Yoshihiro Furuichi1,2, Katsutoshi Sugimoto3, Hisashi Oshiro4, Masakazu Abe3, Hirohito Takeuchi3, Yuu Yoshimasu3, Takao Itoi3. 1. Department of Gastroenterology and Hepatology, Tokyo Medical University, 6-7-1 Nishishinjuku, Shinjuku-ku, Tokyo, 160-0023, Japan. furuichi@tokyo-med.ac.jp. 2. Department of Gastroenterology, Niiza Shiki Central General Hospital, Saitama, Japan. furuichi@tokyo-med.ac.jp. 3. Department of Gastroenterology and Hepatology, Tokyo Medical University, 6-7-1 Nishishinjuku, Shinjuku-ku, Tokyo, 160-0023, Japan. 4. Department of Pathology, Jichi Medical University, Tochigi, Japan.
Abstract
PURPOSE: Measurement of spleen stiffness (SS) using ultrasound (US) elastography is useful for predicting portal hypertension. However, the mechanism leading to increased SS remains unclear. We jointly developed a new US elastography system (Aplio i-series, Canon Medical Systems) that can easily measure organ viscosity (dispersion slope: DS). We analyzed the cause of increased SS by calculating the shear wave speed (SWs, which reflects fibrosis) and DS of the spleen in carbon tetrachloride (CCL4) rat liver cirrhosis models. METHODS: A total of 13 Sprague-Dawley rats were randomly divided into four groups (C group: 3 rats as control, 2D group: 3 rats injected with CCL4 twice in 1 week, 4D group: 4 rats injected 4 times in 1 week, 6W group: 3 rats injected twice a week for 6 weeks). The SWs and the DS of each group were calculated, and histopathological analysis was performed. RESULTS: The spleen SWs of the 6W group was significantly higher than that of the C group (p = 0.044). The spleen DS did not change after CCL4. The liver SWs of the 4D and 6W groups was significantly higher than that of the C group (p = 0.012 and 0.007, respectively) with fibrosis change on histopathology, and the DS of the 4D group was significantly higher than that of the C group (p = 0.033). Splenic fibrosis was confirmed in the 6W group, but inflammation and necrosis were not seen. CONCLUSION: SS increased due to fibrosis and can be predicted based on SWs and DS values.
PURPOSE: Measurement of spleen stiffness (SS) using ultrasound (US) elastography is useful for predicting portal hypertension. However, the mechanism leading to increased SS remains unclear. We jointly developed a new US elastography system (Aplio i-series, Canon Medical Systems) that can easily measure organ viscosity (dispersion slope: DS). We analyzed the cause of increased SS by calculating the shear wave speed (SWs, which reflects fibrosis) and DS of the spleen in carbon tetrachloride (CCL4) ratliver cirrhosis models. METHODS: A total of 13 Sprague-Dawley rats were randomly divided into four groups (C group: 3 rats as control, 2D group: 3 rats injected with CCL4 twice in 1 week, 4D group: 4 rats injected 4 times in 1 week, 6W group: 3 rats injected twice a week for 6 weeks). The SWs and the DS of each group were calculated, and histopathological analysis was performed. RESULTS: The spleen SWs of the 6W group was significantly higher than that of the C group (p = 0.044). The spleen DS did not change after CCL4. The liver SWs of the 4D and 6W groups was significantly higher than that of the C group (p = 0.012 and 0.007, respectively) with fibrosis change on histopathology, and the DS of the 4D group was significantly higher than that of the C group (p = 0.033). Splenic fibrosis was confirmed in the 6W group, but inflammation and necrosis were not seen. CONCLUSION: SS increased due to fibrosis and can be predicted based on SWs and DS values.