LAUSR

Editorial for “Using Intravoxel Incoherent Motion and Dynamic Contrast-Enhanced MR Imaging to Early Detect Tissue Injury and Microcirculation Alteration in Hepatic Injury Induced by Intestinal Ischemia Reperfusion in the Rat Model” Recent advances in MRI technology have made it possible to acquire not only morphological information, but also functional information even in MR equipment of clinical use. In terms of hepatic functional information, diffusion and perfusion parameters such as apparent diffusion coefficient (ADC) measurement, bi-exponential intravoxel incoherent motion (IVIM), and tri-exponential IVIM technique are getting used in clinical analyses of liver disease. IVIM is first established by Le Bihan, which is used as a quantitative parameter of diffusion and perfusion of water molecules. Dynamic contrast-enhanced MR technique provides us different quantitative parameters about hemodynamic perfusion. Ischemic/reperfusion injury (IRI) of various organs is one of the pathologies related to blood flow that has been attracting attention recently. IRI is defined as the paradoxical exacerbation of cellular dysfunction and death, following restoration of blood flow to previously ischemic tissues. IRI occurs in a wide range of organs. Reactive oxygen species (ROS) play a role in tissue damage during IRI. Ye et al applied bi-exponential IVIM-DWI for quantitative analysis of the cellular injury and microcirculation alterations in hepaticIRI (HIRI). And they revealed that IVIM-DWI can quantitatively characterize an animal model of HIRI, with D and ADC sensitive in early detection of cellular injury, as well as fair to good correlation between f, ADC, and microcirculation alteration. Cheung et al applied diffusion tensor imaging (DTI) and clarified that DTI can characterize HIRI by detecting the transient change in both mean diffusivity and fractional anisotropy. These authors directly analyze the HIRI using liver MR imaging technique. Intestinal ischemia is a vascular emergency, which is caused by thromboembolism, atherosclerosis, severe hypotension, and intestinal torsion. Intestinal ischemia may cause infarction of intestinal tissue and cause intestinal perforation. To restore intestinal function, reperfusion is necessary to maintain oxygen supply to the intestine. However, reperfusion of the blood flow to the ischemic intestine may cause intestinal-IRI (IIRI). Reperfused intestines produce ROS and damage associated molecules, cytokines, and neutrophil infiltration, and which not only damage the intestine but also damage distant organs, which causes multiple organ failure (MOF). In this issue of JMRI, Yang et al, successfully clarified that monitoring IIRI using not the intestinal MR imaging but the liver MR quantitative parameters obtained by IVIM and DCE-MRI is feasible. In detail, they established the rat IIRI model and tried to monitor the early tissue damage and microcirculation alteration of the liver, which is caused by IIRI. Although there are several limitations, this study demonstrated that IVIM and DCE-MRI can noninvasively estimate hepatic pathophysiological processes in a rat IIRinduced hepatic injury model. The change in microcirculation and perfusion seemed to be the major factors in IIR-induced hepatic injury. This study contains an important message that early monitoring of the potential MOF caused by IRI of distant organs might be objectively estimated by liver quantitative imaging such as IVIM and DCE-MRI. Although further study might be needed for practical use of monitoring early stage of MOF using quantitative liver imaging parameters, the results of their study suggest the possibility of using liver