents enables molecular imaging in real-time, and thus the diagnostic potential of US is expanded, opening up a new field of US applications. Objective quantification of altered tissue (e.g., synovial proliferation, tumours) is still demanding and might be improved by the use of three-dimensional imaging and software tools as parametric evaluation. Real-time sonoelastography (EUS) is a new development for visualization of tissue elasticity by measurement of tissue displacement in terms of tissue stiffness changes, promising new insights into tendon disorders. Image fusion is an exciting development that enables superimposition of CT/MRI data sets on real-time US scanning. This technique might be helpful in guiding injections under real-time conditions even in regions less easily accessible by US as, for instance, the axial skeleton, and can additionally provide an interesting tool for teaching MSK imaging and ways to guide interventions.

CONCLUSION

In summary, exciting developments are expanding the applications of US in the MSK field, offering the advantages of real-time performance, high tissue resolution and relative speed at a reasonable cost.

Real-time sonoelastography: findings in patients with symptomatic achilles tendons and comparison to healthy volunteers

PURPOSE

Real-time sonoelastography (SE), a newly introduced ultrasound technique, has already shown conclusive results in breast, prostate, and thyroid tumor diagnostics. This study investigated the performance of SE for the differentiation of Achilles tendon alterations of tendinopathy compared to clinical examination and conventional ultrasound (US).

MATERIALS AND METHODS

Achilles tendons in 25 consecutive patients with chronic Achilles tendinopathy and 25 healthy volunteers were examined clinically by US and by SE.

RESULTS

In the healthy volunteers, SE showed the tendon to be hard (93 %), while distinct softening was found in 57 % of the patients. SE showed more frequent involvement of the distal (64 %) and middle third (80 %) than the proximal third (28 %) of the Achilles tendon. Using SE a mean sensitivity of 94 %, specificity of 99 %, and accuracy of 97 % were found when clinical examination was used as the reference standard. The correlation to US was 0.89. Mild softening was found in 7 % of the healthy volunteers and in 11 % of the patients.

CONCLUSION

Our results emphasize that only distinct softening of Achilles tendons is comparable to clinical examination and US findings. However, mild softening might be explained by very early changes in tissue elasticity in the case of Achilles tendinopathy, which should be assessed in follow-up studies.

Is sonoelastography of value in assessing tendons?

Sonoelastography is a newly introduced ultrasound technique that evaluates tissue elasticity and thus provides additional information to that offered by conventional ultrasound images. In the musculoskeletal field, sonoelastography can help improve estimation of tendon stiffness. In this article, the principles and future developments of sonoelastography are discussed using the strongest and thickest tendon of the human body, the Achilles tendon, for illustrative purposes. Preliminary findings of sonoelastography in healthy and pathological Achilles tendons, technical considerations, examination technique and several limitations are addressed. The usefulness of elastography can be expected to increase rapidly in the musculoskeletal field, as soon as we learn to interpret elastographic artifacts as well as to take advantage of the new information provided by sonoelastography.