Present status of ultrasound elastography for the diagnosis of pancreatic tumors: review of the literature

Ultrasound elastography is a relatively new diagnostic technique for measuring tissue elasticity (hardness). This review describes the types and evaluation methods of elastographies used in diagnosing pancreatic tumors. It also evaluates the diagnostic ability of transabdominal (US) or endoscopic ultrasonography (EUS) elastography for pancreatic tumors, based on findings from a search of published articles. Twenty articles (2096 cases) were selected from the databases. The types of elastography used for the diagnosis of pancreatic tumors were strain elastography and shear wave elastography. The evaluation methods of elastography and their diagnostic abilities (sensitivity and specificity) were 0.78 (95% confidence interval 0.65–0.87) and 0.82 (0.63–0.94) for color pattern diagnosis (US), 0.82 (0.77–0.86) and 0.70 (0.64–0.76) for color pattern diagnosis (EUS), 0.94 (0.90–0.97) and 0.87 (0.81–0.92) for strain ratio (EUS), 0.92 (0.90–0.94) and 0.79 (0.75–0.82) for histogram analysis (EUS), and 0.90 (0.82–0.95) and 0.82 (0.57–0.72) for shear wave elastography. In conclusion, there are many types of elastographies and evaluation methods, and the diagnostic ability for pancreatic tumors is high for each evaluation method.