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Pre-and Post-TIPS rCBFs in the gray matter, white matter and whole brain. a rCBF in the gray matter; b rCBF in the white matter; c rCBF in the whole brain; Note: Data were displayed in 95 % two-side confidence intervals on mean values. Note: rCBF = relative cerebral blood flow
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Short- and long-term effects of transjugular intrahepatic portosystemic shunt (TIPS) on cerebral blood flow (CBF) in patients with cirrhosis are still unclear. The purpose of this longitudinal study was to explore CBF alteration patterns in cirrhotic patients after TIPS. Thirteen cirrhotic patients (7 male, 6 female, mean age 50.0 ± 9.3 years) unde...
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Citations
... Due to the sudden change in the cerebral blood flow in a short period of time, HE is a potential complication shortly after TIPS. When the brain has gradually adapted 3 months after procedure, the cerebral blood flow has also slowly decreased to preoperative levels and the blood ammonia level decreased, without increasing the incidence of HE (6). In the present study, post-TIPS HE was observed during follow-ups in 34.7% of the patients. ...
Background/aims:
Early hepatic encephalopathy (HE) is one of the most common complications developed after undergoing transjugular intrahepatic portosystemic shunt (TIPS). Hence, its early prevention and treatment are important. This study aimed at establishing a model to predict early post-TIPS HE.
Materials and methods:
Clinical data of 262 patients who underwent TIPS procedure was analyzed retrospectively. Patients were divided into early post-TIPS HE and non-early post-TIPS HE groups, based on the presence of HE within 3 months after TIPS. About 70% of the patients were randomly selected as the model group to establish a prediction model, and the remaining 30% were used as the validation group to test the model. The independent risk factors for early HE post-TIPS were identified and selected using single factor analysis and multi-factor logistic regression analysis. Subsequently the prediction model was established and validated.
Results:
Age, Child-Pugh classification, and fibrinogen were found to be the independent risk factors for early post-TIPS HE., The logistic regression model was established based on these factors and their regression coefficients: p=1/{1+exp[4.829-1.975*age-1.110*(Child-Pugh classification)+1.724*loge (fibrinogen in g/L)]}. Finally, the model was validated among a set of 79 patients from the validation group.
Conclusion:
The logistic regression model based on age, Child-Pugh classification, and fibrinogen for early post-TIPS HE can effectively predict the risk of early HE after TIPS.
... Many MR techniques such as conventional T1 and T2 weighted imaging, diffusion weighted imaging (DWI), diffusion tensor imaging (DTI), proton magnetic resonance spectroscopy ( 1 H-MRS), susceptibility-weighted imaging (SWI), arterial spin labeling (ASL) MR perfusion imaging have been used to detect cerebral abnormalities in various central nervous system diseases, including diabetes-related brain damage (Biessels and Reijmer 2014;Zhang et al. 2013;Ranjan et al. 2005;Zhu et al. 2015;Heikkilä et al. 2010;Chai et al. 2015;Zheng et al. 2013). In recent years, rs-fMRI is increasingly used to investigate the neural basis of cognitive dysfunction in DM patients. ...
Diabetes mellitus is a common metabolic disease which is associated with increasing risk for multiple cognitive declines. Alterations in brain functional connectivity are believed to be the mechanisms underlying the cognitive function impairments. During the past decade, resting-state functional magnetic resonance imaging (rs-fMRI) has been developed as a major tool to study brain functional connectivity in vivo. This paper briefly reviews the diabetes-associated cognitive impairment, analysis algorithms and clinical applications of rs-fMRI. We also provide future perspectives of rs-fMRI in diabetes.
... Increased glutamine/glutamate signal and decreased myo-inositol signal (Haussinger et al. 2000) MR perfusion imaging Regional CBF slightly increased at 1 week after TIPS (Zheng et al. , 2013b; Post-TIPS CBF sharply decreased to below the pre-TIPS level at 3 months after insertion, remains at a low level (Zheng et al. 2013b); CBF changes might be associated with ammonia levels in HE (Zheng et al. 2013a); To predict the development of overt HE after TIPS (Zheng et al. , 2013a BOLD-fMRI Detection of abnormal brain activities compared with pre-TIPS (Ni et al. 2014;Qi et al. 2012) Most significantly altered brain function with substantially decreased and increased brain activities at median 3-month follow-up (Ni et al. 2014;Qi et al. 2012) Decreased ReHo in multiple regions and increased ReHo in the caudate and insula at 1-year follow-up (Ni et al. 2014). ...
... Increased glutamine/glutamate signal and decreased myo-inositol signal (Haussinger et al. 2000) MR perfusion imaging Regional CBF slightly increased at 1 week after TIPS (Zheng et al. , 2013b; Post-TIPS CBF sharply decreased to below the pre-TIPS level at 3 months after insertion, remains at a low level (Zheng et al. 2013b); CBF changes might be associated with ammonia levels in HE (Zheng et al. 2013a); To predict the development of overt HE after TIPS (Zheng et al. , 2013a BOLD-fMRI Detection of abnormal brain activities compared with pre-TIPS (Ni et al. 2014;Qi et al. 2012) Most significantly altered brain function with substantially decreased and increased brain activities at median 3-month follow-up (Ni et al. 2014;Qi et al. 2012) Decreased ReHo in multiple regions and increased ReHo in the caudate and insula at 1-year follow-up (Ni et al. 2014). ...
... ASL has been proven to be helpful in monitoring short-and long-term CBF changes following TIPS. It appears that the short-term common effects of TIPS may be generally increased CBF (Fig. 4), whereas decreased CBF may be closely related to the development of HE after TIPS (Zheng et al. , 2013b. The decreased CBF might indicate that patients are unable to tolerate the shunt which results in overt HE. ...
Hepatic encephalopathy (HE) is a common complication after implantation of a transjugular intrahepatic portosystemic shunt (TIPS). Neuroimaging offers a variety of techniques for non-invasive evaluation of alterations in metabolism, as well as structural and functional changes of the brain in patients after TIPS implantation. In this article, we review the epidemiology and pathophysiology of post-TIPS HE. The potential of neuroimaging including positron emission tomography and multimodality magnetic resonance imaging to investigate the pathophysiology of post-TIPS HE is presented. We also give a perspective on the role of neuroimaging in this field.
... Although this review focused on the ASL applications in neuroradiology, ASL is also used in cardiac, renal, hepatic, prostate, and musculoskeletal imaging [85][86][87][88][89]. Further development of more robust sequences with multislice imaging capabilities will hopefully improve the clinical acceptance of ASL. ...
Purpose: Arterial spin labeling (ASL) techniques have been implemented across a diverse range of clinical and experimental applications. This review aims to evaluate the current feasibility of ASL in clinical neuroradiology based on recent improvements to ASL sequences and highlight areas for potential clinical applications. Methods and Materials: In December 2014, a literature search was conducted on PubMed Central, EMBASE, and Scopus using the search terms: "arterial spin labeling, neuroradiology," for studies published between 2009 and 2014 (inclusive). Of 483 studies matching the inclusion criteria, the number of studies using continuous, pseudocontinuous, pulsed, and velocity-selective ASL sequences was 42, 209, 226, and 3, respectively. Studies were classified based on several common clinical applications according to the type of ASL sequence used. Studies using pulsed ASL and pseudo-continuous ASL were grouped based on common sequences. Results: The number of clinical studies was 264. Numerous studies applied ASL to stroke management (43 studies), drug testing (21 studies), neurodegenerative diseases (40 studies), and psychiatric disorders (26 studies). Conclusions: This review discusses several factors hindering the implementation of clinical ASL and ASL-related radiofrequency safety issues encountered in clinical practice. However, a limited number of search terms were used. Further development of robust sequences with multislice imaging capabilities and reduced radiofrequency energy deposition will hopefully improve the clinical acceptance of ASL.
... They exhibited that 7 out of 9 patients experienced a global CBF increase, while the remaining 2 had a global CBF decrease by 16% and 31%, respectively, who suffered from multiple episodes of OHE during follow-up. In another study, Zheng et al [46] further studied short-and long-term effects of TIPS on CBF in patients with cirrhosis. In this longitudinal study, the baseline CBF level was established by performing ASL MRI 1-9 d before TIPS, and the follow-up MR examinations were performed about 1 wk, 3 mo, 6-9 mo and 12-18 mo after TIPS. ...
Hepatic encephalopathy (HE) is a neuropsychiatric complication of cirrhosis or acute liver failure. Currently, HE is regarded as a continuous cognitive impairment ranging from the mildest stage, minimal HE to overt HE. Hyperammonaemia and neuroinflammation are two main underlying factors which contribute to the neurological alterations in HE. Both structural and functional impairments are found in the white mater and grey mater involved in HE. Although the investigations into HE pathophysiological mechanism are enormous, the exact pathophysiological causes underlying HE remain controversial. Multimodality magnetic resonance imaging (MRI) plays an important role in helping to understand the pathological process of HE. This paper reviews the up-to-date multimodality MRI methods and predominant findings in HE patients with a highlight of the increasingly important role of blood oxygen level dependent functional MRI.
Hepatic encephalopathy (HE) is a neurological or neuropsychological complication due to liver failure or portosystemic shunting. The clinical manifestation is highly variable, which can exhibit mild cognitive or motor impairment initially, or gradually progress to a coma, even death, without treatment. Neuroimaging plays a critical role in uncovering the neural mechanism of HE. In particular, multimodality MR imaging is able to assess both structural and functional derangements of the brain with HE in focal or neural network perspectives. In recent years, there has been rapid development in novel MR technologies and applications to investigate the pathophysiological mechanism of HE. Therefore, it is necessary to update the latest MR findings regarding HE by use of multimodality MRI to refine and deepen our understanding of the neural traits in HE. Herein, this review highlights the latest MR imaging findings in HE to refresh our understanding of MRI application in HE.
Objectives:
To assess how the severity of hepatic encephalopathy (HE) affects perfusion and metabolic changes in cirrhotic patients and the association between severity and liver disease and anemia.
Methods:
The study groups comprised 31 healthy subjects and 33 cirrhotic patients who underwent MR examinations, and blood and neuropsychological tests. Of the cirrhotic patients, 14 were unaffected, and 11 had covert HE (CHE) and 8 overt HE (OHE). Global cerebral blood flow (CBF), oxygen extraction fraction (OEF), and metabolic rate of oxygen (CMRO2) were noninvasively measured by phase-contrast and T2-relaxation-under-spin-tagging MRI. Correlations were performed between MR measurements, hematocrits, ammonia levels, Child-Pugh scores and neuropsychological test scores.
Results:
Compared with the values in healthy subjects, CBF was higher in unaffected patients, the same in CHE patients and lower in OHE patients, OEF was higher in all patients, and CMRO2 was the same in unaffected and CHE patients and lower in OHE patients. Hematocrit was negatively correlated with CBF and OEF, but not with CMRO2. Ammonia level was negatively correlated with CBF and CMRO2, and Child-Pugh score was negatively correlated with CMRO2.
Conclusions:
The severity-associated alterations in cirrhotic patients indicate that homeostasis of oxygen delivery and oxidative metabolism in HE is regulated by multiple mechanisms. These physiological alterations appeared to be associated with the degree of anemia, ammonia level, and liver function.
Key points:
• CBF, OEF and CMRO2 did not change monotonically with HE progression. • Anemia possibly contributed to CBF and OEF changes in cirrhotic patients. • Liver dysfunction mainly contributed to changes in CMRO2 in cirrhotic patients.
The methylated derivative of L-arginine, asymmetric dimethylarginine (ADMA) is synthesized in different mammalian tissues including the brain. ADMA acts as an endogenous, nonselective, competitive inhibitor of all three isoforms of nitric oxide synthase (NOS) and may limit L-arginine supply from the plasma to the enzyme via reducing its transport by cationic amino acid transporters. Hepatic encephalopathy (HE) is a relatively frequently diagnosed complex neuropsychiatric syndrome associated with acute or chronic liver failure, characterized by symptoms linked with impaired brain function leading to neurological disabilities. The L-arginine-nitric oxide (NO) pathway is crucially involved in the pathomechanism of HE via modulating important cerebral processes that are thought to contribute to the major HE symptoms. Specifically, activation of this pathway in acute HE leads to an increase in NO production and free radical formation, thus, contributing to astrocytic swelling and cerebral edema. Moreover, the NO-cGMP pathway seems to be involved in cerebral blood flow (CBF) regulation, altered in HE. For this reason, depressed NO-cGMP signaling accompanying chronic HE and ensuing cGMP deficit contributes to the cognitive and motor failure. However, it should be remembered that ADMA, a relatively little known element limiting NO synthesis in HE, may also influence the NO-cGMP pathway regulation. In this review, we will discuss the contribution of ADMA to the regulation of the NO-cGMP pathway in the brain, correlation of ADMA level with CBF and cognitive alterations observed during HE progression in patients and/or animal models of HE.
Patients with cirrhosis and portal hypertension are at an increased risk of the development of circulatory dysfunction that may potentially result in multiple organ failure. Apart from the liver, this may involve the heart, lungs, kidneys, the immune system, the adrenal glands, and other organ systems. As the disease progresses, the circulation becomes hyperdynamic, and signs of cardiac, pulmonary, and renal dysfunction are observed, in addition to reduced survival. Infections and an altered cardiac function known as cirrhotic cardiomyopathy may be precipitators for the development of other complications such as hepatorenal syndrome. In patients with chronic organ dysfunction, various precipitating events may induce an acute-on-chronic renal failure and acute-on-chronic liver failure that negatively affect the prognosis. Future research on the pathophysiologic mechanisms of the complications and the precipitating factors is essential to understand the basics of the treatment of these challenging conditions. The aim of the present review is to focus on the development and precipitating factors of various organ failures in patients with decompensated cirrhosis.
The exact neuro-pathophysiological effect of transjugular intrahepatic portosystemic shunt (TIPS) on brain function remains unclear. The purpose of this study was to investigate the longitudinal brain activity changes in cirrhotic patients with TIPS insertion using resting-state functional MRI (fMRI) with regional homogeneity (ReHo) method.
Fifteen cirrhotic patients without overt hepatic encephalopathy (OHE) planned for TIPS procedure and 15 age- and gender-matched healthy controls were included in this study. Eleven of the 15 patients underwent repeated fMRI examinations at median 7-day following TIPS, 8 patients in median 3-month, and 7 patients in median 1-year follow-up duration, respectively. Regional homogeneity was calculated by the Kendall's coefficient of concordance (KCC) and compared between patients before TIPS and healthy controls with two-sample t test as well as pre-and post-TIPS patients with paired t test. Correlations between the pre- and post-TIPS changes of ReHo and the changes of venous blood ammonia level and number connection test type A (NCT-A)/digit symbol test (DST) scores were calculated by crossing subjects.
Compared with healthy controls, 15 cirrhotic patients before TIPS procedure showed decreased ReHo in the bilateral frontal, parietal, temporal and occipital lobes and increased ReHo in the bilateral caudate. Compared with the pre-TIPS patients, 11 post-TIPS patients in the median 7-day follow-up examinations demonstrated decreased ReHo in the medial frontal gyrus (MFG), superior parietal gyrus (SPG), middle/superior temporal gyrus (M/STG), anterior cingulate cortex (ACC), caudate, and increased ReHo in the insula. Eight post-TIPS patients in the median 3-month follow-up examinations showed widespread decreased ReHo in the bilateral frontal and parietal lobes, ACC, caudate, and increased ReHo in the insula and precuneus/cuneus. In the median 1-year follow-up studies, seven post-TIPS patients displayed decreased ReHo in the bilateral frontal and parietal lobes, ACC, supplementary motor area (SMA), posterior cingulate cortex (PCC), and increased ReHo in the caudate and insula (P<0.05, Alphasim corrected). The changes of ReHo values in bilateral IPL, MFG, caudate and SMA were correlated with changes of DST scores during the median 3-month follow-up (all P<0.05).
The TIPS implantation had a persistent effect on brain function in cirrhotic patients including both predominant impairment and compensation mechanisms, with the most significant alterations in the median 3-month period after TIPS. The ReHo analysis may be potentially valuable for uncovering the mechanism of TIPS' effects on brain function.
