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.

Nerve entrapment syndromes: detection by ultrasound.

Nerve entrapment syndromes are commonly encountered in clinical practice. Accurate diagnosis and management require a knowledge of peripheral neuroanatomy and the recognition of key clinical symptoms and findings. Nerve entrapment syndromes are frequently associated with structural abnormalities of the affected nerve. Therefore, imaging allows the evaluation of the cause, severity, and etiology of the entrapment. High-resolution ultrasonography can depict early and chronic morphological changes within the entire nerve course and is therefore an ideal modality for diagnosing various nerve entrapment syndromes in different regions. This review article presents some of the most common types of nerve entrapment, with special focus on ultrasound imaging and key findings.

Intraobserver Assessment of Shear Wave Elastography in Tensor Fasciae Latae and Gluteus Maximus Muscle: The Importance of the Hip Abductor Muscles in Runners Knee Compared to Healthy Controls.

BACKGROUND: Iliotibial band syndrome (ITBS) represents one of the most common running related injuries. The pathophysiology is postulated to be caused by excessive ITB tension, impingement and irritation of soft tissues at the lateral femoral epicondyle. However, direct evidence has yet to be found and the multifactorial etiology is under discussion. The purpose was to evaluate stiffness of ITB, gluteus maximus (GM) and tensor fasciae latae (TFL) muscles using shear wave elastography (SWE). METHODS: In 14 patients with clinically verified ITBS and 14 healthy controls, three SWE measurements each of ITB, GM and TFL in both legs was performed to determine measurement reliability and between-group and -leg differences. RESULTS: The mean value of ITB was 12.8 m/s with ICC of 0.76, whereas the values measured in the GM were 3.02 m/s with an ICC of 0.87. No statistically significant difference in controls compared to patients were found (p = 0.62). The mean value of TFL was 5.42 m/s in healthy participants, compared to 3.89 m/s patients with an ICC of 0.98 (p = 0.002). CONCLUSION: Although SWE showed no difference in ITB stiffness, significant differences for TFL muscle stiffness in runner's knee was found, suggesting that the hip abductor muscles might play a bigger role in the pathophysiology of ITBS. We aimed to implement baseline values for stiffness assessments and prove reliability for further prospective studies of SWE in runner's knee.

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.

Magnetic resonance imaging of musculoskeletal infections.

Magnetic resonance imaging (MRI) is a powerful imaging modality in the evaluation of musculoskeletal (MSK) soft tissue, joint, and bone infections. It allows prompt diagnosis and assessment of the extent of disease, which permits timely treatment to optimize long-term clinical outcomes. MRI is highly sensitive and specific in detecting the common findings of MSK infections, such as superficial and deep soft tissue oedema, joint, bursal and tendon sheath effusions, lymphadenopathy, bone marrow oedema, erosive bone changes and periostitis, and bone and cartilage destruction and sequestration. Contrast-enhanced MRI allows detection of non-enhancing fluid collections and necrotic tissues, rim-enhancing abscesses, heterogeneously or diffusely enhancing phlegmons, and enhancing active synovitis. Diffusion-weighted imaging (DWI) is useful in detecting soft-tissue abscesses, particularly in patients who cannot receive gadolinium-based intravenous contrast. MRI is less sensitive than computed tomography (CT) in detecting soft-tissue gas. This article describes the pathophysiology of pyogenic MSK infections, including the route of contamination and common causative organisms, typical MR imaging findings of various soft tissue infections including cellulitis, superficial and deep fasciitis and necrotizing fasciitis, pyomyositis, infectious bursitis, infectious tenosynovitis, and infectious lymphadenitis, and of joint and bone infections including septic arthritis and osteomyelitis (acute, subacute, and chronic). The authors also discuss MRI findings and pitfalls related to infected hardware and diabetic foot infections, and briefly review standards of treatment of various pyogenic MSK infections.

Monosodium Urate Crystal Deposition in Coronary Artery Plaque by 128-Slice Dual-Energy Computed Tomography: An Ex Vivo Phantom and In Vivo Study.

OBJECTIVE: Monosodium uric acid (MSU) crystals may accumulate in the coronary plaque. The objective was to assess whether dual-energy computed tomography (DECT) allows for detection of MSU in coronary plaque. METHODS: Patients were examined with 128-slice DECT applying a cardiac electrocardiogram-gated and peripheral extremity protocol. Patients were divided into 3 groups: gout (tophi >1 cm in peripheral joints), hyperuricemia (>6.5 mg/dL serum uric acid), and controls. The groups were matched for cardiovascular risk factors. Monosodium uric acid-positive (+) and calcified plaque were distinguished, and the coronary artery calcium score was calculated. Ex vivo phantom: MSU solutions were diluted in different NaCL solutions (5%/10%/15%/20%/25%). Coronary artery models with 2 different plaque types (MSU+ and calcified) were created. RESULTS: A total of 96 patients were included (37 with gout, 33 with hyperuricemia, and 26 controls). Monosodium uric acid-positive plaques were found more often in patients with gout as compared with controls (91.9% vs 0.38%; P < 0.0001), and the number of plaques was higher (P < 0.0001). Of 102 MSU+ plaques, 26.7% were only MSU+ and 74.2% were mixed MSU+/calcified. Monosodium uric acid-positive plaque had mean 232.3 Hounsfield units (range, 213-264). Coronary artery calcium score was higher in patients with gout as compared with controls (659.1 vs 112.4 Agatston score; P < 0.001). Patients with gout had more MSU+ plaques as compared with patients with hyperuricemia (91.6% vs 2.9%; P < 0.0001), and coronary artery calcium score was higher (659.1 vs 254 Agatston score; P < 0.001), but there was no difference between patients with hyperuricemia and controls. Ex vivo phantom study: MSU crystals were detected by DECT in solutions with a concentration of 15% or greater MSU and could be distinguished from calcified. CONCLUSIONS: Coronary MSU+ plaques can be detected by DECT in patients with gout.

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.

Shear Wave Elastography of the Plantar Fascia: Comparison between Patients with Plantar Fasciitis and Healthy Control Subjects.

BACKGROUND: The purpose of this study was to evaluate plantar fasciae of healthy subjects and patients with plantar fasciitis by shear wave velocity (SWV) and stiffness with correlation to B-Mode and color Doppler ultrasonography (CDUS) and to establish cut-off values. METHODS: This observational study was conducted with the approval of the Institutional Review Boards (IRBs) of our institution. 108 unilateral plantar fasciae were evaluated by including 87 consecutive patients (mean age 51.7; range: 29-82) (66 women and 21 men) with plantar fasciitis and 21 asymptomatic age matched healthy volunteers (mean age 47.3; range: 32-58) (15 women and 6 men). All patients were prospectively imaged between July 2018 and March 2019. B-mode US was used to measure thickness and CDUS to grade vascularity. SWE measurements were repeated 3 times and mean was used for statistical analysis. RESULTS: Mean SWV value in healthy subjects was 6.94 m/s and in patients 4.98 m/s with a mean stiffness value of 152.88 kPa and 93.54 kPa respectively (p < 0.001). For SWV a cut-off value of 6.16 m/s had a specificity of 80.95% and sensitivity of 79.31%. For stiffness a cut-off value of 125.57 kPa had a specificity of 80.95% and sensitivity of 80.46%. No correlation to CDUS was found. The mean thickness of healthy fascias was 3.3 mm (range 2.4-3.9) compared to 6.1 mm (range 2.0-22.0) in plantar fasciitis (p < 0.001) with no correlation to SWV or to stiffness (r² = 0.02, p = 0.06). CONCLUSION: SWE allows quantitative assessment of plantar fascia stiffness, which decreases in patients with plantar fasciitis. No correlation to the thickness of the plantar fascia was found, therefore it represents an independent factor for the diagnosis of plantar fasciitis and could be helpful in addition to thickness measurement in unclear cases.

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.

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 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%).

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 Evaluation, Imaging, and Management of Adolescent Idiopathic and Adult Degenerative Scoliosis.

We provide a comprehensive review of the clinical presentation, imaging evaluation, classification, and management of adolescent idiopathic and adult degenerative scoliosis.

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.

Nerve Entrapment Syndromes at the Wrist and Elbow by Sonography.

Nerve entrapment syndromes of the upper extremity are associated with structural abnormalities or by an intrinsic abnormality of the nerve. Nerve entrapment syndromes generally have a typical clinical presentation, and findings on physical examination and in conjunction with electrodiagnostic studies imaging is used to evaluate the cause, severity, and etiology of the entrapment. With the development of high-frequency linear array transducers (12-24 MHz), ultrasound (US) is incomparable in terms of spatial resolution to depict morphological aspects and changes in nerves. US can identify the abnormalities causing entrapment, such as fibrous bands, ganglia, anomalous muscles, and osseous deformities, with the advantage of dynamic assessment under active and passive examination. US is a unique diagnostic modality that allows superb visualization of both large and small peripheral terminal nerve branches of the upper extremity and enables the correct diagnosis of various nerve entrapment syndromes.