Improved sensitivity and positive predictive value of contrast-enhanced intraoperative ultrasound in colorectal cancer liver metastasis: a systematic review and meta-analysis

Intraoperative contrast-enhanced ultrasound has an outcome-relevant impact on surgery of primary and metastatic liver lesions

PURPOSE

Complete resection of the affected tissue remains the best curative treatment option for liver-derived tumors and colorectal liver metastases. In addition to preoperative cross-sectional imaging, contrast-enhanced intraoperative ultrasound (CE-IOUS) plays a crucial role in the detection and localization of all liver lesions. However, its exact role is unclear. This study was designed to evaluate the clinical and oncological impact of using CE-IOUS in the surgical treatment of these diseases.

MATERIALS AND METHODS

Over the three-year study period, 206 patients with primary liver tumors and hepatic metastases were enrolled in this prospective, monocentric study to evaluate the impact of CE-IOUS in liver surgery. Secondary outcomes included comparing the sensitivity and specificity of CE-IOUS with existing preoperative imaging modalities and identifying preoperative parameters that could predict a strategic impact of CE-IOUS. In addition, the oncological significance of CE-IOUS was evaluated using a case-cohort design with a minimum follow-up of 18 months.

RESULTS

CE-IOUS findings led to a change in surgical strategy in 34% of cases (n=70/206). The accuracy in cases with a major change could be confirmed histopathologically in 71.4% of cases (n=25/35). The impact could not be predicted using parameters assumed to be clinically relevant. An oncological benefit of a CE-IOUS adapted surgical approach was demonstrated in patients suffering from HCC and colorectal liver metastases.

CONCLUSION

CE-IOUS may significantly increase R0 resection rates and should therefore be used routinely as an additional staging method, especially in complex liver surgery.

The Effect of Hepatic Surgical Margins of Colorectal Liver Metastases on Prognosis: A Systematic Review and Meta-Analysis

Introduction: Colorectal cancer is the third most common malignancy, with around half of patients developing liver metastases. Hepatectomy is the preferred treatment, but its success depends on several factors, including surgical margins. Various surgical margins have been suggested to achieve optimal results. This systematic review and meta-analysis aim to explore the impact of negative surgical margins ranging from 1 to 10 mm, and >10 mm on survival, with the objective of identifying optimal surgical margins. Methods: A systematic literature search was conducted on the MEDLINE, Scopus, and Cochrane databases. The six included studies that examined the effect of surgical margins at the aforementioned distances on patient survival. Studies were assessed for risk of bias using the Quality in Prognosis Studies tool. Statistical analysis was performed using SPSS software. Results: The results of the meta-analysis revealed the superiority of wider surgical margins (>10) on overall survival compared to smaller margins (1-10 mm), as the HR was calculated to be 1.38 [1.10; 1.73]. Specifically, negative margins between 1 and 10 mm are linked to a 38% increased risk of mortality compared to margins larger than 10 mm. The low heterogeneity indicates consistent findings across studies, and the statistically significant hazard ratio underscores the importance of aiming for larger surgical margins to enhance patient outcomes. In the subgroup that included only studies in which patients received neoadjuvant therapy, the HR was 1.48 [1.06; 2.07], further emphasizing the importance of ensuring negative surgical margins in today's era. Conclusions: In summary, this systematic review and meta-analysis highlights the impact of surgical margin width on the survival of patients with colorectal liver metastases, as well as the importance of margin optimization in surgical management strategies.

The treatment response evaluation through the combination of contrast-enhanced ultrasound and squamous cell carcinoma antigen in cervical cancer

Background

The evaluation of the treatment response after concurrent chemotherapy and radiotherapy (CCRT) for locally advanced cervical cancer is closely related to the formulation of treatment strategies. Magnetic resonance imaging (MRI) is a recommended method for efficacy evaluation; however, a unified consensus has not yet been reached on its use, and it has its limitations. This study aimed to evaluate the diagnostic value of a combination of contrast-enhanced ultrasound (CEUS) parameters and the squamous cell carcinoma antigen (SCC-Ag) to establish another efficient and feasible examination method.

Methods

The data of 94 patients with cervical cancer who underwent transvaginal contrast-enhanced ultrasound (TV-CEUS) from October 2020 to March 2023 were retrospectively collected. Based on the inclusion and exclusion criteria, 70 patients diagnosed with cervical squamous cell carcinoma (SCC) who underwent CCRT were selected for inclusion in the study. The patients were divided into the residual disease (RD) group (comprising 26 patients) and the complete response (CR) group (comprising 44 patients) according to the diagnostic standard. Data on the grayscale echogenicity, color Doppler flow imaging (CDFI), CEUS parameters, and the SCC-Ag of all the patients were collected by two experienced radiologists. Inter-observer reliability was assessed using the intraclass correlation coefficient (ICC). Receiver operating characteristic (ROC) curves were created based on the non-parametric U-test or t-test results for the two groups. Delong's test was used to compare the area under the curve (AUC) between different ROC curves. A subgroup analysis was conducted based on the patient's age, tumor diameter, and disease stage.

Results

The ICCs between the two observers ranged from 0.915 and 0.947. Hypervascular hyper-enhancement in the arterial phase, hypo-enhancement in the venous phase, and the SCC-Ag differed significantly between the RD and CR groups (P<0.05). The AUC of the ROC curve combining these indicators was 0.890 [95% confidence interval (CI): 0.792-0.989], which was higher than the AUC of any indicator alone (P<0.05). The subgroup analysis showed that the AUCs of the patients aged ≥53 and <53 years were 0.922 (95% CI: 0.816-1.00) and 0.896 (95% CI: 0.782-1.00), respectively, those of the patients with stage II, III, and IV were 0.881 (95% CI: 0.732-1.00), 0.955 (95% CI: 0.894-1.00), and 1.000 (95% CI: 1.00-1.00), respectively, and those of the patients with a tumor diameter ≤10 mm, 10 mm < tumor diameter (post) <20 mm, and tumor diameter (post) ≥20 mm were 0.976 (95% CI: 0.910-1.00), 0.883 (95% CI: 0.763-1.00), and 1.00 (95% CI: 1.00-1.00) respectively.

Conclusions

Transvaginal ultrasound (TVUS), TV-CEUS, and the SCC-Ag can be used in combination to evaluate the patient response to CCRT in locally advanced cervical SCC. This integrated approach enhanced the accuracy of the diagnosis of residual lesions and may be helpful in treatment plan optimization.

Contrast-Enhanced Sonography of the Liver: How to Avoid Artifacts

Contrast-enhanced sonography (CEUS) is a very important diagnostic imaging tool in clinical settings. However, it is associated with possible artifacts, such as B-mode US-related artifacts. Sufficient knowledge of US physics and these artifacts is indispensable to avoid the misinterpretation of CEUS images. This review aims to explain the basic physics of CEUS and the associated artifacts and to provide some examples to avoid them. This review includes problems related to the frame rate, scanning modes, and various artifacts encountered in daily CEUS examinations. Artifacts in CEUS can be divided into two groups: (1) B-mode US-related artifacts, which form the background of the CEUS image, and (2) artifacts that are specifically related to the CEUS method. The former includes refraction, reflection, reverberation (multiple reflections), attenuation, mirror image, and range-ambiguity artifacts. In the former case, the knowledge of B-mode US is sufficient to read the displayed artifactual image. Thus, in this group, the most useful artifact avoidance strategy is to use the reference B-mode image, which allows for a simultaneous comparison between the CEUS and B-mode images. In the latter case, CEUS-specific artifacts include microbubble destruction artifacts, prolonged heterogeneous accumulation artifacts, and CEUS-related posterior echo enhancement; these require an understanding of the mechanism of their appearance in CEUS images for correct image interpretation. Thus, in this group, the most useful artifact avoidance strategy is to confirm the phenomenon's instability by changing the examination conditions, including the frequency, depth, and other parameters.

Etching reaction of carbon quantum dot-functionalized MnO2 nanosheets with an enzymatic product for photoelectrochemical immunoassay of alpha-fetoprotein

An etching reaction-based photoelectrochemical (PEC) immunoassay was developed to monitor alpha-fetoprotein (AFP) by coupling with the enzymatic product toward the dissolution of MnO2 nanosheets.