Brain magnetic resonance imaging radiomics features associated with hepatic encephalopathy in adult cirrhotic patients.

PURPOSE: Hepatic encephalopathy (HE) is a potential complication of cirrhosis. Magnetic resonance imaging (MRI) may demonstrate hyperintense T1 signal in the globi pallidi. The purpose of this study was to evaluate the performance of MRI-based radiomic features for diagnosing and grading chronic HE in adult patients affected by cirrhosis. METHODS: Adult patients with and without cirrhosis underwent brain MRI with identical imaging protocol on a 3T scanner. Patients without history of chronic liver disease were the control population. HE grading was based on underlying liver disease, severity of clinical manifestation, and number of encephalopathic episodes. Texture analysis was performed on axial T1-weighted images on bilateral lentiform nuclei at the level of the foramina of Monro. Diagnostic performance of texture analysis for the diagnosis and grading of HE was assessed by calculating the area under the receiver operating characteristics (AUROC) with 95% confidence interval (CI). RESULTS: The final study population consisted of 124 patients, 70 cirrhotic patients, and 54 non-cirrhotic controls. Thirty-eight patients had history of HE with 22 having an HE grade > 1. The radiomic features predicted the presence of HE with an AUROC of 0.82 (95% CI: 0.73, 0.90; P < .0001; 82% sensitivity, 66% specificity). Radiomic features predicted grade 1 HE (AUROC 0.75; 95% CI: 0.61, 0.89; P < .0001; 94% sensitivity, 60% specificity) and grade ≥ 2 HE (AUROC 0.82; 95% CI: 0.71, 0.93; P < .0001, 95% sensitivity, 57% specificity). CONCLUSION: In cirrhotic patients, MR radiomic is effective in predicting the presence of chronic HE and in grading its severity.

Evolution of indeterminate hepatocellular nodules at Gd-EOB-DPTA-enhanced MRI in cirrhotic patients.

PURPOSE: To retrospectively analyze the evolution of indeterminate hepatocellular nodules in cirrhotic patients on serial Gd-EOB-DPTA-enhanced MRI, and to identify predictors of HCC development. MATERIALS AND METHODS: This IRB approved study included 33 cirrhotic patients with 69 indeterminate hepatocellular nodules (mean diameter 1.1 cm) at baseline Gd-EOB-DPTA-enhanced MRI and a Gd-EOB-DPTA-enhanced-MRI follow-up of at least 2 years. Two radiologists evaluated size and signal intensity of each nodule at baseline and follow-up. Age, cirrhosis etiology, and HCC history were recorded. Data were compared between nodules that became HCCs at follow-up (HCC) and those that did not (no-HCC). RESULTS: On follow-up, 5/69 nodules became HCCs and 64/69 showed indeterminate characteristics. HCC history was more frequently found in HCCs than in no-HCCs. Age, sex, and cirrhosis etiology were not significantly different between HCCs and no-HCCs. HCCs had a significantly greater baseline diameter and increase in size than no-HCCs. Hepatobiliary phase hypointensity was significantly more common in HCCs than in no-HCCs. Multivariate regression analysis showed that increase in size (OR 10.48; sensitivity, 100%; specificity, 81.2%; p < 0.001) and hepatobiliary phase hypointensity (OR 1.02; sensitivity, 100%; specificity, 78.1%; p < 0.001) was associated with HCC development. CONCLUSION: Indeterminate hepatocellular nodules at Gd-EOB-DPTA-enhanced MRI in cirrhotic patients rarely became HCCs. Hepatobiliary phase hypointensity had a weak association with HCC development.

Assessment of cerebral microbleeds by susceptibility-weighted imaging at 3T in patients with end-stage organ failure.

PURPOSE: Cerebral microbleeds (CMBs) are small rounded lesions representing cerebral hemosiderin deposits surrounded by macrophages that results from previous microhemorrhages. The aim of this study was to review the distribution of cerebral microbleeds in patients with end-stage organ failure and their association with specific end-stage organ failure risk factors. MATERIALS AND METHODS: Between August 2015 and June 2017, we evaluated 15 patients, 9 males, and 6 females, (mean age 65.5 years). Patients population was subdivided into three groups according to the organ failure: (a) chronic kidney failure (n = 8), (b) restrictive cardiomyopathy undergoing heart transplantation (n = 1), and (c) end-stage liver failure undergoing liver transplantation (n = 6). The MR exams were performed on a 3T MR unit and the SWI sequence was used for the detection of CMBs. CMBs were subdivided in supratentorial lobar distributed, supratentorial non-lobar distributed, and infratentorial distributed. RESULTS: A total of 91 microbleeds were observed in 15 patients. Fifty-nine CMBs lesions (64.8%) had supratentorial lobar distribution, 17 CMBs lesions (18.8%) had supratentorial non-lobar distribution and the remaining 15 CMBs lesions (16.4%) were infratentorial distributed. An overall predominance of supratentorial multiple lobar localizations was found in all types of end-stage organ failure. The presence of CMBs was significantly correlated with age, hypertension, and specific end-stage organ failure risk factors (p < 0.001). CONCLUSIONS: CMBs are mostly founded in supratentorial lobar localization in end-stage organ failure. The improved detection of CMBs with SWI sequences may contribute to a more accurate identification of patients with cerebral risk factors to prevent complications during or after the organ transplantation.

Radiomics Analysis of Preprocedural CT Imaging for Outcome Prediction after Transjugular Intrahepatic Portosystemic Shunt Creation.

PURPOSE: To evaluate the role of radiomics in preoperative outcome prediction in cirrhotic patients who underwent transjugular intrahepatic portosystemic shunt (TIPS) using "controlled expansion covered stents". MATERIALS AND METHODS: This retrospective institutional review board-approved study included cirrhotic patients undergoing TIPS with controlled expansion covered stent placement. From preoperative CT images, the whole liver was segmented into Volumes of Interest (VOIs) at the unenhanced and portal venous phase. Radiomics features were extracted, collected, and analyzed. Subsequently, receiver operating characteristic (ROC) curves were drawn to assess which features could predict patients' outcomes. The endpoints studied were 6-month overall survival (OS), development of hepatic encephalopathy (HE), grade II or higher HE according to West Haven Criteria, and clinical response, defined as the absence of rebleeding or ascites. A radiomic model for outcome prediction was then designed. RESULTS: A total of 76 consecutive cirrhotic patients undergoing TIPS creation were enrolled. The highest performances in terms of the area under the receiver operating characteristic curve (AUROC) were observed for the "clinical response" and "survival at 6 months" outcome with 0.755 and 0.767, at the unenhanced and portal venous phase, respectively. Specifically, on basal scans, accuracy, specificity, and sensitivity were 66.42%, 63.93%, and 73.75%, respectively. At the portal venous phase, an accuracy of 65.34%, a specificity of 62.38%, and a sensitivity of 74.00% were demonstrated. CONCLUSIONS: A pre-interventional machine learning-based CT radiomics algorithm could be useful in predicting survival and clinical response after TIPS creation in cirrhotic patients.

Statistical Approaches to Characterize Functional Connectivity in Brain and Physiologic Networks on a Single-Subject Basis.

The trend toward personalized medicine necessitates drawing conclusions from descriptive indexes of physiopathological states estimated from individual recordings of biomedical signals, using statistical analyses that focus on subject-specific differences between experimental conditions. In this context, the present work introduces an approach to assess functional connectivity in brain and physiologic networks by pairwise information-theoretic measures of coupling between signals, whose significance and variations between conditions are statistically validated on a single-subject basis through the use of surrogate and bootstrap data analyses. The approach is illustrated on single-subject recordings of (i) resting-state functional magnetic resonance imaging (rest-fMRI) signals acquired in a pediatric patient with hepatic encephalography associated to a portosystemic shunt and undergoing liver vascular shunt correction, and of (ii) cardiovascular and cerebrovascular time series acquired at rest and during head-up tilt in a subject suffering from orthostatic intolerance.

Statistical Approaches to Identify Pairwise and High-Order Brain Functional Connectivity Signatures on a Single-Subject Basis.

Keeping up with the shift towards personalized neuroscience essentially requires the derivation of meaningful insights from individual brain signal recordings by analyzing the descriptive indexes of physio-pathological states through statistical methods that prioritize subject-specific differences under varying experimental conditions. Within this framework, the current study presents a methodology for assessing the value of the single-subject fingerprints of brain functional connectivity, assessed both by standard pairwise and novel high-order measures. Functional connectivity networks, which investigate the inter-relationships between pairs of brain regions, have long been a valuable tool for modeling the brain as a complex system. However, their usefulness is limited by their inability to detect high-order dependencies beyond pairwise correlations. In this study, by leveraging multivariate information theory, we confirm recent evidence suggesting that the brain contains a plethora of high-order, synergistic subsystems that would go unnoticed using a pairwise graph structure. The significance and variations across different conditions of functional pairwise and high-order interactions (HOIs) between groups of brain signals are statistically verified on an individual level through the utilization of surrogate and bootstrap data analyses. The approach is illustrated on the single-subject recordings of resting-state functional magnetic resonance imaging (rest-fMRI) signals acquired using a pediatric patient with hepatic encephalopathy associated with a portosystemic shunt and undergoing liver vascular shunt correction. Our results show that (i) the proposed single-subject analysis may have remarkable clinical relevance for subject-specific investigations and treatment planning, and (ii) the possibility of investigating brain connectivity and its post-treatment functional developments at a high-order level may be essential to fully capture the complexity and modalities of the recovery.

Imaging of hepatocellular carcinoma recurrence after liver transplantation.

Liver transplantation (LT) provides the highest survival benefit to patients with unresectable hepatocellular carcinoma (HCC). The Milan criteria have been developed for the selection of LT candidates with the goal of improving survival and maintaining an acceptable risk of HCC recurrence. Despite this, recurrence of HCC after LT occurs in up to 20% of cases and represents a major concern due to the poor prognosis of these patients. Furthermore, several extended criteria for the selection of LT candidates have been proposed to account for the growing demand for organs and the resultant increase in the risk of HCC recurrence. Radiologists should be aware that HCC can recur after LT with multiple organ involvement. Knowledge of the location and radiologic appearance of recurrent HCC is necessary to ensure the choice of the most appropriate therapy. This paper aims to comprehensively summarize the spectrum of HCC recurrence after LT and to examine and discuss the imaging features of these lesions. CRITICAL RELEVANCE STATEMENT: This paper aims to share a review of imaging findings of HCC recurrence after LT and to make radiologists familiar with the spectrum of this disease.

Cognitive outcomes in patients treated with neuromuscular electrical stimulation after coronary artery bypass grafting.

Objective: Mechanisms of neurocognitive injury as post-operative sequelae of coronary artery bypass grafting (CABG) are not understood. The systemic inflammatory response to surgical stress causes skeletal muscle impairment, and this is also worsened by immobility. Since evidence supports a link between muscle vitality and neuroprotection, there is a need to understand the mechanisms by which promotion of muscle activity counteracts the deleterious effects of surgery on long-term cognition. Methods: We performed a clinical trial to test the hypothesis that adding neuromuscular electrical stimulation (NMES) to standard rehabilitation care in post-CABG patients promotes the maintenance of skeletal muscle strength and the expression of circulating neuroprotective myokines. Results: We did not find higher serum levels of neuroprotective myokines, except for interleukin-6, nor better long-term cognitive performance in our intervention group. However, a greater increase in functional connectivity at brain magnetic resonance was seen between seed regions within the default mode, frontoparietal, salience, and sensorimotor networks in the NMES group. Regardless of the treatment protocol, patients with a Klotho increase 3 months after hospital discharge compared to baseline Klotho values showed better scores in delayed memory tests. Significance: We confirm the potential neuroprotective effect of Klotho in a clinical setting and for the first time post-CABG.

Neurological Screening in Elderly Liver Transplantation Candidates: A Single Center Experience.

BACKGROUND: Cerebral small vessels disease (cSVD) is an age-related disorder and risk factor for stroke and cognitive/motor impairments. Neurological complications (NCs) are among the causes of adverse outcomes in older liver transplant recipients. This study sought to determine whether cSVD predicts acute NCs in over 65-year-old liver transplant patients. METHODS: Data were collected, from a retrospective medical chart review, of 22 deceased donor liver transplant recipients aged 65 years or older with a pre-operative brain magnetic resonance imaging (MRI). We used the Fazekas score (0-3) as a quantitative measurement of the vascular lesion load seen in the MRI. We analyzed all post-operative acute NCs occurring during the hospital stay and any other non-NC. RESULTS: cSVD was recognized in all patients. Neurological complications (NCs) occurred in 18.1% of patients with toxic-metabolic encephalopathy the most frequent diagnosis (13.64%). More severe cSVD was associated with seizures (p = 0.0362), longer hospital stay (p 0.0299), and disability (p 0.0134). In our elderly cohort, hepatic encephalopathy (HE) (p 0.0287) and ascites (p 0.0270) were predictors of NCs after liver transplantation. Ascites and/or variceal bleeding and severity of liver disease were associated with adverse post-operative outcomes. The small sample size limited the statistical analysis power. CONCLUSIONS: We present the preliminary data of a single-center retrospective study aimed at understanding the cSVD role on NCs and non-NCs after a liver transplantation in elderly patients. This would encourage a more appropriate multicenter prospective study that will definitely confirm if a neurological screening in old age liver transplant candidates is appropriate.

Transjugular intrahepatic portosystemic shunt (TIPS) complications: what diagnostic radiologists should know.

Transjugular intrahepatic portosystemic shunt (TIPS) is an effective therapy for portal hypertension complications and can successfully treat variceal bleeding and refractory ascites. Although TIPS is relatively safe, procedural- or shunt-related morbidity can reach 20%, and procedural complications have a fatality rate of 2%. Delayed recognition and treatment of TIPS complications can lead to life-threatening clinical scenarios. Complications can vary from stent migration or malpositioning to nontarget organ injury, TIPS dysfunction, encephalopathy, or liver failure. This review aims to outline the role of diagnostic radiology in assessing post-TIPS complications.

Temperature Measurement by Diffusion-Weighted Imaging.

Diffusion-weighted imaging (DWI) thermometry is a magnetic resonance-based imaging tool that allows the noninvasive measurement of brain core temperature. Although only applicable to cerebrospinal fluid, it is thought to be potentially useful in assessing the thermal pathophysiology of the brain in both patients and healthy subjects. The objective of this article is to provide a concise but thorough review of the basic physical principles and the principal applications of DWI thermometry as a potential method to elucidate the pathophysiology of several brain diseases and neurologic syndromes.

Multiple sclerosis: prevalence of the 'central vein' sign in white matter lesions on gadolinium-enhanced susceptibility-weighted images.

AIMS: To evaluate prospectively whether an intravenous gadolinium injection could improve the detection of the central vein sign on susceptibility-weighted imaging sequences obtained with a 1.5 T magnetic resonance scanner in patients with multiple sclerosis compared to unenhanced susceptibility-weighted images. MATERIALS AND METHODS: This prospective, institution review board-approved study included 19 patients affected by multiple sclerosis (six men; 13 women; mean age 40.8 years, range 20-74 years). Patients had the relapsing-remitting clinical subtype in 95% of cases, and only one (5%) patient had the primary progressive clinical subtype of multiple sclerosis. T2-weighted images, fluid-attenuated inversion recovery images, unenhanced and contrast-enhanced susceptibility-weighted images were evaluated in consensus by two neuroradiologists for the presence of the central vein sign. The readers were blinded to magnetic resonance imaging reports, clinical information, the presence and the localisation of focal hyperintense white matter lesions. Any discordance between readers was resolved through a joint review of the recorded images with an additional neuroradiologist. RESULTS: A total of 317 multiple sclerosis lesions were analysed. The central vein sign had a higher prevalence detection rate on gadolinium-enhanced susceptibility-weighted images (272 of 317 lesions, 86%) compared to unenhanced susceptibility-weighted images (172 of 317 lesions, 54%). CONCLUSION: Gadolinium-enhanced susceptibility-weighted imaging improves the detection rate of the central vein sign in multiple sclerosis lesions.

Resting-State Functional Magnetic Resonance Imaging for Surgical Neuro-Oncology Planning: Towards a Standardization in Clinical Settings.

Resting-state functional magnetic resonance imaging (rest-f-MRI) is a neuroimaging technique that has demonstrated its potential in providing new insights into brain physiology. rest-f-MRI can provide useful information in pre-surgical mapping aimed to balancing long-term survival by maximizing the extent of resection of brain neoplasms, while preserving the patient's functional connectivity. Rest-fMRI may replace or can be complementary to task-driven fMRI (t-fMRI), particularly in patients unable to cooperate with the task paradigm, such as children or sedated, paretic, aphasic patients. Although rest-fMRI is still under standardization, this technique has been demonstrated to be feasible and valuable in the routine clinical setting for neurosurgical planning, along with intraoperative electrocortical mapping. In the literature, there is growing evidence that rest-fMRI can provide valuable information for the depiction of glioma-related functional brain network impairment. Accordingly, rest-fMRI could allow a tailored glioma surgery improving the surgeon's ability to increase the extent of resection (EOR), and simultaneously minimize the risk of damage of eloquent brain structures and neuronal networks responsible for the integrity of executive functions. In this article, we present a review of the literature and illustrate the feasibility of rest-fMRI in the clinical setting for presurgical mapping of eloquent networks in patients affected by brain tumors, before and after tumor resection.

Seizure in isolated brain cryptococcoma: Case report and review of the literature.

BACKGROUND: Central nervous system (CNS) cryptococcosis is an invasive fungal infection predominantly seen among immunosuppressed patients causing meningitis or meningoencephalitis. Rarely, cryptococcosis can affect immunologically competent hosts with the formation of localized CNS granulomatous reaction, known as cryptococcoma. Common symptoms of CNS cryptococcoma are headaches, consciousness or mental changes, focal deficits, and cranial nerve dysfunction. Rarely, seizures are the only presenting symptom. CASE DESCRIPTION: We report the case of an immunocompetent patient with a solitary CNS cryptococcoma presenting with a long history of non-responsive generalized seizure who has been successfully operated. CONCLUSION: CNS cryptococcoma is a rare entity, and in immunocompetent patients, its diagnosis can be challenging. The pathophysiology of lesion-related seizure is discussed along with a review of the pertinent literature.

Imaging of calcified hepatic lesions: spectrum of diseases.

Hepatic calcifications have been increasingly identified over the past decade due to the widespread use of high-resolution Computed Tomography (CT) imaging. Calcifications can be seen in a vast spectrum of common and uncommon diseases, from benign to malignant, including cystic lesions, solid neoplastic masses, and inflammatory focal lesions. The purpose of this paper is to present an updated review of CT imaging findings of a wide range of calcified hepatic focal lesions, which can help radiologists to narrow the differential diagnosis.

Resting-State Functional Connectome in Patients with Brain Tumors Before and After Surgical Resection.

PURPOSE: High-grade glioma surgery has evolved around the principal belief that a safe maximal tumor resection improves symptoms, quality of life, and survival. Mapping brain function has been recently improved by resting-state functional magnetic resonance imaging (rest-fMRI), a novel imaging technique that explores networks connectivity at "rest." METHODS: This prospective study analyzed 10 patients with high-grade glioma in whom rest-fMRI connectivity was assessed both in single-subject and in group analysis before and after surgery. Seed-based functional connectivity analysis was performed with CONN toolbox. Network identification focused on 8 major functional connectivity networks. A voxel-wise region of interest (ROI) to ROI correlation map to assess functional connectivity throughout the whole brain was computed from a priori seeds ROI in specific resting-state networks before and after surgical resection in each patient. RESULTS: Reliable topography of all 8 resting-state networks was successfully identified in each participant before surgical resection. Single-subject functional connectivity analysis showed functional disconnection for dorsal attention and salience networks, whereas the language network demonstrated functional connection either in the case of left temporal glioblastoma. Functional connectivity in group analysis showed wide variations of functional connectivity in the default mode, salience, and sensorimotor networks. However, salience and language networks, salience and default mode networks, and salience and sensorimotor networks showed a significant correlation (P uncorrected <0.0025; P false discovery rate <0.077) in comparison before and after surgery confirming non-disconnection of these networks. CONCLUSIONS: Resting-state fMRI can reliably detect common functional connectivity networks in patients with glioma and has the potential to anticipate network alterations after surgical resection.

CT and MR imaging of cystic renal lesions.

Cystic renal lesions are a common incidental finding on routinely imaging examinations. Although a benign simple cyst is usually easy to recognize, the same is not true for complex and multifocal cystic renal lesions, whose differential diagnosis includes both neoplastic and non-neoplastic conditions. In this review, we will show a series of cases in order to provide tips to identify benign cysts and differentiate them from malignant ones.

Outcome of LR-3 and LR-4 observations without arterial phase hyperenhancement at Gd-EOB-DTPA-enhanced MRI follow-up.

OBJECTIVE: The aim of this study was to retrospectively analyze the outcome of LR-3 and LR-4 without arterial phase hyperenhancement (APHE), and identify which features could predict LR-5 progression on serial Gd-EOB-DTPA-enhanced MRI follow-up. METHODS: Forty-nine cirrhotic patients with 55 LR-3 and 19 LR-4 without APHE were evaluated. Observations were classified as decreased, stable or increased in category at follow-up. Observation size and LI-RADS major and ancillary features were evaluated. RESULTS: Seventeen/fifty-five (31%) LR-3 and 8/19 (42%) LR-4 progressed to LR-5 at follow-up. Baseline LI-RADS major and ancillary features were not significantly different among LR-3 and LR-4. A diameter ≥ 10 mm significantly increased LR-5 progression risk of LR-3 (OR = 6.07; 95% CI: 0.12; 60.28]; P < .001). LR-4 with a diameter ≥ 10 mm more likely become LR-5 at follow-up (OR = 8.95; 95% CI: 0.73; 111.8; P = .083]). CONCLUSION: LR-3 and LR-4 without APHE were often downgraded or remained stable in category on Gd-EOB-DTPA-enhanced MRI follow-up.

Focal confluent fibrosis in cirrhotic liver: natural history studied with serial CT.

OBJECTIVE: The objective of this study was to assess the long-term natural history of focal confluent fibrosis in cirrhotic liver with CT. MATERIALS AND METHODS: Two radiologists retrospectively reviewed in consensus 118 liver CT examinations in 26 patients (19 men, seven women; age range, 32-68 years; mean age, 50 years) performed over approximately 6 years. Helical CT scans were obtained before and 30-35 and 65-70 seconds after injection of 125-150 mL of contrast medium at a rate of 4-5 mL/s. Proof of cirrhosis was based on liver transplantation (n = 6), biopsy (n = 9), or imaging findings (n = 11). The number, location, and attenuation of fibrotic lesions and presence of trapped vessels were evaluated. Variation of hepatic retraction associated with the development of focal confluent fibrosis lesions was assessed using the ellipsoid volume formula and an arbitrary retraction index. RESULTS: Each radiologist identified 41 focal confluent fibrosis lesions. All lesions were identified by both radiologists. Twelve patients (46%) had a single lesion, 13 (50%) had two lesions, and one (4%) had three lesions. Thirty-four (83%) of 41 lesions were located in segment IV, VII, or VIII. Thirty-two lesions (78%) were hypoattenuating on unenhanced images, 25 lesions (61%) were hypoattenuating on hepatic arterial phase images, and 20 lesions (49%) were isoattenuating on portal venous phase images. Seven lesions (17%) were or became hyperattenuating at follow-up on portal venous phase images. Trapped vessels were found in six lesions (15%). The retraction index showed a significant increase over time (r = 0.423, p < or = 0.0001). CONCLUSION: The degree of capsule retraction associated with focal confluent fibrosis evolves with time and relates to the natural evolution of cirrhosis.