PURPOSE: To prospectively assess functional magnetic resonance (MR) imaging during hypercapnia and hyperoxia for monitoring changes in liver perfusion and hemodynamics in rats. MATERIALS AND METHODS: All experiments were performed with approval of an animal care and use committee. Functional T2*-weighted gradient-echo MR images of the rat liver were acquired during hyperoxia and graded hypercapnia (n=24). Additional images were acquired during portal vein ligation (n=4), induced hypovolemia (n=5), and 70% hepatectomy (n=5). Hypercapnic effects were confirmed with Doppler ultrasonography and with gadopentetate dimeglumine. Differences between groups were analyzed by using Wilcoxon rank sum test, except for the graded hypercapnia, for which one-way analysis of variance was used. RESULTS: Liver signal intensity (SI) increased due to hyperoxia; the percentage change in SI was seven times greater than that in muscle tissue; this reflects higher vascularity of the liver. Liver SI decreased due to hypercapnia; the percentage change in SI was negative in the liver but positive in the muscle (P<.001). Induced hypovolemia resulted in considerable decreases in functional MR imaging response; this reflects lower liver perfusion. Clinical applicability of the functional MR imaging method was proved by monitoring changes in liver perfusion that resulted from liver resection. CONCLUSION: In the liver, the magnitude of the percentage change in SI induced by hypercapnia and hyperoxia reflects changes in total blood volume; whereas percentage change in SI values induced by hypercapnia from a negative to a positive value reflects relative changes in portal-to-arterial blood flow ratio. (c) RSNA, 2007.
PURPOSE: To prospectively assess functional magnetic resonance (MR) imaging during hypercapnia and hyperoxia for monitoring changes in liver perfusion and hemodynamics in rats. MATERIALS AND METHODS: All experiments were performed with approval of an animal care and use committee. Functional T2*-weighted gradient-echo MR images of the rat liver were acquired during hyperoxia and graded hypercapnia (n=24). Additional images were acquired during portal vein ligation (n=4), induced hypovolemia (n=5), and 70% hepatectomy (n=5). Hypercapnic effects were confirmed with Doppler ultrasonography and with gadopentetate dimeglumine. Differences between groups were analyzed by using Wilcoxon rank sum test, except for the graded hypercapnia, for which one-way analysis of variance was used. RESULTS: Liver signal intensity (SI) increased due to hyperoxia; the percentage change in SI was seven times greater than that in muscle tissue; this reflects higher vascularity of the liver. Liver SI decreased due to hypercapnia; the percentage change in SI was negative in the liver but positive in the muscle (P<.001). Induced hypovolemia resulted in considerable decreases in functional MR imaging response; this reflects lower liver perfusion. Clinical applicability of the functional MR imaging method was proved by monitoring changes in liver perfusion that resulted from liver resection. CONCLUSION: In the liver, the magnitude of the percentage change in SI induced by hypercapnia and hyperoxia reflects changes in total blood volume; whereas percentage change in SI values induced by hypercapnia from a negative to a positive value reflects relative changes in portal-to-arterial blood flow ratio. (c) RSNA, 2007.
Authors: Pier Paolo Mainenti; Federica Romano; Laura Pizzuti; Sabrina Segreto; Giovanni Storto; Lorenzo Mannelli; Massimo Imbriaco; Luigi Camera; Simone Maurea Journal: World J Radiol Date: 2015-07-28
Authors: Ning Jin; Jie Deng; Tamuna Chadashvili; Yue Zhang; Yang Guo; Zhuoli Zhang; Guang-Yu Yang; Reed A Omary; Andrew C Larson Journal: Radiology Date: 2010-01 Impact factor: 11.105
Authors: Katia Beider; Michal Abraham; Michal Begin; Hanna Wald; Ido D Weiss; Ori Wald; Eli Pikarsky; Rinat Abramovitch; Evelyne Zeira; Eithan Galun; Arnon Nagler; Amnon Peled Journal: PLoS One Date: 2009-04-02 Impact factor: 3.240