Posterior reversible encephalopathy syndrome, part 1: fundamental imaging and clinical features

Transient cortical weakness following cerebral angiography: A new syndrome

Transient cortical blindness is a known complication of iodinated contrast administration and is believed to reflect osmotic injury or autoregulatory dysfunction of the posterior circulation. Here, we report 2 cases of postangiography transient cortical weakness, a rare clinical analog to transient cortical blindness that affects the anterior circulation. The symptoms, timeline, and imaging findings of transient cortical weakness are distinct from more common post-procedural complications such as acute ischemic stroke or transient ischemic attack.

Contrast-induced encephalopathy in patients with advanced chronic kidney disease: What the nephrologist needs to know

Contrast-induced encephalopathy is a neurological complication related to contrast used in endovascular procedures or computed tomography (CT). The main risk factors are arterial hypertension, diabetes mellitus, chronic kidney disease (CKD), hyperosmolar contrasts, the amount of infused contrast and its direct infusion in the posterior cerebral territory, or pathologies with blood-brain barrier damage. Symptomatology is non-specific and may present as altered level of consciousness, neurological focality or seizures. Diagnosis is done by exclusion after ischemic or hemorrhagic stroke has been ruled out; CT or MRI are useful for differentiation. Generally, it appears shortly after exposure and the symptoms lasts 48-72h with complete recovery, although cases with persistence of symptoms or longer duration have been described. Treatment consists of monitoring, supportive measures and kidney replacement therapy (KRT) with hemodialysis (HD) in patients in chronic KRT program. It is important for the nephrologist to be aware of this entity given the susceptibility of the patient on HD as well as its potential therapeutic role in these patients.

Brain magnetic resonance imaging findings in children with neurological complications of coronavirus disease 2019 (Omicron variant): a multicenter retrospective observational study

BACKGROUND

An increasing rate of encephalopathy associated with coronavirus disease 2019 (COVID-19) has been observed among children. However, the literature on neuroimaging data in children with COVID-19 is limited.

OBJECTIVE

To analyze brain magnetic resonance imaging (MRI) of pediatric COVID-19 patients with neurological complications.

MATERIALS AND METHODS

This multicenter retrospective observational study analyzed clinical (n=102, 100%) and neuroimaging (n=93, 91.2%) data of 102 children with COVID-19 infections and comorbid acute neurological symptoms. These children were hospitalized at five pediatric intensive care units (PICUs) in China between December 1, 2022, and January 31, 2023.

RESULTS

All patients were positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as detected via reverse transcriptase polymerase chain reaction. About 75.7% of the children were infected with the Omicron variant BF.7 strain. Brain MRI was performed 1-12 days following the onset of neurological symptoms, which revealed acute neuroimaging findings in 74.2% (69/93) of cases, including evidence of acute necrotizing encephalopathy (33/69, 47.8%), encephalitis (31/69, 44.9%), reversible splenial lesion syndrome (3/69, 4.3%), reversible posterior leukoencephalopathy (1/69, 1.4%), and hippocampal atrophy (1/69, 1.4%).

CONCLUSIONS

Overall, these data highlighted five neuroimaging patterns associated with the outbreak of the SARS-CoV-2 Omicron variant, with acute necrotizing encephalopathy being the most common of these neuroimaging findings. Rarely, the brain MRI of these pediatric COVID-19 patients also demonstrate hippocampal atrophy.

Posterior Reversible Encephalopathy Syndrome in a Late Postpartum Patient With a Rare Complication of Subarachnoid Hemorrhage

Posterior reversible encephalopathy syndrome (PRES) is considered a neuroclinical syndrome of headache, confusion, visual changes, and seizures associated with neuroimaging findings of posterior cerebral white matter edema. Although the incidence of the syndrome is largely unknown, this condition is becoming increasingly recognized. The prognosis is generally good with most symptoms resolving within one week and lesions on imaging resolving in two weeks. Death and significant neurological disability have been reported but are relatively rare. In this report, we present a 10-day postpartum patient with an atypical history of headache and seizure-like activity. Neuroimaging revealed findings consistent with PRES as well as a rare complication of subarachnoid hemorrhage. This case highlights the importance of clinicians considering preeclampsia/eclampsia-induced PRES when encountering a postpartum patient with headache and hypertension to further reduce morbidity and mortality in this patient population.

Patterns and Outcomes of Acute Central Nervous System Complications During Treatment of Childhood Acute Lymphoblastic Leukemia: A Single-center Experience

Central nervous system (CNS) complications are considered adverse events during the treatment of pediatric acute lymphoblastic leukemia (ALL). This study aimed to assess the incidence, types, clinical and radiologic patterns, risk factors, and the fate of different CNS complications during the treatment of pediatric ALL. A retrospective study included 390 patients with pediatric ALL, treated according to St. Jude total XV protocol at the National Cancer Institute, Cairo University, from January 2012 to December 2017. Thirty-nine (10%) patients developed different types of CNS complications. Nineteen (4.9%) patients had cerebrovascular complications, 12 (3.1%) patients had posterior reversible encephalopathy syndrome (PRES), and 6 (1.5%) patients had leukoencephalopathy; both CNS infections and leukemic infiltrates were diagnosed in one patient each. CNS complications were significantly higher in patients older than 10 years old, patients with high-risk disease, and patients who were classified as CNS III status with a statistically significant P value of 0.040, 0.020, and 0.002, respectively. There were 31 (79.5%) cases that achieved complete recovery, 6 (15.4%) patients who died, and 2 (5.1%) patients who developed residual neurological deficits. In conclusion, pediatric patients with ALL, who presented with older age, high-risk disease initially, and had initial CNS III status, were at higher risk of developing acute CNS complications during their treatment period. Patients who developed visual disturbances were associated with unfavorable outcomes. Despite that, around 80% of patients showed complete recovery, but still, 15% of them died from these complications.

Imaging of Reversible Cerebral Vasoconstriction Syndrome and Posterior Reversible Encephalopathy Syndrome

PRES and RCVS are increasingly recognized due to the wider use of brain MRI and increasing clinical awareness. Imaging plays a crucial role in confirming the diagnosis and guiding clinical management for PRES and RCVS. Imaging also has a pivotal role in determining the temporal progression of these entities, detecting complications, and predicting prognosis. In this review, we aim to describe PRES and RCVS, discuss their possible pathophysiological mechanisms, and discuss imaging methods that are useful in the diagnosis, management, and follow-up of patients.

COVID-19-related posterior reversible encephalopathy syndrome: insights from a clinical case

In the present case report, a 50-year-old female presented with hemiparesis and blurred vision and was subsequently diagnosed with posterior reversible encephalopathy syndrome (PRES) associated with coronavirus disease 2019 (COVID-19). Magnetic resonance imaging revealed cortico-subcortical edema with hyperintensities bilaterally in the frontoparietal and bi-occipital regions. Although PRES is a neurotoxic disorder that typically affects white matter of the brain and often is associated with hypertension, renal failure, and autoimmune disorders, recent studies have suggested that COVID-19 increases the risk of PRES. This case report presents a unique instance of COVID-19-related PRES. Unlike most previously reported cases occurring during the acute phase of severe COVID-19, our patient experienced PRES during the recovery phase with mild initial symptoms, such as fatigue and mild fever. The article discusses the pathophysiology of PRES, the potential mechanisms by which COVID-19 leads to PRES, and the treatment and outcome of the patient.

Superinfected COVID-19 in a young patient with posterior reversible encephalopathy syndrome: A case report

Posterior reversible encephalopathy syndrome (PRES) is a clinical syndrome with central nervous system (CNS) symptoms usually related to autoregulatory cerebral failure and high blood pressure. Neuroimaging is critical to diagnosis. Neurological presentations of COVID-19 disease are categorized into CNS symptoms and peripheral nervous system (PNS) symptoms. The patient was a 15-year-old female with SARS-CoV-2 pneumonia who developed PRES with a typical clinical and radiological appearance. She was treated with dexamethasone, phenytoin, sodium valproate and remdesivir. The patient was discharged after recovery of symptoms and was in good general condition. It is recommended that in patients affected by COVID-19 with neurological symptoms, the PRES can be considered in the differential diagnosis.

Pediatric Posterior Reversible Encephalopathy Syndrome: A Review With Emphasis on Neuroimaging Characteristics

Posterior reversible encephalopathy syndrome (PRES) is a neurological disorder characterized by the sudden onset of seizures, headaches, and visual disturbances. Its exact cause is unknown, but several triggers and associated conditions are identified, including high blood pressure, kidney dysfunction, and various medications. Magnetic resonance imaging (MRI) plays a crucial role in diagnosis due to its high sensitivity and specificity for detecting characteristic features. Pediatric PRES exhibit age-dependent differences in triggers, radiological findings, and clinical course. The lesions typically involve the posterior cortical and subcortical white matter, but atypical locations and features are also observed. While generally reversible with appropriate treatment, PRES carries a risk of permanent neurological damage. Despite increasing cases, the current literature on pediatric PRES remains limited. This review highlights the need for further research to understand the mechanisms, delineate distinct clinical and radiological features, and develop precise diagnostic and management strategies for pediatric patients.

Case report: A case of posterior reversible encephalopathy in postpartum preeclampsia

RATIONALE

Posterior reversible encephalopathy syndrome is a neurological condition characterized by headache, convulsions, altered consciousness, and visual disturbance with specific radiological features, which is characterized by contrast enhancement in the occipital lobe on T2-weighted image. We report a case of sudden visual impairment of both eyes 6 days after childbirth diagnosed as postpartum preeclampsia and posterior reversible encephalopathy syndrome (PRES) through radiological examination.

PATIENT CONCERNS

A 31-year-old female patient with headache and visual disturbance visited the clinic.

DIAGNOSIS

Visual acuity was light perception in the right eye and hand motion in the left eye; pupillary light reflections of both eyes were normal. In the field of view test, the waveform was not observed in the defect pattern visual field power test, and the amplitude was greatly reduced in the visual field test. 1+ proteinuria was observed on urine test and magnetic resonance imaging showed contrast enhancement under both parietal and occipital cortex.

INTERVENTIONS

Hospitalization was done for blood pressure control and examination of related disease under suspicion of PRES caused by postpartum preeclampsia.

OUTCOMES

Four weeks after diagnosis, vision and visual field defects recovered to normal, and the previously observed lesion on magnetic resonance imaging completely improved 3 months after the initial visit, and it was diagnosed as PRES.

LESSONS

PRES in postpartum preeclampsia can cause rapid vision and symptoms, visual field loss, and accurate follow-up diagnosis with relevant imaging and clinical patterns can improve vision.

Posterior reversible encephalopathy syndrome in a patient with late postpartum eclampsia

RATIONALE

Posterior reversible encephalopathy syndrome (PRES) is a rare complication commonly associated with headache and acute changes in blood pressure that results from a variety of causes, culminating in vasogenic cerebral edema in the occipital and parietal lobes of the brain.

PATIENT CONCERNS

We report here a woman who suffered from headache, generalized tonic-clonic seizures, and cortical blindness in the late postpartum period.

DIAGNOSES

Posterior reversible encephalopathy syndrome.

INTERVENTIONS

The patient was treated with amlodipine besylate tablets for hypertension, dehydration with mannitol and glycerin fructose, and antispasmodic treatment with sodium valproate and oxcarbazepine.

OUTCOMES

On day 2, the patient became conscious, headache and vision improved. One week later, symptoms and signs disappeared, blood pressure returned to normal, and brain MRI lesions disappeared in re-examination.

LESSONS

Eclampsia associated with PRES is reversible in most cases, but it is a serious and potentially life-threatening obstetric emergency. If adequate treatment is provided in a timely manner, most women will make a full recovery. Attention needs to be paid to timely and adequate treatment, as well as appropriate follow-up and support for patients with PRES.

Delayed-Onset Psychosis Secondary to Tacrolimus Neurotoxicity After Lung Transplant: A Case Report and Systematic Review

BACKGROUND

Tacrolimus is the most common immunosuppressant used after transplant, yet it can result in moderate-to-severe neurotoxicity in up to 32% of patients. Signs of neurotoxicity can vary from mild (tremor or headache) to severe (posterior reversible encephalopathy syndrome or psychosis. Prompt recognition and management is needed to lead to symptom resolution.

OBJECTIVE

The objective of this study is to describe the clinical presentation of tacrolimus-induced psychosis, a type of tacrolimus-inducted neurotoxicity, and distinguish it from other central nervous system disturbances, including delirium.

METHODS AND RESULTS

We present a case of delayed onset tacrolimus-induced psychosis with focus on unique clinical features and management strategies. We conducted a systematic review of cases of tacrolimus-induced psychosis using the PubMed database and included 15 manuscripts in our review.

CONCLUSIONS

Tacrolimus-induced psychosis is a unique presentation of tacrolimus-related neurotoxicity and can present without the cardinal symptoms of delirium. The data on isolated psychotic symptoms are limited with current literature focusing on more common presentations of tacrolimus-induced neurotoxicity, such as delirium and tremor. Development of psychosis can occur later in the treatment course and at normal tacrolimus serum levels. It can improve with antipsychotic therapies, but primary management should include cross-titration to an alternate immunosuppressant regimen.

Beyond the Shadows: Unravelling the Menace of Methanol-Induced Posterior Reversible Encephalopathy Syndrome

Posterior reversible encephalopathy syndrome (PRES) is a clinical-radiological illness characterized by neurological symptoms and reversible changes in neuroimaging. We discuss the case of a 45-year-old patient with an alcohol use disorder who presented with an altered mental state in the emergency room. Home-made alcohol, known to contain significant quantities of methanol, was recently consumed in excess by the said patient. The diagnosis of PRES was supported by magnetic resonance imaging (MRI), which showed bilateral hyperintense regions in the temporo-occipital lobes and diffuse cerebral edema. The development of PRES and chronic alcoholism, as well as binge drinking and possible endothelial dysfunction, are all highlighted in this case study. For individuals with PRES, early identification and adequate care are essential for reducing complications and improving outcomes.

Convexity subarachnoid haemorrhage: a practical guide

Atraumatic convexity subarachnoid haemorrhage describes spontaneous bleeding into the convexities of the brain sulci without parenchymal involvement. Its many causes include reversible cerebral vasoconstriction syndrome, cerebral sinus venous thrombosis, posterior reversible encephalopathy syndrome and (in older people) cerebral amyloid angiopathy. We describe the clinical and radiological features of non-traumatic convexity subarachnoid haemorrhage with its various presentations, causes, treatments and prognoses, and use clinical vignettes to highlight important clinical points and pitfalls.

Rare central nervous system manifestation of granulomatosis with polyangiitis in a 12-year-old child: A case report

To share a unique case of granulomatosis with polyangiitis (GPA) identified in a child with CNS involvement, specifically PRES (posterior reversible encephalopathy syndrome). Discuss this uncommon manifestation's clinical characteristics, diagnostic process, and treatment. We are currently discussing a 12-year-old female patient who presented with a chronic cough, shortness of breath, and a new-onset fever. Upon further examination, the patient was diagnosed with GPA, confirmed through positive cytoplasmic antineutrophil cytoplasmic antibodies (C-ANCA), a renal biopsy, and multiple lung cavitary lesions. During her hospitalization, the patient also experienced neurological symptoms, including a severe headache, blurred vision, loss of consciousness, and an abnormal neurological exam, which led to brain MR imaging. The imaging revealed evidence of small vessel vasculitis with confluent T2 hyper signal intensity of gray-white matter junctions in both parietooccipital and frontal lobes containing hemorrhagic components, suggesting Posterior reversible encephalopathy syndrome. This case of Wegener's granulomatosis is noteworthy due to its occurrence in a pediatric patient with CNS involvement, specifically (posterior reversible encephalopathy syndrome). This event highlights the importance of recognizing that autoimmune disorders can present infrequently in young patients. Diagnosing Wegener's granulomatosis can be challenging, particularly when the CNS is affected. However, when appropriate treatment is initiated promptly, favorable outcomes can be achieved, as evidenced by the patient's improved condition with the prednisolone, captopril, and Rituximab treatment plan. Further research is necessary to understand better the underlying pathophysiology and optimal management of CNS involvement in GPA, particularly in the pediatric population.

Optic pathway involvement in the posterior reversible encephalopathy syndrome: A case report and review of the literature

Posterior reversible encephalopathy syndrome (PRES) is a clinico-radiological condition characterized by reversible vasogenic edema of the white matter and acute neurological symptoms. PRES typically affects the parieto-occipital regions but rarely affects the optic pathway. Herein, we describe a case of central-variant PRES in a 57-year-old man with abnormal signal intensities in the optic pathway on magnetic resonance imaging (MRI). The patient underwent hemodialysis, initiated diuretics and antihypertensive medications, and the abnormal signal intensities of the brainstem and optic pathway on MRI improved. Although rare, PRES can affect the optic pathway, thus suggesting the possibility of fragility of the optic pathway itself to hyperperfusion.

Ultrasonographic Vasospasm and Outcome of Posterior Reversible Encephalopathy and Cerebral Vasoconstriction Syndromes

PURPOSE

Posterior reversible encephalopathy syndrome (PRES) and reversible cerebral vasoconstriction syndrome (RCVS) are often complicated by vasospasm and ischemia. Monitoring with transcranial color-coded Doppler (TCCD) could be useful, but its role is not established. We studied the incidence of ultrasonographic vasospasm (uVSP) in PRES/RCVS and its relationship with ischemic lesions and clinical outcome.

MATERIALS AND METHODS

We conducted a multicenter retrospective study of all patients with PRES/RCVS from 2008 to 2020 who underwent TCCD and magnetic resonance imaging (MRI). TCCD exams were analyzed for uVSP. Diffusion-weighted MRI was analyzed for positive lesions (DWI-positive). Functional outcome was assessed by modified Rankin scale (mRS) at 90 days. The associations with outcomes were determined by logistic regression.

RESULTS

We included 80 patients (mean age of 46 (standard deviation, 17) years; 66% females; 41 with PRES, 28 with RCVS and 11 with overlap phenotype). uVSP was detected in 25 (31%) patients. DWI-positive lesions were more often detected in uVSP-positive than uVSP-negative patients (36% vs. 15%; adjusted odds ratio [aOR] 4.05 [95% CI 1.06 - 15.5], P=0.04). DWI-positive lesions were independently associated with worse functional prognosis (mRS 2-6, 43% vs. 10%; aOR, 10 [95% CI 2.6 - 43], P<0.01). Having additional uVSP further increased the odds of a worse outcome (P interaction=0.03).

CONCLUSION

Ultrasonographic vasospasm was detected in a third of patients with PRES/RCVS and was associated with brain ischemic lesions. TCCD bedside monitoring can help to stratify patients at risk for cerebral ischemia, a strong predictor of functional outcome.

Hemolytic Anemia-Related Acute Kidney Injury: A Case Report With Complications Including Posterior Reversible Encephalopathy Syndrome

INTRODUCTION

The condition known as posterior reversible encephalopathy syndrome (PRES) is characterized by symptoms such as headaches, seizures, and vision problems due to brain swelling, which often can be seen in brain scans. While there have been some cases of PRES linked to conditions such autoimmune diseases and high blood pressure, we're sharing a unique case here. Our case involves severe kidney damage caused by idiopathic hemolytic anaemia. The patient also experienced loss of consciousness, seizures, and headache. Brain scans confirmed the signs of PRES. We managed to help the patient recover fully through careful treatment, including fluids, managing seizures, and transfusions.

CASE DETAILS

Our patient was dealing with severe kidney damage from idiopathic hemolytic anaemia. They had episodes of loss of consciousness, seizures, and headaches. Brain scans showed that they had PRES.

DIAGNOSIS AND TREATMENT

We found out that the patient had severe kidney damage because of hemolytic anaemia, and she also had PRES. We treated her by giving fluids, managing her seizures, and doing blood transfusions, along with other supportive care.

CONCLUSIONS

With our treatment, the patient got better, her neurological symptoms improved, and her brain scans showed fewer signs of PRES. This case tells us something interesting - sometimes, anaemia can lead to rare neurological problems like PRES. We need to be aware of these possibilities to help patients better. Our successful treatment in this case emphasizes how important quick and comprehensive care can be for good outcomes.

Posterior reversible encephalopathy syndrome following uneventful clipping of an unruptured intracranial aneurysm: A case report

BACKGROUND

Posterior reversible encephalopathy syndrome (PRES) is characterized mainly by occipital and parietal lobe involvement, which can be reversible within a few days. Herein, we report a rare case of PRES that developed after craniotomy for an unruptured intracranial aneurysm (UIA).

CASE SUMMARY

A 59-year-old man underwent clipping surgery for the treatment of UIA arising from the left middle cerebral artery. Clipping surgery was performed uneventfully, and he regained consciousness quickly immediately after the surgery. At the 4th hour after surgery, he developed a disorder of consciousness and aphasia. Magnetic resonance imaging revealed cortical and subcortical T2/FLAIR hyperintensities in the parietal, occipital, and frontal lobes ipsilaterally, without restricted diffusion, consistent with unilateral PRES. With conservative treatment, his symptoms and radiological findings almost completely disappeared within weeks. In our case, the important causative factor of PRES was suspected to be a sudden increase in cerebral perfusion pressure associated with temporary M1 occlusion.

CONCLUSION

Our unique case highlights that, to our knowledge, this is the second report of PRES developing after craniotomy for the treatment of UIA. Surgeons must keep PRES in mind as one of the causes of perioperative neurological abnormality following clipping of an UIA.

Status Epilepticus as a Presenting Feature in Posterior Reversible Encephalopathy Syndrome: Tertiary Care Center Experience

Background

Though epileptic seizures are common in posterior reversible encephalopathy syndrome (PRES), status epilepticus (SE) as the presenting feature is rare.

Objective

To study the clinical spectrum and outcome of patients with SE as presenting feature of PRES.

Methods

This is a retrospective study. PRES was diagnosed based on the clinical features and imaging findings on brain MRI (n = 40) which became normal after 6 months follow-up imaging. Patients with SE as the initial manifestation of PRES were identified. Baseline information regarding the clinical presentation, etiology, past history of illness, treatment history, imaging findings, EEG and long-term clinical outcome.

Result

Seizure was the most common presentation seen in 31 patients (77.5%). The etiologies in PRES were preeclampsia, or eclampsia [n = 33 (82.5%)], hypertensive encephalopathy [n = 3 (7.5%)], systemic lupus erythematosus (SLE), AIP, and chronic renal failure (CRF) in one patient each [n = 01 (2.5%)]. Brain MRI showed the involvement of parieto-occipital lobes (n = 33 [82.5%]) mostly. Status epilepticus (generalized convulsive) was the presenting feature in eight cases (20%). Among them, five cases (0.5%) had a history of chronic epilepsy. In the remaining three patients, SLE and acute intermittent porphyria, CRF precipitated the SE.

Conclusion

The study highlights the clinico-etiological spectrum of PRES and the identification of SE within its context leading to the early diagnosis and management if treated early. The role of antenatal care is important for the identification and treatment of etiologies, blood pressure, proper antiepileptic drug compliance and appropriate counseling.

How to cite this article

Prasad P. Status Epilepticus as a Presenting Feature in Posterior Reversible Encephalopathy Syndrome: Tertiary Care Center Experience. Indian J Crit Care Med 2023;27(7):488-492.

Nivolumab-Induced PRES (Posterior Reversible Encephalopathy Syndrome)

PRES (posterior reversible encephalopathy syndrome) is a clinical-radiographic syndrome comprising clinical symptoms, including headache, vision abnormalities, nausea/vomiting, seizures, and posterior cerebral white matter edema seen as radiographic changes. Commonly, PRES is known to occur with severely elevated blood pressure, or eclampsia. However, in recent times, increasing cases of PRES have been observed in patients being treated with immunotherapy or chemotherapy. Nivolumab is an immunotherapy used in the treatment of various cancers and is an increasingly identified cause of PRES. A few case reports exist in the literature. We report a case of nivolumab-induced PRES.

Optic nerve sheath diameter measurements using ultrasonography to diagnose raised intracranial pressure in preeclampsia: an observational study

Objective

To estimate the incidence of raised intracranial pressure (ICP) as evident by enlarged optic nerve sheath diameter (ONSD) by ocular ultrasound among patients with preeclampsia and its relationship to severity of disease.

Material and Methods

Sixty pregnant mothers with preeclampsia were compared to 30 normotensive, uncomplicated pregnant controls. For ONSD measurement, a 7-MHZ linear probe was used and three values from each optic nerve were taken and the mean of six values of both eyes was recorded. All study subjects were followed until seven days after delivery.

Results

Two cut off values (5.8 mm and 4.6 mm) were used to compare ONSD in severe and non-severe preeclampsia with that of healthy pregnant individuals. The incidence of raised ICP among severe preeclampsia above 5.8 mm and 4.6 mm cut-off were 43.3% and 90%, respectively, before delivery. ONSD was significantly elevated among preeclampsia subjects at both cut-off values at pre-delivery (p=0.004 for ONSD >5.8 mm and p<0.001 for ONSD >4.6 mm) compared to controls. There a significant association between presence of neurological manifestations and enlarged ONSD (p<0.001 for ONSD >5.8 mm and p=0.04 for ONSD >4.6 mm) before delivery.

Conclusion

Severe preeclampsia with neurological features was associated with increased ONSD, reflecting raised ICP. Further studies are needed to compare ONSD values with invasive ICP monitoring for better understanding of this relationship.

Evaluation and management of acute high-grade immunotherapy-related neurotoxicity

Immune checkpoint inhibitor monoclonal antibodies allow the host's immune system to attack tumors, which has revolutionized cancer care over the last decade. As the use of immune checkpoint inhibitors has expanded, so have autoimmune-like complications known as immune-related adverse events. These include the infrequent but increasingly more common, potentially deadly neurological immune related adverse events. When feeling acutely ill, patients will often seek care not from their oncologist but from their family physician, clinics, emergency, and urgent care sites, or other available providers. Thus, while assessing acutely ill cancer patients who are experiencing neurological symptoms, non-oncologists should be prepared to recognize, diagnose, and treat neurological immune related adverse events in addition to more familiar conditions. This narrative review is designed to update acute care clinicians on current knowledge and to present a symptom-based framework for evaluating and treating neurological immune related adverse events based on the leading immunotoxicity organizations' latest recommendations.

Hereditary Angioedema: Diagnosis, Clinical Implications, and Pathophysiology

Hereditary angioedema (HAE) is an autosomal dominant disorder caused by a mutation in the C1 esterase inhibitor gene. HAE affects 1/50,000 people worldwide. Three main types of HAE exist: type I, type II, and type III. Type I is characterized by a deficiency in C1-INH. C1-INH is important in the coagulation complement, contact systems, and fibrinolysis. Most HAE cases are type I. Type I and II HAE result from a mutation in the SERPING1 gene, which encodes C1-INH. Formally known as type III HAE is typically an estrogen-dependent or hereditary angioedema with normal C1-INH activity. Current guidelines now recommend subdividing hereditary angioedema with normal C1 esterase inhibitor gene (HAE-nl-C1-INH formerly known as HAE type III) based on underlying mutations such as in kininogen-1 (HAE-KNG1), plasminogen gene (PLG-HAE), myoferlin gene mutation (MYOF-HAE), heparan sulfate-glucosamine 3-sulfotransferase 6 (HS3ST6), mutation in Hageman factor (factor XII), and in angiopoietin-1 (HAE-ANGPT-1). The clinical presentation of HAE varies between patients, but it usually presents with nonpitting angioedema and occasionally abdominal pain. Young children are typically asymptomatic. Those affected by HAE usually present with symptoms in their early 20s. Symptoms can arise as a result of stress, infection, or trauma. Laboratory testing shows abnormal levels of C1-INH and high levels of bradykinin. C4 and D-dimer levels can also be monitored if an acute HAE attack is suspected. Acute treatment of HAE can include IV infusions of C1-INH, receptor antagonists, and kallikrein inhibitors. Short- and long-term prophylaxis can also be administered to patients with HAE. First-line therapies for long-term prophylaxis also include IV infusion of C1-INH. This review aims to thoroughly understand HAE, its clinical presentation, and how to treat it.

Posterior reversible encephalopathy syndrome following septicemia in patient with myasthenia gravis

Posterior reversible encephalopathy syndrome is a clinicoradiologic entity characterized by seizure, headaches, visual symptoms, impaired consciousness, and vasogenic cerebral edema of occipital and parietal lobes of the brain. Magnetic resonance imaging (MRI) is the diagnostic gold standard. The pathophysiology of posterior reversible encephalopathy syndrome is still unknown, but it is thought to be closely related to several medical conditions including hypertension, preeclampsia, eclampsia, immunosuppressive agents, transplantation, and sepsis. We report a rare case of posterior reversible encephalopathy syndrome in patient with myasthenia gravis and sepsis. A 22-year-old male was diagnosed with myasthenia gravis combined with sepsis due to pneumonia. During his recovery, the patient suffered multiple generalized convulsions and subsequent loss of consciousness. On cranial MRI, the abnormalities were observed with hyperintense within the subcortical white matter of the temporal, parietal, and bilateral occipital lobes on T2-weighted and T2 FLAIR. Reversibility of the symptoms and characteristic imaging findings led us to a diagnosis of posterior reversible encephalopathy syndrome. Early recognition and management of posterior reversible encephalopathy syndrome as a cause of encephalopathy in patients with septicemia and myasthenia gravis is necessary to prevent secondary complications in this condition.

Clinical application of brain perfusion imaging in detecting stroke mimics: A review

Stroke mimics constitute a significant proportion of patients with suspected acute ischemic stroke. These conditions may resemble acute ischemic stroke and demonstrate abnormalities on perfusion imaging sequences. The most common stroke mimics include seizure/epilepsy, migraine with aura, brain tumors, functional disorders, infectious encephalopathies, Wernicke's encephalopathy, and metabolic abnormalities. Brain perfusion imaging techniques, particularly computed tomography perfusion and magnetic resonance perfusion, are being widely used in routine clinical practice for treatment selection in patients presenting with large vessel occlusion. At the same time, the utilization of these imaging modalities enables the opportunity to better diagnose patients with stroke mimics in a time-sensitive setting, leading to appropriate management, decision-making, and resource allocation. In this review, we describe patterns of perfusion abnormalities that could discriminate patients with stroke mimics from those with acute ischemic stroke and provide specific case examples to illustrate these perfusion abnormalities. In addition, we discuss the challenges associated with interpretation of perfusion images in stroke-related pathologies. In general, perfusion imaging can provide additional information in some cases-when used in combination with conventional magnetic resonance imaging and computed tomography-and might help in detecting stroke mimics among patients who present with acute onset focal neurological symptoms.

Posterior reversible encephalopathy syndrome after lung transplantation: Risk factors and management

INTRODUCTION

Posterior reversible encephalopathy syndrome is a rare neurologic complication that can occur under immunosuppressive therapy with CNI after organ transplantation.

METHODS

We retrospectively reviewed medical records of 545 patients who underwent lung transplantation between 2012 and 2019. Within this group, we identified 30 patients with neurological symptoms typical of PRES and compared the characteristics of patients who were diagnosed with PRES (n = 11) to those who were not (n = 19).

RESULTS

The incidence of PRES after lung transplantation was 2%. Notably, 73% of the patients with PRES were female and the mean age was 39.2. Seizure (82% vs. 21%, p = .002) was the most common neurological presentation. The risk of developing PRES was significantly associated with age (OR = .92, p < .0001) and having cystic fibrosis (CF) (OP = 10.1, p < .0001). Creatinine level (1.9 vs. 1.1 mg/dl, p = .047) and tacrolimus trough level (19.4 vs. 16.5 ng/ml, p = .048) within 1 week prior to neurological symptoms were significantly higher in patients with PRES.

CONCLUSION

Renal insufficiency and high tacrolimus levels are associated with PRES. A change of immunosuppressive drug should be done after confirmed PRES diagnosis or immediately in case of severe neurological dysfunction to improve neurological outcomes and minimize the risk of early allograft rejection.

Sequential measurement of the neurosensory retina in hypertensive disorders of pregnancy: a model of microvascular injury in hypertensive emergency

Optical coherence tomography of the eye suggests the retina thins in normal pregnancy. Our objectives were to confirm and extend these observations to women with hypertensive disorders of pregnancy (HDP). Maternal demographics, clinical/laboratory findings and measurements of macular thickness were repeatedly collected at gestational ages <20 weeks, 20-weeks to delivery, at delivery and postpartum. The primary outcome was the change in macular thickness from non-pregnant dimensions in women with incident HDP compared to non-hypertensive pregnant controls. Secondary outcomes were the relationship(s) between mean arterial pressure (MAP) and macular response. Data show macular thicknesses diminished at <20 weeks gestation in each of 27 pregnancies ending in HDP (mean 3.94 µm; 95% CI 4.66, 3.21) and 11 controls (mean 3.92 µm; 5.05, 2.79; P < 0.001 versus non-pregnant dimensions in both; P = 0.983 HDP versus controls). This thinning response continued to delivery in all controls and in 7 women with HDP superimposed on chronic hypertension. Macular thinning was lost after 20 weeks gestation in the other 20 women with HDP. MAP at loss of macular thinning in women without prior hypertension (n = 12) was identical to MAP at enrollment. However, mean MAP subsequently rose 19 mmHg (15, 22) leading to de novo HDP in all 12 women. Loss of thinning leading to a rise in MAP was also observed in 8 of 15 women with HDP superimposed on chronic hypertension. We conclude the macula thins in most women in early pregnancy. Those who lose this early macular thinning response often develop blood pressure elevations leading to HDP.

Acute obstructive hydrocephalus in posterior reversible encephalopathy syndrome

Posterior reversible encephalopathy syndrome (PRES) is an uncommon, subacute neurological disorder that presents radiologically with a pattern of bilateral parieto-occipital areas of vasogenic oedema. Conditions commonly associated with PRES include autoimmune disorders, cytotoxic drugs, metabolic abnormalities and, most frequently, hypertensive emergencies. Clinically, headache, visual disturbances, seizures and an altered level of consciousness are often reported. The outcome is favourable if the underlying cause is addressed. Posterior fossa involvement resulting in obstructive hydrocephalus is a rare presentation and may be misdiagnosed as a mass lesion or infection, leading to delayed or unnecessary treatment. We describe the clinical presentation, findings on neuroimaging and conservative management of a man with PRES resulting in severe cerebellar oedema and acute obstructive hydrocephalus. This case illustrates that awareness of atypical neuroimaging in PRES is important for the management of these patients and to avoid morbidity and mortality.

Paediatric posterior reversible encephalopathy syndrome: is there an association of blood pressure with imaging severity and atypical magnetic resonance characteristics?

BACKGROUND

Posterior reversible encephalopathy syndrome (PRES) is relatively uncommon in paediatric patients; however, its pathophysiology remains obscure.

OBJECTIVE

The aims of this study were to find an association or correlation between (1) blood pressures and (2) imaging severity and the presence of atypical imaging features in children with PRES.

MATERIALS AND METHODS

We performed a retrospective cross-sectional evaluation in children diagnosed with PRES. We reviewed radiologic findings along with each patient's clinical profile and outcome. We categorised imaging severity into mild, moderate and severe, and assessed the MR imaging pattern, enhancement and diffusion restriction for each child. We assessed both associations and correlations between variables using the chi-square test, Cramer V and Kendall tau b.

RESULTS

A total of 63 children met the inclusion criteria (31 boys; mean age 9.7 years). A total of 42 children (67%) had an elevated blood pressure. Imaging showed parieto-occipital lobe involvement pattern in 24 (38%) children, frontal lobe pattern in 25 (40%) and cerebellar involvement in 12 (19%). Three (5%) had haemorrhage, 15 (24%) had contrast enhancement and 19 (30%) had positive diffusion restriction (cytotoxic oedema). We found no statistically significant association between imaging severity and blood pressures (P=0.11), nor any association between blood pressure and atypical imaging findings such as diffusion restriction (P=0.1), enhancement (P=0.11) or haemorrhage (P=0.33).

CONCLUSION

According to our results, there is no statistically significant association or correlation between blood pressure and either imaging severity or atypical imaging features in children with PRES. Further prospective studies are warranted.

Risk of Stroke After Posterior Reversible Encephalopathy Syndrome

BACKGROUND

Posterior reversible encephalopathy syndrome (PRES) can cause short-term cerebrovascular complications, such as brain infarction and hemorrhage. We hypothesized that PRES is also associated with an increased long-term risk of stroke.

METHODS

We performed a retrospective cohort study in the United States using statewide all-payer claims data from 2016 to 2018 on all admissions to nonfederal hospitals in 11 states. Adults with PRES were compared with adults with renal colic (negative control) and transient ischemic attack (TIA; positive control). Any stroke and the secondary outcomes of ischemic and hemorrhagic stroke were ascertained using International Classification of Diseases, Tenth Revision, Clinical Modification codes. We excluded prevalent stroke. We used time-to-event statistics to calculate incidence rates and Cox proportional hazards analyses to evaluate the association between PRES and stroke, adjusting for demographics and stroke risk factors. In a sensitivity analysis, outcomes within 2 weeks of index admission were excluded.

RESULTS

We identified 1606 patients with PRES, 1192 with renal colic, and 38 216 with TIA. Patients with PRES had a mean age of 56±17 years; 72% were women. Over a median follow-up of 0.9 years, the stroke incidence per 100 person-years was 6.1 (95% CI, 5.0-7.4) after PRES, 1.0 (95% CI, 0.62-1.8) after renal colic, and 9.7 (95% CI, 9.4-10.0) after TIA. After statistical adjustment for patient characteristics and risk factors, patients with PRES had an elevated risk of stroke compared with renal colic (hazard ratio [HR], 2.3 [95% CI, 1.7-3.0]), but lower risk than patients with TIA (HR, 0.67 [95% CI, 0.54-0.82]). In secondary analyses, compared with TIA, PRES was associated with hemorrhagic stroke (HR, 2.0 [95% CI, 1.4-2.9]). PRES was associated with ischemic stroke when compared with renal colic (HR, 1.9 [95% CI, 1.4-2.7]) but not when compared with TIA (HR, 0.49 [95% CI, 0.38-0.63]). Results were similar with 2-week washout.

CONCLUSIONS

Patients with PRES had an elevated risk of incident stroke.

Amyloid-Related Imaging Abnormalities with Emerging Alzheimer Disease Therapeutics: Detection and Reporting Recommendations for Clinical Practice

Monoclonal antibodies are emerging disease-modifying therapies for Alzheimer disease that require brain MR imaging for eligibility assessment as well as for monitoring for amyloid-related imaging abnormalities. Amyloid-related imaging abnormalities result from treatment-related loss of vascular integrity and may occur in 2 forms. Amyloid-related imaging abnormalities with edema or effusion are transient, treatment-induced edema or sulcal effusion, identified on T2-FLAIR. Amyloid-related imaging abnormalities with hemorrhage are treatment-induced microhemorrhages or superficial siderosis identified on T2* gradient recalled-echo. As monoclonal antibodies become more widely available, treatment screening and monitoring brain MR imaging examinations may greatly increase neuroradiology practice volumes. Radiologists must become familiar with the imaging appearance of amyloid-related imaging abnormalities, how to select an appropriate imaging protocol, and report findings in clinical practice. On the basis of clinical trial literature and expert experience from clinical trial imaging, we summarize imaging findings of amyloid-related imaging abnormalities, describe potential interpretation pitfalls, and provide recommendations for a standardized imaging protocol and an amyloid-related imaging abnormalities reporting template. Standardized imaging and reporting of these findings are important because an amyloid-related imaging abnormalities severity score, derived from the imaging findings, is used along with clinical status to determine patient management and eligibility for continued monoclonal antibody dosing.

Comparison of Clinical Manifestations, Laboratory, Neuroimaging Findings, and Outcomes in Children With Posterior Reversible Encephalopathy Syndrome (PRES) in Children With and Without Renal Disease

BACKGROUND

To demonstrate and compare the clinical manifestations, laboratory findings, and neuroimaging findings of posterior reversible encephalopathy syndrome (PRES) in children with and without underlying renal disease.

METHODS

The study included 23 children with a diagnosis of PRES from January 2009 to March 2019. All data, including clinical manifestations, laboratory findings, underlying medical illness, and neuroimaging results, were obtained.

RESULTS

Sixteen had underlying renal disease. The median age of PRES onset was 10.3 years in children with renal disease and 9.8 years in children without renal disease. Higher blood pressure at the baseline, on admission, and at the onset of PRES was found in the renal disease group more than in the nonrenal disease group (P < 0.05). Seizures were likely seen in the renal disease group compared with the nonrenal disease group (P = 0.03). Generalized tonic-clonic seizures were the most common seizure type in both groups. An initial CT scan revealed vasogenic edema in 75% of the renal group and 85.7% of the nonrenal group. During a long-term follow-up, all children recovered without significant neurological deficits or subsequent epilepsy.

CONCLUSIONS

Hypertension and higher baseline blood pressure are more common in children with renal disease who develop PRES compared with nonrenal disease. Seizures are more common in the renal disease group. A computed tomographic (CT) scan can help with PRES diagnosis when magnetic resonance imaging is not available. All children with PRES recovered without significant neurological deficits or subsequent epilepsy.

Polyarteritis nodosa presenting with posterior reversible leukoencephalopathy syndrome

A man in his 20s presented following a generalised tonic-clonic seizure on a background of a recent diagnosis of hepatitis B (HBV). During admission, he was severely hypertensive and imaging findings confirmed a diagnosis of posterior reversible leukoencephalopathy syndrome (PRES). The patient subsequently developed multiorgan involvement with an axonal sensorimotor neuropathy, vascular cutaneous lesions and multiple bilateral renal and splenic infarcts. Based on the 2012 Revised International Chapel Hill Consensus Criteria, a diagnosis of polyarteritis nodosa (PAN) with secondary PRES was made. The patient was given intravenous methylprednisolone, followed by a prolonged course of oral prednisolone, and tenofovir antiviral therapy to target HBV seroconversion. He made a good neurological recovery with resolution of imaging changes. This case highlights the importance of a low threshold for systemic screening for young patients presenting with PRES secondary to uncontrolled hypertension and the importance of viral screening, particularly for HBV.

Foreign accent syndrome and other neuropsychological sequelae of a parieto-occipital lesion following COVID-19 associated posterior reversible encephalopathy syndrome

OBJECTIVE

We describe a previously fit and well 54-year-old female who acquired a range of severe and persisting neuropsychological impairments following a posterior reversible encephalopathy syndrome (PRES) complication of COVID-19. The initial presentation included aphasia, a neurogenic foreign accent syndrome (FAS) and a persisting complete cortical blindness from the underpinning parieto-occipital brain injury.

METHOD

Neuropsychological single clinical case report.

RESULTS

The patient retained insight and made good early progress with their adjustment to the numerous losses caused by the COVID-19 associated acquired brain injury. Comprehensive neuropsychological investigation characterised an acalculia, along with deficits in focused, sustained and divided attention impacting on verbal memory, working memory and executive functioning, amongst numerous relative strengths.

CONCLUSION

Similar to PRES from other aetiologies, COVID-19 associated PRES can in some cases cause irreversible acquired brain injury. The diverse neuropsychological effects need to be comprehensively investigated and managed. This case adds to the neuropsychological literature on PRES, FAS and acquired brain injury as a rare complication of SARS-CoV-2.

Reversible cerebral vasoconstriction syndrome: review of neuroimaging findings

Reversible cerebral vasoconstriction syndrome (RCVS) is a group of disorders characterized by segmental narrowing and dilatation of medium-to-large cerebral arteries, clinically presenting with recurrent episodes of sudden-onset thunderclap headaches, with or without focal neurological deficits. Cerebral vasoconstriction is typically reversible, with spontaneous resolution within 3 months. Although the syndrome has generally a benign course, patients with neurological deficits may experience worse outcome. The main imaging finding is segmental constriction of intracranial arteries, which can be associated with subarachnoid hemorrhage and/or ischemic foci. Other possible findings are intracranial hemorrhage, subdural bleeding and cerebral edema. The latter may have a pattern which can resemble that of posterior reversible encephalopathy syndrome, a condition that can overlap with RCVS. New imaging techniques, such as vessel wall imaging and arterial spin labeling, are proving useful in RCVS and are giving new insights into the pathophysiology of this condition. In this paper, we aim to review neuroimaging findings of RCVS.

Imaging of Headache Attributed to Vascular Disorders

Imaging is essential in the diagnosis of vascular causes of headaches. With advances in technology, there are increasing options of imaging modalities to choose from, each with its own advantages and disadvantages. This article will focus on imaging pearls and pitfalls of vascular causes of headaches. These include aneurysms, vasculitides, vascular malformations, and cerebral venous thrombosis.

Arterial Spin Labeling technique and clinical applications of the intracranial compartment in stroke and stroke mimics - A case-based review

Magnetic resonance imaging perfusion (MRP) techniques can improve the selection of acute ischemic stroke patients for treatment by estimating the salvageable area of decreased perfusion, that is, penumbra. Arterial spin labeling (ASL) is a noncontrast MRP technique that is used to assess cerebral blood flow without the use of intravenous gadolinium contrast. Thus, ASL is of particular interest in stroke imaging. This article will review clinical applications of ASL in stroke such as assessment of the core infarct and penumbra, localization of the vascular occlusion, and collateral status. Given the nonspecific symptoms that patients can present with, differentiating between stroke and a stroke mimic is a diagnostic dilemma. ASL not only helps in differentiating stroke from stroke mimic but also can be used to specify the exact mimic when used in conjunction with the symptomatology and structural imaging. In addition to a case-based overview of clinical applications of the ASL in stroke and stroke mimics in this article, the more commonly used ASL labeling techniques as well as emerging ASL techniques, future developments, and limitations will be reviewed.

A Case Report of Posterior Reversible Encephalopathy Syndrome (PRES) in a Nonsevere Case of COVID-19

Posterior reversible encephalopathy syndrome (PRES) is a rare complication that the exact pathophysiological mechanism of which is still unclear. PRES most often occurs in connection with severe hypertension and autoimmune diseases. It can also appear during chemotherapy or immunosuppressive treatment. A 38-year-old woman with a negative medical history was admitted to the local hospital due to loss of consciousness accompanied by seizures and high values of blood pressure, and a PCR test for COVID-19 was positive. The patient’s condition was preceded by weakness, wet cough, runny nose, and low-grade fever for three days. Due to the conducted diagnostics after negative CT scans and angio CT studies, an MRI of the head with contrast was performed, where changes characteristic of PRES syndrome were found. During the hospitalization, the patient did not require invasive ventilation and did not receive antiviral drugs or tocilizumab as a result of treatment for her high blood pressure values, and after establishing the diagnosis, the patient was discharged home with a significant improvement in her well-being. In the literature, there are discussions as to whether COVID-19 predisposes patients to PRES. Isolated cases have been described, but its frequency is not yet established. Case reports in the literature appear to be specifically associated with a severe course of the disease, unlike in our patient. Even with a mild course of COVID, the diagnosis of PRES should be taken into account in patients with seizures, visual disturbances, or other focal neurological deficits.

Posterior Reversible Encephalopathy Syndrome Following Chemotherapy and Immune Checkpoint Inhibitor Combination in a Patient with Small-Cell Lung Cancer

Posterior reversible encephalopathy syndrome (PRES) is a rare neurological complication that occurs following a sudden blood pressure increase. We report the case of a 64-year-old patient presenting PRES several hours after the administration of a combination of chemotherapy and a checkpoint inhibitor (carboplatin-etoposide-atezolizumab) for small-cell lung cancer. He presented consciousness disorders associated with partial epileptic seizure secondarily generalized. His arterial blood pressure was elevated and brain imaging showed multiple bilateral subcortical parietal, temporal, occipital and cerebellar T2 high signals, predominantly in the posterior region. There were no abnormal T1 signals nor bleeding but a left apparent diffusion coefficient restriction was noted. On arterial spin labelling perfusion sequences, there was an increased perfusion within the left temporo-parieto-occipital, left thalamic and right cerebellar regions. Finally, the neurological symptoms completely regressed after several days of optimal antihypertensive and antiepileptic treatment. The clinical context and radiological features, as well as the progressive resolution of the neurological symptoms, were all in favor of PRES. PRES can occur after the administration of chemotherapy and/or immunotherapy. Prompt diagnosis is crucial through a spectrum of suspicious clinical and radiological characteristics that must be rapidly recognized to quickly anticipate the optimal therapeutic strategy and avoid unnecessary complications.

Cerebral perfusion in posterior reversible encephalopathy syndrome measured with arterial spin labeling MRI

BACKGROUND AND PURPOSE

The pathophysiologic basis of posterior reversible encephalopathy syndrome (PRES) remains controversial. Hypertension (HTN)-induced autoregulatory failure with subsequent hyperperfusion is the leading hypothesis, whereas alternative theories suggest vasoconstriction-induced hypoperfusion as the underlying mechanism. Studies using contrast-based CT and MR perfusion imaging have yielded contradictory results supporting both ideas. This work represents one of the first applications of arterial spin labeling (ASL) to evaluate cerebral blood flow (CBF) changes in PRES.

MATERIALS AND METHODS

After obtaining Institutional Review Board approval, MRI reports at our institution from 07/2015 to 09/2020 were retrospectively searched and reviewed for mention of "PRES" and "posterior reversible encephalopathy syndrome." Of the resulting 103 MRIs (performed on GE 1.5 Tesla or 3 Tesla scanners), 20 MRIs in 18 patients who met the inclusion criteria of clinical and imaging diagnosis of PRES and had diagnostic-quality pseudocontinuous ASL scans were included. Patients with a more likely alternative diagnosis, technically non-diagnostic ASL, or other intracranial abnormalities limiting assessment of underlying PRES features were excluded. Perfusion in FLAIR-affected brain regions was qualitatively assessed using ASL and characterized as hyperperfusion, normal, or hypoperfusion. Additional quantitative analysis was performed by measuring average gray matter CBF in abnormal versus normal brain regions.

RESULTS

HTN was the most common PRES etiology (65%). ASL showed hyperperfusion in 13 cases and normal perfusion in 7 cases. A hypoperfusion pattern was not identified. Quantitative analysis of gray matter CBF among patients with visually apparent hyperperfusion showed statistically higher perfusion in affected versus normal appearing brain regions (median CBF 100.4 ml/100 g-min vs. 61.0 ml/ 100 g-min, p < 0.001).

CONCLUSION

Elevated ASL CBF was seen in the majority (65%) of patients with PRES, favoring the autoregulatory failure hypothesis as a predominant mechanism. Our data support ASL as a practical way to assess and noninvasively monitor cerebral perfusion in PRES that could potentially alter management strategies.