Diagnostic Performance of Acoustic Radiation Force Impulse Elastography for the Differentiation of Benign and Malignant Superficial Lymph Nodes: A Meta-analysis

Research progress of ultrasound in accurate evaluation of cartilage injury in osteoarthritis

Osteoarthritis (OA) is a prevalent cause of joint algesia, loss of function, and disability in adults, with cartilage injury being its core pathological manifestation. Since cartilage damage is non-renewable, the treatment outcome in the middle and late stages of OA is unsatisfactory, which can be minimized by changing lifestyle and other treatment modalities if diagnosed and managed in the early stages, indicating the importance of early diagnosis and monitoring of cartilage injury. Ultrasound technology has been used for timely diagnosis and even cartilage injury treatment, which is convenient and safe for the patient owing to no radiation exposure. Studies have demonstrated the effectiveness of ultrasound and its various quantitative ultrasound parameters, like ultrasound roughness index (URI), reflection coefficient (R), apparent integrated backscatter (AIB), thickness, and ultrasound elastography, in the early and accurate assessment of OA cartilage pathological changes, including surface and internal tissue, hardness, and thickness. Although many challenges are faced in the clinical application of this technology in diagnosis, ultrasound and ultrasound-assisted techniques offer a lot of promise for detecting early cartilage damage in OA. In this review, we have discussed the evaluation of ultrasonic cartilage quantitative parameters for early pathological cartilage changes.

Shear wave elastography versus strain elastography to identify benign superficial lymph nodes: sonographic assessment with histopathological confirmation

Background

Differentiation between benign and malignant superficial lymph nodes (LNs) presents clinical dilemma. No specific criteria are established with conventional ultrasound to make a distinction. We aimed to study the added value of shear wave velocity (SWV) measurement with acoustic radiation force impulse (ARFI) and strain elastography (SE) to identify benign superficial LNs. The study included 115 superficial LNs subjected to conventional ultrasonography, 4-scale strain elastography and shear wave velocity measurement using ARFI. Histopathological analysis was obtained for all examined nodes.

Results

SE correctly diagnosed 89.3% of the reactive and 92.2% of the metastatic LNs and erroneously diagnosed 72.7% of the lymphoma LNs as being benign. Overall sensitivity, specificity, PPV, NPV and accuracy were 74.4%, 73%, 85.3%, 57.4% and 73.9%, respectively. The receiver operating curve analysis of SWV measurement using ARFI revealed a cut-off value of ≥ 2.70 m/sec to recognize malignant LNs and to obtain best sensitivity (88.5%) and specificity (89.2%) (Area under the curve: 0.819, 95% confidence interval (CI): 0.744 and 0.894). The PPV, NPV and accuracy were 94.5%, 78.6% and 88.7%, respectively. As compared to SE, ARFI boosted the diagnostic accuracy of lymphoma LNs from 27.3 to 68.2% and showed better specificity and NPV to identify benign LN as contrasted to SE.

Conclusions

SE could be adequate to differentiate reactive from metastatic LN but not from Lymphomas. Shear wave elastography is a reasonable imaging modality to identify benign lymph nodes. ARFI at a cut-off value of < 2.7 m/sec was superior to SE and the best B-mode features.

Ultrasound elastography

Physicians have used palpation as a diagnostic examination to understand the elastic properties of pathology for a long time since they realized that tissue stiffness is closely related to its biological characteristics. US elastography provided new diagnostic information about elasticity comparing with the morphological feathers of traditional US, and thus expanded the scope of the application in clinic. US elastography is now widely used in the field of diagnosis and differential diagnosis of abnormality, evaluating the degree of fibrosis and assessment of treatment response for a range of diseases. The World Federation of Ultrasound Medicine and Biology divided elastographic techniques into strain elastography (SE), transient elastography and acoustic radiation force impulse (ARFI). The ARFI techniques can be further classified into point shear wave elastography (SWE), 2D SWE, and 3D SWE techniques. The SE measures the strain, while the shear wave-based techniques (including TE and ARFI techniques) measure the speed of shear waves in tissues. In this review, we discuss the various techniques separately based on their basic principles, clinical applications in various organs, and advantages and limitations and which might be most appropriate given that the majority of doctors have access to only one kind of machine.

Comparison of point and two-dimensional shear wave elastography of the spleen in healthy subjects

BACKGROUND

Few systematic comparative studies of the different methods of physical elastography of the spleen are currently available.

AIM

To compare point shear wave and two-dimensional elastography of the spleen considering the anatomical location (upper, hilar, and lower pole).

METHODS

As part of a prospective clinical study, healthy volunteers were examined for splenic elasticity using four different ultrasound devices between May 2015 and April 2017. The devices used for point shear wave elastography were from Siemens (S 3000) and Philips (Epiq 7), and those used for two-dimensional shear wave elastography were from GE (Logiq E9) and Toshiba (Aplio 500). In addition, two different software versions (5.0 and 6.0) were evaluated for the Toshiba ultrasound device (Aplio 500). The study consisted of three arms: A, B, and C.

RESULTS

In study arm A, 200 subjects were evaluated (78 males and 122 females, mean age 27.9 ± 8.1 years). In study arm B, 113 subjects were evaluated (38 men and 75 women, mean age 26.0 ± 6.3 years). In study arm C, 44 subjects were enrolled. A significant correlation of the shear wave velocities at the upper third of the spleen (r = 0.33088, P < 0.0001) was demonstrated only for the Philips Epiq 7 device compared to the Siemens Acuson S 3000. In comparisons of the other ultrasound devices (GE, Siemens, Toshiba), no comparable results could be obtained for any anatomical position of the spleen. The influencing factors age, gender, and body mass index did not show a clear correlation with the measured shear wave velocities.

CONCLUSION

The absolute values of the shear wave elastography measurements of the spleen and the two different elastography methods are not comparable between different manufacturers or models.

What does liver elastography measure? Technical aspects and methodology

Elastography can be thought as an extension of the ancient technique of palpation. After giving a short introduction to the history of elastography, the different technologies that are nowadays available and the physics behind them, the article focuses on the assessment of liver stiffness in patients with diffuse liver disease using shear wave elastography (SWE). Practical advices on how to perform the SWE techniques and on the factors that should be considered for a correct interpretation of the results are given. This paper aimed to provide a practical guide for beginners and advanced clinical users to better understand technical aspects, methodologies and terminology.