Foreword to the Second Set of WFUMB Guidelines and Recommendations on the Clinical Use of Ultrasound Elastography

Chinese Ultrasound Doctors Association Guideline on Operational Standards for 2-D Shear Wave Elastography Examination of Musculoskeletal Tissues

The Ultrasound Physician Branch of the Chinese Medical Doctor Association sought to develop evidence-based recommendations on the operational standards for 2-D shear wave elastography examination of musculoskeletal tissues. A consensus panel of 22 Chinese musculoskeletal ultrasound experts reviewed current scientific evidence and proposed a set of 12 recommendations for 13 key issues, including instruments, operating methods, influencing factors and image interpretation. A final consensus was reached through discussion and voting. On the basis of research evidence and expert opinions, the strength of recommendation for each proposition was assessed using a visual analog scale, while further emphasizing the best available evidence during the question-and-answer session. These expert consensus guidelines encourage facilitation of the standardization of clinical practices for collecting and reporting shear wave elastography data.

Hepatic Tumor Stiffness Measured by Shear Wave Elastography Is Prognostic for HCC Progression Following Treatment With Anti-PD-1 Antibodies Plus Lenvatinib: A Retrospective Analysis of Two Independent Cohorts

Background

The clinical significance of liver stiffness (LS) measured by shear wave elastography (SWE) in programmed cell death protein-1 (PD-1) inhibitors treated advanced hepatocellular carcinoma (HCC) patients remains unknown. This study aimed to explore the prognostic value of baseline LS by SWE prior to PD-1 inhibitor treatment in combination with lenvatinib.

Methods

We retrospectively evaluated patients (n=133) with HCC who received anti-PD-1 antibodies plus lenvatinib at two high-volume medical centres, between January 2020 and June 2021. Univariate and multivariate logistic regression analysis were used to develop a novel nomogram. RNA sequencing and immunohistochemical staining were used to assess the heterogeneity of biological and immune characteristics associated with tumor stiffness.

Results

The objective response rate (ORR) and disease control rate (DCR) of the whole population were 23.4% and 72.2%, respectively. A LS value of the baseline tumorous foci of 19.53 kPa had the maximum sum of sensitivity and specificity, making it the optimal cut-off value for predicting PD-1 inhibitor efficacy. The nomogram comprised baseline tumor LS and albumin-bilirubin grade (ALBI), which provided favorable calibration and discrimination in the training dataset with an AUC of 0.840 (95%CI: 0.750-0.931) and a C-index of 0.828. Further, it showed acceptable discrimination in the validation cohort, with an AUC of 0.827 (95%CI: 0.673-0.980) and C-index of 0.803. The differentially expressed genes enriched in high stiffness tumors were predominantly associated with metabolic pathways, while those enriched in low stiffness tumors were related to DNA damage repair. Furthermore, patients with high stiffness tumors had a relatively lower infiltration of immune cells and histone deacetylase pathway inhibitors were identified as candidate drugs to promote the efficacy of immunotherapy.

Conclusions

Baseline LS value of tumorous foci by SWE—that is, before administration of a PD-1 inhibitor in combination with lenvatinib—is a convenient predictor of PD-1 inhibitor efficacy in patients with advanced HCC, which has potential to be used for pretreatment stratification to optimize treatment of advanced HCC.

Strain Imaging in the Evaluation of Thyroid Nodules: The Associated Factors Leading to Misdiagnosis

This study analyzed which imaging characteristics may contribute to misdiagnosis of benign and malignant thyroid nodules (TNs) through strain imaging (SI). We analyzed SI parameters and conventional ultrasound (CUS) characteristics of 264 nodules with histopathology results and we applied binary logistic regression analysis to select independent variables for incorrect SI results. The elastography imaging (EI) score and the virtual touch tissue imaging (VTI) score of malignant TNs were remarkably higher than that in benign TNs. VTI, of which the false-positive rate (FPR), the false-negative rate (FNR), and the cutoff value were 47.6% (39/82), 17.6% (32/182) and 3.5, presented higher diagnostic performance than EI. Aspect ratio (odd ratio [OR]: 14.208) and intra-nodular calcification (OR: 20.384) were significantly associated with false-positive VTI findings, while posterior acoustic feature (OR: 30.424) was significantly associated with false-negative VTI findings. Sex (OR: 0.221) and aspect ratio (OR: 0.268) were negatively associated with false-negative EI findings. In conclusion, sex and aspect ratio significantly affect the accuracy of EI results, while aspect ratio, intra-nodular calcification and posterior acoustic features notably affect the accuracy of VTI results. These CUS features of TNs should not be ignored before explaining SI examination results.