新谷 修平¹, 稲富 理¹, 廣江 光亮¹, 友澤 裕樹³, 井上 明星³, 木村 英憲², 西田 淳史¹, 辻 喜久⁴, 渡辺 嘉之³, 安藤 朗¹

Shuhei SHINTANI¹, Osamu INATOMI¹, Kosuke HIROE¹, Yuki TOMOZAWA³, Akitoshi INOUE³, Hidenori KIMURA², Atsushi NISHIDA¹, Yoshihisa TSUJI⁴, Yoshiyuki WATANABE³, Akira ANDOH¹

¹滋賀医科大学医学部内科学講座（消化器）, ²滋賀医科大学医学部附属病院光学医療診療部, ³滋賀医科大学医学部附属病院放射線部, ⁴滋賀医科大学医学部附属病院総合診療科

¹Department of Medicine, Shiga University of Medical Science, ²Department of Endoscopy, Shiga University of Medical Science Hospital, ³Department of Radiology, Shiga University of Medical Science Hospital, ⁴Department of General Medicine, Shiga University of Medical Science Hospital

キーワード : chronic pancreatitis, endoscopic ultrasound, elastography

目的：超音波内視鏡（endoscopic ultrasound: EUS）は慢性膵炎（chronic pancreatitis: CP）の診断に広く用いられているが，Rosemont分類（Rosemont criteria: RC）による線維化の評価は概して主観的である．EUSを用いたせん断波エラストグラフィ（Shear wave elastography using EUS: EUS-SWE）は膵線維化の評価のための客観的アプローチであると提唱されている．しかし，どの膵領域を測定対象に選択するべきかは不明である．本研究の目的は膵の部位別にEUS-SWEを行い，CPの診断精度を比較することである．方法：EUS-SWEを受けたCPまたはCPを疑う50例の後ろ向き解析を実施した．RCに基づいて症例を2群（CP群と非CP群）に分類した．せん断波の速度（velocities of the shear wave: Vs）の測定によって膵硬度を評価し，Vsのカットオフ値を決定した．VsとRCとの相関および膵硬度に影響を及ぼすRC因子を評価した．結果：CP群では非CP群よりすべての領域でVsが有意に高値であった（P < 0.001）．VsによるCPの診断精度は膵体部で最も高かった［曲線下面積（area under the curve: AUC）：0.87］．すべての領域でRCの所見数とVsとの有意な相関が認められ，相関係数は膵体部で最も高かった（rs = 0.55）．多変量解析の結果から，蜂巣状分葉エコーがVsに関する独立因子であることが明らかになった（P = 0.02）．結論：膵体部はEUS-SWEによる膵硬度の評価に適した領域である．また，Vsの定量化はCPの診断に有用な客観的指標である．

Purpose : Although endoscopic ultrasound（EUS）has been widely used for diagnosing chronic pancreatitis（CP）, the assessment of fibrosis using the Rosemont criteria（RC）is generally subjective. Shear wave elastography using EUS（EUS-SWE）has been advocated as an objective approach to evaluating pancreatic fibrosis; however, it is unknown which pancreatic region should be selected for measurement. This study aims to compare the diagnostic accuracy in diagnosing CP by measurement site. Methods : Fifty patients with CP or suspected CP who underwent EUS-SWE were retrospectively analyzed. As per the RC, they were classified into two groups : CP and non-CP. Pancreatic stiffness was evaluated by measuring the velocities of the shear wave（Vs）in addition to determining the relevant cutoff value of Vs for diagnosing CP. The correlation between Vs and RC, and the RC factors affecting pancreatic stiffness were evaluated. Results : In the CP group, the Vs were notably higher in all regions（P < 0. 001）. The Vs for diagnostic accuracy of CP were highest in the body［area under the curve（AUC）: 0. 87］. A significant correlation was seen between the number of RC and Vsin all regions, with the correlation coefficient being highest in the pancreatic body（rs = 0. 55）. Multivariate analysis revealedthat lobularity with honeycombing was an independent factor for pancreatic stiffness（P = 0. 02）. Conclusion : The pancreatic body is a suitable region for assessing pancreatic stiffness using EUS-SWE. Additionally, quantifying Vs is a valuable objective indicator for diagnosing CP.