Introduction
Pancreatic cancer is one of the most aggressive malignancies, with a poor five-year survival rate. Therefore, optimizing diagnostic strategies is a critical priority. Endoscopic ultrasound (EUS) plays a key role in characterizing focal pancreatic masses (FPM). The development of ancillary EUS techniques including contrast-enhanced EUS (CH-EUS), strain ratio elastography (SRE) and Detective Flow Imaging (DFI) has enhanced the assessment of vascularization and tissue stiffness, potentially improving the differentiation between benign and malignant lesions. Emerging evidence suggests that these parameters may provide valuable insights into the malignant potential of FPM [1,2,3]. This study evaluates whether the combined use of CH-EUS, SRE, and DFI improves diagnostic accuracy in predicting pancreatic ductal adenocarcinoma (PDAC).
Aims & Methods
Single-center, retrospective study including consecutive patients who underwent biliopancreatic EUS for FPM between October 2023 and April 2025 at the Digestive Diseases Unit of Sant’Andrea University Hospital, Rome. During EUS evaluation, CH-EUS, SRE, and DFI were performed to characterize lesions. The final diagnosis was confirmed by histopathology (EUS fine-needle biopsy) and/or radiological workup (Computed Tomography, Magnetic Resonance Imaging, Positron Emission Tomography), with a follow-up of at least 6 months. For CH-EUS, lesions were categorized as hypoenhanced, isoenhanced or hyperenhanced compared to surrounding parenchyma in the early arterial phase after injection of 8 mL of sulphur hexafluoride microbubbles, a second-generation ultrasound contrast agent. Hypoenhanced lesions were considered predictive of PDAC [4]. SRE was assessed using the ultrasound system’s embedded software, comparing a region of interest (ROI) in the FPM with the intestinal wall. A strain ratio>10 was considered predictive of PDAC [5,6]. DFI was employed to evaluate the microvascularization, classifying lesions as hypovascular or hypervascular, with hypovascularity considered predictive of PDAC [7,8].
Results
Overall, 59 patients were included, 27 (45.8%) females, with a median age of 69 years (27–88). About lesions 37 (62.7%) were in the head, 14 (23.7%) in the body, and 8 (13.6%) in the tail, with a median diameter of 25 mm (8–63 mm). Among these, 41 (69.5%) were PDAC, 3 (5.1%) were inflammatory lesions, 2 (3.4%) were metastasis and 13 (22%) were neuroendocrine tumors (G1-G2). CH-EUS was performed in 34 cases (57.6%), SRE in 29 (49.2%), and DFI in 37 (62.7%). All three modalities were applied in 20 (33.9%) cases and combinations of DFI with another technique were used in 13 (22.1%).
The sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) for PDAC of each modality, alone and in combination, are summarized in Table 1.
| Modality | Sensitivity (%) | Specificity (%) | Accuracy (%) | PPV (%) | NPV (%) |
| CH-EUS (hypoenhanced) | 63.2 | 86.7 | 73.5 | 85.7 | 65.0 |
| SRE (strain ratio >10) | 88.2 | 75.0 | 82.8 | 83.3 | 81.8 |
| DFI (hypovascularization) | 83.3 | 84.6 | 83.8 | 90.9 | 73.3 |
| CH-EUS + DFI (n = 27) | 62.5 | 90.9 | 74.1 | 90.9 | 62.5 |
| SRE + DFI (n = 24) | 66.7 | 100.0 | 79.2 | 100.0 | 64.3 |
| CH-EUS + SRE + DFI (n = 20) | 63.6 | 100.0 | 80.0 | 100.0 | 69.2 |
Table 1: Diagnostic performance of ancillary techniques and their combination for PDAC detection
Conclusion
Multimodal approaches by using ancillary EUS techniques (CH-EUS, SRE and DFI), particularly combinations including DFI, showed a high specificity and PPV in predicting malignant FPM. Therefore, a multimodal EUS approach may improve post-test probability for PDAC.
References
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