桑原 崇通, 原 和生, 水野 伸匡, 羽場 真, 奥野 のぞみ

Takamichi KUWAHARA, Kazuo HARA, Nobumasa MIZUNO, Shin HABA, Nozomi OKUNO

愛知県がんセンター消化器内科部

Department of Gastroenterology, Aichi Cancer Center Hospital

キーワード : elastography, strain, shear wave, pancreas

超音波elastographyは組織の弾性（硬さ）を測定する新しい診断方法である．本総説では，膵腫瘍診断に利用されるelastographyの種類と評価法に焦点を当てる．また，既報の検証から経腹壁超音波（transabdominal ultrasonography: US）elastographyないし超音波内視鏡（endoscopic ultrasonography: EUS）elastographyによる膵腫瘍の診断能について評価する．データベースより20論文（症例数：2096）を選択した．膵腫瘍の診断に利用されるelastographyには，strain elastography とshear wave elastographyの2種類がある．Elastographyの評価法と診断能（感度/特異度）は，USのカラーパターン診断では0.78（95％信頼区間：0.65-0.87）/0.82（0.63-0.94），EUSのカラーパターン診断では0.82 （0.77-0.86）/0.70（0.64-0.76），EUSのstrain ratioは0.94（0.90-0.97）/0.87（0.81-0.92），EUSのヒストグラム解析は0.92（0.90-0.94）/0.79（0.75-0.82），shear wave elastographyは0.90（0.82-0.95）/0.82（0.57-0.72）であった．様々な種類のelastographyと評価法が存在するが，そのいずれも膵腫瘍について高い診断能を有すると結論付けられる．

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.