Exploring a novel composite method using non-contrast EUS enhanced microvascular imaging and cyst fluid analysis to differentiate pancreatic cystic lesions

Abstract

Background and aims: Differentiating pancreatic cystic lesions (PCLs) remains a diagnostic challenge. The use of high-definition imaging modalities which detect tumor microvasculature have been described in solid lesions. We aim to evaluate the usefulness of cystic microvasculature when used in combination with cyst fluid biochemistry to differentiate PCLs.

Methods: We retrospectively analyzed 110 consecutive patients with PCLs from 2 Italian Hospitals who underwent EUS with H-Flow and EUS fine needle aspiration to obtain cystic fluid. The accuracy of fluid biomarkers was evaluated against morphological features on radiology and EUS. Gold standard for diagnosis was surgical resection. A clinical and radiological follow up was applied in those patients who were not resected because not surgical indication and no signs of malignancy were shown.

Results: Of 110 patients, 65 were diagnosed with a mucinous cyst, 41 with a non-mucinous cyst, and 4 with an undetermined cyst. Fluid analysis alone yielded 76.7% sensitivity, 56.7% specificity, 77.8 positive predictive value (PPV), 55.3 negative predictive value (NPV) and 56% accuracy in diagnosing pancreatic cysts alone. Our composite method yielded 97.3% sensitivity, 77.1% specificity, 90.1% PPV, 93.1% NPV, 73.2% accuracy.

Conclusions: This new composite could be applied to the holistic approach of combining cyst morphology, vascularity, and fluid analysis alongside endoscopist expertise.

Keywords: Cystic neoplasm; EUS; Fluid; H-flow; Pancreatic cysts; Vascularization.