Evaluation of the diagnostic performance of the EFSUMB CEUS Pancreatic Applications guidelines (2017 version): a retrospective single-center analysis of 455 solid pancreatic masses

Added Value of Dynamic Contrast-Enhanced Ultrasound Analysis for Differential Diagnosis of Small (≤20 mm) Solid Pancreatic Lesions

OBJECTIVE

To evaluate the added value of dynamic contrast-enhanced ultrasound (DCE-US) analysis in pre-operative differential diagnosis of small (≤20 mm) solid pancreatic lesions (SPLs).

METHODS

In this retrospective study, patients with biopsy or surgerical resection and histopathologically confirmed small (≤20 mm) SPLs were included. One wk before biopsy/surgery, pre-operative B-mode ultrasound and contrast-enhanced ultrasound were performed. An ultrasonic system (ACUSON Sequoia, Siemens Medical Solutions, PA, USA) equipped with a 5C1 MHz convex array transducer was utilized. A dose of 1.5 ml SonoVue (Bracco, Italy) was injected as the contrast agent. Time-intensity curves were generated using VueBox software (Bracco) and various DCE-US quantitative parameters were subsequently calculated after curve fitting. Univariate and multivariate logistic regression analysis were utilized.

RESULTS

From August 2020 to November 2023, a total of 76 patients (31 males and 45 females; mean age: 61.9 ± 10.5 y) with 76 small (≤20 mm) SPLs were included. Mean size of the lesions was 16.4 ± 0.4 mm (range: 7-20 mm). Final diagnosis included 37 benign and 39 malignant small SPLs. On B-mode ultrasound, the majority of malignant (37/39, 94.9%) and benign SPLs (30/37, 81.1%) were hypo-echoic lesions with ill-defined borders and irregular shapes (p > 0.05). During the arterial phase of contrast-enhanced ultrasound, most SPLs (59/76, 77.6%) exhibited iso-enhancement when compared with surrounding pancreatic parenchyma. Subsequently, 82.1% (32/39) of malignant SPLs and 35.1% (13/37) of benign SPLs demonstrated wash-out in the venous phase and showed hypo-enhancement in venous and late phases (p > 0.05). Compared with benign SPLs, the time-intensity curves of small malignant SPLs revealed earlier and lower enhancement in the arterial phase, and a faster decline during the venous phase with a decreased area under the curve. Among the quantitative parameters, a lower peak enhancement ratio and higher fall time ratio were more common in small malignant SPLs (p < 0.05). For DCE-US analysis, the combined areas under the curve of significant quantitative parameters was 0.919, with 87.2% sensitivity and 86.5% specificity when differentiating between small malignant and benign SPLs. This result was better than contrast-enhanced computed tomography, which has a sensitivity of 74.4% and a specificity of 75.7%.

CONCLUSION

DCE-US analysis provides added value for the pre-operative differential diagnosis of small malignant SPLs.

Ultrasound Contrast Agents: Current Role in Adults and Children for Various Indications

Intravenous contrast-enhanced ultrasound (CEUS) is a rapidly evolving imaging technique that uses a microbubble contrast agent to enhance ultrasonographic images by augmenting characterization of blood vessels and organ perfusion. CEUS is considered as a useful problem-solving tool and as an indicated first-line imaging modality in select settings. CEUS technique has an inherent advantage over its predecessor B-mode and Doppler imaging. This article reviews different approved and off-label use of CEUS in the pediatric and adult population and also discusses Food and Drug Administration-approved contrast agents in the United States, their reported side effects, and ongoing efforts in the field.

Efficacy of color Doppler ultrasound and contrast-enhanced ultrasound in identifying vascular invasion in pancreatic ductal adenocarcinoma

OBJECTIVES

To compare color Doppler ultrasound and contrast-enhanced ultrasound (CEUS) in evaluating vascular invasion in pancreatic ductal adenocarcinoma (PDAC).

MATERIALS AND METHODS

This retrospective study included 210 patients with PDAC who were evaluated by color Doppler ultrasound, CEUS, and contrast-enhanced computed tomography (CECT) at our institution between January 2017 and December 2020. Pathologic results were used as the gold standard in patients who underwent surgical and intraoperative exploration. For nonsurgical patients, CECT results were used as the reference standard. The vessels evaluated included those in the peripancreatic arterial system and venous system. The diagnostic performances of color Doppler ultrasound and CEUS for vascular invasion were compared.

RESULTS

In 51 patients who underwent surgery and intraoperative exploration, color Doppler ultrasound and CEUS differed only in assessing venous system invasion in patients with PDAC of the pancreatic body and tail, with the former being superior to the latter. In 159 nonsurgical patients, there was no difference between CEUS and color Doppler ultrasound in assessing superior mesenteric arteriovenous invasion. CEUS was superior to color Doppler ultrasound in evaluating the celiac artery and its branches, with an accuracy of up to 97.8% for some vessels. Color Doppler ultrasound was ideal for evaluating the splenic and portal veins.

CONCLUSION

CEUS is more suitable for the evaluation of peripancreatic arteries than color Doppler. CEUS combined with color Doppler ultrasound can be used as a potential supplement to CECT and is also expected to be used to evaluate vascular invasion of PDAC after chemotherapy.

CRITICAL RELEVANCE STATEMENT

Contrast-enhanced US and color Doppler in the assessment of vascular invasion in pancreatic ductal adenocarcinoma have their respective advantages, through standardized ultrasound processes are expected to improve the efficiency of inspection.

KEY POINTS

Contrast-enhanced US has unique advantages in assessing pancreatic ductal adenocarcinoma invasion of the celiac artery. Doppler imaging is of high value in assessing venous system invasion. Standardization of ultrasound imaging procedures for pancreatic ductal adenocarcinoma is expected to improve efficiency.

Development and validation of a nomogram model based on pretreatment ultrasound and contrast-enhanced ultrasound to predict the efficacy of neoadjuvant chemotherapy in patients with borderline resectable or locally advanced pancreatic cancer

OBJECTIVES

To develop a nomogram using pretreatment ultrasound (US) and contrast-enhanced ultrasound (CEUS) to predict the clinical response of neoadjuvant chemotherapy (NAC) in patients with borderline resectable pancreatic cancer (BRPC) or locally advanced pancreatic cancer (LAPC).

METHODS

A total of 111 patients with pancreatic ductal adenocarcinoma (PDAC) treated with NAC between October 2017 and February 2022 were retrospectively enrolled. The patients were randomly divided (7:3) into training and validation cohorts. The pretreatment US and CEUS features were reviewed. Univariate and multivariate logistic regression analyses were used to determine the independent predictors of clinical response in the training cohort. Then a prediction nomogram model based on the independent predictors was constructed. The area under the curve (AUC), calibration plot, C-index and decision curve analysis (DCA) were used to assess the nomogram's performance, calibration, discrimination and clinical benefit.

RESULTS

The multivariate logistic regression analysis showed that the taller-than-wide shape in the longitudinal plane (odds ratio [OR]:0.20, p = 0.01), time from injection of contrast agent to peak enhancement (OR:3.64; p = 0.05) and Peaktumor/ Peaknormal (OR:1.51; p = 0.03) were independent predictors of clinical response to NAC. The predictive nomogram developed based on the above imaging features showed AUCs were 0.852 and 0.854 in the primary and validation cohorts, respectively. Good calibration was achieved in the training datasets, with C-index of 0.852. DCA verified the clinical usefulness of the nomogram.

CONCLUSIONS

The nomogram based on pretreatment US and CEUS can effectively predict the clinical response of NAC in patients with BRPC and LAPC; it may help guide personalized treatment.