Value of Shear Wave Elastography in the Diagnosis of Gouty and Non-Gouty Arthritis

Current Techniques in the Imaging of Gout

Gout is a common inflammatory arthritis with well-described imaging characteristics. Radiography depicts erosive change and in advanced cases, tophus deposition near joints and in association with tendons or bursae. Computed tomography demonstrates the same features but may also use dual-energy or photon-counting techniques that allow for tissue composition analysis and the specific identification of monosodium urate deposition. Magnetic resonance imaging (MRI) is useful in identifying tophi and the damage associated with gout, such as bone erosion and cartilage loss in advanced cases. MRI also helps differentiate gout from other types of inflammatory arthritis, infection, or tumor that may have a similar clinical presentation. Ultrasound is widely used in the diagnosis of gout and also useful in procedural guidance of joint aspiration or soft tissue biopsy.

Systematic literature review to inform the EULAR recommendations for the use of imaging in crystal-induced arthropathies in clinical practice

OBJECTIVE

To summarise current data regarding the use of imaging in crystal-induced arthropathies (CiAs) informing a European Alliance of Associations for Rheumatology task force.

METHODS

We performed four systematic searches in Embase, Medline and Central on imaging for diagnosis, monitoring, prediction of disease severity/treatment response, guiding procedures and patient education in gout, calcium pyrophosphate dihydrate deposition (CPPD) and basic calcium phosphate deposition (BCPD). Records were screened, manuscripts reviewed and data of the included studies extracted. The risk of bias was assessed by validated instruments.

RESULTS

For gout, 88 studies were included. Diagnostic studies reported good to excellent sensitivity and specificity of dual-energy CT (DECT) and ultrasound (US), high specificity and lower sensitivity for conventional radiographs (CR) and CT. Longitudinal studies demonstrated sensitivity to change with regard to crystal deposition by US and DECT and inflammation by US and structural progression by CR and CT. For CPPD, 50 studies were included. Diagnostic studies on CR and US showed high specificity and variable sensitivity. There was a single study on monitoring, while nine assessed the prediction in CPPD. For BCPD, 56 studies were included. There were two diagnostic studies, while monitoring by CR and US was assessed in 43 studies, showing a reduction in crystal deposition. A total of 12 studies with inconsistent results assessed the prediction of treatment response. The search on patient education retrieved two studies, suggesting a potential role of DECT.

CONCLUSION

This SLR confirmed a relevant and increasing role of imaging in the field of CiAs.

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.

Reliability and Agreement of Point and 2-D Shear-Wave Elastography in Assessing the Sciatic Nerve Stiffness

Information is lacking about the reliability and agreement of different shear-wave elastographic modes in the peripheral nervous system evaluation. The aim of this observational study was to evaluate reproducibility and agreement of two different shear-wave elastographic modes for measuring the sciatic nerve stiffness in patients affected by osteoarthrosis. Two sets of three measurements were conducted bilaterally on the sciatic nerve of 20 patients with point and 2-D shear-wave elastography by a unique expert sonographer. This consecutive case series study was performed in 1 mo. No significant difference was found comparing the first with the second set of evaluations (p = 0.08 for point shear-wave elastography and 0.3 for 2-D shear-wave elastography). Correlation between the two sets of measurements was good and excellent (0.799 with point shear-wave elastography and 0.877 with 2-D shear-wave elastography). Intra-class coefficient correlation between the two sets of measurements was excellent for both shear-wave elastographic modes (0.869 and 0.938, respectively); no agreement between them was demonstrated (analysis of variance [ANOVA] test: p = 0.014).Despite the lack of agreement owing to the different procedures for measuring, both shear-wave elastographic modes allow reliable stiffness measurements of the sciatic nerve and may be used to evaluate stiffness changes.

Quantification of skin lesions using high-frequency ultrasound and shear wave elastography in port-wine stain patients: a clinical study

Background

This study aimed to assess the different types of port-wine stain (PWS) skin lesions quantitatively using high-frequency ultrasound (US) and shear wave elastography (SWE) before and after treatment, and investigate the feasibility and application value of high-frequency US and SWE in PWSs.

Methods

A total of 195 PWS patients with 238 skin lesions before treatment and 72 follow-up PWS patients with 90 skin lesions were assessed using high-frequency US and SWE. The skin lesions were divided into four groups: pink-type, purple-type, thickened-type, and nodular-type PWSs. Gray-scale US was used to observe normal skin, observe the skin changes of lesions, and assess the skin thickness. The thickened skin was calculated. Power Doppler (PD) signal grades were used to assess the skin blood signals. SW velocity (in m/s) and Young's elastic modulus (in kPa) were used to assess the stiffness of normal skin and skin lesions. The heightened SWE was also calculated.

Results

The dermis hypoechogenicity, thickness of thickened skin, and skin PD signal grades were significantly higher in all PWS-type groups compared with the normal-skin group (all P<0.05). The thickened skin and skin PD signal grades in the nodular-type and thickened-type group were significantly thicker and higher than those in the pink-type and purple-type group (all P<0.05). The PD signal grades in the purple-type was significantly higher than that in the pink-type group (P<0.05). All SWE values of PWS lesions were significantly higher in the transverse section than those in the longitudinal section (all P<0.05). The differences in heightened E_mean, E_min, C_mean, and C_min between each PWS group and the normal-skin group were not significant. The heightened E_max and C_max in the nodular-type PWS group was significantly higher than those in the normal-skin group and pink-type, and purple-type PWS groups (all P<0.05). The heightened E_max and C_max were significantly higher in the thickened-type PWS group than those in the normal-skin group (all P<0.05). In the evaluation of therapeutic effects, the ratio of dermis hypoechogenicity in pink-type lesions significantly decreased, and thickened skins in all groups were significantly thinned (all P<0.05). The differences of PD signal grades, heightened E_max, and C_max in all groups between pre-treatment and post-treatment showed no significance.

Conclusions

High-frequency US and SWE show feasibility and application values assessing PWS skin lesions. Their features include dermis hypoechogenicity, thicker skin, higher PD signal grades, higher E_max, and higher C_max. Thicker skin is thus the best feature for assessing therapeutic effect.

Differentiating the acute phase of gout from the intercritical phase with ultrasound and quantitative shear wave elastography

OBJECTIVES

To evaluate the value of ultrasound (US) in differentiating the acute phase of gout from the intercritical phase, particularly using shear wave elastography (SWE).

METHODS

57 gout patients were prospectively enrolled and divided into acute phase and intercritical phase groups. The patients underwent US and SWE examinations for the first metatarsophalangeal joints with the same protocol. Maximum synovial thickness was measured. US features were reviewed by two radiologists independently. The maximum (E_max) and mean (E_mean) elastic moduli of synovium were calculated. Diagnostic performances of US, SWE and combined US and SWE were evaluated.

RESULTS

US findings demonstrated that the colour Doppler flow signal grade in the acute phase was higher than that in the intercritical phase (p = 0.001), whereas no differences were found for B-mode US features between the two groups (all p > 0.05). For SWE, E_max and E_mean were significantly higher in the intercritical phase than in the acute phase (both p < 0.001). The areas under the receiver operating characteristic curve (AUROCs) were 0.494-0.553 for B-mode US, 0.735 for colour Doppler US (CDUS), 0.887 for E_max and 0.882 for E_mean. The combination of CDUS and SWE increased the AUROC, sensitivity and accuracy significantly in comparison with CDUS alone (all p < 0.001). However, the combined set did not show stronger diagnostic performance in comparison with SWE alone.

CONCLUSION

SWE increases the diagnostic performance in differentiating the acute phase of gout from the intercritical phase in comparison with conventional US.

KEY POINTS

• Colour Doppler flow signal grade is higher in acute phase of gout than in intercritical phase. • SWE demonstrates that synovium stiffness is higher in intercritical phase of gout than in acute phase. • SWE increases diagnostic performance in differentiating acute phase of gout from intercritical phase in comparison with conventional US.