Neuro

Imaging plays a central role in the diagnosis of hydrocephalus, CT is the first imaging test in emergency patients, but MRI is the first-line imaging modality. Hydrocephalus can be divided into communicating and non-communicating and obstructive and non-obstructive, depending if there is an obstruction in the ventricular system or the subarachnoid space. Communicating hydrocephalus can be further subdivided in: a) cases with no obstruction to CSF absorption, normal pressure hydrocephalus (NPH) is the most important cause in this category. b) cases with obstruction to CSF absorption due to damage to arachnoid granulations, as occurs in subarachnoid haemorrhage and meningitis. Non-communicating hydrocephalus implies a mechanical problem affecting the passage of CSF through the ventricular system (masses or stenosis in the ventricular system). MRI is useful in detecting the cause and location of the obstruction, imaging protocol should always include sagittal high-resolution T2WI, and especially rewarding are balanced steady-state gradient echo sequences that appear as highly T2 weighted sequences without fluid artefact. When an inflammatory aetiology is suspected, imaging with contrast agent administration is necessary. However, the diagnosis of NPH is difficult because of commonly associated diseases, such as Alzheimer's disease and microangiopathy. With MRI we try to predict which patients are going to respond to a ventricular shunt and include the following parameters: ventriculomegaly with frontal and temporal horns of the lateral ventricles most affected, dilated sylvian fissures, tight high convexity, acute callosal angle, and focal sulcal dilation.

Cerebral microbleeds (CMBs) are detected with increasing frequency since MRI has become more widely available over the last decade. Especially with the introduction of high magnetic field strength (3T) and newer dedicated MR imaging sequences such as susceptibility weighted imaging (SWI), CMBs are increasingly recognized. CMBs are detected on SWI as small hypointense foci with a maximum size of 5-10 mm. They represent focal accumulations of hemosiderin-containing macrophages with paramagnetic properties causing signal loss due to susceptibility effects. CMBs may be observed as an incidental finding in the normal aging population, as well as in various disorders such as Alzheimer dementia, cerebral amyloid angiopathy, stroke, and trauma. Rare causes include endocarditis, cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), and radiation therapy. Small (so-called type IV) cavernous malformations may be indistinguishable from CMBs. Not every black dot on SWI constitutes a CMB; phase information obtained with SWI allows to discriminate CMBs from calcifications. Clinical information and previous medical history of the patient, spatial distribution of the lesions (superficial or lobar versus deep, supratentorial versus infratentorial), morphology, and associated imaging findings such as convexity subarachnoid hemorrhage, cortical superficial siderosis, prior lobar intracerebral hemorrhage, white matter abnormalities, are important clues to obtain the correct diagnosis.

In this lecture I will review the basic concepts about brain maturation and myelination, and how to set up a baseline MR study of the brain in the pediatric age group. I will also examine some frequent pitfalls in pediatric neuroimaging, focussing on a frequent finding: pineal gland cysts. Then, I will address the main congenital malformations of the brain, highlighting the role of MR with diffusion tensor imaging (DTI) in their understanding and classification. I will also examine the principal neurocutaneous syndromes, such as Neurofibromatosis type 1 and 2, tuberous sclerosis, Sturge-Weber syndrome, and von Hippel-Lindau disease. Finally, I will elucidate a few basic concepts about leukodystrophies, focusing on pattern recognition based on MR, and understanding how to differentiate them from acquired white matter disorders, notably acute disseminated encephalomyelitis.

This lecture is part of a series of lectures aimed at preparation for the neuroradiology part of the EDiR examination.

The fifth edition (2016) of the WHO Classification of Tumors of the CNS is the worldwide standard for classifying and grading brain neoplasms. Standardised MR brain tumour protocol is crucial for the preoperative evaluation and interpretation of postoperative changes. Brain tumour imaging objectives include the diagnosis of a brain tumour and the ability to distinguish it from non-tumoral lesions, assessment of histological grade of the tumour, delineation of the tumour borders and extension, differentiation between a tumour and peritumoral oedema, and finally the evaluation of possible recurrence and therapy-induced phenomena. In this lecture, two major issues will be discussed: the value of different conventional and advanced MRI techniques in evaluation of CNS tumours; most common spine tumours not to miss.

The correct and prompt diagnosis of ischemic stroke and/or stroke mimics is crucial to assist clinicians in proper triaging and therapy decisions. A stroke mimic represents a non-stroke disorder with a presentation suggestive of acute ischemic stroke. The list of possible stroke mimics consists of seizures and postictal phenomena, headaches, metabolic disturbances, toxicities, and space-occupying lesions. A variety of non-neurological conditions such as systemic infection, cardiovascular events, and psychiatric issues may also masquerade as acute ischemic strokes. In this lecture, key-imaging features of stroke mimics will be discussed in detail.

Acquired toxic-metabolic encephalopathies encompass a wide range of causes including metabolic causes like hypo-/hyperglycemia, hepatic and uremic encephalopathy, or osmotic demyelination, hypertension, exposure to toxic substances, or drug abuse. Clinical history is extremely important in the evaluation of the patient. Best recognised on MRI, these disorders tend to show bilateral and symmetrical involvement of the deep grey matter and cerebral white matter. Some peculiar locations, DWI features and clues from proton MR spectroscopy will guide the radiologists on the way to the diagnosis. In this session, participants will review and practice the imaging features of the most common acquired toxic-metabolic encephalopathies with representative cases.

Children presenting with acute disease involving the head and neck often display an aspecific clinical picture characterised by pain, fever, malaise, and local or generalised swelling. Regional involvement ranges from the orbits to the paranasal sinuses, temporal bone, skull base, craniocervical junction, upper airway, and neck. Emergent presentations in the head and neck compartment can be grossly categorised into traumatic and non-traumatic, the latter comprising infectious, inflammatory, congenital, and neoplastic conditions. Imaging studies play a fundamental role in the diagnosis of these conditions and provide a basis for subsequent management, including the identification of situations that may dictate immediate surgical treatment. The choice of the most appropriate imaging method is significantly influenced by the patient’s clinical conditions and stability (or lack thereof). Although both ultrasound and X-rays often are used, this presentation will mostly focus on findings at CT and MRI.

This presentation reviews the brain imaging findings of the most common acute neurological non-traumatic disorders in pediatric patients. From the clinical point of view, a wide differential diagnosis of diseases that can occur abruptly in the emergency room is discussed. The most frequent acute symptomatology and manifestations are seizures, headache, irritability, lethargy, paresis, fever, nausea and vomiting. Beyond trauma, there are other entities to consider when a pediatric patient has an acute neurological clinical presentation. Among them, vascular aetiology stands out, whether in the form of an arterial stroke, venous thrombosis or vascular malformation. Other important causes are infections, drugs and their side effects, tumours, metabolic and demyelinating diseases. Neuroimaging techniques include computed tomography (CT), magnetic resonance (MR) and, even cerebral ultrasound in neonates and infants. The combination of basic neuroimaging methods and other advanced techniques such as angiographic and perfusion studies, allow proper differential diagnosis, correct management of the acute neurological onset in children and its subsequent follow-up.

T2 hyperintensities are a very common finding on brain MRI, especially in elderly. Indeed, white matter hyperintensities (WMH) might be detected in up to 50% in healthy subjects before 50yo. Beside non-specific WMH of the centrum semiovale and the brainstem suggesting microangiopathy, numerous diseases harbour brain T2 hyperintensities. To further discuss their aetiology and improve MR protocol, three tips are given on their location, their appearance on other weighted images, and patient’s history.

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system that is characterised by inflammation, demyelination and degenerative changes. The clinical use of Magnetic Resonance Imaging (MRI) in patients with MS has advanced markedly over the past few years. The benefits of the 2010 McDonald MRI criteria included the focus on lesion location; the presence of gadolinium-enhancing and gadolinium-non-enhancing lesions allows very early diagnosis in some patients who undergo a single MRI examination at any time after symptom onset. Be presented the basic symptoms differentiating demyelinating changes from other hyperintensive lesions in T2 images dependent in the brain and spinal cord. To assure how to be confident with the correct diagnosis of MS lesions present.

Acute disseminated encephalomyelitis (ADEM) is a severe, immune-mediated inflammatory-demyelinating disorder of the central nervous system that predominantly affects the white matter of the brain and spinal cord characterised clinically by new-onset polyfocal neurologic symptoms including encephalopathy, coupled with neuroimaging evidence of multifocal white matter inflammatory-demyelinating lesions. The disorder is mainly a condition of the pediatric age group, but on rare occasions, adults and elderly patients can also be affected. In the absence of specific biologic markers, the diagnosis of ADEM is based on clinical and radiologic features. This presentation includes special consideration of the value of neuroimaging in the diagnoses of ADEM and the distinction with and other immune-mediated inflammatory demyelinating diseases, in particular, multiple sclerosis.

Imaging findings in meningitis are unspecific. Computed tomography (CT) is the initial method to exclude other pathologies. Magnetic resonance imaging (MRI) findings include several indirect features suggesting meningeal pathology. Most important MR techniques to detect meningitis are FLAIR with and without gadolinium, diffusion-weighted MR imaging (DWI), postcontrast-T1WI. This lecture will teach you how to interpret MR imaging findings on different MR techniques to make a correct diagnosis of meningitis.

TIA represents a major public health issue. It is crucial to identify the cause of TIA to avoid an acute stroke. The radiologist plays an important role in the management of patients with TIA. Indeed, the objective of imaging is to detect parenchymal and/or vascular abnormalities that can explain the transient clinical symptoms. Such abnormalities are frequently subtle, and the imaging protocol can be thus optimised to further improve the diagnostic performance. MRI or CT can be used, with the advantage for MRI of better visualisation of parenchymal lesions. Imaging of the supra-aortic trunks is an important step of the diagnostic work-up. Using MRI, optimised diffusion, perfusion (including arterial spin labelling) and post-contrast 3D TSE sequences can be also very useful.

Intracranial venous sinus thrombosis is an important cause of stroke, especially in young patients and children, and only imaging can make the diagnosis. Imaging is essential to establish the venous thrombosis diagnosis but also to evaluate and monitor associated brain lesions. Obtaining orthogonal imaging planes improves the venous thrombosis diagnosis accuracy. CT multiplanar reconstructions (MPR) views improve the CT accuracy for depicting venous thrombosis, especially cortical venous thrombosis. On MRI, the use of T2*WI and T1WI on two orthogonal planes, such as axial and coronal, are highly accurate to depict vessel thrombosis. An important pitfall is that a low T2 signal inside of a venous structure does not exclude thrombosis since a subacute thrombus is hypointense on T2WI (and isointense on T1WI) due to the presence of deoxyhaemoglobin. Computed Tomography Venogram (CTV) or Contrast-Enhanced Magnetic Resonance Venogram (CE-MRV) prove the presence of venous thrombosis by exhibiting complete or partial filling defects inside the dural sinus and/or veins. Venous thrombosis is well-known clinical and imaging mimicker with different forms of presentation. It is extremely important to think on venous thrombosis in the differential diagnosis of a brain lesion, since in a significant number of cases is not suspected by the clinician, and choose the correct imaging protocol.