The Promise of Molecular Imaging: Focus on Central Nervous System Infections.

Central nervous system (CNS) infections can lead to high mortality and severe morbidity. Diagnosis, monitoring, and assessing response to therapy of CNS infections is particularly challenging with traditional tools, such as microbiology, due to the dangers associated with invasive CNS procedures (ie, biopsy or surgical resection) to obtain tissues. Molecular imaging techniques like positron emission tomography (PET) and single-photon emission computed tomography (SPECT) imaging have long been used to complement anatomic imaging such as computed tomography (CT) and magnetic resonance imaging (MRI), for in vivo evaluation of disease pathophysiology, progression, and treatment response. In this review, we detail the use of molecular imaging to delineate host-pathogen interactions, elucidate antimicrobial pharmacokinetics, and monitor treatment response. We also discuss the utility of pathogen-specific radiotracers to accurately diagnose CNS infections and strategies to develop radiotracers that would cross the blood-brain barrier.

The Changing Epidemiology of Central Nervous System Infection: Can Radiologists Keep Up?

Diagnostic radiologists can increase their clinical value by supplementing image pattern recognition with knowledge of epidemiology and geographic distribution of central nervous system (CNS) infections and their causative organisms. This article reviews the changing global disease patterns, as well as zoonotic outbreaks of henipaviruses, coronaviruses, and other emerging, reemerging, and vector-borne organisms; case examples highlight typical imaging features of CNS infections and their mimics. Technical advances in neuroimaging help to enhance the value of radiologists to the multidisciplinary team and the responses to future pandemic preparation.

Imaging of Congenital/Childhood Central Nervous System Infections.

This article highlights the changing profile of the pediatric patient with central nervous system infection as countries develop and the roles of different imaging modalities such as cranial ultrasound, MR imaging, and computed tomography. It discusses the commonly encountered congenital toxoplasmosis, rubella, cytomegalovirus, herpes simplex (TORCH) infections, Group B Streptococcal and Escherichia coli infections in the neonatal period, and disease outbreaks affecting children. Iatrogenic, opportunistic, and immune-mediated changes as well as long-term effects of infection and mimics of infection are also discussed. Variety of images is provided to show the range of neuroimaging findings encountered, particularly on cranial ultrasound and MR imaging.

Role of imaging in CNS infections.

Neuroinfections are seen in both adults and children. These can result in serious morbidity and if left untreated and/or associated with comorbidities can be life threatening. Cross-sectional imaging like computed tomography (CT) and magnetic resonance imaging (MRI) are advised by the clinicians for the diagnosing, confirmation of the diagnosis, assess any complications of the infection, and also for follow up. Though CT is the initial imaging investigation commonly asked by the clinician, due to its lesser soft tissue resolution, early brain changes may not be seen on CT. MRI has better soft tissue resolution with no ionizing radiation to the patient and helps in detecting the early signs of infection. Appropriate MRI, not only helps the radiologist to reduce the number of possibilities of the causative organism but also differentiates tumors from infection. However, CT is useful to assess the bony changes and also easily available and affordable cross-sectional imaging modality worldwide. The review summarizes the approach of the radiologist to central nervous system (CNS) infections and their typical imaging characteristic features.

An Adolescent With Neurobrucellosis Caused by Brucella abortus Cattle Vaccine Strain RB51.

We present the case of an 18-year-old female with a 1-month history of fever, headache, and double vision, whose examination revealed papilledema and cranial nerve VI palsy. Blood cultures grew Brucella abortus cattle vaccine strain RB51, which is inherently resistant to rifampin. We discuss the management of the first known case of neurobrucellosis by this strain.

[Neurological complications in haematopoietic stem cell transplant patients]. / Complicaciones neurológicas en pacientes sometidos a trasplante de progenitores hematopoyéticos.

INTRODUCTION: Neurological complications are some of the most important complications that can occur in a patient undergoing haematopoietic stem cell transplantation (HSCT), not only because of the high mortality rate, but also because of the sequelae that appear in survivors. The causes of such complications are manifold and very often coexist in the same patient: toxicity of the conditioning regimen, graft-versus-host disease and its treatment, infections and their treatment, platelets and coagulation disorders, liver failure or arterial hypertension with low platelet count. AIMS: The aim of the present study is to provide a clinical description and to describe the risk factors for complications involving the central nervous system that may occur during the course of HSCT, in order to assist in the early detection of these disorders that may have a negative influence on the morbidity and mortality of these patients. DEVELOPMENT: The following types of neurological complications are described: central nervous system infections, vascular complications, pharmacological toxicity, metabolic complications, immune-mediated disorders and post-HSCT carcinogenesis, and effects of graft-versus-host disease and thrombotic microangiopathy on the nervous system. CONCLUSIONS: The patient undergoing HSCT is at particular risk for the development of neurological complications. Early diagnosis and treatment are needed to try to reduce the high morbidity and mortality in these patients.

TITLE: Complicaciones neurológicas en pacientes sometidos a trasplante de progenitores hematopoyéticos.Introducción. Las complicaciones neurológicas son algunas de las más importantes que se pueden presentar en un paciente sometido a un trasplante de progenitores hematopoyéticos (TPH), no sólo porque conllevan una mortalidad elevada, sino también por las secuelas que aparecen en los supervivientes. Las causas de dichas complicaciones son múltiples y, muy frecuentemente, coexisten en el mismo paciente: toxicidad del régimen de acondicionamiento, enfermedad del injerto contra el hospedador y su tratamiento, infecciones y su tratamiento, plaquetopenia y trastornos de la coagulación, fallo hepático o hipertensión arterial con plaquetopenia. Objetivos. El objetivo del presente estudio es el de aportar una descripción clínica y de los factores de riesgo de las complicaciones sobre el sistema nervioso central que pueden presentarse en el curso de un TPH, para ayudar en la detección precoz de estos trastornos que pueden influir negativamente en la morbimortalidad de estos pacientes. Desarrollo. Se describen los siguientes tipos de complicaciones neurológicas: infecciones sobre el sistema nervioso central, complicaciones vasculares, toxicidad farmacológica, complicaciones metabólicas, trastornos inmunomediados y carcinogenia pos-TPH, y efectos de la enfermedad del injerto contra el hospedador y de la microangiopatía trombótica sobre el sistema nervioso. Conclusiones. El paciente sometido a TPH es de especial riesgo para el desarrollo de complicaciones neurológicas. Se precisan un diagnóstico y un tratamiento precoces para intentar disminuir la elevada morbimortalidad de estos pacientes.

Non-traumatic pediatric intracranial hypertension: key points for different etiologies, diagnosis, and treatment.

Intracranial hypertension can be an acute life-threatening event or slowly deteriorating condition, leading to a gradual loss of neurological function. The diagnosis should be taken in a timely fashioned process, which mandates expedite measures to save brain function and sometimes life. An optimal management strategy is selected according to the causative etiology with a core treatment paradigm that can be utilized in various etiologies. Distinct etiologies are intracranial bleeds caused by traumatic brain injury, spontaneous intracranial hemorrhage (e.g., neonatal intraventricular hemorrhage), or the rare pediatric hemorrhagic stroke. The other primary pediatric etiologies for elevated intracranial pressure are intracranial mass (e.g., brain tumor) and hydrocephalus related. Other unique etiologies in the pediatric population are related to congenital diseases, infectious diseases, metabolic or endocrine crisis, and idiopathic intracranial pressure. One of the main goals of treatment is to alleviate the growing pressure and prevent the secondary injury to brain parenchyma due to inadequate blood perfusion and eventually inadequate parenchymal oxygenation and metabolic state. Previous literature discussed essential characteristics of the treatment paradigm derived mainly from pediatric brain traumatic injuries' treatment methodology. Yet, many of these etiologies are not related to trauma; thus, the general treatment methodology must be tailored carefully for each patient. This review focuses on the different possible non-traumatic etiologies that can lead to intracranial hypertension with the relevant modification of each etiology's treatment paradigm based on the current literature.

Neuroradiology of infectious diseases.

PURPOSE OF REVIEW: Early diagnosis of central nervous system (CNS) infections is crucial given high morbidity and mortality. Neuroimaging in CNS infections is widely used to aid in the diagnosis, treatment and to assess the response to antibiotic and neurosurgical interventions. RECENT FINDINGS: The Infectious Diseases Society of America (IDSA) guidelines have clear recommendations for obtaining a computerized tomography of the head (CTH) prior to lumbar puncture (LP) in suspected meningitis. In the absence of indications for imaging or in aseptic meningitis, cranial imaging is of low utility. In contrast, cranial imaging is of utmost importance in the setting of encephalitis, bacterial meningitis, ventriculitis, bacterial brain abscess, subdural empyema, epidural abscess, neurobrucellosis, neurocysticercosis, and CNS tuberculosis that can aid clinicians with the differential diagnosis, source of infection (e.g., otitis, sinusitis), assessing complications of meningitis (e.g., hydrocephalus, venous sinus thrombosis, strokes), need for neurosurgical interventions and to monitor for the response of therapy. Novel imaging techniques such as fast imaging employing steady-state acquisition (FIESTA), susceptibility-weighted imaging (SWI), and chemical exchange saturation transfer (CEST) contrast are briefly discussed. SUMMARY: Though the radiological findings in CNS infections are vast, certain patterns along with clinical clues from history and examination often pave the way to early diagnosis. This review reiterates the importance of obtaining cranial imaging when necessary, and the various radiological presentations of commonly encountered CNS infections.

Neuroimaging of CNS infection in haematological malignancy: important signs and common diagnostic pitfalls.

Patients with haematological malignancy are at increased risk of developing central nervous system (CNS) infections, which are associated with significant morbidity and mortality. Neuroimaging plays a pivotal role in the diagnostic pathway of these patients; however, layers of complexity are added to image interpretation by the heterogeneity in imaging manifestations of haematological malignancies in the CNS, overlapping imaging features of CNS infection, treatment-related parenchymal changes and the presence of intracranial comorbidity. In this article, we review important intracranial findings of CNS infection cases accrued in 1,855 studies over more than a decade at a specialist tertiary centre. We offer schema to identify common and important neuroimaging features, discuss key differential diagnoses and frequent diagnostic pitfalls.

Cerebral protothecosis mimicking high-grade glioma.

Prototheca wickerhamii is a common, indolent alga that seldom causes central nervous system infections in humans. We report the first UK case of cerebral protothecosis in an immunocompetent 56-year-old woman who presented with a 5-month history of intermittent fatigue followed by a 2-week history of symptoms, including right arm and leg weakness, a loss of fine motor coordination, worsening gait, right facial tingling, diplopia and a metallic oral taste. MRI scans revealed a multifocal abnormality suggestive of high-grade glioma. Given the clinical presentation, absence of immunodeficiency and characteristic MRI features, a diagnosis of high-grade glioma was deemed most likely by the multidisciplinary team. Surgical biopsy provided material for histopathological and microbiological diagnosis. She underwent a 2-year course of antimicrobials with surveillance MRI scans. The patient made a good functional recovery but still retains mild neurological sequelae.

Morphological characteristics of infected subdural hematoma: Comparison with images of chronic subdural hematoma.

OBJECTIVES: Infected subdural hematoma (ISH) is a rare type of subdural empyema, with fewer than 50 cases reported to date. Its radiological features have not been adequately described, making diagnosis challenging. At our institution, two adults presented with ISH, which exhibited a characteristic shape on preoperative imaging. PATIENTS AND METHODS: This study examined ISH cases and chronic subdural hematoma (CSH) cases that underwent surgery at the Ishikawa Prefectural Central Hospital between January 2016 and March 2018. To distinguish ISH from CSH, we focused on three specific radiological features: the biconvex shape of the hematoma, presence of a high-density region at the lower end of the hematoma on plain computed tomography (CT), and presence of a hyper-intense signal within the hematoma on diffusion weighted imaging (DWI). RESULTS: We analyzed 30 ISH (current and previously reported) and 102 CSH cases in our study. We found no statistically significant associations between the hematoma type (ISH or CSH) and the presence of a high-density region at the lower end of the hematoma on plain CT (p = 0.13) or the presence of hyperintensity in the hematoma on DWI (p = 1.00). Conversely, a statistically significant association was found between the hematoma type and the biconvex shape of the hematoma (p < 0.01). CONCLUSION: These results suggest that the shape of the hematoma on imaging provides valuable information that can be used to differentiate ISH from CSH and optimize therapeutic approaches.

Neonatal Neuroimaging.

Significant advances in the field of neonatal imaging has resulted in the generation of large complex data sets of relevant information for routine daily clinical practice, and basic and translational research. The evaluation of this data is a complex task for the neonatal imager who must distinguish normal and incidental findings from clinically significant abnormalities which are often adjunctive data points applicable to clinical evaluation and treatment. This review provides an overview of the imaging manifestations of disease processes commonly encountered in the neonatal brain. Since MRI is currently the highest yield technique for the diagnosis and characterization of the normal and abnormal brain, it is therefore the focus of the majority of this review. When applicable, discussion of some of the pertinent known pathophysiology and neuropathological aspects of disease processes are reviewed.

Intracranial CNS Infections: A Literature Review and Radiology Case Studies.

Acute infections of the intracranial central nervous system (CNS) often present as neurological emergencies, where missed or delayed diagnosis and treatment can be catastrophic to the patient. Accurate and timely identification of the underlying etiologies, which are critical in directing life-saving therapies, can be achieved through neuroimaging. This article will provide a thorough review of radiologic findings in common infections of the brain, from primarily compartmentalized infections of multimicrobial etiologies, to CNS manifestations of specific immunocompromised-selective pathogens, of herpes simplex virus, and of tuberculosis. We also briefly discuss the epidemiology, etiology, clinical features, treatment guidelines, complications, and long-term sequelae of these infections.

CNS Infections in Immunoincompetent Patients : Neuroradiological and Clinical Features.

In patients with immunodeficiency the pathogen spectrum of central nervous system (CNS) infections is broader and different from that of immunocompetent patients. Numerous opportunistic infections are characterized by a high prevalence of viral, bacterial and parasitic pathogens, and depend on the type of impaired immune defense, for example impaired T­cell or monocyte function, monoclonal antibody treatment, and impaired granulocyte function. Neuroradiological features as well as laboratory findings are often different and versatile in comparison to immunocompetent individuals and pathognomonic imaging findings do not exist; however, knowledge of possible pathways of pathogens in the CNS and preferred tissue affection may help in narrowing down differential diagnoses. Therefore, knowledge of the type of patient and the performed immunomodulatory therapy is essential for the neuroradiological assessment and the differential diagnostic considerations. Moreover, parenchymal reactions in the sense of an immune reconstitution inflammatory syndrome (IRIS) can occur when immunocompetence is restored. This review focus on the most common pathologies in immunocompromised patients, and an overview of imaging features but also of pathology and clinical aspects is given. The synopsis of anamnestic information, clinical findings and structured analysis of the lesion pattern, its spread and short-term follow-up may increase the correct diagnostic classification; however, the gold standard is still determination of the pathogen in the cerebrospinal fluid (CSF), blood cultures or biopsies.

Cranial Imaging and Lumbar Puncture in Patients With Suspected Central Nervous System Infection.

BACKGROUND: Performing cranial imaging prior to lumbar punctures (LPs) in patients with suspected central nervous system (CNS) infections has been associated with delayed treatments and poor outcomes. Various guidelines provide different criteria for cranial imaging prior to LP. METHODS: We describe the use of cranial imaging in a cohort of adult patients with suspected CNS infections, and evaluated adherence to the recommendations made in the Infectious Disease Society of America (IDSA), European Society of Clinical Microbiology and Infectious Diseases (ESCMID), Swedish, and Dutch guidelines. We also analyzed the association between cranial imaging and the time between emergency department entrance and intravenous antibiotic administration. RESULTS: From 2012-2015, 203 patients with suspected CNS infections were included, of whom 56 (27%) were diagnosed with CNS infections and 16 were diagnosed with bacterial meningitis (8%). Cranial imaging, in all cases computed tomography (CT), was performed in 130 patients (64%) and led to the deferral of LPs in 7 (5%). Criteria by the IDSA, ESCMID, Swedish, and Dutch guidelines showed indications for imaging in 64%, 39%, 39%, and 40% of patients, respectively. The times between emergency department arrivals and the start of antibiotic therapy between patients with and without CT before LP were similar (median 134 [interquartile range (IQR) 58-292] vs. 141 minutes [IQR 52-227], respectively; Mann-Whitney U P = .74). CONCLUSIONS: A cranial CT prior to LP was done in the majority of patients with a suspected CNS infection, irrespective of guideline indications. The ESCMID, Swedish, and Dutch guidelines were more restrictive in advising imaging, compared to the IDSA guidelines. Performing cranial imaging prior to LP was not associated with treatment delays in this Dutch cohort study.

Unusual cranial infection caused by Citrobacter Koseri.

A 60-year-old female had a frontal bone intraosseous meningioma resected 10 years previously. On follow up CT head, an enlarging intraosseous frontal bone lesion was noted. This was thought to be a recurrent frontal meningioma. Intraooperatively, she was found to have an abscess deep to the cranioplasty.

Infectious Etiologies of Stroke.

Central nervous system (CNS) infections are a frequently underappreciated potential etiology of cerebrovascular disease. Highlighted in this review are a selection of infectious agents that lead to cerebrovascular complications through various mechanisms including multifocal vasculopathy, focal infiltrative vasculitis and vasospasm, and direct vessel wall invasion and thrombus formation. Diagnosis of stroke due to underlying CNS infection requires a high index of clinical suspicion and careful consideration of neuroimaging, serum, and cerebrospinal fluid studies in addition to a detailed history and neurologic examination. Prompt and targeted treatment is essential in these conditions, which frequently herald a poor prognosis. Specifically, cerebrovascular complications associated with varicella zoster virus, syphilis, tuberculosis, aspergillosis, and acute bacterial meningitis are addressed here in detail.