Efficacy of Contrast-Enhanced Harmonic Endoscopic Ultrasound for Pancreatic Solid Tumors with a Combination of Qualitative and Quantitative Analyses: A Prospective Pilot Study

Introduction: Image evaluation of contrast-enhanced harmonic endoscopic ultrasound (CEH-EUS) and additional time-intensity curve (TIC) analysis enable qualitative and quantitative analyses of pancreatic tumor based on real-time perfusion imaging.

Aims: To evaluate the efficacy of CEH-EUS with a combination of qualitative and quantitative analyses of pancreatic solid tumors.

Methods: Patients were scheduled to undergo EUS-guided fine needle aspiration (FNA) for pancreatic solid tumors were prospectively enrolled between 11/2016 and 12/2018 and underwent CEH-EUS. The vascular and enhancement patterns were qualitatively evaluated and heterogeneous enhancement was defined to be indicative of malignancy. The echo intensity change during 60 s in the tumor was quantitatively evaluated by time intensity curve analysis.

Results: In total, 100 patients were enrolled in this study. The final diagnoses were malignant lesions in 87 patients and benign legions in 13 patients. There were four categories of enhancement and patterns: hypovascular with heterogeneous, hypovascular with homogeneous, hypervascular heterogeneous, and hypervascular homogeneous enhancement. The diagnostic capability of qualitative analysis was the sensitivity, specificity, and accuracy of 89%, 62%, and 85%, respectively. With respect to time intensity curve analysis, the time to peak of malignant lesions was significantly shorter than those of benign lesions (P = 0.0009) with an optimal cutoff value of 12.81 s on the receiver operating characteristic curve analysis. With the combination of qualitative and quantitative analyses, the sensitivity, specificity, and accuracy were improved to 100%, 54%, and 94%, respectively.

Conclusions: CEH-EUS with combined qualitative and quantitative analyses for pancreatic tumors might be useful as a complement for EUS-FNA. The UMIN Clinical Trials Registry (UMIN000025192).