Magnetic resonance features of pyogenic brain abscesses and differential diagnosis using morphological and functional imaging studies: a pictorial essay

Diffusion-weighted imaging-based radiomics model using automatic machine learning to differentiate cerebral cystic metastases from brain abscesses

OBJECTIVES

To develop a radiomics model based on diffusion-weighted imaging (DWI) utilizing automated machine learning method to differentiate cerebral cystic metastases from brain abscesses.

MATERIALS AND METHODS

A total of 186 patients with cerebral cystic metastases (n = 98) and brain abscesses (n = 88) from two clinical institutions were retrospectively included. The datasets (129 from institution A) were randomly portioned into separate 75% training and 25% internal testing sets. Radiomics features were extracted from DWI images using two subregions of the lesion (cystic core and solid wall). A thorough image preprocessing method was applied to DWI images to ensure the robustness of radiomics features before feature extraction. Then the Tree-based Pipeline Optimization Tool (TPOT) was utilized to search for the best optimized machine learning pipeline, using a fivefold cross-validation in the training set. The external test set (57 from institution B) was used to evaluate the model's performance.

RESULTS

Seven distinct TPOT models were optimized to distinguish between cerebral cystic metastases and abscesses either based on different features combination or using wavelet transform. The optimal model demonstrated an AUC of 1.00, an accuracy of 0.97, sensitivity of 1.00, and specificity of 0.93 in the internal test set, based on the combination of cystic core and solid wall radiomics signature using wavelet transform. In the external test set, this model reached 1.00 AUC, 0.96 accuracy, 1.00 sensitivity, and 0.93 specificity.

CONCLUSION

The DWI-based radiomics model established by TPOT exhibits a promising predictive capacity in distinguishing cerebral cystic metastases from abscesses.

Pediatric and adult meningeal, parenchymal, and spinal tuberculosis: A neuroimaging review

Neurotuberculosis is defined as a tuberculous infection of the meninges, brain parenchyma, vessels, cranial and spinal nerves, spinal cord, skull, and spine that can occur either in a localized or in a diffuse form. It is a heterogeneous disease characterized by many imaging appearances and it has been defined as "the great mimicker" due to similarities with many other conditions. The diagnosis of central nervous system (CNS) tuberculosis (TB) is based on clinical presentation, neuroimaging findings, laboratory and microbiological findings, and comprehensive evaluation of the response to anti-TB drug treatment. However, the absence of specific symptoms, the wide spectrum of neurological manifestations, the myriad of imaging findings, possible inconclusive laboratory results, and the paradoxical reaction to treatment make the diagnosis often challenging and difficult, potentially delaying adequate treatment with possible devastating short-term and long-term neurologic sequelae. Familiarity with the imaging characteristics helps in accurate diagnosis and may prevent or limit significantly morbidity and mortality. The goal of this review is to provide a comprehensive up-to-date overview of the conventional and advanced imaging features of CNS TB for radiologists, neuroradiologists, and pediatric radiologists. We discuss the most typical neurotuberculosis imaging findings and their differential diagnosis in children and adults with the goal to provide a global overview of this entity.

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.

Pertinence of Streptococcus anginosus group in intracerebral abscesses in the era of extended antibiotic resistance

AIMS

• To study the incidence of Streptococcus anginosus group (SAG) in pyogenic or community acquired intra cerebral abscess. • To understand the risk factors for the same. • To analyze the specific radiological features and clinical outcome after surgery and antibiotic therapy.

METHODS

This is a retrospective observational study of case series over a period of one year. Patients diagnosed with intracerebral abscess were included in the study. Pus collected from were received in the laboratory and processed according to the standard protocols. Data regarding the clinical findings and demographics were collected from medical records.

FINDINGS

A total of 202 samples were studied. 103 were found to be pyogenic. SAG were isolated from 21 samples (20.38%) and all the isolates were sensitive to Penicillin. Age of the patients ranged from 18months to 68years. Male preponderance was noted with male to female ratio of 4:1. Otogenic infections were the most common predisposing factors and focus of infection could not be ascertained in 5 patients. All patients were treated with surgical intervention and antibiotics (Vancomycin, Amikacin and Metronidazole) for 6 weeks and recovery was remarkable. One patient succumbed to the illness.

CONCLUSION

SAG can be an aggressive pathogen with propensity for abscess formation. Chronic Suppurative Otitis Media (CSOM) is still a major cause of intracerebral abscess in developing country like India which is a benign and curable disease and should not be neglected. Injudicious use of antibiotics and negligence regarding the dose and duration of therapy from both patients and health care providers is the major cause for common infections to become more difficult to treat and succumbing to complications.

Case report on successful treatment for brain abscess in a Japanese monkey (Macaca fuscata)

BACKGROUND

A brain abscess in human beings is a focal infection of the central nervous system frequently characterized by areas of localized cerebritis and central necrosis surrounded by a well vascularized capsule. A brain abscess, although sporadically reported, is relatively rare disease in domestic animals (horses, cattle, goats and alpacas), companion animals (dogs and cats) and laboratory nonhuman primates. Brain abscesses are life threatening disease that needs early and aggressive veterinary therapy.

CASE PRESENTATION

The purpose of this study on a brain abscess in a Japanese monkey was to report the investigational and therapeutic processes including clinical observations, hematological and serum biochemical profiles, and magnetic resonance imaging (MRI) features, probiotic and antibiotic therapy. In clinical observation, the monkey presented with slowly progressive gentle and depressed behavioral change. Hematological findings showed that slightly declined platelet counts gradually increased in the course of the treatment. Serum biochemical profiles revealed initial markedly elevated. A series of chemotherapy provide prominent relief from the influence of the brain abscess. MRI images illustrated that a brain abscess was located in the right frontal lobe and the mass was delineated by a thick rim, indicating the capsule formation stage. The lesion chronologically decreased in size over the course of treatment. Until 11 weeks after treatment of the brain abscess, the size of brain abscess continued to reduce, leaving an organized lesion trace. To the best of my knowledge, this is the first report on successful treatment for a brain abscess in a Japanese monkey (Macaca fuscata).

CONCLUSIONS

Medical management of simian brain abscesses is possible based on the controlled and resolving nature of the lesions as determined by MRI and completion of a of chemical antibiotic treatment presented in this study.

Radiologic diagnosis of non-traumatic paediatric head and neck emergencies

Imaging plays a crucial role in evaluating paediatric patients with non-traumatic head and neck lesions in an emergency setting because clinical manifestations of these entities can overlap. For this reason, radiologists must be familiar with the clinical and imaging findings of prevalent paediatric head and neck emergencies. In this review, we present techniques and imaging clues for common complications of pathological processes in the paediatric head and neck, with a focus on the clinical scenario as a starting point for the radiologic approach.

MR Protocols for Paediatric Neurosurgical Common Conditions: An Update Guide for Neurosurgeons

The biggest challenge for clinicians and surgeons when it comes to radiological examinations is the ability to request the right modalities and to understand the strengths and limitations of each modality. This is particularly important in paediatric neurosciences where despite magnetic resonance imaging (MRI) being the main imaging modality, there are several protocols, technical limitations of specific scanners and issues related to sedation that need to be taken into account. In this chapter, we describe a simple approach for six common neurosurgical conditions to guide the paediatric neurosurgeons in requesting the right MR protocol and understanding the rationale of it.Paediatric neuro-oncology, epilepsy and neck/skull base protocols are discussed elsewhere in this book and therefore will not be a focus in this chapter (Bernasconi et al., Epilepsia 60:1054-68, 2019; D'Arco et al., Neuroradiology 64:1081-100; 2022; Avula et al., Childs Nerv Syst 37:2497-508; 2021).

Outcome of medical treatment of otogenic brain abcess without therapeutic drainage: A case of central vertigo

Otogenic brain abscess is a severe infection that must be treated as early as possible. Rare cases with a high mortality rate can be reduced by recognizing the red flags of a brain abscess, such as headaches, mental status changes, fever, and focal neurological deficits. Those could be supported by modern diagnostic management and adequate antibiotic therapy that was able to penetrate the central nervous system and abscesses. We report a case of a cerebellar abscess of the 49-year-old man with the chief complaint of vertigo. It was accompanied by chronic progressive headache, fever, bidirectional nystagmus, abnormal Romberg test, and abnormal cerebellar signs. Magnetic resonance imaging (MRI) of the head with contrast showed a right cerebellar abscess with an infectious source of otitis media and mastoiditis. The MRI evaluation showed improvement after admistered metronidazole 500 mg every 6 hours (week 22) and cefixime 200 mg every 12 hours (week 13). Long-term antibiotic treatment can be an alternative if surgery cannot be performed. However, surgery is still considered if there is no good clinical response during medical therapy.

Guidelines for magnetic resonance imaging in pediatric head and neck pathologies: a multicentre international consensus paper

The use of standardized imaging protocols is paramount in order to facilitate comparable, reproducible images and, consequently, to optimize patient care. Standardized MR protocols are lacking when studying head and neck pathologies in the pediatric population. We propose an international, multicenter consensus paper focused on providing the best combination of acquisition time/technical requirements and image quality. Distinct protocols for different regions of the head and neck and, in some cases, for specific pathologies or clinical indications are recommended. This white paper is endorsed by several international scientific societies and it is the result of discussion, in consensus, among experts in pediatric head and neck imaging.

Into the Unknown: Diagnosing Mysterious Brain Lesions

The case discussed involves a 49-year-old male with simultaneous pancreas-kidney transplant who presented with fever, headache and was found to have multifocal brain lesion on brain imaging. This article is protected by copyright. All rights reserved.

Hemodynamic Imaging in Cerebral Diffuse Glioma-Part A: Concept, Differential Diagnosis and Tumor Grading

Diffuse gliomas are the most common primary malignant intracranial neoplasms. Aside from the challenges pertaining to their treatment-glioblastomas, in particular, have a dismal prognosis and are currently incurable-their pre-operative assessment using standard neuroimaging has several drawbacks, including broad differentials diagnosis, imprecise characterization of tumor subtype and definition of its infiltration in the surrounding brain parenchyma for accurate resection planning. As the pathophysiological alterations of tumor tissue are tightly linked to an aberrant vascularization, advanced hemodynamic imaging, in addition to other innovative approaches, has attracted considerable interest as a means to improve diffuse glioma characterization. In the present part A of our two-review series, the fundamental concepts, techniques and parameters of hemodynamic imaging are discussed in conjunction with their potential role in the differential diagnosis and grading of diffuse gliomas. In particular, recent evidence on dynamic susceptibility contrast, dynamic contrast-enhanced and arterial spin labeling magnetic resonance imaging are reviewed together with perfusion-computed tomography. While these techniques have provided encouraging results in terms of their sensitivity and specificity, the limitations deriving from a lack of standardized acquisition and processing have prevented their widespread clinical adoption, with current efforts aimed at overcoming the existing barriers.

Advanced Magnetic Resonance Imaging in Pediatric Glioblastomas

The shortly upcoming 5th edition of the World Health Organization Classification of Tumors of the Central Nervous System is bringing extensive changes in the terminology of diffuse high-grade gliomas (DHGGs). Previously "glioblastoma," as a descriptive entity, could have been applied to classify some tumors from the family of pediatric or adult DHGGs. However, now the term "glioblastoma" has been divested and is no longer applied to tumors in the family of pediatric types of DHGGs. As an entity, glioblastoma remains, however, in the family of adult types of diffuse gliomas under the insignia of "glioblastoma, IDH-wildtype." Of note, glioblastomas still can be detected in children when glioblastoma, IDH-wildtype is found in this population, despite being much more common in adults. Despite the separation from the family of pediatric types of DHGGs, what was previously labeled as "pediatric glioblastomas" still remains with novel labels and as new entities. As a result of advances in molecular biology, most of the previously called "pediatric glioblastomas" are now classified in one of the four family members of pediatric types of DHGGs. In this review, the term glioblastoma is still apocryphally employed mainly due to its historical relevance and the paucity of recent literature dealing with the recently described new entities. Therefore, "glioblastoma" is used here as an umbrella term in the attempt to encompass multiple entities such as astrocytoma, IDH-mutant (grade 4); glioblastoma, IDH-wildtype; diffuse hemispheric glioma, H3 G34-mutant; diffuse pediatric-type high-grade glioma, H3-wildtype and IDH-wildtype; and high grade infant-type hemispheric glioma. Glioblastomas are highly aggressive neoplasms. They may arise anywhere in the developing central nervous system, including the spinal cord. Signs and symptoms are non-specific, typically of short duration, and usually derived from increased intracranial pressure or seizure. Localized symptoms may also occur. The standard of care of "pediatric glioblastomas" is not well-established, typically composed of surgery with maximal safe tumor resection. Subsequent chemoradiation is recommended if the patient is older than 3 years. If younger than 3 years, surgery is followed by chemotherapy. In general, "pediatric glioblastomas" also have a poor prognosis despite surgery and adjuvant therapy. Magnetic resonance imaging (MRI) is the imaging modality of choice for the evaluation of glioblastomas. In addition to the typical conventional MRI features, i.e., highly heterogeneous invasive masses with indistinct borders, mass effect on surrounding structures, and a variable degree of enhancement, the lesions may show restricted diffusion in the solid components, hemorrhage, and increased perfusion, reflecting increased vascularity and angiogenesis. In addition, magnetic resonance spectroscopy has proven helpful in pre- and postsurgical evaluation. Lastly, we will refer to new MRI techniques, which have already been applied in evaluating adult glioblastomas, with promising results, yet not widely utilized in children.

Spinal and cranio-cervical mycetoma: a difficult surgery, with poor prognosis

BACKGROUND

Few central nervous systems (CNS) cases of actinomycetoma have been recorded in the literature, and most were reported in tropical and subtropical regions. The management of this invasive infection is difficult, especially when it affects the spine and the cranio-cervical regions.

CASE

We report an unusual case of a cranio-cervical junction actinomycetoma, in a patient presenting a cerebellar syndrome from brainstem compression. The CT scan showed a compressive solid osteolytic lesion in the cranio-cervical junction. The patient underwent cranio-cervical decompression and lesion resection. The diagnosis of actinomycetoma was confirmed on immune-histochemistry and molecular analysis. At 4 months' follow-up, the patient presented a fatal recurrence disseminating within the cerebellum and the spine.

CONCLUSION

The surgical treatment of CNS actinomycetoma presented poor prognosis and a disseminating recurrence. We believe that clinicians and surgeons must be informed about these "new" infectious pathologies that are so difficult to treat, especially with the arrival of migrant patients from endemic countries in conflict.

Bacterial meningitis imaging in children

In this review, we provide the data on the modern use of different MRI modalities and computer tomography (CT) as diagnostic and prognostic tools for meningitis of various etiology, first of all, bacterial purulent meningitis. Each of these techniques has its own field of application depending on the stage of the disease and the patients condition (necessity of intensive care procedures, ventilation support). The opinions on the diagnostic value of CT and structural MRI data differ and depend on the etiology and phase of the inflammatory process. In the recent years, the techniques of multiparametric MRI are widely implemented in the practice. Beside structural MRI, they include diffusion-weighted imaging (DWI), diffusion tensor imaging (DTI) and MR spectroscopy (MRS), as well as studies with artificial contrast; there are some reports that these modalities are more effective as a diagnostic tool in meningitis. Thus, the use of multiparametric MRI techniques and CT with contrast is promising and justified for the diagnostics of patients with bacterial purulent meningitis from the viewpoint of enhanced sensitivity.

Brain MRI findings in relation to clinical characteristics and outcome of tuberculous meningitis

Neuroradiological abnormalities in tuberculous meningitis (TBM) are common, but the exact relationship with clinical and inflammatory markers has not been well established. We performed magnetic resonance imaging (MRI) at baseline and after two months treatment to characterise neuroradiological patterns in a prospective cohort of adult TBM patients in Indonesia. We included 48 TBM patients (median age 30, 52% female, 8% HIV-infected), most of whom had grade II (90%), bacteriologically confirmed (71%) disease, without antituberculotic resistance. Most patients had more than one brain lesion (83%); baseline MRIs showed meningeal enhancement (89%), tuberculomas (77%), brain infarction (60%) and hydrocephalus (56%). We also performed an exploratory analysis associating MRI findings to clinical parameters, response to treatment, paradoxical reactions and survival. The presence of multiple brain lesion was associated with a lower Glasgow Coma Scale and more pronounced motor, lung, and CSF abnormalities (p-value <0.05). After two months, 33/37 patients (89%) showed worsening of MRI findings, mostly consisting of new or enlarged tuberculomas. Baseline and follow-up MRI findings and paradoxical responses showed no association with six-month mortality. Severe TBM is characterized by extensive MRI abnormalities at baseline, and frequent radiological worsening during treatment.

Advanced multimodality MR imaging of a cerebral nocardiosis abscess in an immunocompetent patient with a focus on Amide Proton Transfer weighted imaging

Cerebral nocardiosis abscess is a very rare entity in an immunocompetent patient. In this case report multiparametric and multimodality MR imaging characteristics of a pyogenic brain abscess caused by Nocardia Farcinica are discussed with a specific focus on amide proton transfer weighted imaging as a modern non-invasive, molecular MR imaging method which detects endogenous mobile protein and peptide concentration and tissue pH changes in pathologic brain lesions. The imaging characteristics are reviewed and discussed in respect to possible differential diagnoses, especially malignant tumorous lesions.

Computed tomography and magnetic resonance imaging in pediatric salivary gland diseases: a guide to the differential diagnosis

Salivary gland pathologies in children are frequent, particularly viral infections, but rarely need cross-sectional imaging. However, when a mass involves the salivary spaces (primarily or as a secondary invasion from other neck spaces) it may pose problems in the differential diagnosis and in immediate management. Infrequently, systemic autoimmune diseases can also involve the salivary parenchyma in children and correctly interpreting the constellation of findings in the whole body is critical for the diagnosis. Distinguishing between cystic and solid masses is the first step for radiologists in order to narrow down the diagnosis. Location and spatial extension are the most important elements differentiating cystic masses, while signal characteristics, internal structure and local invasion help in the differential diagnosis of solid masses.

Cerebral abscesses imaging: A practical approach

Brain abscesses (BAs) are focal infections of the central nervous system (CNS) that start as a localised area of weakening of the brain parenchyma (cerebritis) and develops into a collection of pus surrounded by a capsule. Pyogenic (bacterial) BAs represent the majority of all BAs; in some cases, the diagnostic and therapeutic management can be challenging. Imaging has a primary role in differentiating BAs from other lesions. Conventional magnetic resonance imaging (cMRI) is essential for the identification of the lesion, its localisation and its morphological features. However, cMRI does not allow to reliably differentiate BAs from other intracranial mass lesions such as necrotic tumours. Advanced sequences, such as diffusion-weighted imaging (DWI), perfusion-weighted imaging (PWI) and proton MR spectroscopy (¹H-MRS) are very useful in the differential diagnosis from other brain lesions, such as non-pyogenic abscesses or necrotic tumours, and provide essential information on structural, vascular and metabolic characteristics allowing greater neuroradiological confidence. The aim of this pictorial review is to provide a practical approach showing the added value of more advanced MRI techniques in their diagnostic management.

Diffusion-Weighted Imaging in Oncology: An Update

To date, diffusion weighted imaging (DWI) is included in routine magnetic resonance imaging (MRI) protocols for several cancers. The real additive role of DWI lies in the "functional" information obtained by probing the free diffusivity of water molecules into intra and inter-cellular spaces that in tumors mainly depend on cellularity. Although DWI has not gained much space in some oncologic scenarios, this non-invasive tool is routinely used in clinical practice and still remains a hot research topic: it has been tested in almost all cancers to differentiate malignant from benign lesions, to distinguish different malignant histotypes or tumor grades, to predict and/or assess treatment responses, and to identify residual or recurrent tumors in follow-up examinations. In this review, we provide an up-to-date overview on the application of DWI in oncology.

Effects of effective stereotactic radiosurgery for brain metastases on the adjacent brain parenchyma

Background

To evaluate whether functional and metabolic MRI can detect radiation-induced alterations in the adjacent areas after effective stereotactic radiosurgery (SRS) for brain metastases. If confirmed, these techniques may be suited for monitoring the timely stratification of patients for neuroprotective treatments after irradiation.

Methods

Inclusion criteria were complete response, partial response, or stable disease on routine follow-up MR-scans. Multiparametric 3T-MRI was performed with diffusion-weighted imaging, dynamic susceptibility perfusion-weighted imaging, and two-dimensional proton MR-spectroscopy. Parameters were measured in the SRS-treated target and in the adjacent parenchyma up to both 0.75 cm and 1.5 cm from the target border.

Results

Nineteen lesions in sixteen consecutive patients met the inclusion criteria. The median follow-up time was 39 months (range, 10–142) with 41 multiparametric MR-examinations in total. We found low values of N-acetyl-aspartate up to 1.5 cm from the target borders of SRS (P = 0.043) associated with high values of choline (P = 0.004) at the end of the observation period. Lactate levels in the adjacent tissue declined over time, whereas continuously high apparent-diffusion-coefficient values were noted (P < 0.001).

Conclusion

Multiparametric MRI can depict radiobiological effects and their time course at a distance from the effectively treated site after SRS for brain metastases, even if conventional MRI findings are inconspicuous.

Brain abscess in immunocompetent adult patients

Brain abscess is a focal infection of the brain due to contiguous spread of pathogens following otitis, sinusitis, neurosurgery or traumatic brain injury or through hematogenous dissemination. Classical symptoms consisting of headache, fever, and focal signs may be absent on admission and brain MRI with contrast plays a major role in diagnosis. Initial management consists of stereotactic aspiration for microbiological documentation empirical treatment covering common pathogens, including oral streptococci, staphylococci, anaerobes, and Enterobacteriaceae. De-escalation of antimicrobials based on microbiology is safe only when samples have been processed optimally, or when primary diagnosis is endocarditis. A 6-week combination of third-generation cephalosporin and metronidazole will cure most cases of community-acquired brain abscess in immunocompetent adults. Significant advent in brain imaging, minimally invasive surgery, molecular biology, and antibacterial agents, has dramatically improved the prognosis. Main indicators of outcome include altered mental status at presentation and intraventricular rupture.

Brain abscess in pediatric age: a review

OBJECTIVE

The purpose of the paper is to examine the current state of the art about epidemiology, diagnosis, and treatment of this infection.

METHODS

A review of the literature was performed through a PubMed search of original articles, case reports, and reviews using the key words "brain abscess," "cerebral abscess," "brain infection," "intracranial suppuration," "otogenic brain abscess," "otitis complications," and "sinusitis complications."

RESULTS

Pediatric brain abscess is a rare but serious infection, often involving patients with specific risk factors and burdened by a high risk of morbidity and mortality. Brain abscess incidence and mortality decreased over the years, thanks to improved antibiotic therapy, new neurosurgical techniques, and the wide spread of vaccinations. There are no guidelines for the adequate diagnostic-therapeutic pathway in the management of brain abscesses; therefore, conflicting data emerge from the literature. In the future, multicentric prospective studies should be performed in order to obtain stronger evidences about brain abscesses management. Over the next few years, changes in epidemiology could be observed because of risk factors changes.

Primary central nervous system post-transplant lymphoproliferative disorders: the spectrum of imaging appearances and differential

OBJECTIVE

Central nervous system post-transplant lymphoproliferative disorder (CNS-PTLD) is a rare disease that presents with non-specific signs and symptoms. The purpose of this article is to present the imaging appearances of CNS-PTLD by magnetic resonance imaging. We highlight the differential diagnostic considerations including primary central nervous system lymphoma, glioblastoma, cerebral abscess, and metastatic disease. This is an important topic to review since in daily practice the diagnosis of CNS-PTLD is often not initially considered when present due to its rarity and the lack of radiologists' familiarity with the disease.

CONCLUSION

Knowing the unique imaging features of CNS-PTLD narrows the differential diagnosis, facilitates the diagnostic work-up, and optimizes making the diagnosis. Advanced MRI data for CNS PTLD is limited but is promising for helping with narrowing the differential diagnosis.

Management of brain abscesses: where are we now?

INTRODUCTION

Brain abscesses affect all age groups and are not peculiar to a particular country, race, or geographical location. It is a disease that, in the past, carried a high morbidity and mortality. With improvements in medical technology and expertise, outcomes have improved tremendously. The causative organisms vary vastly and have evolved with time. Treatment of brain abscesses is primarily with antimicrobial therapy but surgery plays a vital role in achieving better outcomes.

CONTENT

In this article, we review the literature to find out how the epidemiology of this disease has changed through the years and re-visit the basic pathological process of abscess evolution and highlight the new research in the biochemical pathways that initiate and regulate this process. We also highlight how magnetic resonance imaging and its various modalities have improved diagnostic accuracy. Finally, we discuss the pros and cons of traditional open surgery versus newer minimally invasive methods.

The Tunnel Sign Revisited: A Novel Observation of Cerebral Melioidosis Mimicking Sparganosis

The tunnel sign has been described as a specific feature of cerebral sparganosis. We present a case of a 55-year-old gentleman found to have cerebral melioidosis and with initial imaging mimicking the appearance of sparganosis. This suggests that the tunnel sign in brain abscesses may be specific for infection by Burkholderia Pseudomallei, Spirometra Mansoni or Listeria Monocytogenes.

Pyogenic brain abscess and subdural empyema: presentation, management, and factors predicting outcome

PURPOSE

To describe the presentation and management of bacterial brain abscess and subdural empyema in adults treated at two tertiary centers. In addition, to identify factors that may predict a poor clinical outcome.

METHODS

A retrospective analysis of data obtained from clinical records was performed, followed by multivariate regression analysis of patient and treatment-related factors.

RESULTS

113 patients were included with a median age of 53 years and a male preponderance. At presentation symptoms were variable, 28% had a focal neurological deficit, and 39% had a reduced Glasgow coma scale (GCS). Brain abscesses most frequently affected the frontal, temporal, and parietal lobes while 36% had a subdural empyema. An underlying cause was identified in 76%; a contiguous ear or sinus infection (43%), recent surgery or trauma (18%) and haematogenous spread (15%). A microbiological diagnosis was confirmed in 86%, with streptococci, staphylococci, and anaerobes most frequently isolated. Treatment involved complex, prolonged antibiotic therapy (> 6 weeks in 84%) combined with neurosurgical drainage (91%) and source control surgery (34%). Mortality was 5% with 31% suffering long-term disability and 64% achieving a good clinical outcome. A reduced GCS, focal neurological deficit, and seizures at presentation were independently associated with an unfavorable clinical outcome (death or disability).

CONCLUSIONS

Complex surgical and antimicrobial treatment achieves a good outcome in the majority of patients with bacterial brain abscess and subdural empyema. Factors present at diagnosis can help to predict those likely to suffer adverse outcomes. Research to determine optimal surgical and antibiotic management would be valuable.

Ring-enhancing lesions in neonatal meningitis: an analysis of neuroradiology pitfalls through exemplificative cases and a review of the literature

Very often the clinical course of neonatal meningitis (NM) is characterized by sudden worsening, at times associated with cerebrovascular complications and strokes or the formation of cerebral abscesses. The immediate recognition of these pathological patterns is pivotal in providing clinicians with useful information to differentiate between those different pathological entities, which may both present as ring-enhancing lesions on neuroradiology investigations. Understanding their natural history and diagnostic features is of paramount importance to timely adopt the most appropriate medical and surgical management.

ADC Benchmark Range for Correct Diagnosis of Primary and Recurrent Middle Ear Cholesteatoma

OBJECTIVES

Magnetic resonance imaging (MRI) and in particular diffusion-weighted imaging (DWI) have been broadly proven to be the reference imaging method to discriminate between cholesteatoma and noncholesteatomatous middle ear lesions, especially when high tissue specificity is required. The aim of this study is to define a range of apparent diffusion coefficient (ADC) values within which the diagnosis of cholesteatoma is almost certain.

METHODS

The study was retrospectively conducted on a cohort of 124 patients. All patients underwent first- or second-look surgery because primary or secondary acquired cholesteatoma was clinically suspected; they all had preoperative MRI examination 15 days before surgery, including DWI from which the ADC maps were calculated.

RESULTS

Average ADC value for cholesteatomas was 859,4 × 10-6 mm2/s (range 1545 × 10-6 mm2/s; IQR = 362 × 10-6 mm2/s; σ = 276,3 × 10-6 mm2/s), while for noncholesteatomatous inflammatory lesions, it was 2216,3 × 10-6 mm2/s (range 1015 × 10-6 mm2/s; IQR = 372,75 × 10-6 mm2/s; σ = 225,6 × 10-6 mm2/s). Interobserver agreement with Fleiss' Kappa statistics was 0,96. No overlap between two groups' range of values was found and the difference was statistically significant for p < 0.0001.

CONCLUSIONS

We propose an interval of ADC values that should represent an appropriate benchmark range for a correct differentiation between cholesteatoma and granulation tissue or fibrosis of noncholesteatomatous inflammatory lesions.

Magnetic Resonance Imaging in degenerative disease of the lumbar spine: Fat Saturation technique and contrast medium

Purpose: To examine both anterior and posterior elements of the lumbar spine in patients with low back pain using MRI T2-weighted sequences with Fat Saturation (FS) and contrast enhanced T1-weighted sequences with FS.Materials and methods: Two thousand eight hundred and twenty (2820) patients (1628 male, 1192 female, mean age 54) presenting low back pain underwent MRI standard examination (Sagittal T1w TSE and T2w TSE, axial T1 SE) with the addition of sagittal and axial T2w Fat Sat (FS) sequences. Among all the patients, 987 (35%) have been studied adding Contrast Enhanced (CE) T1w FS sequences after administration of contrast medium. Results: Among 987 patients studied with contrast medium, we found: active-inflammatory intervertebral osteochondrosis in 646 (65%) patients; degenerative-inflammatory changes in facet joints (facet joint effusion, synovitis, synovial cysts) in 462 (47%); spondylolysis in 69 (7%); degenerative-inflammatory changes of the flava, interspinous and supraspinous ligaments in 245 (25%); inflammatory changes of posterior perispinal muscles in 84 (8%) patients. Conclusions: In patients with suspected no-disc-related low back pain, the implementation of T2w FS and CE T1w FS sequences to the standard MR protocol could allow a better identification of degenerative-inflammatory changes more likely associated to the pain. (www.actabiomedica.it)

Traumatic fractures in adults: missed diagnosis on plain radiographs in the Emergency Department

Radiography remains the imaging standard for fracture detection after trauma. The radiographic diagnosis of most fractures and dislocations poses little difficulty to radiologists: however, occasionally these injuries are quite subtle or even impossible to detect on radiographs. Missed diagnoses of fracture potentially have important consequences for patients, clinicians, and radiologists. Radiologists play a pivot role in the diagnostic assessment of the trauma patients: emergency radiologists who are more practiced at seeking out and discerning traumatic fractures can provide an invaluable service to their clinical colleagues by ensuring that patients do not endure delayed diagnoses. This is a narrative review article aims to highlight the spectrum of fractures in adults potentially missed on plain radiographs, the causes of error in diagnosis of fractures in the emergency setting and the key elements to reduce misdiagnosis of fractures.

Acute and overuse elbow trauma: radio-orthopaedics overview

The correct management of acute, subacute and overuse-related elbow pathologies represents a challenging diagnostic and therapeutic problem. While major trauma frequently requires a rapid surgical intervention, subluxation and minor trauma allow taking more time for diagnostics and planning the correct elective treatment after careful clinical and radiological investigation. In these conditions, communication between orthopaedic surgeon and radiologist allow to create a detailed radiology report, tailored to the patient's and surgeon's needs and optimal to plan proper management. Imaging technique as X-Ray, CT, US, MRI, CTA and MRA all belong to the radiologist's portfolio in elbow diagnostics. Detailed knowledge of elbow pathology and its classification and of the possibilities and limits of each imaging technique is of crucial importance to reach the correct diagnosis efficiently. The aim of this review is to present the most frequent elbow pathologies and suggest a suitable diagnostic approach for each of them.

Clinical and instrumental assessment of herniated discs after nucleoplasty: a preliminary study

BACKGROUND AND AIM

The therapy for low back pain boasts different approaches; one of these is nucleoplasty. We wanted to assess the effectiveness of nucleoplasty both by clinical response both by MR imaging evaluation, including even extrusions larger than one third of the spinal canal.

METHODS

Fifty-seven patients were treated with nucleoplasty in our hospital, 11 of these patients accepted both clinical and MRI evaluation after six months from treatment. The clinical evaluation was performed with Visual Analogue Scale (VAS) of pain, scored before and after the procedure. MRI evaluation consisted of analysing some imaging parameters of disc protrusions before and after the treatment.

RESULTS

In 10 out of 11 (91%) patients, VAS was reduced and only 1 out of 11 (9%) had the same pain after procedure. The mean of decrease of VAS score was 64%. In our population 8/11 (72%) patients had a herniation larger than 1/3 of the sagittal diameter of spinal canal and 100% of them had an improvement with a mean VAS reduction value of 75%. With MRI evaluation, the mean percentage of expulsion before and after treatment was respectively 40% and 34%. The expulsion decreased in 7/13 discs, remained equal in 4/13, and increased in 2/13 discs. Among the 9 larger protrusions, 3 didn't change, 6 reduced with a decrease mean value of 13%. Other MRI parameters didn't change significantly.

CONCLUSIONS

Our preliminary experience supports the success of coblation on pain relief, aiming to show progressively that this treatment is suitable even in case of great extrusions, which are generally treated only with surgical approach. It's not clear the usefulness of MRI control yet, even if in most of cases we could have found a certain reduction of expulsion degree.

Scapular fractures: a common diagnostic pitfall

Scapular fractures are one of the most difficult fractures to diagnose on radiographs. Detection can be challenging because of the obscuration by the overlying structures or incomplete imaging due to difficult patient collaboration. Familiarity with imaging characteristics of these abnormalities will allow radiologists to better diagnose and characterize scapular fractures. Three-dimensional computed tomographic scans are considered the gold standard for scapular diagnoses. Treatment strategies differ depending on the type of scapular fractures, but the site and degree of displacement will determine whether surgical intervention should be considered. Complications can occur in fractures that are undiagnosed or improperly evaluated. The purpose of this article is to describe imaging features of traumatic scapular injury, and discuss the role of diagnostic imaging in clinical decision making after shoulder trauma. (www.actabiomedica.it)

Rotator cuff calcific tendinopathy: from diagnosis to treatment

Rotator cuff calcific tendinopathy (RCCT) is a very common condition caused by the presence of calcific deposits in the rotator cuff (RC) or in the subacromial-subdeltoid (SASD) bursa when calcification spreads around the tendons. The pathogenetic mechanism of RCCT is still unclear. It seems to be related to cell-mediated disease in which metaplastic transformation of tenocytes into chondrocytes induces calcification inside the tendon of the RC. RCCT is a frequent finding in the RC that may cause significant shoulder pain and disability. It can be easily diagnosed with imaging studies as conventional radiography (CR) or ultrasound (US). Conservative management of RCCT usually involves rest, physical therapy, and oral NSAIDs administration. Imaging-guided treatments are currently considered minimally-invasive, yet effective methods to treat RCCT with about 80% success rate. Surgery remains the most invasive treatment option in chronic cases that fail to improve with other less invasive approaches. (www.actabiomedica.it)

Radiofrequency ablation of osteoid osteoma

Osteoid osteoma is a benign bone neoplasm with a reported incidence of 2-3% among all bone primary tumors. Although it is a small and benign lesion, it is often cause of patient complaint and discomfort. It is generally characterized by a long lasting, unremitting pain that typically exacerbates at night, often leading to sleep deprivation and functional limitation of the skeletal segment involved, with a significant reduction of patient daily life activities and consequent worsening of the overall quality of life. Over decades, complete surgical resection has represented the only curative treatment for symptomatic patients. In the last years, new percutaneous ablation techniques, especially radiofrequency ablation, have been reported to be a safe and effective alternative to classical surgery, with a low complication and recurrence rate, and a significant reduction in hospitalization cost and duration. The aim of this article is to provide an overview about the radiofrequency thermal ablation procedure in the treatment of osteoid osteoma. (www.actabiomedica.it)

Imaging of pediatric foot disorders

Infants and children undergo imaging studies to evaluate a wide variety of congenital and acquired disorders. Imaging protocols have to consider the patient’s comfort, level of anxiety, and smaller size. The first imaging study is usually made with plain radiographs. The routine radiographic examination of the foot includes the anteroposterior (AP), lateral, and oblique projections. Magnetic Resonance Imaging (RMI) provides excellent anatomic detail of cartilage, vasculature and soft tissue thanks to superior soft tissue contrast and spatial resolution, so is valuable in many cases. According to the clinical and objective signs, guided by the radiographs images, we can be oriented to perform Computed Tomography (CT), CT imaging or MRI imaging. CT imaging is useful to observe the bones but it has the disadvantage of using radiation and doesn’t adequately define the bone’s non-ossified portions. On the contrary, MRI imaging is very useful in identifying the cartilaginous parts and vascular and soft tissues, thanks to its superior contrast and spatial resolution. Finally, it is important to orientate the diagnostic process keeping in mind the clinical sign of the patient and to use the most appropriate diagnostic technique. (www.actabiomedica.it)

Developments in the management of bone metastases with interventional radiology

Interventional radiology has known an exponential growth in the last years. Technological advances of the last decades, have made it possible to use new treatments on a larger scale, with safe and effective results. They could be considered as palliative treatments for painful lesions but also curative procedures, as single treatment or specially in combination with other techniques (surgery, radiation and oncology therapies, etc.).The main diffuse techniques are those of thermal ablation that destroy the target lesion through the heat; however there are also endovascular therapies that destroy the target tissue thanks to devascularization. Finally the is also the possibility to stabilize pathological fractures or impending fractures. In this paper all the most diffuse and effective techniques are reviewed and also a discussion of the main indications is done, with an analisys of the success and complications rates.

Magnetic Resonance Imaging correlates of benign and malignant alterations of the spinal bone marrow

BACKGROUND AND AIM OF THE WORK

Bone marrow (BM) abnormalities in the spine are a common, sometimes unexpected, finding on Magnetic Resonance Imaging (MRI), which is the most sensitive imaging modality to evaluate the marrow, and their interpretation can be difficult for the unexperienced radiologist. In this review, the MRI appearance of normal age-related BM changes, as well as the imaging features of benign and malignant diseases, are presented.

DISCUSSION

A large variety of BM signal alterations has been identified and described, including normal variants, BM reconversion,  degenerative changes, infections, spondyloarthritis and osteonecrosis, trauma, neoplastic lesions (both primary or metastatic), post-radiation and chemotherapy sequelae.

CONCLUSIONS

Knowledge of normal age-related BM appearance, normal variants and patterns of involvement in focal and diffuse bone diseases is essential, together with clinical and laboratory data, to narrow the list of the possible differential diagnoses. The radiologist should be familiar with these signal changes, as they can sometimes be discovered incidentally. In this context, it is equally important not to attribute pathological significance to benign alterations and to promptly detect signs of malignant diseases.

Head and Neck: Skull Base Imaging

There are a myriad of head and neck pathologies that extend from the extracranial to the intracranial compartment, traversing the skull base, and knowledge of the imaging appearance of this pathology is critical to practicing neurosurgeons. This article reviews some of the important inflammatory or acquired head and neck pathology along the skull base, neoplastic skull base lesions, and the intracranial extension of head and neck malignancy. Focus will be on the relevant anatomy, appropriate imaging protocols to evaluate these processes, as well as the differentiating imaging findings on computed tomography and magnetic resonance imaging.

Differential diagnosis of multiple sclerosis in Latin America

Improvement of multiple sclerosis (MS) diagnoses leads to earlier and correct disease management. The differential diagnostic workup for MS comprises a large variety of medical conditions. There are general guidelines and criteria for diagnosing MS worldwide, but awareness of regional differences needs to be kept in mind. Latin American patients who are screened for MS diagnoses may require an approach that is not exactly the same as that used for patients in North America, western Europe or Asia. In the present review, the conditions that are important for the differential diagnoses of MS in Latin America are reviewed. They include infections, metabolic diseases, nutritional deficits and other autoimmune conditions that physicians in charge of these patients need to be familiar with.

Imaging of post-surgical treatment and of related complications in spinal trauma

Spinal trauma is a devastating event with a high morbidity and mortality. The rationale of imaging is to diagnose the traumatic abnormalities and characterize the type of injury, to estimate the severity of the lesions, to evaluate the potential spinal instability. In case of spinal instability, the goals of operative treatment are decompression of the spinal cord canal and stabilization of the disrupted vertebral column. Particularly, diagnostic imaging, mainly by CT and MR, has a main role in the post-treatment evaluation. The neuroradiological evaluation of the postoperative spine requires a general knowledge of the surgical approach to each spinal region and of the normal temporal evolution of expected postoperative changes. The neuroradiologist should evaluate the devices implanted, their related complications and promptly alert the surgeon of acute complications, mainly vascular and infective. During the follow-up, it is mandatory to know and search chronic complications as pseudomeningocele, accelerated degenerative disease, arachnoiditis, peridural fibrosis. Knowledge of specific complications relating to each surgical approach will assist the neuroradiologist in interpretation of postoperative images.

Unexpected hosts: imaging parasitic diseases

Radiologists seldom encounter parasitic diseases in their daily practice in most of Europe, although the incidence of these diseases is increasing due to migration and tourism from/to endemic areas. Moreover, some parasitic diseases are still endemic in certain European regions, and immunocompromised individuals also pose a higher risk of developing these conditions. This article reviews and summarises the imaging findings of some of the most important and frequent human parasitic diseases, including information about the parasite's life cycle, pathophysiology, clinical findings, diagnosis, and treatment. We include malaria, amoebiasis, toxoplasmosis, trypanosomiasis, leishmaniasis, echinococcosis, cysticercosis, clonorchiasis, schistosomiasis, fascioliasis, ascariasis, anisakiasis, dracunculiasis, and strongyloidiasis. The aim of this review is to help radiologists when dealing with these diseases or in cases where they are suspected. Teaching Points • Incidence of parasitic diseases is increasing due to migratory movements and travelling. • Some parasitic diseases are still endemic in certain regions in Europe. • Parasitic diseases can have complex life cycles often involving different hosts. • Prompt diagnosis and treatment is essential for patient management in parasitic diseases. • Radiologists should be able to recognise and suspect the most relevant parasitic diseases.

Neurological involvement in hereditary hemorrhagic telangiectasia

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant disorder characterized by epistaxis, telangiectases, and multi-organ vascular dysplasia. Head and neck localizations of HHT are recurrent, frequent associated with serious complications. The aim of this study was to describe the clinical and imaging patterns of neurological involvement in HHT and to discuss the role of interventional radiology in the management of HHT patients. Based on a multidisciplinary experience of twenty years at our center, we report here the different aspects of neurological involvement of HHT. Depending on the genetic type of the disease, vascular abnormalities may affect different organs. The knowledge of neurological involvement according to specific localization of HHT makes detection easier. As cerebral or spinal arteriovenous fistula may be present in patients with epistaxis or pulmonary arteriovenous malformations (PAVMs), radiologists should be able to detect high-risk lesions and prevent related complications. Finally, we review indications and techniques of embolization for hemorrhagic lesions and emphasize that endovascular therapies are very effective and safe in experienced hands. Head and neck imaging is commonly used for the diagnosis of HHT. Imaging plays also a key role for patient evaluation before treatment as pluridisciplinary management is needed.