Efficacy of contrast-enhanced harmonic endoscopic ultrasonography in the differentiation of pancreatic cancer and focal pancreatitis

Objective To evaluate the efficacy of contrast-enhanced harmonic EUS (CH-EUS) in the differentiation of pancreatic cancer and focal pancreatitis.Methods Patients with a diagnosis of pancreatic cancer and focal pancreatitis by CH-EUS were enrolled.Final diagnosis was confirmed by EUS-FNA or histopathology and follow-up of 6 months.The efficacy of CH-EUS in the differentiation of pancreatic cancer and focal pancreatitis was determined,and the characteristics of CH-EUS images were analyzed.Results A total of 56 patients were enrolled,with an average age of (56 ± 12) years old.The final diagnosis as focal pancreatitis in 21 patients,pancreatic cancer in 35.Enhancement pattern of normal pancreas by CH-EUS was simultaneous with the adjacent tissues,with obvious peak and homogeneous isoenhancement.The timing of enhancement of most of pancreatic cancer by CH-EUS was later than the adjacent normal pancreatic tissue,with early subsidence and no obvious peak.Ninety-seven percent (34/35) malignant lesions were shown to have inhomogeneous hypoenhancement within the lesion,1 case had a homogeneous isoenhancement pattern which was diagnosed to have chronic pancreatitis with pancreatic cancer and 1 case had hyperenhancement separation in the center of the cancer.Enhancement of focal pancreatitis was simultaneous with the surrounding pancreatic tissues with obvious peak,76.2％ (16/21) of the inflammatory lesions were shown to have homogeneous isoenhancement.The sensitivity,specificity and accuracy of CH-EUS in the differentiation of pancreatic cancer and focal pancreatitis was 90.5％,97.1％ and 94.6％,positive and negative predictive value was 95.0％ and 94.4％,positive and negative likelihood ratio was 31.7 and 0.1.Conclusions CH-EUS can effectively realtime identify pancreatic cancer and focal inflammation by clearly showing the vascular structures,and can be used as a valuable new method for clinical diagnosis. Key words: Pancreatic diseases ;  Endosonography;  Diagnostic, differential;  Contrast enhanced harmonic