Fungal versus bacterial brain abscesses: is diffusion-weighted MR imaging a useful tool in the differential diagnosis?

Cerebritis, optic ischemia, and cavernous sinus thrombosis arising from sinonasal mucormycosis

Brain and ocular infections can be the worst and fatal consequences of sinonasal infections in immunomodulated or immunocompromised patients. We report a case of a 35-year-old female who received an allogenic hematopoietic stem cell transplantation for acute myeloid leukemia, suffering from maxillo-spheno-ethmoidal rhinosinusitis which was complicated by cavernous sinus thrombosis, orbital cellulitis, optic ischemia and cerebritis.

Radiological differentiation between bacterial orbital cellulitis and invasive fungal sino-orbital infections

PURPOSE

Invasive fungal orbital infections (IFOI) may be difficult to differentiate from sinogenic bacterial orbital cellulitis (OC). This study investigates the features differentiating OC from IFOI on magnetic resonance imaging (MRI).

METHODS

Retrospective study of adult patients with sinogenic OC and IFOI with pre-intervention MRI. Patients without post-septal involvement, non-sinogenic OC (e.g.: secondary to trauma) and poor-quality scans were excluded. Independent Sample's t test and Fisher's exact test were conducted with p < 0.05 deemed statistically significant.

RESULTS

Eleven cases each of OC (Mean age: 41.6 ± 18.4 years-old, Male: 10) and IFOI (Mean age: 65.0 ± 16.6 years-old, Male: 9) between 2006 and 2023. IFOI patients were older, more likely immunocompromised and had a lower mean white-cell count (p value = 0.005, 0.035 and 0.017, respectively). The ethmoid and maxillary sinuses were most commonly involved in both entities. Pre-septal and lacrimal gland involvement were more common in OC (p = 0.001 and 0.008, respectively). Infiltrative OC orbital lesions were poorly demarcated, whilst those in IFOI were expansile/mass-like invading the orbit from the adjacent paranasal sinuses. Specific IFOI features included loss-of-contrast-enhancement (LoCE) of paranasal sinus tissues with orbital extension. Extra-orbital and -sinonasal extension indicative of IFOI included contiguous skull base or pterygopalatine fossa involvement, retro-antral and masticator space stranding and vasculitis.

CONCLUSION

This study describes the key MRI features of IFOI including differentiating markers from OC. These specific features, such as LoCE of the paranasal and orbital soft tissues, the location and pattern of contiguous soft-tissue involvement, provide expedient identification of IFOI which necessitate early surgical intervention for microbiological confirmation of an invasive fungal pathology.

Evolution of neuroimaging findings in angioinvasive cerebral aspergillosis in a pediatric patient with leukemia during long-term observation

The central nervous system is one of the most common sites of aspergillosis involvement in immunocompromised people, just after sinopulmonary infections. Neuroimaging modalities are crucial for the diagnosis of cerebral aspergillosis (CA). Here, we describe a rare case of concurrent mixed aspergillosis infection with Aspergillus fumigatus and Aspergillus niger in a 2-year-old leukemic boy. The first neuroimaging finding, which was followed by focal seizures, was recognized as extensive cerebral hemorrhage in the absence of thrombocytopenia and coagulopathy. As the patient survived for more than 4 months after diagnosis, we were able to perform a neuroimaging evaluation during long-term observation. In serial neuroimaging studies, a secondary fungal abscess was observed at the site of hemorrhagic infarctions. Finally, the patient died from bacterial sepsis. In this case study, we try to categorize the neuroimaging findings of CA into distinct phases to better understand how CA changes over time.

Multiparametric imaging in the evaluation of intracerebral abscesses

Cerebral abscesses are uncommon space occupying lesions; they are associated with high morbidity and mortality, though are potentially treatable. Patients often present with non-specific symptoms and may have few clinical signs. Routine clinical imaging may not give a definite diagnosis, as the findings can be indistinguishable from those of other intracranial mass lesions. We review the role of advanced MR techniques to characterise brain abscesses and discuss the role of imaging in monitoring their response to the treatment.

Acute Porphyromonas gingivalis Subdural Abscess with Brain Abscess in the Left Temporal Lobe: A Case Report and Review of Literature

Background

Brain abscesses are a rare but serious complication of focal intracerebral infection.

Case Description

We present a patient of acute subdural abscess with brain abscess in the left temporal lobe. After craniotomy, combined with the Third Next Generation Sequencing and Gene Diagnosis (TNGS & GD) of abscess, we prescribed sensitive antibiotics; the patient recovers well and the abscess did not recur.

Conclusion

For patients with acute subdural abscess, combined craniotomy and the TNGS & GD of abscess could achieve good results.

In vivo assessment of differences in fungal cell density in cerebral cryptococcomas of mice infected with Cryptococcus neoformans or Cryptococcus gattii

In cerebral cryptococcomas caused by Cryptococcus neoformans or Cryptococcus gattii, the density of fungal cells within lesions can contribute to the overall brain fungal burden. In cultures, cell density is inversely related to the size of the cryptococcal capsule, a dynamic polysaccharide layer surrounding the cell. Methods to investigate cell density or related capsule size within fungal lesions of a living host are currently unavailable, precluding in vivo studies on longitudinal changes. Here, we assessed whether intravital microscopy and quantitative magnetic resonance imaging techniques (diffusion MRI and MR relaxometry) would enable non-invasive investigation of fungal cell density in cerebral cryptococcomas in mice. We compared lesions caused by type strains C. neoformans H99 and C. gattii R265 and evaluated potential relations between observed imaging properties, fungal cell density, total cell and capsule size. The observed inverse correlation between apparent diffusion coefficient and cell density permitted longitudinal investigation of cell density changes. Using these imaging methods, we were able to study the multicellular organization and cell density within brain cryptococcomas in the intact host environment of living mice. Since the MRI techniques are also clinically available, the same approach could be used to assess fungal cell density in brain lesions of patients.

Unusual Fungal Endocarditis Causing Disseminated Infection After Renal Transplant

Fungal endocarditis is a relatively uncommon disease; it mostly affects those with intracardiac devices and those with compromised immune systems. Scedosporium apiospermum (S. apiospermum), the asexual state of Pseudoallescheria boydii, has become increasingly reported as an opportunistic pathogen. These filamentous fungi present in soil, sewage, and polluted waters, and was previously recognized to cause human infection after their inhalation or traumatic subcutaneous implantation. In immunocompetent individuals, it usually causes localized diseases depending on the site of entry such as skin mycetoma. However, in immunocompromised hosts, the fungus species appear to disseminate and cause invasive infections, frequently reported to be life-threatening with poor response to antifungal medications. S. apiospermum invasive endocarditis remains a rare complication, mostly cited in immunocompetent hosts with prosthetic cardiac valves or other intracardiac devices and severely immunocompromised patients with hematologic neoplasia. Herein, we describe the case of a renal transplant patient on immunosuppressive medications who presented with S. apiospermum fungal septic infection that invaded the left ventricular outflow tract (LVOT) causing endocarditis with disseminated infection and resulted in poor clinical outcome.

Concomitant extradural, subdural, and intraparenchymal abscesses of the brain in a patient with cerebral melioidosis - A case report

Background

Extra axial abscess of the brain is a rare entity, moreover, extra-axial abscess concomitant with intraparenchymal purulent collections are scarcely reported in the literature. Etiology includes penetrating trauma, paranasal sinusitis, mastoiditis, craniospinal surgeries, and the rare spread of infectious agents through the hematogenous route.

Case description

We present a case of a young male with Burkholderia pseudomallei Central Nervous System (CNS) melioidosis, forming abscesses in extra-axial and intraparenchymal planes without contiguity.

Conclusion

This is to emphasize the importance of MR spectroscopy and other convenient methods in differentiating the etiology in cranial infections.

Clinical applications of diffusion-weighted sequence in brain imaging: beyond stroke

Diffusion-weighted imaging (DWI) is a well-established MRI sequence for diagnosing early stroke and provides therapeutic implications. However, DWI yields pertinent information in various other brain pathologies and helps establish a specific diagnosis and management of other central nervous system disorders. Some of these conditions can present with acute changes in neurological status and mimic stroke. This review will focus briefly on diffusion imaging techniques, followed by a more comprehensive description of the utility of DWI in common neurological entities beyond stroke.

Central nervous system candidiasis beyond neonates: Lessons from a nationwide study

Though candidiasis is the most frequent invasive fungal infection, Candida spp. central nervous system (CNS) infections are rare but severe. To further describe clinico-patho-radiological presentations of this entity, we report a retrospective study from January 2005 to December 2018 including patients aged ≥ 28 days with proven or probable CNS candidiasis in France. Twenty-four patients were included. Seventeen patients (70%) had CNS localization secondary to disseminated candidiasis (10 with hematologic malignancies [HM]; the seven other patients had infective endocarditis [IE]). Among patients with HM, seven previously had lumbar puncture for intrathecal chemotherapy, the three others had IE. Among patients with disseminated infection, magnetic resonance imaging (MRI) evidenced meningitis (17%), micro-abscesses (58%), or vascular complications (67%). Seven patients (30%) had isolated CNS involvement related to neurosurgery (n = 2), CARD9 deficiency (n = 2), intravenous drug use, diabetes mellitus, or no identified predisposing condition (n = 1 each). All evaluated patients with isolated CNS involvement had meningitis on cerebrospinal fluid (CSF) and intracranial hypertension. For the latter patients, MRI evidenced meningitis (71%) or abscesses (57%). Among all patients, cerebrospinal fluid (CSF) culture grew Candida spp. in 31% of cases. CSF βDGlucan or mannan Ag were positive in respectively 86% and 80% of cases. Mortality attributed to CNS candidiasis was 42%: 53% in case of disseminated infection (70% for HM) and 14% in case of localized infection. CNS candidiasis are isolated or occur during disseminated infection in patients with HM and lumbar puncture for intrathecal chemotherapy or during IE. Clinical, radiological finding and outcome highly vary according to CNS localized versus disseminated candidiasis.

LAY SUMMARY

Candida is a yeast and is the most common cause of fungal infections worldwide. Candida central nervous system (CNS) infections are rare, severe, and poorly described. We report a retrospective study from January 2005 to December 2018 including patients aged ≥ 28 days with proven or probable CNS candidiasis in France. Twenty-four patients were included (14 men, median age 51 years). Seventeen patients had CNS localization secondary to disseminated candidiasis from blood to CNS (10 with hematologic malignancies [HM], the seven other patients had infective endocarditis [IE]). Seven patients had isolated CNS involvement related to neurosurgery (n = 2), CARD9 deficiency (n = 2), intravenous drug use (n = 1), diabetes mellitus (n = 1), or no identified risk factor (n = 1).During Candida CNS infections, brain lesions were meningitis abscesses or vascular complications. Cerebrospinal fluid (CSF) culture grew Candida spp. in 31% of cases. Forty-two percent of patients died from infection: 53% in case of disseminated infection (70% for HM) and 14% in case of localized infection.

MRI of Emergent Intracranial Infections and Their Complications

Acute intracranial infections of the central nervous system and skull base are uncommon but time sensitive diagnoses that may present to the emergency department. As symptoms are frequently nonspecific or lack typical features of an infectious process, a high index of suspicion is required to confidently make the diagnosis, and imaging may not only serve as the first clue to an intracranial infection, but is often necessary to completely characterize the disease process and exclude any confounding conditions. Although computed tomography is typically the initial imaging modality for many of these patients, magnetic resonance imaging offers greater sensitivity and specificity in diagnosing intracranial infections, characterizing the full extent of infection, and identifying potential complications. The aim of this article is to serve as a review of the typical and most important imaging manifestations of these infections that can be encountered in the emergent setting.

Intracranial peripherally enhancing lesions in cardiac transplant recipients: A rare case series and literature review

Intracranial peripherally enhancing lesions in immunosuppressed solid organ transplant recipients represent a unique diagnostic and management dilemma due to the vast array of differentials that demand consideration. Diagnosis of the underlying pathology is often guided by the use of magnetic resonance imaging (MRI). We present the first published case series of three cardiac transplant recipients with significantly atypical neuroradiological findings contrary to the tenets of contemporary literature. Our rare case series consists of: (1) A sterile Mycobacterium pyogenic abscess mimicking glioblastoma multiforme due to an immunosuppressed state (2) Epstein Barr Virus encephalitis masquerading as Central Nervous System Post-Transplant Lymphoproliferative Disorder (3) An unusual case of partially treated disseminated Nocardiosis warning of the need to consider the immunosuppressed state and partial treatment response obfuscating classical MRI appearances. We utilise these unprecedented cases as the basis of a literature review to understand the pathophysiology behind the peculiar imaging findings in this rarefied cohort of transplant recipients, and rationalise why the MRI findings in each instance contradicts the accepted imaging patterns. In the setting of potential unreliability of neuroradiology in this immunosuppressed unique subgroup, we hope to impart to clinicians that definitive diagnosis obtained by emergent neurosurgical intervention may be necessary to accurately and expediently guide further medical management.

Nocardia amikacinitolerans and cytomegalovirus: distinctive clinical and radiological characterization of the rare etiologies of brain abscesses: report of 2 cases

Central nervous system infections in immunosuppressed patients are rare but potentially lethal complications that require swift diagnoses and intervention. While the differential diagnosis for new lesions on neuroradiological imaging of immunosuppressed patients typically includes infections and neoplasms, image-based heuristics to differentiate the two has been shown to have variable reliability.The authors describe 2 rare CNS infections in immunocompromised patients with atypical physical and radiological presentations. In the first case, a 59-year-old man, who had recently undergone a renal transplantation, was found to have multifocal Nocardia amikacinitolerans abscesses masquerading as neoplasms on diffusion-weighted imaging (DWI); in the second case, a 33-year-old man with suspected recurrent Hodgkin's lymphoma was found to have a nonpyogenic abscess with cytomegalovirus (CMV) encephalitis.As per review of the literature, this appears to be the first case of brain abscess caused by N. amikacinitolerans, a recently isolated superbug. Despite confirmation through brain biopsy later on in case 1, the initial radiological appearance was atypical, showing subtle diffusion restriction on DWI. Similarly, the authors present a case of CMV encephalitis that presented as a ring-enhancing lesion, which is extremely rare. Both cases draw attention to the reliability of neuroimaging in differentiating an abscess from a neoplasm.

Fungal infections in pediatric neurosurgery

INTRODUCTION

Invasive mycosis of the central nervous system represent a diverse group of diseases that have gradually emerged as not only opportunistic infections in patients with immune susceptibility due to congenital and acquired deficiency, immunomodulation, solid organ and stem cell transplantation, hematological malignancies, and chronic steroid use but also in selected risk populations such as low weight preterm infants, patients with shunted hydrocephalus and external ventricular drainages, skull base surgery, and head injury.

OBJECTIVES

The purpose of this review is to familiarize the pediatric neurosurgeon with the most common mycosis and their clinical scenarios which can be encountered in the clinical practice, with special emphasis on clinical, radiological, and laboratory diagnosis beyond classical microorganism cultures as well as options in medical and surgical treatment given the high incidence of morbidity and mortality associated with these challenging entities.

METHODS

We conducted an online database review (Ovid, PubMed) gathering relevant English language literature published in the last 20 years with special emphasis on recent breakthroughs in the diagnosis and treatment of invasive mycosis of the CNS as well as reported cases within the pediatric neurosurgical literature and their surgical management.

RESULTS

Fungal agents capable of invading the CNS can behave as aggressive entities with rapid progression manifesting as overwhelming meningoencephalitis with vascular compromise or can lead to space-occupying lesions with abscess formation which require prompt diagnosis by either laboratory identification of the components of these biological agents and their host response or by obtaining tissue specimens for microbiological identification which may not be straightforward due to prolonged culture time.

CONCLUSION

Following a high degree of suspicion with prompt initiation of antifungal agents and reversal of potential immunosuppressant therapies along with neurosurgical evacuation of intracranial collections or removal of infected hardware (CSF shunts) can lead to more optimistic outcomes of these complex clinical scenarios.

Fatal Balamuthia mandrillaris brain infection associated with improper nasal lavage

We report the case of a 69-year-old female who presented with a chronic nasal skin rash, new onset focal seizure, and a cerebral ring-enhancing lesion after a year of improper nasal irrigation. Despite aggressive and novel anti-amoebic treatment, she died as a result of a Balamuthia mandrillaris brain infection.

Role of diffusion-weighted imaging in skull base lesions: A pictorial review

Skull base lesions can be related to wide number of pathologies including infections, benign and malignant tumors. Accurate diagnosis and differentiation between these entities is important for prompt and appropriate treatment. However, computed tomography and routine magnetic resonance imaging techniques only provide information on the extent of the lesions, with limited ability to differentiate between benign and malignant lesions. Diffusion-weighted imaging can help in many such situations by providing additional information, including help in differentiating benign from malignant lesions, so that appropriate treatment can be initiated. In this review article, we illustrate the imaging findings of the spectrum of skull base lesions, emphasizing the role of diffusion-weighted imaging in this domain.

Pyogenic brain abscess with atypical features resembling glioblastoma in advanced MRI imaging

Differentiation between infectious and neoplastic brain processes is crucial for treatment planning. Advanced magnetic resonance imaging techniques, such as diffusion, perfusion, susceptibility weighted imaging, and magnetic resonance spectroscopy, enhance the imaging differences between these two pathologies. However, despite the utilization of these advanced techniques, the pathologic process may be confound by atypical findings. Here, we report a case of an autistic patient with multiple brain lesions with diffusion weighted imaging, susceptibility weighted imaging, and perfusion patterns resembling features of a multicentric glioblastoma, which were confirmed surgically, neuropathologically, and bacteriologically as brain abscesses. We discuss the differentiation of these different entities in the light of advanced magnetic resonance imaging techniques.

Neurologic emergencies in HIV-negative immunosuppressed patients

HIV-negative immunosuppressed patients comprise a heterogeneous group including transplant patients, patients undergoing treatment with immunosuppressors, uremic patients, alcoholics, undernourished patients, diabetics, patients on dialysis, elderly patients, and those diagnosed with severe or neoplastic processes. Epileptic seizures, focal neurologic signs, and meningoencephalitis are neurologic syndromes that require urgent action. In most of these situations, neuroimaging tests are necessary, but the findings can be different from those observed in immunocompetent patients in function of the inflammatory response. Infectious disease is the first diagnostic suspicion, and the identification of an opportunistic pathogen should be oriented in function of the type and degree of immunosuppression. Other neurologic emergencies include ischemic stroke, cerebral hemorrhage, neoplastic processes, and pharmacological neurotoxicity. This article reviews the role of neuroimaging in HIV-negative immunodepressed patients with a neurologic complication that requires urgent management.

Psoas Abscess Secondary to Urinary Tract Fungal Infection

Psoas abscess is a rare condition where infection spreads from a nearby or distant septic focus to the psoas sheath. The causative bacterial organisms at distal sites reach the psoas via lymphatic or hematogenous spread, whereas infection from nearby sites that include the urinary system reaches the psoas directly. There are few reports that account for bacterial infection after endourological procedures as the cause of direct spread of infection to the psoas muscle.² We report a case of psoas abscess caused by fungal infection that spread from an injured left ureter to the psoas sheath.

Infektionen

In diesem Kapitel werden zunächst die für die Neurointensivmedizin wesentlichen bakteriellen Infektionen (Meningitis, spinale und Hirnabszesse, Spondylodiszitis, septisch-embolische Herdenzephalitis) abgehandelt, die trotz gezielt eingesetzter Antibiotika und neurochirurgischer Therapieoptionen noch mit einer erheblichen Morbidität und Mortalität behaftet sind. Besonderheiten wie neurovaskuläre Komplikationen, die Tuberkulose des Nervensystems, Neuroborreliose, Neurosyphilis und opportunistische Infektionen bei Immunsuppressionszuständen finden hierbei besondere Berücksichtigung. Der zweite Teil dieses Kapitels behandelt akute und chronische Virusinfektionen des ZNS sowie in einem gesonderten Abschnitt die HIVInfektion und HIV-assoziierte Krankheitsbilder sowie Parasitosen und Pilzinfektionen, die in Industrieländern seit Einführung der HAART bei HIV zwar eher seltener, aber mit zunehmender Globalisierung auch in unseren Breiten immer noch anzutreffen sind.

Differentiation of pyogenic and fungal brain abscesses with susceptibility-weighted MR sequences

INTRODUCTION

Conventional magnetic resonance imaging (MRI) techniques are insufficient to determine the causative agent of brain abscesses. We investigated: (1) the value of susceptibility-weighted MR sequences (SWMRS) in the differentiation of fungal and pyogenic brain abscesses; and (2) the effect of different SWMRS (susceptibility-weighted imaging (SWI) versus venous blood oxygen level dependent (VenoBOLD)) for the detection of specific imaging characteristics of pyogenic brain abscesses.

METHODS

We studied six patients with fungal and ten patients with pyogenic brain abscesses. Imaging characteristics on conventional MRI, diffusion-weighted imaging (DWI) and SWMRS were recorded in all abscesses. All lesions were assessed for the presence of a "dual-rim sign" on SWMRS.

RESULTS

Homogenously hyperintense lesions on DWI were present in 60 % of patients with pyogenic abscesses, whereas none of the patients with fungal abscesses showed such lesions. On SWMRS, 90 % of patients with pyogenic abscesses and 60 % of patients with fungal abscesses had only lesions with a low-signal-intensity rim. On SWI, the dual-rim sign was apparent in all pyogenic abscesses. None of the fungal abscesses on SWI (P = 0.005) or any of the pyogenic abscesses on VenoBOLD (P = 0.005) were positive for a dual-rim sign.

CONCLUSIONS

In fungal abscesses, the dual-rim sign is not present but a prominent peripheral rim or central susceptibility effects on SWI will be seen. The appearance of pyogenic abscesses on SWMRS depends on the used sequence, with the dual-rim sign a specific feature of pyogenic brain abscesses on SWI.

MRI-DWI improves the early diagnosis of brain abscess induced by Candida albicans in preterm infants

OBJECTIVE

To investigate the diagnostic value of magnetic resonance imaging (MRI) in brain abscess induced by invasive fungal infection (IFI) of the central nervous system.

METHODS

The clinical data of eight preterm infants with IFI of the central nervous system were retrospectively analyzed. All these eight children received three sequential brain MRI modes T1WI, T2WI and DWI during hospitalization and after discharge.

RESULTS

All these eight preterm infants were infected with Candida albicans, seven of which were manifested by brain abscess and four were accompanied by meningitis. MRI of seven infants with brain abscess indicated extensive invasion including involvement of subcortical white matter, deep periventricular white matter and semiovale center white matter. MRI examination was conducted within 11 d following infection on four cases and showed diffuse or multiple miliary nodules, hyper-intense signal on DWI, while insignificant signal changes on T1WI and T2WI. DWI signal nearly disappeared three weeks later. T1WI/T2WI signal changed most significantly 2-4 weeks following infection, with nodules ring-shaped, hyper-intense signal around T1WI and hypo-intense signal in the center. Signal on T2WI was just on the opposite. Severe cases presented fusion of different degrees. Significant enhanced effect was observed on T1WI. Four weeks later, the lesion gradually became fewer and smaller on T1WI, transferred into dot or line-like hyper-intense signal and presented obviously hypo-intense signal on T2WI. Dynamic MRI of two cases showed delayed myelination and corpus callosum thinning.

CONCLUSION

MRI-DWI and dynamic MRI changes can improve the early diagnosis of brain abscess induced by Candida albicans in preterm infants.

Diffusion-weighted imaging in the diagnosis of enterovirus 71 encephalitis

BACKGROUND

In the early phase of viral encephalitis, conventional MRI may appear normal. Diffusion-weighted imaging (DWI) is a sensitive tool for detecting early changes in cellular function in the central nervous system.

PURPOSE

To investigate the usefulness of DWI in the diagnosis of enterovirus 71 (EV71) encephalitis, and to determine whether DWI is superior to conventional MR sequences.

MATERIAL AND METHODS

MRI scans in 26 patients were retrospectively evaluated for distribution of lesions on T1-weighted images (T1WI), T2-weighted images (T2WI), fluid-attenuated inversion recovery (FLAIR), and DWI. Contrast-to-noise ratios (CNRs) were calculated for all regions on each sequence and differences in the four MRI sequences were assessed using CNRs. Apparent diffusion coefficient (ADC) values were measured for all regions to look for true restriction of diffusion.

RESULTS

Fifteen out of 26 cases showed positive findings on MR imaging. The brain stem was involved in 11 patients, cortex and subcortical white matter in four patients. DWI was more sensitive in detecting the abnormalities (89.7%) compared to T2WI (48.7%), FLAIR (41.0%), and T1WI (35.9%), and the positive ratio of DWI was significantly higher compared to other sequences. Furthermore, no significant difference was found between T2WI and FLAIR (P = 0.649). The corresponding mean CNRs were 8.73 ± 2.57, 83.59 ± 29.28, 24.22 ± 6.22, and 132.27 ± 78.32 on T1WI, T2WI, FLAIR, and DWI, respectively. The absolute values of CNRs of lesions on DWI were significantly greater than those on other sequences.

CONCLUSION

DWI appears to be more sensitive in detecting EV71 encephalitis than conventional MRI sequences. This capability may improve the accuracy in diagnosing EV71 encephalitis, especially at the early stage.

Neuroimaging of pediatric intracranial infection--part 2: TORCH, viral, fungal, and parasitic infections

In the second half of this 2-part review, the neuroimaging features of the most common viral, fungal, and parasitic infections of the pediatric central nervous system are discussed. Brief discussions of epidemiology and pathophysiology will be followed by a review of the imaging findings and potential differential considerations.

Infektionen

Trotz Weiterentwicklung moderner Antibiotika in den letzten Jahren sind die Letalitätszahlen der bakteriellen (eitrigen) Meningitis weiterhin hoch; Überlebende haben häufig neurologische Residuen. Die ungünstigen klinischen Verläufe der bakteriellen Meningitis sind meist Folge intrakranieller Komplikationen, wie z. B. eines generalisierten Hirnödems, einer zerebrovaskulären arteriellen oder venösen Beteiligung oder eines Hydrozephalus.

Diffusion imaging in brain infections

Diffusion-weighted magnetic resonance imaging (DWI) provides image contrasts that are different from conventional magnetic resonance techniques. DWI is particularly sensitive for detecting acute ischemic stroke, but it also has many other clinical applications, including the evaluation of central nervous system (CNS) infections. This article addresses the role of DWI in the differential diagnosis of CNS infections, and discusses the most common DWI findings for each type of infection.

Brain abscess in children

✓ Although it is uncommon, pediatric brain abscess remains a serious, life-threatening neurological problem. Those with congenital heart disease, an ongoing infection, or an immunocompromised state are particularly at risk. The symptoms on presentation may include those associated with a space-occupying lesion in the brain, and neuroimaging has made the diagnosis of brain abscess more reliable. Prompt diagnosis and treatment are required to lessen neurological morbidity and the risk of death. Treatment includes medical management with appropriate and specific antimicrobials. Although the effectiveness of medical management has improved and some children may be treated with antimicrobial therapy alone, surgical evaluation remains an important component of the treatment algorithm for most pediatric patients.