[Neuroradiology for the Ophthalmologist - Part 2 Efference]. / Neuroradiologie für den Augenarzt. Teil 2: Efferenz.

Eye movements are a complex task requiring a large number of structures coordinated by three cranial nerves and their centres in the brainstem. Various pathologies may affect any part of the pathway controlling the eye movements and their diagnosis is often based on history and clinical examination. Modern advances in computed tomography and magnetic resonance imaging have recently added a valuable tool in the diagnosis of oculo-motor-related diseases.

Craniocervical fractures management in case of craniocervical pneumatization: case report and review of the literature.

INTRODUCTION: Extensive craniocervical pneumatization (CCP) refers to an abnormal pneumatization extended from the temporal bone into adjacent bone structures, especially the skull base and the craniocervical junction. The etiology remains controversial; however several studies reported a correlation with recurrent Valsalva maneuvers or Eustachian tube dysfunction. Although some cases requiring surgical treatment have been reported, conservative treatment remains the gold standard. The authors aimed to describe a case of CCP, complicated by a spontaneous fracture of a pneumatized left occipital condyle. Furthermore, they reviewed all previously reported cases of fractures in CCP in order to propose a standardized approach to this pathology. METHODS: A total of 148 studies were retrieved. Of those, 23 studies (including 26 patients in addition to our case) were included in the review. These studies consisted of case reports or small case series (up to 3 patients). RESULTS: In 3 patients (11.1%), bone pneumatization involved C0; all remaining patients had both C0 and C1 pneumatization, while in 7 cases (25.9%), an extension to C2 and/or C3 was reported. Radiological follow-up was performed in 20 patients (74.1%), showing in all of the cases either stability (6 patients, 22.2%), improvement, or complete resolution (6 patients, 22.2% vs 8 patients, 29.7%). Two patients underwent surgical intervention. CONCLUSIONS: This review suggests that fractures secondary to CCP are extremely rare and are associated to a good clinical and radiological outcome with conservative treatment. Ear, nose, and throat (ENT) evaluation is recommended to detect cases who need treatment for a subjacent middle ear disease.

[Neuroradiology for the Ophthalmologist]. / Neuroradiologie für den Augenarzt.

Computer tomography (CT) and magnet resonance imaging (MRI) are valuable imaging tools in order to examine various pathologies of the visual pathways. The advantage of CT is its short acquisition time of a few minutes, its availability making it an ideal tool in emergency medicine. It is extremely valuable in patients with cranio-cerebral trauma when an orbital or skull fracture or an intracerebral haemorrhage has to be assessed. In addition, CT-Angiography is used in the management of patients with an acute stroke. CT is mandatory to visualize the orbit in many conditions. The most important disadvantage is its use of ionizing radiation. Thus, CT is contraindicated in pregnant woman. Contrast of soft tissue as brain tissue is inferior compared to MRI. The latter has a high sensitivity in visualizing all kind of brain pathologies including tumours, inflammatory conditions or brain oedema as a result of a stroke. In contrast to CT, MRI (without contrast agent) can be used in pregnant women. The disadvantages of MRI are its long acquisition time, its contraindication in patients with metallic implants including pacemaker and its low resolution of bony tissue. Both imaging tools are often used in a complementary way in many orbital diseases, pathologies affecting bony structures, pathologies with calcifications and in stroke patients.

Human herpesvirus 6 encephalitis in a patient treated with everolimus for renal cell carcinoma.

INTRODUCTION: Everolimus is a mammalian target of rapamycin inhibitor and is approved as second-line treatment or beyond for renal cell carcinoma. We report a case of a 75-year-old male treated with everolimus for metastatic renal cell carcinoma, after sunitinib treatment, who was diagnosed with human herpesvirus 6 encephalitis. CASE REPORT: After 39 months of everolimus, 10 mg per day, our patient was admitted with fever, consciousness disorders and a partial epileptic crisis. Laboratory tests revealed lymphopenia (170 lymphocytes/mm3), and polymerase chain reaction in cerebrospinal fluid was positive for human herpesvirus 6. Brain magnetic resonance imaging study demonstrated hippocampal abnormality and a pontine lesion. MANAGEMENT AND OUTCOME: The patient stopped everolimus treatment indefinitely. He received ganciclovir initially intravenously, with a rapid clinical improvement, as well as polyvalent immunoglobulins were given to correct hypogammaglobulinemia. Two months later, antiviral therapy was switched to oral ganciclovir, which was never stopped. A new lumbar puncture was performed one month after the initiation of antiviral treatment, which did not reveal human herpesvirus 6 DNA anymore. DISCUSSION: Human herpesvirus 6 encephalitis is more common in hematopoietic stem cell transplant recipients and HIV patients. This is the first case probably associated to everolimus treatment. In contrast to most patients diagnosed with this infection, who either die or develop neurologic sequelae, our patient almost fully recovered two months later.

Imaging spectrum of Bing-Neel syndrome: how can a radiologist recognise this rare neurological complication of Waldenström's macroglobulinemia?

OBJECTIVES: Bing-Neel syndrome (BNS) is a rare neurological complication of Waldenström's macroglobulinemia. The aim of this study is to describe the spectrum of radiological manifestations of this syndrome and their prevalence in order to facilitate its early diagnosis. METHODS: Twenty-four patients with BNS were diagnosed between 1994 and 2016 in eight centres in France. We retrospectively examined the medical records of these patients as well as the corresponding literature, focusing on imaging studies. Recorded data were statistically analysed and radiological findings described. RESULTS: The mean age of our patients was 62.4 years (35-80 years). The vast majority of patients were men, with a male to female ratio of 9:1. Findings included parenchymal or meningeal involvement or both. The most common finding was leptomeningeal infiltration, either intracranial or spinal, with a prevalence reaching 70.8%. Dural involvement was present in 37.5% of patients. In 41.7% (10/24) of patients, there was parenchymal involvement with a higher prevalence of brain comparing to medullar involvement (33.3% and 23.1% respectively). High T2 signal of the parenchyma was identified in 41.7% of patients and high signal in diffusion was evident in 25% of them. Intraorbital or periorbital involvement was also detected in four cases. A proposition regarding the appropriate imaging protocol completed our study. CONCLUSION: BNS's diagnosis remains challenging. Central nervous system MRI findings in the setting of known or suspected Waldenström's macroglobulinemia appear to be highly suggestive of BNS and appropriate imaging protocols should be implemented for their depiction. KEY POINTS: • Diagnosis of Bing-Neel syndrome (BNS) remains challenging and recent expert recommendations include MRI in the diagnostic criteria for the syndrome. • The most common radiological manifestations of BNS are leptomeningeal/dural infiltration or parenchymal involvement of brain or spinal cord, but many atypical forms may exist with various presentations. • Appropriate imaging protocol for BNS should include enhanced MRI studies of both brain and spine.

Guideline for the diagnosis, treatment and response criteria for Bing-Neel syndrome.

Bing Neel syndrome is a rare disease manifestation of Waldenström's macroglobulinemia that results from infiltration of the central nervous system by malignant lymphoplasmacytic cells. In this guideline we describe the clinical symptoms, as well as the appropriate laboratory and radiological studies, that can aid in the diagnosis. The presentation of Bing Neel syndrome may be very diverse, and includes headaches, cognitive deficits, paresis, and psychiatric symptoms. The syndrome can present in patients with known Waldenström's macroglobulinemia, even in the absence of systemic progression, but also in previously undiagnosed patients. Diagnostic work-up should include cerebral spinal fluid analysis with multiparameter flow cytometry to establish B-cell clonality, protein electrophoresis and immunofixation for the detection and classification of a monoclonal protein as well as molecular diagnostic testing for immunoglobulin gene rearrangement and mutated MYD88. MRI of the brain and spinal cord is also essential. The second challenge is to expand our knowledge of prognosis and treatment outcome. Prospective clinical trials on Bing Neel syndrome patients that employ uniform treatment along with appropriate laboratory cerebral spinal fluid assessments and standardized MRI protocols will be invaluable, constituting a significant step forward in delineating treatment outcome for this intriguing disease manifestation.

Bing-Neel syndrome, a rare complication of Waldenström macroglobulinemia: analysis of 44 cases and review of the literature. A study on behalf of the French Innovative Leukemia Organization (FILO).

Central nervous system involvement by malignant cells is a rare complication of Waldenström macroglobulinemia, and this clinicopathological entity is referred to as the Bing-Neel syndrome. There is currently no consensus on the diagnostic criteria, therapeutic approaches and response evaluation for this syndrome. In this series, we retrospectively analyzed 44 French patients with Bing-Neel syndrome. Bing-Neel syndrome was the first manifestation of Waldenström macroglobulinemia in 36% of patients. When Waldenström macroglobulinemia was diagnosed prior to Bing-Neel syndrome, the median time interval between this diagnosis and the onset of Bing-Neel syndrome was 8.9 years. This study highlights the possibility of the occurrence of Bing-Neel syndrome without any other evidence of progression of Waldenström macroglobulinemia. The clinical presentation was heterogeneous without any specific signs or symptoms. Biologically, the median lymphocyte count in the cerebrospinal fluid was 31/mm(3). Magnetic resonance imaging revealed abnormalities in 78% of the cases. The overall response rate after first-line treatment was 70%, and the overall survival rate after the diagnosis of Bing-Neel syndrome was 71% at 5 years. Altogether, these results suggest that Bing-Neel syndrome should be considered in the context of any unexplained neurological symptoms associated with Waldenström macroglobulinemia. The diagnostic approach should be based on cerebrospinal fluid analysis and magnetic resonance imaging of the brain and spinal axis. It still remains difficult to establish treatment recommendations or prognostic factors in the absence of large-scale, prospective, observational studies.

The impact of transsphenoidal surgery on pituitary function in patients with non-functioning macroadenomas.

PURPOSE: Transsphenoidal surgery for non-functioning pituitary adenomas (NFPAs) can alter pituitary function. We assessed the rates of improvement and deterioration of pituitary function by axis and searched for predictive factors of these outcomes. METHODS: We reviewed consecutive medical files from patients having had transsphenoidal surgery for NFPA between 2004 and 2018. Pituitary functions and MRI imaging were analyzed prior and after surgery. The occurrence of recovery and new deficit were documented per axis. Prognostic factors of hormonal recovery and new deficits were searched. RESULTS: Among 137 patients analyzed, median tumor size of the NFPA was 24.8 mm and 58.4% of patients presented visual impairment. Before surgery, 91 patients (67%) had at least one abnormal pituitary axis (hypogonadism: 62.4%; hypothyroidism: 41%, adrenal insufficiency: 30.8%, growth hormone deficiency: 29.9%; increased prolactin: 50.8%). Following surgery, the recovery rate of pituitary deficiency of one axis or more was 46% and the rate of new pituitary deficiency was 10%. Rates of LH-FSH, TSH, ACTH and GH deficiency recovery were 35.7%, 30.4%, 15.4%, and 45.5% respectively. Rates of new LH-FSH, TSH, ACTH and GH deficiencies were 8.3%, 1.6%, 9.2% and 5.1% respectively. Altogether, 24.6% of patients had a global pituitary function improvement and only 7% had pituitary function worsening after surgery. Male patients and patients with hyperprolactinemia upon diagnosis were more likely to experience pituitary function recovery. No prognostic factors for the risk of new deficiencies were identified. CONCLUSION: In a real-life cohort of patients with NFPAs, recovery of hypopituitarism after surgery is more frequent than the occurrence of new deficiencies. Hence, hypopituitarism could be considered a relative indication for surgery in patients with NFPAs.

Malformations of cortical development of the human brain: a pictorial essay.

During development in utero of the human brain, an error in one or more of the orderly processes of neuroblast proliferation and differentiation, neuroblast migration and cortical organization may result in disordered neocortical development. Nowadays, the consequent malformations of the cerebral cortex and associated structures are detectable on pre- and postnatal examination with growing frequency, thanks to the evolution of modern imaging modalities. In particular, magnetic resonance imaging (MRI), due to its excellent contrast differentiation and multiplanar capabilities as well as the development of even newer techniques, such as diffusion tensor imaging and spectroscopy, has surpassed all other forms of imaging for the thorough exploration and analysis of congenital anomalies of the central nervous system. These malformations comprise a heterogeneous group of conditions in terms of both the timing and etiology of the developmental aberration as well as the resulting morphological phenotype, including epilepsy, developmental delay/intellectual disability and focal neurological deficits. This study briefly presents some typical examples of congenital malformations of cortical development of the human brain that are encountered in practice. It is our belief that familiarity with the MRI presentations of these conditions can be of considerable value for adequate disease management and genetic counseling.

Cerebrovascular Complications and Vessel Wall Imaging in COVID-19 Encephalopathy-A Pilot Study.

BACKGROUND AND PURPOSE: Coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is associated with several complications of the central nervous system (CNS), including acute encephalopathy. METHODS: In this pilot study, we report a series of 39 patients (66.5 ± 9.2 years; 10.3% female) with acute encephalopathy, who underwent a standard brain magnetic resonance imaging (MRI) at 1.5 T during the acute symptomatic phase. In addition to diffusion-weighted imaging, MR angiography and susceptibility-weighted images, high-resolution vascular black blood sequences (in 34 cases) were used to investigate the vasculature of the brain. RESULTS: In 29 out of 34 patients with COVID-19 encephalopathy (85%) with high-resolution vessel wall imaging, we found a circular enhancement and thickening of the basilar and vertebral arteries, without any correlation with ischemia or microbleeds (reported in 21% and 59%, respectively). CONCLUSION: We report a high prevalence of vascular changes suggestive of endotheliitis as reported in other organs. This could suggest an inflammatory mechanism underlying this encephalopathy.

COVID-19 is Associated with an Unusual Pattern of Brain Microbleeds in Critically Ill Patients.

BACKGROUND AND PURPOSE: Covid-19, initially described as a respiratory system's infection, is currently more and more recognized as a multiorganic disease, including neurological manifestations. There is growing evidence about a potential neuroinvasive role of SARS-CoV-2. The purpose of this study is to describe new findings, in the form of cerebral microbleeds affecting different brain structures, observed in MRIs of critically ill patients. METHODS: For this purpose, the MR images of 9 patients with a common pattern of abnormal findings (2 women/7 men; 55-79 years of age; mean age: 67.7 years) were depicted. All patients were tested positive for SARS-CoV-2 and presented with delayed recovery of consciousness or important agitation, requiring brain MRI. RESULTS: All patients had suffered from severe (5/9) or moderate (4/9) acute respiratory distress syndrome, requiring prolonged stay in the intensive care unit. Their common MRI finding was the presence of microbleeds in unusual distribution with a specific predilection for the corpus callosum. Other uncommon locations of microbleeds were the internal capsule (5/9), as well as middle cerebellar peduncles (5/9). Subcortical regions were also affected in the majority of patients. CONCLUSIONS: Brain MRI raised evidence that Covid-19 or its related treatment may involve the brain with an unusual pattern of microbleeds, predominantly affecting the corpus callosum. The mechanism of this finding is still unclear but the differential diagnosis should include thrombotic microangiopathy related to direct or indirect-through the cytokine cascade-damage by the SARS-CoV-2 on the endothelium of brain's vessels, as well as mechanisms similar to the hypoxemia brain-blood-barrier injury.

Morphological and Advanced Imaging of Epilepsy: Beyond the Basics.

The etiology of epilepsy is variable and sometimes multifactorial. Clinical course and response to treatment largely depend on the precise etiology of the seizures. Along with the electroencephalogram (EEG), neuroimaging techniques, in particular, magnetic resonance imaging (MRI), are the most important tools for determining the possible etiology of epilepsy. Over the last few years, there have been many developments in data acquisition and analysis for both morphological and functional neuroimaging of people suffering from this condition. These innovations have increased the detection of underlying structural pathologies, which have till recently been classified as "cryptogenic" epilepsy. Cryptogenic epilepsy is often refractory to anti-epileptic drug treatment. In drug-resistant patients with structural or consistent functional lesions related to the epilepsy syndrome, surgery is the only treatment that can offer a seizure-free outcome. The pre-operative detection of the underlying structural condition increases the odds of successful surgical treatment of pharmacoresistant epilepsy. This article provides a comprehensive overview of neuroimaging techniques in epilepsy, highlighting recent advances and innovations and summarizes frequent etiologies of epilepsy in order to improve the diagnosis and management of patients suffering from seizures, especially young patients and children.

Incidentalomas in Spine and Spinal Cord Imaging.

Incidentalomas are common in magnetic resonance imaging (MRI) of the spine. These incidental findings (IFs) can be seen involving the spinal cord, nerve root, vertebral body, posterior arch and the extraspinal region. This review article describes the imaging findings, stratifies the IFs similar to the computed tomography (CT) colonography reporting and data system and briefly mentions the current recommendations for further evaluation and management of IFs. Radiologists are the first to detect these lesions, suggest further evaluation and management of IFs. It is therefore mandatory for them to be aware of recommendations in clinical practice in order to avoid increased patient anxiety, excessive healthcare expenditure and inadvertent therapeutic procedures.

Iterative Algorithms Applied to Treated Intracranial Aneurysms.

PURPOSE: To investigate the impact of iterative metal artifact reduction (iMAR) on artifacts related to neurosurgical clips or endovascular coils when combined to filtered back projection (FBP) or advanced modelled iterative reconstruction (ADMIRE). MATERIAL AND METHODS: In this study 21 unenhanced brain computed tomography (CT) examinations were reconstructed with FBP and level 2 of ADMIRE, both techniques with and without iMAR algorithm, resulting in 4 series per acquisition. Subjective assessment of artifact reduction was performed as a double-blinded evaluation with a 5-point-scale. Objective analysis was performed by comparing central tendencies and distributions of voxel densities. The central tendency was assessed as the mean voxel density in Hounsfield units. The distribution was assessed by evaluating the shape and asymmetry of the histograms of voxels densities with measures of kurtosis and skewness, respectively. RESULTS: Inter-reader agreement was excellent (>0.8). FBP and ADMIRE without iMAR were scored 4 and with iMAR 5. Unusual artifacts were noted in all of the series reconstructed with iMAR, especially when combined with ADMIRE. Kurtosis revealed statistical differences for all reconstruction techniques (p ≤ 0.0007) except for the association of FBP with iMAR (p = 0.2211) for the coiling population and skewness demonstrated no statistical difference in any population (p ≥ 0.0558), confirming the subjective analysis results, except for the ADMIRE algorithm with or without iMAR (p ≤ 0.0342) in the coiling population. CONCLUSION: iMAR led to the reduction in artifacts due to intracranial metallic devices. However, it created a new artifact in the form of a halo of photon-starvation, especially when combined with ADMIRE. The combination of FBP and iMAR seems more suitable, combining the beneficial metal artifact reduction without the emergence of a halo of photon starvation just around the point of interest.

Clinical applications of diffusion weighted imaging in neuroradiology.

Diffusion-weighted imaging (DWI) has revolutionised stroke imaging since its introduction in the mid-1980s, and it has also become a pillar of current neuroimaging. Diffusion abnormalities represent alterations in the random movement of water molecules in tissues, revealing their microarchitecture, and occur in many neurological conditions. DWI provides useful information, increasing the sensitivity of MRI as a diagnostic tool, narrowing the differential diagnosis, providing prognostic information, aiding in treatment planning and evaluating response to treatment. Recently, there have been several technical improvements in DWI, leading to reduced acquisition time and artefacts and enabling the development of diffusion tensor imaging (DTI) as a tool for assessing white matter. We aim to review the main clinical uses of DWI, focusing on the physiological mechanisms that lead to diffusion abnormalities. Common pitfalls will also be addressed. TEACHING POINTS: • DWI includes EPI, TSE, RESOLVE or EPI combined with reduced volume excitation. • DWI is the most sensitive sequence in stroke diagnosis and provides information about prognosis. • DWI helps in the detection of intramural haematomas (arterial dissection). • In diffusion imaging, ADC is inversely proportional to tumour cellularity. • DWI and DTI derived parameters can be used as biomarkers in different pathologies.