塩屋 晋吾, 平賀 真雄, 橋口 正史, 川村 健人, 大久保 友紀, 林 尚美, 佐々木 崇, 坂口 右己, 中村 克也, 重田 浩一朗

Shingo SHIOYA, Masao HIRAGA, Masafumi HASHIGUCHI, Kento KAWAMURA, Yuki OOKUBO, Naomi HAYASHI, Takashi SASAKI, Yuuki SAKAGUCHI, Katsuya NAKAMURA, Kouichirou SHIGETA

霧島市立医師会医療センター

Kirishima City Medical Association Medical Center

キーワード : chronic hepatitis C, fibrosis, B-mode, FibroScan, stiffness

目的：慢性肝疾患で最も初期に起こる形態変化として肝左葉内側区域（S4）の萎縮が報告されている．Bモード画像によりC型慢性肝炎患者のS4の萎縮を評価し，FibroScan^®（以下，FS）による肝線維化指標との比較を行った．対象と方法：対象はC型慢性肝疾患で腹部超音波検査とFSを同日に施行した52例．S4形態は，門脈左枝横行部‐S4辺縁間距離（以下，S4距離）で評価した．肝線維化は，FSのStiffnessの中央値をgold standardとして判断した．S4距離とStiffness，各血液検査データ，脾腫との相関を検討した．結果：S4距離をFSにおける肝線維化staging毎に評価するとF0，F1，F2，F3，F4では平均4.0 mm，4.2 mm，7.6 mm，7.9 mm，9.5 mmと長くなり，F0とF2・F3・F4間，F1とF2・F3・F4間に有意差を認めた．Cut off値を5.6 mmとするとF2以上はsensitivity 91.3％，specificity 80.0％で区別できた．S4距離と各血液検査データとの間に相関を認めた．脾腫との間には相関は認めなかった．結語：S4距離での肝線維化評価は，簡易的かつ客観的肝線維化stagingの新しい評価法の1つとなり得ることが示唆された．特に，F1以下とF2以上を高率に検出できる点で臨床的に有用な手段と考える．

Purpose: Atrophy of the internal segment of the left hepatic lobe (S4) has been reported as the first morphological change in chronic liver disease. S4 atrophy was evaluated by B-mode ultrasound, and the results were compared with liver fibrosis index estimated by FibroScan (FS). Material and Method: Fifty-two cases with hepatitis C were examined with abdominal ultrasonography and FS on the same day that they were enrolled. S4 atrophy was evaluated by the distance between the transverse portion of the portal vein and the edge of the S4 (S4 distance). Liver fibrosis was determined as the median of the stiffness on FS as the gold standard. The correlation between S4 distance and stiffness, each blood test date, and spleen index were assessed. Results: The S4 distance became longer with progression of liver fibrosis, i.e., 4.0, 4.2, 7.6, 7.9, and 9.5 mm (mean) for F0, F1, F2, F3, and F4, respectively. There were significant differences between F0 and F2, F0 and F3, F0 and F4, F1 and F2, F1 and F3, and F1 and F4. At a cut-off value of 5.6 mm, it was possible to distinguish F2 or higher with a sensitivity of 91.3% and a specificity of 80.0%. There was a significant correlation between the S4 distance and each blood test data, but not the spleen index. Conclusion: Our findings suggested that S4 distance could serve as a new index for easily and objectively staging hepatic fibrosis. In particular, it was a clinically useful tool in that it could detect fibrosis ≥F2.