The distribution of urate deposition within the extremities in gout: a review of 148 dual-energy CT cases

Dual-energy CT in musculoskeletal imaging: technical considerations and clinical applications

Dual-energy CT stands out as a robust and innovative imaging modality, which has shown impressive advancements and increasing applications in musculoskeletal imaging. It allows to obtain detailed images with novel insights that were once the exclusive prerogative of magnetic resonance imaging. Attenuation data obtained by using different energy spectra enable to provide unique information about tissue characterization in addition to the well-established strengths of CT in the evaluation of bony structures. To understand clearly the potential of this imaging modality, radiologists must be aware of the technical complexity of this imaging tool, the different ways to acquire images and the several algorithms that can be applied in daily clinical practice and for research. Concerning musculoskeletal imaging, dual-energy CT has gained more and more space for evaluating crystal arthropathy, bone marrow edema, and soft tissue structures, including tendons and ligaments. This article aims to analyze and discuss the role of dual-energy CT in musculoskeletal imaging, exploring technical aspects, applications and clinical implications and possible perspectives of this technique.

Advanced Imaging of Gout and Other Inflammatory Diseases Around the Knee

The knee is one of the most commonly affected joints in the course of inflammatory arthropathies, such as crystal-induced and autoimmune inflammatory arthritis. The latter group includes systemic connective tissue diseases and spondyloarthropathies. The different pathogenesis of these entities results in their varied radiologic images. Some lead quickly to joint destruction, others only after many years, and in the remaining, destruction will not be a distinguishing radiologic feature.Radiography, ultrasonography, and magnetic resonance imaging have traditionally been the primary modalities in the diagnosis of noninflammatory and inflammatory arthropathies. In the case of crystallopathies, dual-energy computed tomography has been introduced. Hybrid techniques also offer new diagnostic opportunities. In this article, we discuss the pathologic findings and imaging correlations for crystallopathies and inflammatory diseases of the knee, with an emphasis on recent advances in their imaging diagnosis.

Management of Gout in the Hand and Wrist

Gout, or monosodium urate deposition disease, is the most common form of inflammatory arthritis that affects almost 4% of adults in the United States.Medical management involves lifestyle modifications and urate-lowering therapy to reduce the frequency of gout flares, decrease the tophi size, and improve upper extremity function. Goals for surgical management of gout include functional optimization, symptomatic treatment, and cosmetic restoration.This article focuses on the medical and surgical treatment of the common manifestations of gout in the upper extremity including tophi, tenosynovitis, joint contractures, neural compression, and arthropathy.

[Detection of Monosodium Urate Crystal of Hand and Wrist in Suspected Gouty Arthritis Patients on Dual-Energy CT and Relationship with Serum Urate Level]

Purpose

We retrospectively investigated the characteristics of patients with monosodium urate (MSU) deposits of the hand and wrist on dual-energy CT (DECT) compared to those without. We also attempted to determine the pattern of MSU distribution in DECT.

Materials and Methods

In total, 93 patients were included who had undergone DECT for evaluation of the hand or wrist pain under the clinical impression of gouty arthritis. The total volume of MSU deposits on DECT was calculated and the pattern of MSU distribution on DECT was analyzed. Also, the level of the serum urate at the time of DECT and the highest level of the serum urate of the patients were obtained from their records and the relationship between MSU and serum urate level was evaluated.

Results

The range of the volume of MSU deposits on DECT was 0.01-16.11 cm³ (average: 1.07 cm³). The average level of serum urate was significantly higher in the MSU positive group than that in the MSU negative group. MSU deposits were most frequently observed in the wrists followed by fingers and digitorum tendons.

Conclusion

On DECT, MSU deposits were most frequently detected in the wrist and related with high serum urate level.

Summary Report of the Arthritis Foundation and the American Orthopaedic Foot & Ankle Society's Symposium on Targets for Osteoarthritis Research: Part 1: Epidemiology, Pathophysiology, and Current Imaging Approaches

This first of a 2-part series of articles recounts the key points presented in a collaborative symposium sponsored jointly by the Arthritis Foundation and the American Orthopaedic Foot & Ankle Society with the intent to survey the state of scientific knowledge related to incidence, diagnosis, pathologic mechanisms, and injection treatment options for osteoarthritis (OA) of the foot and ankle. A meeting was held virtually on December 3, 2021. A group of experts were invited to present brief synopses of the current state of knowledge and research in this area. Part 1 overviews areas of epidemiology and pathophysiology, current approaches in imaging, diagnostic and therapeutic injections, and genetics. Opportunities for future research are discussed. The OA scientific community, including funding agencies, academia, industry, and regulatory agencies, must recognize the needs of patients that suffer from arthritis of foot and ankle. The foot and ankle contain a myriad of interrelated joints and tissues that together provide a critical functionality. When this functionality is compromised by OA, significant disability results, yet the foot and ankle are generally understudied by the research community. Level of Evidence: Level V - Review Article/Expert Opinion.

The Clinical Utility of Dual-Energy Computed Tomography in the Diagnosis of Gout-A Cross-Sectional Study

Dual-energy computed tomography (DECT) is an imaging technique that detects monosodium urate (MSU) deposits. This study aimed to assess the clinical utility of DECT in the diagnosis of gout. A total of 120 patients with clinical suspicion of gout who underwent DECT were retrospectively enrolled. The sensitivity and specificity of DECT alone, American College of Rheumatology (ACR)/European Alliance of Associations for Rheumatology (EULAR) classification criteria without DECT, and ACR/EULAR criteria with DECT were assessed. Additionally, an analysis of gout risk factors was performed. When artifacts were excluded, any MSU volume provided the best diagnostic value of DECT (AUC = 0.872, 95% CI 0.806−0.938). DECT alone had a sensitivity of 90.4% and specificity of 74.5%. Although ACR/EULAR criteria without DECT provided better diagnostic accuracy than DECT alone (AUC = 0.926, 95% CI 0.878−0.974), the best value was obtained when combing both (AUC = 0.957, 95% CI 0.924−0.991), with 100% sensitivity and 76.6% specificity. In univariate analysis, risk factors for gout were male sex, presence of tophi, presence of MSU deposits on DECT, increased uric acid in serum (each p < 0.001), and decreased glomerular filtration rate (GFR) (p = 0.029). After logistic regression, only increased serum uric acid (p = 0.034) and decreased GFR (p = 0.018) remained independent risk factors for gout. Our results suggest that DECT significantly increases the sensitivity of the ACR/EULAR criteria in the diagnosis of gout.

Activation of the transcription factor NRF2 mediates the anti-inflammatory properties of a subset of over-the-counter and prescription NSAIDs

Nonsteroidal anti-inflammatory drugs (NSAIDs) inhibit cyclooxygenase (COX) enzymes and are ubiquitously used for their anti-inflammatory properties. However, COX inhibition alone fails to explain numerous clinical outcomes of NSAID usage. Screening commonly used NSAIDs in primary human and murine myeloid cells demonstrated that NSAIDs could be differentiated by their ability to induce growth/differentiation factor 15 (GDF15), independent of COX specificity. Using genetic and pharmacologic approaches, NSAID-mediated GDF15 induction was dependent on the activation of nuclear factor erythroid 2-related factor 2 (NRF2) in myeloid cells. Sensing by Cysteine 151 of the NRF2 chaperone, Kelch-like ECH-associated protein 1 (KEAP1) was required for NSAID activation of NRF2 and subsequent anti-inflammatory effects both in vitro and in vivo. Myeloid-specific deletion of NRF2 abolished NSAID-mediated tissue protection in murine models of gout and endotoxemia. This highlights a noncanonical NRF2-dependent mechanism of action for the anti-inflammatory activity of a subset of commonly used NSAIDs.

Role of Dual-Energy Computed Tomography in the Identification of Monosodium Urate Deposition in Gout Patients: A Comprehensive Analysis of 828 Joints According to Structural Joint Damage

Background

Dual-energy computed tomography (DECT) has become a promising, non-invasive procedure for the visualization, characterization, and quantification of monosodium urate (MSU) crystals, which aids clinicians in the diagnosis of gout. In this study, we aimed to examine the diagnostic accuracy of DECT in the evaluation of gout.

Methodology

This cross-sectional retrospective study included patients who were clinically diagnosed with gout and underwent a DECT scan.

Results

A majority (80.4%) of the MSU deposits were found in the ankle joints. The presence of MSU deposits on DECT scan was highly correlated with bone erosion in the upper limb (odds ratio [OR] = 132; 95% confidence interval [CI] = 17.3-1004.3), bone sclerosis in the lower limb (OR = 36.4; 95% CI = 15.4-86.1), bone erosion in metacarpophalangeal joints (OR = 160; 95% CI = 42.7-600.2), and bone sclerosis in metatarsophalangeal joints (OR = 35.6; 95% CI = 15.5-81.9). Using linear regression analysis on patient-level data, correlations were found between DECT MSU crystal deposition and damage on all categories of structural joint damage showing significant association with erosion (r = 0.91, p < 0.001) and space narrowing (r = 0.75, p < 0.001) but not with joints having periarticular calcification (r = 0.52, p < 0.041).

Conclusions

Our study established DECT as a valid method for detecting MSU deposits and their association with structural joint deterioration in a Vietnamese population.

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.

Urate-lowering therapy for gout and asymptomatic hyperuricemia in the pediatric population: a cross-sectional study of a Japanese health insurance database

BACKGROUND

Our previous research showed that uric acid lowering therapy (ULT) for gout and hyperuricemia is being prescribed for pediatric patients even though these drugs have not been approved for use in children. However, the actual clinical situation has not been clearly elucidated. In this paper, we provide an in-depth look at the details of actual clinical practice.

METHODS

This retrospective cross-sectional study accessed health insurance data for 696,277 children from April 2016 through March 2017 to identify pediatric patients with gout or asymptomatic hyperuricemia, calculate the proportion of patients prescribed ULTs, and analyze population characteristics. Adherence and mean dose for febuxostat and allopurinol, the most commonly prescribed drugs, were also analyzed.

RESULTS

Among children with gout or asymptomatic hyperuricemia, we found that 35.1% (97/276) were prescribed ULT. This proportion increased with age, especially among males. By comorbidity, ULT was prescribed to 47.9% (46/96) of patients with kidney disease, 41.3% (26/63) for cardiovascular disease, 40.0% (6/15) for Down syndrome, and 27.1% (32/118) for metabolic syndrome. In patients with kidney disease, febuxostat was prescribed more than twice as frequently as allopurinol (28 vs. 12). Median values for the medication possession ratio (MPR) of febuxostat and allopurinol were 70.1 and 76.7%, respectively, and prescriptions were continued for a relatively long period for both drugs. Both drugs were prescribed at about half the adult dose for patients 6-11 years old and about the same as the adult dose for patients 12-18 years old.

CONCLUSIONS

This study showed that the continuous management of serum uric acid is being explored using off-label use of ULT in pediatric patients with gout or asymptomatic hyperuricemia in Japan. Drug selection is based on patient characteristics such as sex, age, and comorbidities, and pediatric dosage is based on usage experience in adults. To develop appropriate pediatric ULT, clinical trials are needed on the efficacy and safety of ULT in the pediatric population.

TRIAL REGISTRATION

UMIN000036029 .

Characteristics of monosodium urate crystal deposition in the foot in the different stages of gout by dual-energy computed tomography

OBJECTIVE

To compare the characteristics of monosodium urate (MSU) crystal deposition at specific anatomical sites of the foot detected by dual-energy computed tomography in patients with different stages of gout.

MATERIALS AND METHODS

This study included 101 patients with gout, 64 had early gout (<3 years) and 37 had late gout (>3 years). We retrospectively compared the total volumes of MSU crystals, the detection rates, and the morphology of MSU crystals at specific anatomical sites in the foot of the patients with different gout durations.

RESULTS

The total volume of MSU crystals in patients with early gout was significantly smaller than that in patients with late gout (P < 0.05). The detection rates and morphology of MSU crystals in the anterior calf tendons, ankle joints, tarsometatarsal joints, and metatarsophalangeal joints differed significantly between the patients with early and late gout (P < 0.05). There were no significant differences in the detection rates of submillimeter MSU crystals at the other specific anatomical sites, except for the tendons of the anterior calf, the ankle joint, and the metatarsal joint (P > 0.05). The submillimeter MSU crystal deposition was most common in the tendons of the posterior calf, the proportions in patients with early gout and late gout were 85.9% and 70.3%. Only submillimeter deposition existed in 52 patients (81.3%) with early gout and 11 patients (29.7%) with late gout at all sites of the foot.

CONCLUSION

Dual-energy computed tomography detection of submillimeter MSU crystal deposits in the foot is of great significance for the diagnosis of gout, especially along tendons.

[Clinical classification and treatment experience of wrist gouty arthritis]

Objective

To explore the clinical characteristics, clinical classification, and treatment of wrist gouty arthritis.

Methods

The clinical data of 24 patients with wrist gouty arthritis and complete follow-up between April 2011 and August 2020 were retrospectively analyzed. There were 21 males and 3 females; the first onset age was 21-72 years, with a median age of 50 years. There were 15 cases of simple wrist joint disease, and 9 cases of other joints (hand, knee, ankle, metatarsophalangeal joint) involvement; 19 cases of wrist joint as the first site. Except for 1 patient with a medical history of 21 years, the time from onset to diagnosis in the remaining 23 patients was 7 days to 9 years, with a median time of 2 months. According to the clinical manifestations, imaging manifestations, lesion range, and intraoperative wrist arthroscopy manifestations of wrist gouty arthritis, they were classified into 5 types from mild to severe. Among the 24 patients, 13 were type Ⅰ, 2 were type ⅡA, 3 were type ⅡB, 2 were type ⅢA, 3 were type Ⅳ, and 1 was type Ⅴ. The time from first onset to diagnosis for type Ⅰ and type Ⅱ patients was (12.7±40.1) months, and for type Ⅲ-Ⅴ patients was (152.0± 88.5) months, the difference was significant ( t=-4.355, P=0.001). Thirteen patients with type Ⅰ received conservative treatment (including diet, exercise, lifestyle intervention, and medication), and 11 patients with type Ⅱ-Ⅴ received surgical treatment (including 1 case of arthroscopic synovial membrane and gout crystal clearing, 1 case of ligament repair, 5 cases of lesion debridement/artificial bone grafting and filling, 3 cases of wrist fusion, and 1 case of tophicectomy). Before and after treatment, the visual analogue scale (VAS) score was used to evaluate the improvement of wrist joint pain; and the range of motion of the wrist joint (including palmar flexion, dorsal extension, radial deviation, and ulnar deviation) was evaluated.

Results

Thirteen conservatively treated patients were followed up 10 months to9 years, with an average of 2.2 years. The VAS scores before treatment and at last follow-up were 6.8±0.7 and 2.9±0.9, respectively, and the difference was significant ( t=12.309, P=0.000). During follow-up, there was no wrist bone and wrist joint damage; wrist joint range of motion basically reached normal. At last follow-up, the wrist joint palmar flexion, dorsal extension, radial deviation, and ulnar deviation significantly improved when compared with the values before treatment ( P<0.05). Eleven surgically treated patients were followed up 5 months to 9 years, with an average of 4.9 years. The swelling and pain of all patients fully relieved, and the VAS scores were 7.3±0.8 before operation, 2.7±0.6 at 1 month after operation, and 2.5±0.6 at last follow-up, which significantly improved after operation ( P<0.05); there was no significant difference between 1 month after operation and last follow-up ( P>0.05). Excluded 3 patients who underwent wrist fusion, the other 8 patients had significantly improved wrist joint palmar flexion, dorsal extension, radial deviation, and ulnar deviation at last follow-up ( P<0.05). The patient's subjective satisfaction with the surgical results reached 100%.

Conclusion

A missed diagnosis or misdiagnosis of wrist gouty arthritis will greatly damage the wrist stability and functions. Early and proper interventions can effectively retard the progress of the disease. For the late-stage cases, a staged surgical protocol is recommended.

Distribution of bony erosions in feet and performance of two bone erosion scores: A dual-energy computed tomography study of 61 patients with gout

OBJECTIVES

To assess the distribution of bone erosions and two erosion scores in the feet of patients with gout and analyze the association between erosion scores and monosodium urate (MSU) crystal deposition using dual-energy computed tomography (DECT).

MATERIALS AND METHODS

We included all patients who underwent DECT of both feet between 2016 and 2019 in our radiology department, with positive detection of MSU deposits. Data on sex, age, treatment, serum urate, and DECT urate volumes were obtained. CT images were analyzed to score bone erosions in 31 sites per foot by using the semi-quantitative method based on the Rheumatoid Arthritis MRI Scoring (RAMRIS) system and the Dalbeth-simplified score. Reproducibility for the two scores was calculated with intraclass correlation coefficients (ICCs). Correlations between clinical features, erosion scores and urate crystal volume were analyzed by the Spearman correlation coefficient (r).

RESULTS

We studied 61 patients (mean age 62.0 years); 3,751 bones were scored. The first metatarsophalangeal joint and the midfoot were the most involved in terms of frequency and severity of bone erosions. The distribution of bone erosions was not asymmetrical. The intra- and inter-observer reproducibility was similar for the RAMRIS and Dalbeth-simplified scores (ICC 0.93 vs 0.94 and 0.96 vs 0.90). DECT urate volume was significantly correlated with each of the two erosion scores (r = 0.58-0.63, p < 0.001). There was a high correlation between the two scores (r = 0.96, p < 0.001).

CONCLUSIONS

DECT demonstrates that foot erosions are not asymmetric in distribution and predominate at the first ray and midfoot. The two erosion scores are significantly correlated with DECT urate volume. An almost perfect correlation between the RAMRIS and Dalbeth-simplified scores is observed.

What is the diagnostic value of dual-energy computed tomography in patients with clinical diagnosis of gout?

OBJECTIVES

To investigate the frequency of monosodium urate (MSU) crystal deposits on dual-energy computed tomography (DECT) in patients with clinical diagnosis of gout and the factors associated MSU crystal positivity.

METHODS

This study was conducted in patients with clinical diagnosis of gout who underwent DECT. Clinical features were compared between patients with positive and those with negative DECT results. A logistic regression analysis was performed to determine the factors associated with MSU crystal positivity on DECT.

RESULTS

A total of 148 patients with clinical diagnosis of gout were included, and MSU crystal deposition on DECT was observed in 64 patients (43.3%). The patients with positive DECT results were more likely to have renal insufficiency, longer disease duration, and higher serum urate level than those with negative. In the multivariable analysis, first gout attack (odds ratio 0.462; 95% confidence interval 0.229-0.931, p = 0.031) was associated with a less likely MSU crystal deposit-positive DECT result. In the subgroup analysis of patients with first attack, serum urate level > 8 mg/dL was associated with DECT positivity.

CONCLUSION

Of the patients with clinical diagnosis of gout, those with renal insufficiency, longer disease duration, and high serum urate level were more likely to be positive of gout on DECT. First gout attack was associated with less likely to be positive for MSU crystal on DECT. Thus, performing DECT scan in the selected patients who had characteristics that highly probability of DECT positivity could increase positive predictive value.

Gouty Involvement of Foot and Ankle: Beyond Flares

The foot and ankle are common locations of deposition of monosodium urate (MSU) crystals, as indicated by the clinical manifestations presented by patients with gout, which are not limited to the acute inflammation of the big toe. We present a narrative literature review aimed to update the gout involvement of foot and ankle and how it affects the quality of life. Cumulative reports indicate that gout, even at the non-tophaceous stage, could cause pain, gait impairment and limit the mobility at lower limbs. These patients may present difficulties in some activities of daily living such as choosing footwear, thus leading to an impaired quality of life. Gout is a curable disease by dissolving MSU crystals but remains unclear how this could modify some of these foot and ankle manifestations, especially when structural damage has already occurred. Furthermore, a collaboration between rheumatologists and podiatrists seems helpful to understand, relieve these symptoms and improve the quality of life in gouty patients.

Prevalence of gout and asymptomatic hyperuricemia in the pediatric population: a cross-sectional study of a Japanese health insurance database

Background

Although gout is rare in children, chronic sustained hyperuricemia can lead to monosodium urate deposits progressing to gout, just as in adults. This study assessed prevalence and characteristics of gout and asymptomatic hyperuricemia, and incidence of gouty arthritis in the pediatric population, using data from Japanese health insurance claims. The diagnosis and treatment of pediatric gout and hyperuricemia were analyzed, and specific characteristics of those patients were assessed. Since Japanese guidelines recommend treatment with uric acid lowering drugs for asymptomatic hyperuricemia as well as for gout, these data were also used to investigate the real-world use of uric acid lowering drugs in a pediatric population.

Methods

This cross-sectional study was based on a 2016–2017 Japanese health insurance claims database, one of the largest epidemiology claims databases available in Japan, which included 356,790 males and 339,487 females 0–18 years of age. Outcomes were measured for prevalence, patient characteristics, treatment with uric acid lowering drugs for gout and asymptomatic hyperuricemia, and prevalence and incidence of gouty arthritis. Because uric acid can be elevated by some forms of chemotherapy, data from patients under treatment for malignancies were excluded from consideration.

Results

Total prevalence of gout and asymptomatic hyperuricemia in 0–18 year-olds was 0.040% (276/696,277 patients), with gout prevalence at 0.007% (48/696,277) and asymptomatic hyperuricemia at 0.033% (228/696,277). Prevalence of gout and asymptomatic hyperuricemia was highest in adolescent males, at 0.135% (176/130,823). The most common comorbidities for gout and asymptomatic hyperuricemia were metabolic syndrome at 42.8% (118/276) and kidney disease at 34.8% (96/276). Of the patients diagnosed with gout or asymptomatic hyperuricemia, 35.1% (97/276) were treated with uric acid lowering drugs. Gouty arthritis developed in 43.8% (21/48) of gout patients during the study, at an incidence of 0.65 flares/person-year.

Conclusions

Even the pediatric population could be affected by asymptomatic hyperuricemia, gout, and gouty arthritis, and uric acid lowering drugs are being used in this population even though those drugs have not been approved for pediatric indications. Such off-label use may indicate a potential need for therapeutic agents in this population.

Trial registration

UMIN000036029.

Differences in Achilles tendon stiffness in people with gout: a pilot study

Background

Gout has been associated with weaker foot/leg muscles and altered gait patterns. There is also evidence of on-going foot pain and an increased risk of tendinopathy, with the Achilles and patella tendons most frequently affected in gout. Additionally, the inflammation associated with gout may change tissue elasticity. Ultrasound imaging utilising shear wave elastography (SWE) offers a non-invasive method of quantifying changes in tendon stiffness. SWE findings have not previously been reported in individuals with gout. We sought to determine differences in Achilles tendon stiffness in people with gout compared to controls (non-gout).

Methods

A cross sectional study comparing 24 people with gout and 26 age/sex-matched controls. Clinical and demographic data were collated, and US imaging used to determine tendon thickness, presence of gouty tophi and/or aggregates and levels of angiogenesis. Ten shear wave elastography (SWE) measures were taken along the centre of a longitudinal section of the mid-portion of each Achilles tendon. Prior to data collection, intra-observer error was good (>0.69). Data were summarised using descriptive statistics and a repeated measures ANCOVA was used to compare SWE measures between the two groups for the left and right foot separately after accounting for Body Mass Index (BMI).

Results

A small proportion of those with gout presented with intra-tendon aggregates and/or intra-tendon tophi in one or both tendons. There was no statistically significant difference in tendon thickness between groups. Neo-vascularity was present in a third of gout participants. SWE findings demonstrated significantly reduced tendon stiffness in those with gout compared to controls: right Achilles mdiff =1.04 m/s (95% CI (0.38 to 1.7) p = 0.003 and left Achilles mdiff = 0.7 m/s (95% CI 0.09 to 1.32) p = 0.025. No relationship between the presence of tophi and SWE values were detected.

Conclusion

Subjects with chronic gout show significantly reduced Achilles tendon stiffness compared to non-gout controls. From a clinical standpoint, our findings were similar to SWE measurements in subjects with Achilles tendinopathy and who did not have gout.

Dual-energy CT in gout patients: Do all colour-coded lesions actually represent monosodium urate crystals?

BACKGROUND

Dual-energy CT (DECT) can acknowledge differences in tissue compositions and can colour-code tissues with specific features including monosodium urate (MSU) crystals. However, when evaluating gout patients, DECT frequently colour-codes material not truly representing MSU crystals and this might lead to misinterpretations. The characteristics of and variations in properties of colour-coded DECT lesions in gout patients have not yet been systematically investigated. The objective of this study was to evaluate the properties and locations of colour-coded DECT lesions in gout patients.

METHODS

DECT of the hands, knees and feet were performed in patients with suspected gout using factory default gout settings, and colour-coded DECT lesions were registered. For each lesion, properties [mean density (mean of Hounsfield Units (HU) at 80 kV and Sn150kV), mean DECT ratio and size] and location were determined. Subgroup analysis was performed post hoc evaluating differences in locations of lesions when divided into definite MSU depositions and possibly other lesions.

RESULTS

In total, 4033 lesions were registered in 27 patients (23 gout patients, 3918 lesions; 4 non-gout patients, 115 lesions). In gout patients, lesions had a median density of 160.6 HU and median size of 6 voxels, and DECT ratios showed an approximated normal distribution (mean 1.06, SD 0.10), but with a right heavy tail consistent with the presence of smaller amounts of high effective atomic number lesions (e.g. calcium-containing lesions). The most common locations of lesions were 1st metatarsophalangeal (MTP1), knee and midtarsal joints along with quadriceps and patella tendons. Subgroup analyses showed that definite MSU depositions (large volume, low DECT ratio, high density) had a similar distribution pattern, whereas possible calcium-containing material (high DECT ratio) and non-gout MSU-imitating lesions (properties as definite MSU depositions in non-gout patients) were primarily found in some larger joints (knee, midtarsal and talocrural) and tendons (Achilles and quadriceps). MTP1 joints and patella tendons showed only definite MSU depositions.

CONCLUSION

Colour-coded DECT lesions in gout patients showed heterogeneity in properties and distribution. MTP1 joints and patella tendons exclusively showed definite MSU depositions. Hence, a sole focus on these regions in the evaluation of gout patients may improve the specificity of DECT scans.

Diagnosis and Treatment of Patellar Tendon Gouty Tophus: A Case Report

The main aim of this case report is to thoroughly describe the steps of diagnosis and treatment in the rare incidence of patellar tendon gouty tophus. The case of a 53-year-old man manual worker who was treated with open excision of the lesion, following failure of extended medical treatment with rheumatological input, is presented. Surgical treatment led to full restoration of the patient's knee function. Open or arthroscopic surgery is a viable option for the unusual case of intratendinous patellar gouty deposition if the patient fails medical management. Medical treatment should still be the mainstay.

Gouty arthritis: Can we avoid unnecessary dual-energy CT examinations using prior radiographs?

OBJECTIVE

The dual-energy CT (DECT) algorithm for urate detection is feasible only if hyperdense deposits are present. Based on our experience, around half of the performed DECT examinations show no such deposits and thus were useless for this indication. Our diagnostic accuracy study investigates whether conventional radiographs can serve as gatekeeper test prior to DECT for reliable exclusion of such radiopaque deposits.

MATERIALS AND METHODS

In this retrospective study, 77 clinically indicated DECT examinations of the hand (n = 29), foot (n = 36) and ankle (n = 12) of 55 patients (13 female, mean age 62±15 years) with suspected gouty arthritis were included. Two blinded readers independently evaluated DECT, gray-scale CT images (reference standard) and corresponding standardized radiographs for the presence/location of dense soft tissue deposits.

RESULTS

Interreader agreement for detection of soft tissue deposits with DECT and radiographs was excellent (DECT: both readers, κ = 1; radiographs: both readers, κ = 0.94). DECT showed soft tissue deposits in 54/77 DECT (70%) scans. 30/54 scans (56%) showed deposits on the corresponding radiographs, while in 24 scans (44%) no deposits were seen on radiographs. Test performance of radiographs for soft tissue deposit detection: sensitivity 56%, specificity 100%, PPV 100%, NPV 48.9%, and accuracy 69%. Low density of the deposits was the main reasons for false-negative radiographs (19 cases, 79%), followed by superimposition of deposits by osseous structures (5 cases, 21%).

CONCLUSION

Conventional radiographs of the hand, foot and ankle cannot serve as a gatekeeper test for reliable exclusion of radiopaque soft tissue deposits prior to DECT.

Ankle joint function during walking in tophaceous gout: A biomechanical gait analysis study

BACKGROUND

The foot and ankle are frequently affected in tophaceous gout, yet kinematic and kinetic changes in this region during gait are unknown. The aim of the study was to evaluate ankle biomechanical characteristics in people with tophaceous gout using three-dimensional gait analysis.

METHODS

Twenty-four participants with tophaceous gout were compared with 24 age-and sex-matched control participants. A 9-camera motion analysis system and two floor-mounted force plates were used to calculate kinematic and kinetic parameters.

RESULTS

Peak ankle joint angular velocity was significantly decreased in participants with gout (P < 0.01). No differences were found for ankle ROM in either the sagittal (P = 0.43) or frontal planes (P = 0.08). No differences were observed between groups for peak ankle joint power (P = 0.41), peak ankle joint force (P = 0.25), peak ankle joint moment (P = 0.16), timing for peak ankle joint force (P = 0.81), or timing for peak ankle joint moment (P = 0.16).

CONCLUSIONS

Three dimensional gait analysis demonstrated that ankle joint function does not change in people with gout. People with gout demonstrated a reduced peak ankle joint angular velocity which may reflect gait-limiting factors and adaptations from the high levels of foot pain, impairment and disability experienced by this population.

Ultrasound scans and dual energy CT identify tendons as preferred anatomical location of MSU crystal depositions in gouty joints

OBJECTIVE

The present study was performed to localize the articular deposition of monosodium urate (MSU) crystal in joints. We compare the detection efficiencies of dual-energy CT (DECT) and ultrasound scans.

METHODS

Analyses by DECT and ultrasound were performed with 184 bilateral joints of the lower limbs of 54 consecutive gout patients. All joints were categorized into (1) knee, (2) ankle, (3) MTP1, and (4) MTP2, and sorted into those with and those without detectable MSU deposition. The comparison of the positive rate between DECT and ultrasound and the agreement was performed using the McNemar test and the Cohen's κ coefficient, respectively. Next, we listed the MSU crystal deposition as assessed by ultrasound between the DECT-positive and -negative joints according to their interior structure. We included tendons, synovia, cartilage, subcutaneous tissue, etc. RESULTS: Among all joints, the percentages with MSU crystal deposition detected by DECT (99/184, 53.8%) and ultrasound (106/184, 57.6%) were comparable (P = 0.530 > 0.05). For MTP1 (21/34, 61.8%; 12/34, 35.3%; P < 0.05) and MTP2-5 (17/34, 50.0%; 10/34, 29.4%, P < 0.05), ultrasound and DECT were more efficient, respectively. The data concordance in 46 of 50 joints (92.00%; κ = 0.769, P < 0.05) for knee; and 27 of 34 joints (79.41%; κ = 0.588, P < 0.05) for MTP2-5 and suggested that tendons were the most frequent anatomical location of MSU crystal deposition.

CONCLUSIONS

The tendons are the most frequent anatomical location of MSU crystal depositions. The concordance rate of knee joints and MTP2-5 joints shows good agreement between DECT and ultrasound depending on the location.

Role of dual-energy CT in the diagnosis and follow-up of gout: systematic analysis of the literature

The aim of this systematic review was to determine the potential role of dual-energy CT in the diagnosis and follow-up of gout with regard to the Outcome Measures in Rheumatology (OMERACT) filter. A systematic analysis of the literature was conducted using the MEDLINE and Cochrane databases and published abstracts of international congresses, according to the criteria of the OMERACT filter: feasibility, reproducibility, validity versus laboratory (serum urate, MSU synovial fluid aspirate) and other imaging modalities for gout, and its sensitivity to change in patients on urate lowering therapy (ULT). Thirty-two articles were found representing a total of 1502 patients. The data on feasibility showed that the examination took little time and involved low levels of radiation but had current limited availability. Intra- and inter-observer reproducibility was excellent, with intra-class correlation coefficients > 0.9. Validity in comparison with polarized-light microscopy showed good sensitivity and specificity (> 80%). The diagnostic performance was better than that of radiography and conventional CT-scan and at least equivalent to that of ultrasonography. The sensitivity to change varied with effect sizes from 0.05 (low) to 1.24 (high) for decrease in the tophus volume following different ULT in gout patients. Dual-energy CT-scan is a reproducible and accurate imaging modality for the diagnosis of gout, particularly for tophaceous gout (intra- or extra-articular). It can become a second-line imaging modality of choice in cases of diagnostic doubt, such as ultrasonography. Its role remains uncertain in the follow-up of gout patients treated with ULT and needs further clarification.

Lumbar spinal stenosis attributable to tophaceous gout: case report and review of the literature

Objectives

Tophaceous gout seldom affects the axial skeleton. Symptoms vary according to the differential localization of urate deposits and the diagnosis is often delayed. Here, we report an unusual case of lumbar spinal stenosis caused by extradural tophaceous deposits.

Methods

We retrospectively reviewed a case of a patient with tophaceous gout of the lumbar spine and reviewed the relevant literature.

Results

A 62-year-old man with a 2-year history of lower back pain and a 3-month history of lower limb radiation pain and intermittent claudication was admitted. After laboratory and imaging investigations he underwent surgical decompression and stabilization. Histological analysis of the extracted specimen confirmed that it was gouty tophus. The patient’s symptoms improved progressively after the operation. He recovered very well with no complications.

Conclusion

The mechanism associated with axial gout is not yet clear. Obesity, inactivity, and previous degenerative disc disease may be the risk factors for spinal tophus. The clinical symptoms are diverse according to the differential localization of urate deposits. It is not easy to diagnose this disease radiographically by routine radiological examination. Analysis of a biopsy specimen is definitely the only way to confirm diagnosis. Surgical treatment should be considered in patients with spinal gout who are experiencing neurological deterioration.

Dual-energy computed tomography has limited diagnostic sensitivity for short-term gout

The aim of this study was to discuss the diagnostic value of dual-energy computed tomography (DECT) in patients with gout during different disease phases. Two hundred twenty-one patients (136 with gout and 85 with other arthritic diseases) were recruited to the study. Arthrosis pain was evaluated in all patients by DECT scans. We calculated the sensitivity and specificity of DECT for the diagnosis of gout, including the first onset period, less than 24 months period, and more than 24 months period. We then investigated the related risk factors of urate crystals volume in the foot. The diagnostic sensitivity of DECT in the first onset, less than 24 months, and more than 24 months groups was 35.71, 61.54, and 92.86%, respectively. The overall sensitivity and specificity values were 80.88 and 88.24%, respectively. The multilinear regression analysis showed that longer disease duration (P = 0.001) and higher serum uric acid (SUA) (P = 0.001) were the two important predictive factors of the monosodium urate (MSU) crystal volume in the foot. DECT provides good diagnostic accuracy for detection of MSU crystal deposits in gout patients. However, DECT has limited diagnostic sensitivity for short-term gout patients, especially for the first onset patients. Longer disease duration and higher SUA were predictive factors of MSU crystal volume.

Clinically-evident tophi are associated with reduced muscle force in the foot and ankle in people with gout: a cross-sectional study

Background

The foot and ankle represent a common site for tophi in people with gout, yet it is unclear whether the presence of tophi is related to impaired muscle function. This study aimed to determine the association between foot and ankle tophi and muscle force in people with gout.

Methods

Participants with gout were stratified into two groups based on the presence of clinically-evident tophi affecting the foot or ankle on physical examination. Isometric muscle force for plantarflexion, dorsiflexion, inversion and eversion was measured using static dynamometry. Mixed-models regression was used to determine the difference in muscle force between the two groups while adjusting for age, disease duration and foot pain. This model was also used to determine the difference in muscle force between presence and absence of tophi at specific locations within the foot and ankle. In addition, Pearson’s correlations were used to determine the association between total foot tophus count and muscle force.

Results

Fifty-seven participants were included (22 with foot or ankle tophi and 35 without foot or ankle tophi). Foot and ankle tophi were most often seen at the Achilles tendon. After adjusting for age, disease duration and foot pain, participants with tophi had significantly reduced muscle force during plantarflexion (P < 0.001), dorsiflexion (P = 0.003), inversion (P = 0.003) and eversion (P = 0.001) when compared to participants without tophi. Those with Achilles tophi had significantly reduced force during plantarflexion (P < 0.001), inversion (P = 0.008) and eversion (P = 0.001). No significant differences in muscle force were observed between the presence and absence of tophi at other foot or ankle locations. There were also no significant correlations between total foot tophus count and muscle force (all P > 0.05).

Conclusion

In people with gout, clinically-evident foot or ankle tophi are associated with muscle force deficits during foot plantarflexion, dorsiflexion, inversion and eversion, which persist despite adjusting for age, disease duration and foot pain. Tophi at the Achilles tendon, which associate with force deficits, may contribute to reduced muscular activation and consequent disuse muscle atrophy.

Value of ultrasonography in the diagnosis of gout in patients presenting with acute arthritis

OBJECTIVE

To evaluate the value of ultrasonographic features of crystal deposition for diagnosing gout in patients presenting with acute arthritis.

MATERIALS AND METHODS

Ultrasound scanning of the most inflamed joint was performed on 89 consecutively enrolled patients with acute arthritis. Two radiologists independently reviewed the ultrasound images, and a consensus was achieved with a third radiologist when the interpretations of four key ultrasound features of gout differed. Arthrocentesis and crystal analysis using compensated polarized light microscopy of aspirates are considered the gold standards for gout diagnosis.

RESULTS

Fifty-three (60%) patients had gout, whereas the remaining 36 (40%) had non-gout arthritis. The mean serum uric acid level was 7.1 mg/dl in patients with gout and 4.7 mg/dl in patients with non-gout arthritis. Three US features differed significantly (p < 0.001) between patients with gout and non-gout arthritis: the double contour sign (42 vs. 8%, respectively), intra-articular aggregates (58 vs. 8%), and tophi (40 vs. 0%). No statistically significant differences in detecting intra-tendinous aggregates (32 vs. 17%, p = 0.14) were observed. The sensitivity and specificity of the double contour sign were 42 and 92%, respectively; those of the intra-articular aggregates were 58 and 92%; and those of tophi were 40 and 100%. The positive predictive values for these three features ranged from 88 to 100%, whereas the negative predictive values ranged from 52 to 60%.

CONCLUSIONS

When the prevalence is high, these three ultrasound features may be a useful adjunct in the diagnosis of acute gout, particularly when specialized microscopic techniques are not available.

Dual-Energy CT for the Musculoskeletal System

The principal advantages of dual-energy computed tomography (CT) over conventional CT in the musculoskeletal setting relate to the additional information provided regarding tissue composition, artifact reduction, and image optimization. This article discusses the manifestations of these in clinical practice-urate and bone marrow edema detection, metal artifact reduction, and tendon analysis, with potential in arthrography, bone densitometry, and metastases surveillance. The basic principles of dual-energy CT physics and scanner design will also be discussed. ^© RSNA, 2016.

New urate depositions on dual-energy computed tomography in gouty arthritis during urate-lowering therapy

Reduction of urate depositions in the joints, on dual-energy computed tomography (DECT), in patients with gout during urate-lowering therapy (ULT) was demonstrated in previous studies. The aim of this study was to further investigate the changes in distribution of urate deposits during ULT. This randomized controlled trial enrolled 46 patients diagnosed with gout from Zhongshan Hospital, China, between October 2013 and June 2014. Epidemiological data, serum uric acid level, and arthritis attacks were recorded at monthly follow-up visits. DECT of bilateral feet and ankles was performed at baseline and after 6 months of ULT. Overall, 163 areas of urate deposition were found in the 46 patients; of these, 133/163 (81.6%) areas were associated with former arthritis attacks. On DECT at 6 months, the number of urate deposits decreased to 126, with 68 areas disappearing and 31 new deposits areas. The mean volume of urate deposits at baseline was 1.3 ± 3.8 cm³, decreasing to 0.6 ± 2.1 cm³ at the end of 6 months (P = 0.01), with 3/46 (6.5%) patients showing complete disappearance of urate deposits. New urate depositions were found in 21/46 (45.7%) patients, while urate depositions in some joints disappeared in some joints in 31/46 (67.4%) patients. High-sensitivity C-reactive protein was significantly lower in patients with new deposits (4.6 ± 9.3 vs. 7.1 ± 7.6 mg/dL; P = 0.01). There is dynamic redistribution of urate depositions in gout patients receiving ULT.

Dual-energy CT in gout - A review of current concepts and applications

Dual‐energy computed tomography (DECT) is a relatively recent development in the imaging of gouty arthritis. Its availability and usage have become increasingly widespread in recent years. DECT is a non‐invasive method for the visualisation, characterisation and quantification of monosodium urate crystal deposits which aids the clinician in the early diagnosis, treatment and follow‐up of this condition. This article aims to give an up to date review and summary of existing literature on the role and accuracy of DECT in the imaging of gout. Techniques in image acquisition, processing and interpretation will be discussed along with pitfalls, artefacts and clinical applications.

Imaging as a potential outcome measure in gout studies: A systematic literature review

OBJECTIVE

Despite major progress in the imaging of gout, it is unclear which domains these techniques can evaluate and whether imaging modalities have the potential to provide valid outcome measures. The aim of this study was to assess the use of imaging instruments in gout according to the Outcomes in Rheumatology Clinical Trials (OMERACT) filter to inform the development of imaging as an outcome measure.

METHODS

A systematic literature search of imaging modalities for gout was undertaken. Articles were assessed by two reviewers to identify imaging domains and summarize information according to the OMERACT filter.

RESULTS

The search identified 78 articles (one abstract). Modalities included were conventional radiography (CR) (16 articles), ultrasound (US) (29), conventional computed tomography (CT) (11), dual energy computed tomography (DECT) (20), and magnetic resonance imaging (MRI) (16). Three domains were identified as follows: urate deposition, joint damage, and inflammation. Although sufficient data were available to assess feasibility, validity, and reliability, comprehensive assessment of discrimination was not possible due to the paucity of prospective imaging studies. CR is widely accessible, inexpensive with a validated damage scoring system. US and MRI offer radiation-free methods of evaluating urate deposition, damage and inflammation, but may be limited by accessibility. DECT provides excellent definition of urate deposition and bone damage, but has restricted availability and requires radiation.

CONCLUSIONS

Imaging methods can detect urate deposition, damage, and inflammation in gout. More than one modality may be required depending on the domains and therapeutic agent of interest. No single imaging method currently fulfils all aspects of the OMERACT filter for any domain.

Getting the Most From Your Dual-Energy Scanner: Recognizing, Reducing, and Eliminating Artifacts

OBJECTIVE

Dual-energy CT (DECT) is an innovative imaging modality that allows superior detection of pulmonary embolism, enhanced detection of urate in gout, and improved assessment of metal prostheses when compared with conventional CT.

CONCLUSION

The primary aim of this review is to describe these DECT protocols and compare each to its respective diagnostic reference standards. Moreover, this review will describe how to recognize, reduce, and eliminate DECT artifacts, thereby maximizing its diagnostic capabilities.

Urate crystals deposition in the feet of overweight juveniles and those with symptomatic hyperuricemia: a dual-energy CT study

BACKGROUND

The present study evaluated the clinical value of dual-energy computed tomography (DECT) for detecting urate crystals in juveniles with symptomatic hyperuricemia.

METHODS

We recruited 24 juveniles (15 male and 9 female) who presented with symptomatic hyperuricemia. The mean body mass index (BMI) was 26.4 kg/m2 (standard deviation, SD 11.3 kg/m2). Fifteen juveniles (71.4%) were overweight. DECT scans of the feet were performed. For post-processing, a color-coding gout software protocol was used.

RESULTS

Urate crystals deposition was observed in 21/24 (87.5%) juveniles with symptomatic hyperuricemia. Urate crystals were detected in or around the anatomic site included the first metatarsophalangeal (MTP) joints (5/24, 20.8%); the calcaneus (5/24, 20.8%); any other toe joints (3/24, 12.5%); the astragalus (3/24, 12.5%); the ankle joints (3/24, 12.5%); the metatarsals (2/24, 8.3%); the cuboid (1/24, 4.2%); and other parts of the feet (2/24, 8.3%). Importantly, urate crystals deposition weas located in the soft tissue (tendon/tendon insertion sites/entheses) around the above-mentioned sites in a majority of these patients.

CONCLUSIONS

Urate crystals deposition can be detected by dual-energy CT in the feet of symptomatic hyperuricemia juveniles. DECT can be a valuable diagnostic tool for helping diagnose in juvenile gout.

The first metatarsophalangeal joint in gout: a systematic review and meta-analysis

Background

The aim of this review was to qualitatively synthesise studies that have investigated characteristics of the first metatarsophalangeal joint (1^st MTP) in gout and to undertake a meta-analysis to estimate the average prevalence of acute 1^st MTP arthritis across studies in people with gout.

Methods

Studies published in English were included if they involved participants who had a diagnosis of gout and presented original findings relating to the following outcome measures associated with the 1^st MTP: epidemiology; clinical features; structural and functional characteristics; and microscopic and imaging features.

Results

Forty-five studies were included in the qualitative synthesis. 1^st MTP pain was a prominent feature in people with gout. People with 1^st MTP gout reported walking- and general-disability. Structural and functional characteristics of 1^st MTP gout included hallux valgus, osteoarthritis, and restricted joint motion. Successful crystal aspiration ranged from 81 to 91 % and positive crystal identification via microscopy ranged from 83 to 93 % in patients with a history of 1^st MTP gout. Imaging features were common at the 1^st MTP including the double contour sign, tophi and erosions. Eleven studies involving 2,325 participants were included in the meta-analysis, providing an estimate of the average prevalence of acute 1^st MTP arthritis across studies of 73 % (95 % prediction interval 40–92 %; range 48–97 %; I² = 93 %).

Conclusions

1^st MTP acute arthritis is highly prevalent in people with gout and has a substantial impact on patient-reported pain and disability. Gout affects the structure and function of the 1^st MTP. Microscopic and imaging studies have demonstrated crystal deposition and joint damage at the 1^st MTP in people with gout.

Foot and ankle muscle strength in people with gout: A two-arm cross-sectional study

BACKGROUND

Foot and ankle structures are the most commonly affected in people with gout. However, the effect of gout on foot and ankle muscle strength is not well understood. The primary aim of this study was to determine whether differences exist in foot and ankle muscle strength for plantarflexion, dorsiflexion, inversion and eversion between people with gout and age- and sex-matched controls. The secondary aim was to determine whether foot and ankle muscle strength was correlated with foot pain and disability.

METHODS

Peak isokinetic concentric muscle torque was measured for ankle plantarflexion, dorsiflexion, eversion and inversion in 20 participants with gout and 20 matched controls at two testing velocities (30°/s and 120°/s) using a Biodex dynamometer. Foot pain and disability was measured using the Manchester Foot Pain and Disability Index (MFPDI).

FINDINGS

Participants with gout demonstrated reduced muscle strength at both the 30°/s and 120°/s testing velocities for plantarflexion, inversion and eversion (P<0.05). People with gout also displayed a reduced plantarflexion-to-dorsiflexion strength ratio at both 30°/s and 120°/s (P<0.05). Foot pain and disability was higher in people with gout (P<0.0001) and MFPDI scores were inversely correlated with plantarflexion and inversion muscle strength at the 30°/s testing velocity, and plantarflexion, inversion and eversion muscle strength at the 120°/s testing velocity (all P<0.05).

INTERPRETATION

People with gout have reduced foot and ankle muscle strength and experience greater foot pain and disability compared to controls. Foot and ankle strength reductions are strongly associated with increased foot pain and disability in people with gout.

Gout tophus on an intradural fascicle: a case description

STUDY DESIGN

Case report and review of literature.

OBJECTIVE

Detailed description of case and review of literature to determine its uniqueness with special regard to intradural gout tophus formation without any boney attachment or underlying systemic gout. Gout tophi commonly involve the peripheral joints of the upper and lower extremities. Rarely, gout tophi are located within the spinal cord, especially without any underlying hyperuricemia.

METHODS

We report the case of a 64-year-old patient presenting with radiculopathy along the right L2-dermatome and bladder dysfunction and review literature for further discussion.

RESULTS

Imaging studies showed a partly calcified round intradural lesion at the level L2 without contrast enhancement. The lesion was removed via a hemilaminectomy L2. It was adherent to a dorsal sensory fascicle exiting with the L2 nerve root. The neuropathological examination showed a gout tophus. Serologic testing revealed no signs of hyperuricemia.

CONCLUSION

To the best of our knowledge, this is the first report of a gout tophus originating from an intradural fascicle and without any boney attachment or underlying systemic gout. The literature is reviewed and possible pathophysiological mechanisms are discussed.

Characteristics of the first metatarsophalangeal joint in gout and asymptomatic hyperuricaemia: a cross-sectional observational study

Background

This study aimed to identify patient-reported outcomes and clinician-assessed characteristics of the first metatarsophalangeal joint (1MTPJ) in people with gout and with asymptomatic hyperuricaemia by comparing them to normouricaemic controls.

Methods

Twenty four people with gout (without current symptoms of acute arthritis), 29 with asymptomatic hyperuricaemia and 34 age- and sex-matched controls participated in this cross-sectional observational study. Patient-reported outcomes included 1MTPJ pain, foot pain and disability, body pain, lower limb function, activity limitation and overall wellbeing. Clinician-assessed characteristics of the 1MTPJ included range of motion (ROM), plantar- and dorsi-flexion force, foot posture, temperature and hallux valgus severity.

Results

Compared to controls, participants with gout reported greater 1MTPJ pain (p = 0.014), greater foot pain and disability (p < 0.001), increased odds of having disabling foot pain (odds ratio (OR) 13.4, p < 0.001), decreased lower limb function for daily living (p = 0.002) and recreational (p < 0.001) activities, increased activity limitation (p = 0.002), reduced overall wellbeing (p = 0.034), reduced ROM (p < 0.001), reduced plantarflexion force (p = 0.012), increased 1MTPJ plantar (p = 0.004), dorsal (p = 0.003) and medial (p = 0.004) temperature and had increased odds of having more severe hallux valgus (OR 0.3 p = 0.041). Compared to controls, participants with asymptomatic hyperuricaemia had increased odds of having disabling foot pain (OR 4.2, p = 0.013), increased activity limitation (p = 0.033), decreased lower limb function for daily living (p = 0.026) and recreational (p = 0.010) activities, increased 1MTPJ plantarflexion force (p = 0.004) and a more pronated foot type (p = 0.036).

Conclusions

People with gout demonstrate 1MTPJ-specific changes indicative of subclinical inflammation, even in the absence of acute arthritis. People with asymptomatic hyperuricaemia, who exhibit no features or symptoms of gout, also report high levels of foot- and lower limb-related pain and disability.

Dual-Energy Computed Tomography: Advantages in the Acute Setting

The aim of this article is to inform and update emergency radiologists in respect of the clinically relevant benefits that dual-energy computed tomography (CT) contributes over conventional single-energy CT in the emergency setting using practical imaging examples. Particular emphasis will be placed on acute gout, bone marrow edema, acute renal colic, acute cardiovascular and neurovascular emergencies aswell as characterization of abdominal incidentalomas. The relevant scientific literature will be summarized and limitations of the technique also will be emphasized to provide the reader with a rounded concept of the current state of technology.