Diffusion-weighted imaging discriminates between cytotoxic and vasogenic edema in a patient with eclampsia

GPR30 alleviated subarachnoid hemorrhage-induced blood-brain barrier dysfunction by activating the PI3K/Akt and Nrf2/HO-1 pathways

The blood-brain barrier (BBB) plays a critical role in the development and outcome of subarachnoid hemorrhage (SAH). This study focuses on the potential mechanism by which G-protein-coupled estrogen receptor 30 (GPR30) affects the BBB after SAH. A rat SAH model was established using an intravascular perforation approach. G1 (GPR30 agonist) was administered to investigate the mechanism of BBB damage after SAH. Brain water content, Western blotting, Evans blue leakage, and immunofluorescence staining were performed. Brain microvascular endothelial cells were induced by hemin to establish SAH model in vitro. By adding LY294002 [a phosphatidylinositol 3-kinase (PI3K) blocker] and zinc protoporphyrin IX (ZnPP IX) [a heme oxygenase 1 (HO-1) antagonist], the mechanism of improving BBB integrity through the activation of GPR30 was studied. In vivo, GPR30 activation improved BBB disruption, as evidenced by decreased cerebral edema, downregulated albumin expression, and reduced extravasation of Evans blue and IgG after G1 administration in SAH rats. Moreover, SAH downregulated the levels of tight junction (TJ) proteins, whereas treatment with G1 reversed the effect of SAH. The protective effect of G1 on BBB integrity in vitro was consistent with that in vivo, as evidenced by G1 reducing the impact of hemin on transendothelial electrical resistance (TEER) value, dextran diffusivity, and TJ protein levels in brain microvascular endothelial cells. In addition, G1 activated the PI3K/ protein kinase B (Akt) and nuclear factor erythroid 2-related factor 2 (Nrf2)/HO-1 pathways both in vivo and in vitro. Furthermore, the administration of LY294002 and ZnPP IX partially reversed the protective effect of G1 on BBB integrity in hemin-stimulated cells. We demonstrated that the activation of GPR30, at least partly through the PI3K/Akt and Nrf2/HO-1 pathways, alleviated BBB damage both in vivo and in vitro. This study introduced a novel therapeutic approach for protecting the BBB after SAH.NEW & NOTEWORTHY The PI3K/Akt and Nrf2/HO-1 pathways might be potential mechanisms by which GPR30 protected the integrity of the BBB in SAH models. Therefore, treatment of SAH with GPR30 activator might be a promising therapeutic strategy.

Posterior Reversible Encephalopathy Syndrome (PRES) and its relation with COPD

Introduction

and importance: PRES is a neurological disorder which is usually seen in adult females with symptoms like headache, altered mental status, seizures, impairment of vision. It is a radiographic diagnosis and can present with complications like status epilepticus, hemorrhagic and ischemic brain strokes.It can be associated with many clinical entities, COPD being one. Treatment is symptomatic.

Case presentation

We present a case of a 68 years female, presenting with clinical pictures of PRES in an episode of Acute Exacerbation of COPD, who has been diagnosed with PRES based on her CT head and MRI head findings. Treated by treating the infection and other symptomatic measures.

Clinical discussion

Our case had similar association with COPD as mentioned in few other articles.

Conclusion

Although rare, PRES is sometimes associated with exacerbation of COPD, and thus should not be ignored.

Prediction of pre-eclampsia by using radiomics nomogram from gestational hypertension patients

Background

Pre-eclampsia (PE) is the main cause of death in maternal and prenatal morbidity. No effective clinical tools could be used for the prediction of PE. A radiomics nomogram based on diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) maps was established to predict PE from gestational hypertension (GH).

Materials and methods

A total of 138 patients with hypertensive disorders of pregnancy were continuously enrolled in the study prospectively, namely, 58 patients with PE and 80 patients with GH. The patients were randomly divided into a training cohort (n = 97) and a test cohort (n = 41). Radiomics features were extracted from DWI and ADC maps. The radiomics signature was constructed using a least absolute shrinkage and selection operator (LASSO) algorithm in the training cohort. A radiomics nomogram was developed by combining the radiomics signature with the selected clinical risk factors. The area under the receiver operating characteristic (ROC) curves (AUC), specificity, sensitivity, accuracy, positive predictive value, and negative predictive values of the radiomics signature, clinical risk factors, and radiomics nomogram were calculated. Decision curve analysis (DCA) was performed to determine the clinical usefulness of the radiomics nomogram.

Results

The LASSO analysis finally included 11 radiomics features, which were defined as the radiomics signature. The individualized prediction nomogram was constructed by integrating the radiomics signature, maternal age, and body mass index (BMI). The nomogram exhibited a good performance both in the training cohort [AUC of 0.89 (95% CI, 0.82–0.95)] and test cohort [AUC of 0.85 (95% CI, 0.73–0.97)] for predicting PE from GH. The DCA indicated that clinicians and patients could benefit from the use of radiomics nomogram.

Conclusion

The radiomics nomogram could individually predict PE from GH. The nomogram could be conveniently used to facilitate the treatment decision for clinicians and patients.

Regional Distribution of Brain Injury After Cardiac Arrest: Clinical and Electrographic Correlates

BACKGROUND AND OBJECTIVES

Disorders of consciousness, EEG background suppression, and epileptic seizures are associated with poor outcome after cardiac arrest. Our objective was to identify the distribution of diffusion MRI-measured anoxic brain injury after cardiac arrest and to define the regional correlates of disorders of consciousness, EEG background suppression, and seizures.

METHODS

We analyzed patients from a single-center database of unresponsive patients who underwent diffusion MRI after cardiac arrest (n = 204). We classified each patient according to recovery of consciousness (command following) before discharge, the most continuous EEG background (burst suppression vs continuous), and the presence or absence of seizures. Anoxic brain injury was measured with the apparent diffusion coefficient (ADC) signal. We identified ADC abnormalities relative to controls without cardiac arrest (n = 48) and used voxel lesion symptom mapping to identify regional associations with disorders of consciousness, EEG background suppression, and seizures. We then used a bootstrapped lasso regression procedure to identify robust, multivariate regional associations with each outcome variable. Last, using area under receiver operating characteristic curves, we then compared the classification ability of the strongest regional associations to that of brain-wide summary measures.

RESULTS

Compared to controls, patients with cardiac arrest demonstrated ADC signal reduction that was most significant in the occipital lobes. Disorders of consciousness were associated with reduced ADC most prominently in the occipital lobes but also in deep structures. Regional injury more accurately classified patients with disorders of consciousness than whole-brain injury. Background suppression mapped to a similar set of brain regions, but regional injury could no better classify patients than whole-brain measures. Seizures were less common in patients with more severe anoxic injury, particularly in those with injury to the lateral temporal white matter.

DISCUSSION

Anoxic brain injury was most prevalent in posterior cerebral regions, and this regional pattern of injury was a better predictor of disorders of consciousness than whole-brain injury measures. EEG background suppression lacked a specific regional association, but patients with injury to the temporal lobe were less likely to have seizures. Regional patterns of anoxic brain injury are relevant to the clinical and electrographic sequelae of cardiac arrest and may hold importance for prognosis.

CLASSIFICATION OF EVIDENCE

This study provides Class IV evidence that disorders of consciousness after cardiac arrest are associated with widely lower ADC values on diffusion MRI and are most strongly associated with reductions in occipital ADC.

Surgically-induced brain injury: where are we now?

Neurosurgical procedures cause inevitable brain damage from the multitude of surgical manipulations utilized. Incisions, retraction, thermal damage from electrocautery, and intraoperative hemorrhage cause immediate and long-term brain injuries that are directly linked to neurosurgical operations, and these types of injuries, collectively, have been termed surgical brain injury (SBI). For the past decade, a model developed to study the underlying brain pathologies resulting from SBI has provided insight on cellular mechanisms and potential therapeutic targets. This model, as seen in a rat, mouse, and rabbit, mimics a neurosurgical operation and causes commonly encountered post-operative complications such as brain edema, neuroinflammation, and hemorrhage. In this review, we elaborate on SBI and its clinical impact, the SBI animal models and their clinical relevance, the importance of applying therapeutics before neurosurgical procedures (i.e., preconditioning), and the new direction of applying venom-derived proteins to attenuate SBI.

Imaging neurological emergencies in pregnancy and puerperium

The altered physiologic state of female patients during and just after pregnancy places them at an increased risk for several potentially life-threatening neurologic disorders. Swift diagnosis of such pathology and related complications is critical in order to reduce risk of morbidity and mortality to both the mother and the fetus. Neuroimaging plays an important role in the emergent diagnosis of pathology associated with pregnancy and puerperium, and it is critical for the radiologist to be cognizant of correlative imaging findings. Furthermore, given concerns regarding risks of neuroimaging to the fetus, it is important for the radiologist to act as an informed consultant regarding balancing fetal risks and the mother's health. The purpose of this review is to elucidate the underlying pathophysiology and neuroimaging findings associated with diagnoses that are unique to or highly associated with pregnancy and puerperium, as well as to understand the role that CT and MR play in diagnosis during and just after pregnancy, and their respective risks to the fetus.

An atypical subacute presentation of posterior reversible encephalopathy syndrome

Posterior reversible encephalopathy syndrome (PRES) characteristically presents with rapid onset of headache, seizure, encephalopathy, and visual changes, along with evidence of parieto-occipital vasogenic edema on magnetic resonance imaging. We describe the case of a 41-year-old female with a protracted presentation of two of the four classic PRES symptoms, which were not immediately recognized as PRES due to the presence of multiple other comorbidities and reasons for encephalopathy. This case highlights the possibility of atypical presentations of PRES and the diagnostic challenges in making this clinical diagnosis when competing diagnoses are present.

Intraoperative Cerebral Perfusion Disturbances During Transcatheter Aortic Valve Replacement

BACKGROUND

Transcatheter aortic valve replacement entails profound and unavoidable hemodynamic perturbations that may contribute to the neurological injury associated with the procedure.

METHODS

Thirty-one patients were monitored with cerebral oximetry as a surrogate marker of perfusion while undergoing transcatheter aortic valve replacement via a transfemoral approach under general anesthesia to detect intraoperative hypoperfusion insult. Serial neurologic, cognitive, and cerebral magnetic resonance imaging assessments were administered to objectively quantify perioperative neurologic injury and ascertain any association with significant cerebral oximetry disturbances.

RESULTS

Cerebral oximetry reacted promptly to rapid ventricular pacing with significant cerebral desaturation, relative to baseline, of greater than 12% and greater than 20% in 12 of 31 (68%) and 9 of 31 (29%) patients, respectively; or to an absolute measurement of less than 50% in 10 of 31 (33%) patients. Hyperemia occurred immediately following relief of aortic stenosis exceeding baseline by greater than 10% and greater than 20% in 14 of 31 (45%) and 5 of 31 (16%) patients. Postoperative cognitive dysfunction was evident in 3 of 31 (10%) patients and new magnetic resonance imaging-defined ischemic lesions were seen in 17 of 28 (61%) patients. No patient experienced clinically apparent stroke.

CONCLUSIONS

Cerebral oximetry reacted promptly to rapid ventricular pacing with significant desaturation and hyperemia a common occurrence. However, no association between this intraoperative insult and objective neurologic injury was detected.

Characterization of Chronic Axonal Degeneration Using Diffusion Tensor Imaging in Canine Spinal Cord Injury: A Quantitative Analysis of Diffusion Tensor Imaging Parameters According to Histopathological Differences

Diffusion tensor imaging (DTI) is more sensitive than conventional magnetic resonance imaging (MRI) for the identification of axonal degeneration. However, no study to date has used DTI to evaluate the severity of axonal degeneration in canine spinal cord injury (SCI). Therefore, the aim of this study was to characterize multi-grade axonal degeneration (mild, moderate, and severe) in a canine model of spinal cord compression injury using DTI. MRI data were obtained from 6 normal dogs and 5 dogs with lumbar SCI 78 days after SCI (L1-L3) using a 3 Tesla MRI scanner. For DTI, transverse multi-shot echo planar imaging sequences (b-value = 0; 800 s/mm²; 12 directions) were used. Regions of interest on DTI maps were selected based on areas of normal white matter (NWM) and mild, moderate, and severe axonal degeneration (AxD) on histopathological images. Statistically significant differences were observed between NWM and AxD, and among different severities of AxD. The severity of AxD demonstrated a negative linear correlation with fractional anisotropy and positive linear correlations with spherical index and radial diffusivity; additionally, positive U-shaped correlations were identified between the severity of AxD and mean diffusivity and axial diffusity (AD). These results demonstrate a potential clinical application for DTI in the noninvasive monitoring of histological changes post-SCI. DTI could be utilized for the early diagnosis and assessment of SCI and, ultimately, used to optimize the treatment and rehabilitation of SCI patients.

Posterior Reversible Encephalopathy Syndrome: A Review

Radiologists may be the first to suggest the diagnosis of posterior reversible encephalopathy syndrome (PRES). PRES is associated with many diverse clinical entities, the most common of which are eclampsia, hypertension, and immunosuppressive treatment. Radiologists should be aware of the spectrum of imaging findings in PRES. When promptly recognized and treated, the symptoms and radiological abnormalities can be completely reversed. When unrecognized, patients can progress to ischemia, massive infarction, and death. In this review, we present an overview of the unique signs observed on computed tomography and magnetic resonance images in PRES that can help in the early diagnosis and treatment that is highly effective in this syndrome.

Quantitative Magnetic Resonance Diffusion-Weighted Imaging Evaluation of the Supratentorial Brain Regions in Patients Diagnosed with Brainstem Variant of Posterior Reversible Encephalopathy Syndrome: A Preliminary Study

BACKGROUND AND PURPOSE

Posterior reversible encephalopathy syndrome (PRES) is a clinicoradiologic entity with several causes, characterized by rapid onset of symptoms and typical neuroimaging features, which usually resolve if promptly recognized and treated. Brainstem variant of PRES presents with vasogenic edema in brainstem regions on magnetic resonance (MR) images and there is sparing of the supratentorial regions. Because PRES is usually caused by a hypertensive crisis, which would likely have a systemic effect and global manifestations on the brain tissue, we thus proposed that some microscopic abnormalities of the supratentorial regions could be detected with diffusion-weighted imaging (DWI) using apparent diffusion coefficient (ADC) analysis in brainstem variant of PRES and hypothesized that "normal-looking" supratentorial regions will increase water diffusion.

METHODS

We retrospectively identified patients with PRES who underwent brain magnetic resonance imaging studies. We identified 11 brainstem variants of PRES patients, who formed the study cohort, and 11 typical PRES patients and 20 normal control subjects as the comparison cohorts for this study. Nineteen regions of interest were drawn and systematically placed. The mean ADC values were measured and compared among these 3 groups.

RESULTS

ADC values of the typical PRES group were consistently elevated compared with those in normal control subjects. ADC values of the brainstem variant group were consistently elevated compared with those in normal control subjects. ADC values of the typical PRES group and brainstem variant group did not differ significantly, except for the pons area.

CONCLUSIONS

Quantitative MR DWI may aid in the evaluation of supratentorial microscopic abnormalities in brainstem variant of PRES patients.

Various Imaging Manifestations of Posterior Reversible Encephalopathy Syndrome (PRES) on Magnetic Resonance Imaging (MRI)

Background

Posterior reversible encephalopathy syndrome (PRES), also called the acute hypertensive encephalopathy and reversible posterior leukoencephalopathy syndrome (RPLS), is a neurotoxic syndrome of cerebral vasoregulation classically characterized by bilaterally symmetrical parieto-occipital edema. However, the imaging findings are variable and may occur in other locations such as the frontal lobes, thalami, basal ganglia and brainstem. Most commonly, PRES presents with hyperintense signals on T2 and FLAIR sequences. Restricted diffusion and hemorrhage are rare. This study presents the typical and atypical manifestations of PRES on 3T MR images.

Material/Methods

It is a retrospective study analyzing a radiology report database and MR images of 92 patients with a clinical and radiological diagnosis of PRES. The brain MRI images of these patients were evaluated. The regions involved and the signal intensity of the affected areas on T1, T2, FLAIR and DW sequences were recorded. The location of the abnormal signal intensity as well as the presence or absence of atypical features such as diffusion restriction and hemorrhage were also recorded.

Results

The most commonly affected region was the parieto-occipital lobes (100%), however, other atypical regions involved were the frontal lobes (30.4%), temporal lobes (8.69%), basal ganglia (22%), cerebellum(17.39%), brainstem(9%) and thalamus(4%). Some of the cases showed restricted diffusion (43%) and hemorrhage (9%).

Conclusions

The involvement of the parieto-occipital, frontal and temporal lobes is common in PRES. Occasionally, there may be an involvement of the basal ganglia, cerebellum and brainstem, with or without hemorrhage and restricted diffusion. Radiologists should be aware of the typical and atypical imaging manifestations of PRES in order to make an accurate diagnosis.

Management of Brain Edema Complicating Stroke

Ischemic brain edema, the accumulation of fluid within the brain parenchyma following stroke, is a predictable consequence of both ischemic and hemorrhagic strokes. Its development is the result of injury to both brain parenchyma and the blood vessels supplying the parenchyma. Ischemic stroke produces both cytotoxic (intracellular) edema, which develops when cells are damaged, and vasogenic (extracellular) edema, which arises from injury to structures essential to blood-brain barrier integrity. An understanding of the distinction between cytotoxic and vasogenic edema is essential in preventing secondary brain injury, since the treatments for the two entities differ. The development of new brain imaging technologies has advanced our understanding of brain edema. Both computed tomography (CT) and magnetic resonance imaging (MRI) can detect edema. Specific MRI sequences such as diffusion-weighted imaging can distinguish cytotoxic and vasogenic subtypes, and thereby detect ischemic cell injury within minutes of the onset of symptoms.

Brain edema causes neurologic deterioration predominantly through its mass effect, which leads to distortion of the intracranial contents and impairment of both regional and global cerebral blood flow (CBF). Edema may also cause local tissue dysfunction. Management of the intracranial hypertension and tissue shifts caused by ischemic brain swelling is based on the fundamental relationship between pressure, flow, and resistance. Interventions are directed at preserving CBF and preventing secondary brain injury. Strategies include reducing intracranial blood volume with hypocapnia, reducing brain volume with osmotic agents, reducing cerebral metabolism with hypothermia and barbiturates, reducing resistance with rheologic agents, increasing blood pressure with vasoconstrictors, and expanding the cranial vault with decompressive surgery. All individual therapies must be used as part of a structured approach that involves frequent serial neurologic assessments, quantitative measures of pressure, flow, and resistance, and prespecified protocols for intervention.

Hypertensive Encephalopathy: Clinical and Neuroradiological Findings

Hypertensive encephalopathy is a syndrome consisting of headache, seizures, visual changes, and other neurologic disturbances in patients with elevated systemic blood pressure. The purpose of this study was to analyse the clinical and neuroradiological findings in nine patients with hypertensive encephalopathy, observed in five years.

CT (n = 13), and MR (n = 12), examinations performed in these patients before and after resolution of symptoms were reviewed. Six had the preeclampsia-eclampsia syndrome, and three had hypertensive encephalopathy due to other causes. CT and MR findings in all patients having these examinations were indicative of oedema in the cortex and subcortical white matter in the occipital lobes. Two of the nine patients also had similar findings in the cerebellum and frontal lobes.

The findings on the CT and MR studies resolved on follow-up examinations performed after the hypertension was corrected.

Our results suggest that the radiological findings associated with hypertensive encephalopathy in the appropriate clinical setting are very useful to achieve an early diagnosis.

Neuroradiology of Pediatric Hemolymphoproliferative Disease

Hemolymphoproliferative diseases (HLD) are among the most common causes of morbidity and mortality in children. In the past few years, the increased effectiveness of treatment modalities has significantly increased overall survival, but has also disclosed new aspects of the natural history of these disorders, among which central nervous system (CNS) involvement. CNS complications of HLD can basically be categorized into direct localization of primary disease, indirect effects of malignancy such as cerebrovascular or infectious complications, and iatrogenic side effects. Magnetic resonance imaging plays an important, often crucial role in the diagnosis of several of these disorders. Close interdisciplinary collaboration between hemato-oncologists and neuroradiologists is of paramount importance to provide affected children with an early diagnosis and proper treatment.

Posterior reversible encephalopathy syndrome in a patient with mixed connective tissue disease: a case report

Background

Posterior reversible encephalopathy is a syndrome highly associated with hypertension and cytotoxic therapy. The syndrome typically presents with headache, visual abnormality, seizures and characteristic vasogenic edema on magnetic resonance imaging. The entity warrants a prompt diagnosis to avoid deteriorating consequences.

Case presentation

In this report, we describe a 15-year-old Iranian boy who was diagnosed with mixed connective tissue disease, and cyclophosphamide pulse therapy was administered. Three days after the second pulse of cyclophosphamide, when he was receiving prednisolone and hydroxycholoroquine, our patient developed generalized tonic-clonic seizures. Magnetic resonance imaging findings showed high signal intensities in the posterior areas of his brain. After 8 days, the brain magnetic resonance imaging abnormalities were resolved following the control of his blood pressure and antiepileptic treatment. These observations have been indicative of posterior reversible encephalopathy syndrome. Nevertheless, our patient developed uncontrollable respiratory distress and eventually died.

Conclusions

To the best of our knowledge, this case is the first report of posterior reversible encephalopathy syndrome in a patient with mixed connective tissue disease. As the patient developed posterior reversible encephalopathy syndrome 3 days after cyclophosphamide pulse therapy to reduce the disease activity, it is hard to accurately determine whether posterior reversible encephalopathy syndrome in this case is a complication of cyclophosphamide or a condition that resulted from the mixed connective tissue disease flare-up.

Late postpartum eclampsia complicated with posterior reversible encephalopathy syndrome: a case report and a literature review

Posterior reversible encephalopathy syndrome (PRES) is a rare but serious clinical-neuroradiological entity characterized by headache, vomiting, visual disturbances, altered mental status, seizures, and unconsciousness associated with the characteristic imaging findings including sub-cortical vasogenic edema at the bilateral parietal and occipital lobes. We describe a case of 28-year-old PRES patient secondary to delayed maternal postpartum eclampsia. This patient was not initially diagnosed with pre-eclampsia and PRES. The diagnosis was established after magnetic resonance imaging. After treatment this patient's PRES resolved. Early diagnosis and treatment are the keys to reverse PRES. A literature review for PRES is provided in this report.

Cerebrovascular Dysfunction in Preeclamptic Pregnancies

Preeclampsia is a hypertensive, multisystem disorder of pregnancy that affects several organ systems, including the maternal brain. Cerebrovascular dysfunction during preeclampsia can lead to cerebral edema, seizures, stroke, and potentially maternal mortality. This review will discuss the effects of preeclampsia on the cerebrovasculature that may adversely affect the maternal brain, including cerebral blood flow (CBF) autoregulation and blood-brain barrier disruption and the resultant clinical outcomes including posterior reversible encephalopathy syndrome (PRES) and maternal stroke. Potential long-term cognitive outcomes of preeclampsia and the role of the cerebrovasculature are also reviewed.

Perioperative posterior reversible encephalopathy syndrome in a patient with no history of hypertension: a case report

Background

Posterior reversible encephalopathy syndrome is characterized by reversible neurological symptoms with leukoencephalopathy detectable by computed tomography (CT) and magnetic resonance (MR) imaging.

Case presentation

We here present a patient with no history of hypertension who, after being transferred back to the ward after undergoing total hysterectomy under general anesthesia, had several seizures and lost consciousness. Posterior reversible encephalopathy syndrome was suspected on the basis of brain CT images and clinical findings. She was treated with respiratory support, sedative drugs, and anticonvulsants, and MR imaging confirmed a diagnosis of posterior reversible encephalopathy syndrome. She regained consciousness and responsiveness the following day.

Conclusions

Clinically, posterior reversible encephalopathy syndrome resembles cerebral infarction or intracranial hemorrhage; MR imaging is useful for differentiating it from these conditions. Including this condition in the differential diagnosis and instituting appropriate treatment is important in minimizing the risk of development of irreversible neurological damage during the perioperative period.

Childhood posterior reversible encephalopathy syndrome: Magnetic resonance imaging findings with emphasis on increased leptomeningeal FLAIR signal

PURPOSE

Posterior reversible encephalopathy syndrome (PRES) is a clinico-radiologic syndrome characterized clinically by headache, seizures, and altered sensorium and radiological changes which are usually reversible. The purpose of this study was to describe the spectrum of magnetic resonance imaging (MRI) findings in childhood PRES, to determine the common etiologies for childhood PRES, and to have an insight into the pathophysiology of PRES.

METHODS

The MRI results of 20 clinically diagnosed cases of PRES between July 2011 and June 2013 were reviewed. The final diagnosis of PRES was based on the clinical presentation and the MRI features at the time of presentation, which resolved on the follow-up imaging. The medical records of the patients were reviewed to determine the underlying medical disease.

RESULTS

Eight out of the 20 patients included in the study were on cyclosporine or tacrolimus based immunosuppressant therapy for kidney transplant. Four patients had severe hypertension at presentation. The most common MRI finding was high T2-fluid-attenuated inversion recovery (FLAIR) signal in the cortex and subcortical white matter of both cerebral hemispheres, particularly in the parietal and occipital lobes (n=16). The second most common MRI finding was increased leptomeningeal FLAIR signal (n=7). Out of seven patients with leptomeningeal signal, five demonstrated leptomeningeal enhancement as well. Four out of these seven patients had no other parenchymal findings.

CONCLUSION

Childhood PRES is commonly seen in the setting of immunosuppressant therapy for kidney transplant, severe hypertension and cancer treatment. There was high incidence of increased leptomeningeal FLAIR signal and leptomeningeal enhancement in our study. It supports the current theory of endothelial injury with increased microvascular permeability as the potential pathophysiology of PRES. Also, absence of elevated blood pressure in majority of the patients in our study supports the theory of direct endothelial injury by some agents leading to vasogenic edema.

Therapy and differential diagnosis of posterior reversible encephalopathy syndrome (PRES) during pregnancy and postpartum

PURPOSE

Posterior reversible encephalopathy syndrome (PRES) is an usually reversible neuro-radiological clinical entity characterized by headache, confusion, visual disturbances or blindness and seizures. It rarely occurs without seizures.

METHODS

We conducted a literature review in MEDLINE about PRES during post partum and pregnancy, focusing on differential diagnosis and therapy. We reviewed 28 articles (case reports, original articles and reviews) describing PRES as well as a case of a severe, immediate postpartum HELLP syndrome (haemolysis, elevated liver enzyme levels, low platelet count) with PRES without generalized seizure.

RESULTS

The development of PRES after delivery is unusual. Magnetic resonance imaging represents the gold standard for the diagnosis of this condition. White matter oedema in the posterior cerebral hemispheres is typical on neuroimaging. PRES is reversible when early diagnosis is established and appropriate treatment is started without delay. The pathogenesis of PRES is discussed and the importance of a prompt diagnosis is emphasized, as the crucial role of rapid blood press reduction.

CONCLUSION

MRI is the diagnostic gold standard and it may be useful in the differential diagnosis. The goal of the therapy is to control elevated blood pressure and to prevent seizures or promptly manage it.

Added Value of MRI over CT of the Brain in Intensive Care Unit Patients

BACKGROUND

Intensive care unit (ICU) patients with neurological impairments often require neuroimaging. However, the relative sensitivity of various imaging modalities of the brain has not yet been explored in this population.

METHODS

In this study, we compare the findings of CT and MRI scans in ICU patients to (1) identify the number and rate of clinically relevant lesion detected by MRI while missed by CT and vice versa and (2) determine specific lesion types for which CT versus MRI discrepancies exist. A review of medical records included CT and MRI reports of patients who underwent these procedures while they were patients in our ICUs between July 2004 and July 2009. MRI and CT were compared regarding their ability to detect clinically relevant abnormalities. Odds ratios with 95% confidence limits were calculated to compare diagnostic categories regarding the rate of discrepant MRI versus CT findings, followed by power analyses to estimate sample sizes necessary to allow for further testing in a larger trial.

RESULTS

MRI revealed clinically relevant additional abnormalities over CT in 129 of 136 patients (95%) that included the detection of additional finding for 15/27 hemorrhagic lesions (55.6%), 33/36 (92%) ischemic strokes, 19/27 (70%) traumatic lesions, 8/14 (57%) infections, 15/24 (62.5%) metabolic abnormalities, and all seven neoplasms. Odds ratio analysis revealed the added sensitivity of MRI to be greater for ischemic and neoplastic lesions than for trauma, metabolic-related abnormalities, infection, or hemorrhage.

CONCLUSIONS

MRI is more sensitive than CT in identifying clinically meaningful lesions in at least a subset of ICU patients, regardless of pathology.

Posterior reversible encephalopathy syndrome--Insight into pathogenesis, clinical variants and treatment approaches

Posterior reversible encephalopathy syndrome is a rare clinicoradiological entity characterized by typical MRI findings located in the occipital and parietal lobes, caused by subcortical vasogenic edema. It was first described as a distinctive syndrome by Hinchey in 1996. Etiopathogenesis is not clear, although it is known that it is an endotheliopathy of the posterior cerebral vasculature leading to failed cerebral autoregulation, posterior edema and encephalopathy. A possible pathological activation of the immune system has been recently hypothesized in its pathogenesis. At clinical onset, the most common manifestations are seizures, headache and visual changes. Besides, tinnitus and acute vertigo have been frequently reported. Symptoms can be reversible but cerebral hemorrhage or ischemia may occur. Diagnosis is based on magnetic resonance imaging, in the presence of acute development of clinical neurologic symptoms and signs and arterial hypertension and/or toxic associated conditions with possible endotheliotoxic effects. Mainstay on the treatment is removal of the underlying cause. Further investigation and developments in endothelial cell function and in neuroimaging of cerebral blood flow are needed and will help to increase our understanding of pathophysiology, possibly suggesting novel therapies.

Risk of subsequent dementia in patients with hypertensive encephalopathy: a nationwide population-based study in Taiwan

BACKGROUND/AIMS

We investigated the association of hypertensive encephalopathy (HE) with subsequent dementia.

METHODS

Using universal insurance claims data, we identified a study cohort of 5,504 participants with HE newly diagnosed between 1997 and 2010 and a comparison cohort of 22,016 healthy participants. Incidence and risks of dementia were estimated for both cohorts until the end of 2010.

RESULTS

The dementia incidence was 1.45-fold [95% confidence interval (CI) = 1.27-1.66] higher in the study cohort than in the comparison cohort, with an adjusted hazard ratio (HR) of 1.38 (95% CI = 1.19-1.59) for the study cohort. The risk was higher for males than for females and elderly patients. With an incidence of 13.4 per 1,000 person-years, the HR of dementia increased to 2.09 (95% CI = 1.18-3.71) for the HE patients with the comorbidities of head injury and diabetes compared to those without HE and comorbidities. The risk of developing dementia declined with the follow-up time.

CONCLUSION

Hypertensive patients with HE displayed a significantly higher risk for dementia than those without HE. The risk increased further in those with the comorbidities of head injury and diabetes. Physicians should be aware of the link between HE and dementia when assessing patients with HE.

Cross sectional imaging of post partum headache and seizures

OBJECTIVES

To evaluate spectrum of causes & their characteristic findings in peripartum head ache and seizures on computed tomography & magnetic resonance imaging.

MATERIALS AND METHODS

Forty patients with complaints of peripartum headache and seizures underwent cross sectional imaging with computed tomography and magnetic resonance imaging during period of June 2011 to May 2012. Age group of subjects in this study was 18 to 38 y. Out of 40 patients 15 had history of eclampsia and remaining 25 patients were normotensive. Subjects with complaints of headache and seizures after six weeks of delivery were excluded from the study. Intravenous contrast was administered in cases with diagnostic dilemma. All results were reported and informed to the referring physicians on priority bases.

RESULTS

Nine patients with peripartum headache and seizures revealed no brain parenchymal or cerebral vascular abnormalities on imaging. Eleven patients with a history of eclampsia showed features of eclamptic encephalopathy. Out 40 patients, 17 patients revealed cortical venous thrombosis with 14 patients showing parenchymal changes. One patient each showed features of meningoencephalitis, ischemic watershed territory infarct & region of gliosis. All results were analysed & tabulated.

CONCLUSION

Eclamptic encephalopathy and cortical venous thrombosis are the major causes for post partum headache and seizures. Rational use of CT & MRI in the early course of the disease helps in characterizing the lesion and providing the appropriate treatment.

Neurocritical care complications of pregnancy and puerperum

Neurocritical care complications of pregnancy and puerperum such as preeclampsia/eclampsia, hemolysis, elevated liver enzymes, low platelets syndrome, thrombotic thrombocytopenic purpura, seizures, ischemic and hemorrhagic stroke, postpartum angiopathy, cerebral sinus thrombosis, amniotic fluid emboli, choriocarcinoma, and acute fatty liver of pregnancy are rare but can be devastating. These conditions can present a challenge to physicians because pregnancy is a unique physiologic state, most therapeutic options available in the intensive care unit were not studied in pregnant patients, and in many situations, physicians need to deliver care to both the mother and the fetus, simultaneously. Timely recognition and management of critical neurologic complications of pregnancy/puerperum can be life saving for both the mother and fetus.

Posterior reversible encephalopathy syndrome in pediatric acute leukemia: Case series and literature review

Posterior reversible encephalopathy syndrome (PRES) is a neurotoxic state coupled with a unique radio imaging appearance. We describe this rare, mostly reversible condition in five cases undergoing similar treatment under preset protocol (MCP-841) for acute lymphoblastic leukemia (ALL) at our centre. Hypertension is a well-known adverse effect of high-dose corticosteroid therapy primarily mediated by its effects on the mineralocorticoid receptor especially in pediatric population and we hypothesize that this may be the etiology of PRES in two of these patients.

Neuroimaging features and predictors of outcome in eclamptic encephalopathy: a prospective observational study

BACKGROUND AND PURPOSE

Posterior reversible encephalopathy syndrome is associated with eclampsia. We assessed the distribution and nature of typical and atypical cranial MR imaging findings in these patients and their correlation with clinical and laboratory data and predictors of outcome.

MATERIALS AND METHODS

Forty-five clinically confirmed cases of eclampsia were included in this prospective observational study. Subjects with hemolysis, elevated liver enzymes, and low platelets syndrome (n = 9) and pre-existing neurologic conditions (1 with cerebral solitary cysticercus granuloma) were excluded. Patients underwent blood investigations and cranial MR imaging.

RESULTS

Twenty-seven patients had abnormal while 8 had normal MR imaging findings. Involvement of brain regions was as follows: frontal, 88.89%; temporal, 44.44%; parietal, 100%; occipital, 100%; deep gray matter, 29.63%; cerebellum, 22.22%; brain stem, 14.81%. Cytotoxic edema was present in 33.33% of cases; 66.67% of patients had mild posterior reversible encephalopathy syndrome; 25.92% had moderate posterior reversible encephalopathy syndrome; and 7.41% had severe posterior reversible encephalopathy syndrome. Abnormal neuroimaging findings were significantly associated with altered sensorium; visual disturbances; status epilepticus; and elevated serum creatinine, uric acid, and lactate dehydrogenase (P=.006, P=.018, P=.015, P=.019, P=.003, and P=.001, respectively). Serum creatinine, uric acid, and lactate dehydrogenase values and the presence of moderate or severe posterior reversible encephalopathy syndrome were significantly associated with mortality (P<.001, P<.001, P=.009, and P=.027, respectively).

CONCLUSIONS

Neuroimaging in eclampsia demonstrates a higher incidence of atypical distributions and cytotoxic edema than previously thought. Altered sensorium; visual disturbances; status epilepticus; and elevated serum uric acid, lactate dehydrogenase, and creatinine are associated with abnormal neuroimaging findings. Higher serum creatinine, uric acid, and lactate dehydrogenase levels and moderate and severe forms of posterior reversible encephalopathy syndrome are possible predictors of poor outcome.

Posterior reversible encephalopathy syndrome in an adult patient undergoing peritoneal dialysis: a case report and literature review

Background

Posterior reversible encephalopathy syndrome (PRES) is a clinical and radiological entity characterized clinically by headache, altered mental status, seizures, visual disturbances, and other focal neurological signs, and radiographically by reversible changes on imaging. A variety of different etiologies have been reported, but the underlying mechanism is thought to be failed cerebral autoregulation. To the best of our knowledge, we report the third known case of PRES in an adult receiving intermittent peritoneal dialysis (PD).

Case presentation

A 23-year-old male receiving PD was brought to hospital after experiencing a generalized seizure. On presentation he was confused and hypertensive. An MRI brain was obtained and showed multiple regions of cortical and subcortical increased T2 signal, predominantly involving the posterior and paramedian parietal and occipital lobes with relative symmetry, reported as being consistent with PRES. A repeat MRI brain obtained three months later showed resolution of the previous findings.

Conclusion

Due to having a large number of endothelium-disrupting risk factors, including hypertension, uremia, and medications known to disrupt the cerebrovascular endothelium, we suggest that those with end-stage renal disease (ESRD) receiving PD are at high risk of developing PRES. Furthermore, we surmise that PRES is likely more prevalent in the ESRD population but is under recognized. Physicians treating those with ESRD must have a high index of suspicion of PRES in patients presenting with neurological disturbances to assure timely diagnosis and treatment.

Posterior reversible encephalopathy syndrome

Posterior reversible encephalopathy syndrome (PRES) is a recently proposed cliniconeuroradiologic entity with several well-known causes, such as hypertensive encephalopathy, eclampsia, and the use of cytotoxic and immunosuppressive drugs, as well as some causes more recently described. PRES is characterized by neuroimaging findings of reversible vasogenic subcortical edema without infarction. The pathogenesis is incompletely understood. Two opposing hypotheses are commonly cited, but the issue is controversial: (1) the current more popular theory suggests that severe hypertension exceeds the limits of autoregulation, leading to breakthrough brain edema; (2) the earlier original theory suggests that hypertension leads to cerebral autoregulatory vasoconstriction, ischemia, and subsequent brain edema. The clinical syndrome of PRES typically involves headache, encephalopathy, visual symptoms, and seizures. The clinical presentation is often nonspecific, and therefore the diagnosis of PRES has come to increasingly rely on magnetic resonance imaging (MRI) abnormalities consistent with PRES with documented recovery clinically and on repeated neuroimaging. The diagnosis has important therapeutic and prognostic implications because the reversibility of the clinical and radiologic abnormalities is contingent on the prompt control of blood pressure and/or discontinuing the offending drug.

Hypertensive encephalopathy and cerebral infarction

Introduction

Hypertensive encephalopathy is one cause of posterior reversible encephalopathy syndrome. Hypertensive encephalopathy and cerebral infarction have only been reported in a few individual case reports.

Case description

A 51-year-old woman presented with hypertensive encephalopathy. T2-weighted images from magnetic resonance imaging showed hyperintense lesions in both occipital and parietal lobes. Diffusion-weighted imaging showed that this represented cytotoxic oedema and perfusion magnetic resonance imaging revealed reduced blood volume and flow. The magnetic resonance imaging was repeated 5 months later and subtotal regression of theT2-hyperintensity had occurred. However, small bilateral infarcts were seen on T1-weighted images. Perfusion magnetic resonance imaging presented reduced blood volume and flow on the right side.

Discussion and evaluation

The patient in this report had posterior reversible encephalopathy syndrome caused by hypertensive encephalopathy. Magnetic resonance imaging of the brain showed bilateral cytotoxic oedema that partially resolved and resulted in small infarcts. The imaging findings are compatible with posterior reversible encephalopathy syndrome with subtotal resolution and infarct evolution.

Conclusion

The case report suggests that the presence of hypertensive encephalopathy and posterior reversible encephalopathy syndrome should alert clinicians and lead to prompt treatment in order to prevent cerebral damage.

Cerebral-autoregulatory dysfunction syndrome

Reversible cerebral vasoconstriction syndrome and reversible posterior leukoencephalopathy syndrome are distinct clinicoradiological disorders which share certain features in terms of aetiology, pathogenesis and symptomatology. We present a case of a young primigravida with eclampsia who developed severe headache, vision loss and hemiparesis in the postpartum phase. MRI of the brain was suggestive of the involvement of anterior as well as posterior circulation and reversibility of widespread angiographic constrictions could be documented on follow-up. Despite the resolution of vascular changes, vision loss did not improve significantly in our case. Such an overlap of findings is unusual and probably represents the spectrum of cerebral-autoregulatory dysfunction occurring in these two syndromes.

Risks of subsequent epilepsy among patients with hypertensive encephalopathy: a nationwide population-based study

BACKGROUND

To determine whether the diagnosis of hypertensive encephalopathy (HE) is linked to an increased risk of subsequent epilepsy by using a nationwide population-based retrospective study.

METHODS

Our study featured a study cohort and a comparison cohort. The study cohort consisted of all patients with newly diagnosed HE between 1997 and 2010, compiled from universal insurance claims data on patients with hypertension taken from the National Health Insurance Research Database. The comparison cohort comprised the remaining hypertensive patients without encephalopathy. The follow-up period was terminated following the development of epilepsy, death, withdrawal from the National Health Insurance system, or the end of 2010. We determined the cumulative incidences and hazard ratios (HRs) of epilepsy development.

RESULTS

The incidence of subsequent epilepsy was 2.25-fold higher in the patients with HE than in comparisons (4.17 vs. 1.85 per 1000 person-years), with an adjusted HR of 2.06 (95% CI=1.66-2.56) in the multivariable Cox proportional-hazards regression analysis. The incidence of epilepsy was higher in men, younger patients with HE, and those with brain disorders.

CONCLUSIONS

We found that, in Taiwan, patients with HE are at an increased risk of subsequent epilepsy. Physicians should be aware of HE's link to epilepsy when assessing patients with HE.

CT and MRI imaging of the brain in MELAS syndrome

Background:

MELAS syndrome (mitochondrial myopathy, encephalopathy, lactic acidosis, stroke-like episodes) is a rare, multisystem disorder which belongs to a group of mitochondrial metabolic diseases. As other diseases in this group, it is inherited in the maternal line.

Case Report:

In this report, we discussed a case of a 10-year-old girl with clinical and radiological picture of MELAS syndrome. We would like to describe characteristic radiological features of MELAS syndrome in CT, MRI and MR spectroscopy of the brain and differential diagnosis.

Conclusions:

The rarity of this disorder and the complexity of its clinical presentation make MELAS patients among the most difficult to diagnose. Brain imaging studies require a wide differential diagnosis, primarily to distinguish between MELAS and ischemic stroke. Particularly helpful are the MRI and MR spectroscopy techniques.

Posterior Reversible Encephalopathy Syndrome Associated with FOLFOX Chemotherapy

Posterior reversible encephalopathy syndrome (PRES) is a clinicoradiologic entity characterized by headaches, altered mental status, seizures, visual loss, and characteristic imaging pattern in brain MRI. The cause of PRES is not yet understood. We report a case of a 27-year-old woman that developed PRES after the use of FOLFOX 5 (oxaliplatin/5-Fluoracil/Leucovorin) chemotherapy for a colorectal cancer.

Cell swelling contributes to thickening of low-dose N-methyl-D-aspartate-induced retinal edema

PURPOSE

The contribution of cell swelling versus vascular leakage in retinal edema remains largely undefined. The objective of this study was to use in vivo magnetic resonance imaging (MRI) to assess retinal cell swelling in the edematous mouse retina.

METHODS

Inner retinal edema was induced by intravitreal injection of 2.5 nmol N-methyl-D-aspartate (NMDA). To assess retinal cell swelling, diffusion MRI was performed at baseline, 3-hours, 1 day, 3 days, and 7 days (n ≥ 5 at each time point) after NMDA injection. To detect retinal vascular leakage, gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA) enhanced MRI was performed at baseline, 3 hours and 1 day (n = 5 for each group) after NMDA injection. Upon the completion of MRI, mouse eyes were enucleated, cryosectioned, and stained for assessing retinal layer thickness and cell death.

RESULTS

Inner retinal cell swelling was hyperintense on diffusion-weighted images at 3 hours and 1 day after NMDA injection. The thickened inner retina was also seen in anatomic MRI and histology. Quantitatively, inner retinal apparent diffusion coefficient (ADC) decreased approximately 20% at 3 hours and 1 day after NMDA injection (P < 0.05 compared with baseline), suggesting cell swelling. Systematic injection of paramagnetic Gd-DTPA did not alter vitreous longitudinal relaxation time (T1) at baseline or at 3 hours after NMDA injection. In contrast, vitreous T1 in mice decreased 16 ± 6% (P < 0.05), reflecting retinal vascular leakage at 1 day after NMDA injection.

CONCLUSIONS

Noninvasive diffusion MRI was performed to detect retinal cell swelling in vivo. Our results demonstrated that retinal cell swelling could directly lead to retinal thickening independent of vascular leakage.

Metabolic encephalopathies

Kinnier Wilson coined the term metabolic encephalopathy to describe a clinical state of global cerebral dysfunction induced by systemic stress that can vary in clinical presentation from mild executive dysfunction to deep coma with decerebrate posturing; the causes are numerous. Some mechanisms by which cerebral dysfunction occurs in metabolic encephalopathies include focal or global cerebral edema, alterations in transmitter function, the accumulation of uncleared toxic metabolites, postcapillary venule vasogenic edema, and energy failure. This article focuses on common causes of metabolic encephalopathy, and reviews common causes, clinical presentations and, where relevant, management.