杤尾 人司¹, 岩崎 信広¹, 中村 仁美¹, 中山 圭子¹, 曽我 登志子¹, 西馬 信一², 福永 豊和², 岡部 純弘², 樫田 博史², 平佐 昌弘², 伊吹 康良², 藤本 敏明¹, 森本 義人¹, 工藤 正俊³, 冨田 周介⁴, 小西 豊⁵, 織野 彬雄¹

Hitoshi TOCHIO¹, Nobuhiro IWASAKI¹, Hitomi NAKAMURA¹, Keiko NAKAYAMA¹, Toshiko SOGA¹, Shinichi NISHIMURA², Toyokazu FUKUNAGA², Yoshihiro OKABE², Hiroshi KASHIDA², Masahiro HIRASA², Yasuyoshi IBUKI², Toshiaki FUJIMOTO¹, Yoshito MORIMOTO¹, Masatoshi KUDO³, Syusuke TOMITA⁴, Yutaka KONISHI⁵, Akio ORINO¹

¹神戸市立中央市民病院臨床検査技術部腹部超音波室, ²神戸市立中央市民病院消化器センター内科, ³近畿大学医学部消化器内科, ⁴冨田クリニック, ⁵神戸市立中央市民病院外科

¹Division of Abdominal Ultrasound, Kobe City General Hospital, 4-6 Nakamachi, Kobe Minatojima, Chuo-ku, Kobe 650-0046, Japan, ²Department of Gastroenterology, Kobe City General Hospital, 4-6 Nakamachi, Kobe Minatojima, Chuo-ku, Kobe 650-0046, Japan, ³Department of Gastroenterology, Kinki University School of Medicine, 377-2 Ohnohigashi, Osakasayama, Osaka 589-8511, Japan, ⁴Tomita Clinic, 1-12-10 Moriminami, Higashinada, Kobe 658-0011, Japan, ⁵Department of Surgery, Kobe City General Hospital, 4-6 Nakamachi, Kobe Minatojima, Chuo-ku, Kobe 650-0046, Japan

キーワード : Ultrasound, Doppler imaging, Hepatic artery, Portal vein, Bifurcation

Objective It has generally been held that each portal branch is always accompanied by a single arterial branch in the liver. During Doppler ultrasound examination, however, we sometimes encounter a portal branch that appears to be associated with two arterial branches, a phenomenon referred to below as this finding or this phenomenon. Here we attempt to confirm that this finding is based on a correct interpretation of the image and to disclose its basic mechanism.
Material and Methods Five cases of chronic liver disease in which this phenomenon appeared were analyzed with B-flow imaging. Videotapes obtained from 30 patients who had chronic liver disease and had undergone ultrasound angiography (USAG) with arterial infusion of CO₂ micro bubbles were reviewed in order to look for similar findings. Sixty-nine healthy controls were also examined with Doppler sonography for this purpose. Histopathologic specimens from 7 patients who had undergone hepatectomy (3 with hepatocellular carcinoma, 3 with metastatic tumor, and 1 with focal nodular hyperplasia) were examined to study the basic structure of the hepatic vessels.
Results and Discussion Three parallel color signals (two pulsatile and one of a constant waveform) observed on Doppler examination were confirmed by the B-flow method to be three independent vessels in all five cases in which both Doppler sonography and B-flow imaging were used. In 13 (43%) of the 30 cases of USAG, two vessels along a portal branch were visualized by the inflow of micro bubbles, indicating that the two vessels were arteries. The trio of one portal and two arterial branches was also detected with Doppler sonography in 12 (17%) of the 69 healthy controls. In 10 (59%) of the 17 cases (5 of liver disease and 12 normal) that showed this finding on Doppler examination, bifurcations of the hepatic artery and portal vein were both visualized. Hepatic arterial branches were found to bifurcate slightly more proximal to the hepatic hilus than the accompanying portal branch. Histopathologic study revealed Glisson's areas that contained one portal branch and two arterial vessels in nontumorous parts of specimens from all 7 patients with hepatectomy.
Conclusion Two arterial branches can be demonstrated along a portal branch as a result of a more-proximal bifurcation of the hepatic artery than of the portal vein.