Antônio José da Rocha

Ischemic Stroke in Adults

Stroke is a neurological deficit attributed to an acute injury of the central nervous system. Imaging plays a key role in evaluating acute stroke patients, guiding treatment and clinical management. Before treatment, it is necessary to exclude intracranial hemorrhage. Imaging of the acute stroke patient before endovascular therapy is necessary to determine the presence of an embolus/thrombus that is amenable to intra-arterial thrombolysis and/or mechanical thrombectomy. Brain perfusion imaging provides information on cerebral hemodynamics

Ischemic Stroke in Children

Stroke in children is being increasingly recognized as a significant source of morbidity and mortality. Children and adolescents with stroke have remarkable differences in presentation compared with adults. Sickle cell disease is a major risk factor of overt and silent strokes in children. Cervicocephalic arterial dissection is an important but probably under-recognized cause of stroke in children. Cerebral vasculitis may be considered in children with either ischemic or hemorrhagic stroke, especially recurrent strokes. Cardiac disease is present in 10–30 % of children with stroke. Owing to the frequency of stroke mimics in childhood, the diagnosis requires the imaging confirmation of an ischemic lesion.

Spinal Cord Infarction

Spinal cord ischemia is an uncommon disease, varying in its presentation, severity, and outcome. Spinal cord ischemia accounts for approximately 14 % of all acute myelopathies and approximately 1–2 % of all vascular neurologic diseases. The severity of the injury depends on several factors including acute hemodynamic instability and poor perfusion, oxygen delivery and demand, local metabolic rate, and the patients’ baseline collateral circulation. Spinal cord ischemia can cause a variety of symptoms and neurological deficits which depend on the affected spinal cord level and artery involved. It is characterized generally by an acute onset which is often preceded by sudden and severe back pain typically at the level of the lesion. Magnetic resonance imaging is the modality of choice for the diagnosis.

Acute Temporal Lobe Lesions

Several diseases may involve the temporal lobe, including benign and malignant ones. Each disorder may result in a distinct imaging pattern, helping to narrow the differential diagnoses. Clinical manifestations depend on the specific site involved. Magnetic resonance imaging allows a detailed structural evaluation usually demonstrating T2 hyperintense lesions, and advanced sequences aid in reaching a definite diagnosis.

Retained Foreign Bodies

Foreign bodies may be ingested, inserted into a body cavity, or deposited into the body by traumatic or iatrogenic injuries. Retained foreign bodies following surgical procedures are a clinically significant problem. The real incidence is unknown since intracranial foreign bodies are seldom reported and the majority consist of materials intentionally left in the cranium. Clinical manifestations may be variable such as acute infections, late-onset seizures, or they remain clinically silent for years. The major role of the radiologist is to recognize these foreign bodies and their potential complications.

Dural Arteriovenous Fistulas

Dural arteriovenous fistulas are abnormal connections between meningeal arteries and dural venous sinuses, meningeal veins, or cortical veins that result in direct arteriovenous shunting. They represent 10–15 % of cerebrovascular malformations with arteriovenous shunting. Their dural arterial supply and lack of a parenchymal nidus differentiate them from pial arteriovenous malformations. Dural arteriovenous fistulas generally are acquired lesions that are frequently associated with prior dural venous sinus thrombosis. Patterns of venous drainage are paramount in determining lesion severity and in guiding treatment. Diagnosis at their early stage may be difficult because of nonspecific clinical and imaging findings. Although the diagnosis has traditionally been by catheter angiography, many of these lesions are now first detected or suspected on cross-sectional imaging.

Meningitis, Empyema, and Brain Abscess in Adults

Central nervous system infections remain an important cause of morbidity and mortality worldwide. Meningitis is the most common manifestation. Pathogens vary based on the location of the infection, geography, vaccination status, age, surgical intervention, and immune status. They are considered medical emergencies requiring immediate diagnosis and therapy, and crucial steps are needed to achieve a good clinical outcome. Lumbar puncture is the first step in their evaluation, and imaging of the brain is often indicated in patients with neurologic deficits, altered immunity, or decreased level of consciousness.

Meningitis, Empyema, and Brain Abscess in Children

Central nervous system infection in children is an important condition for which early recognition is crucial to achieve a favorable clinical outcome. Infectious bacterial meningitis is the most common manifestation of CNS infections in this age group. Despite the fact that the imaging findings may be nonspecific, its clinical presentation has distinct peculiarities. The classical clinical features of infective meningitis in children include apathy, lethargy, stupor, poor feeding, and irritability. Clinical history and imaging techniques may help in the diagnostic workflow.

Metabolic Brain Disorders in Children

Although rare, metabolic brain disorders account for a substantial portion of childhood and adult encephalopathy cases and may cause significant morbidity and mortality. Most of these disorders are inborn errors of metabolism, and brain injury results from the accumulation of endogenous toxic substances or a lack of production of necessary biochemicals. Inborn errors of metabolism can occur at nearly any age, and their clinical signs and symptoms are almost invariably nonspecific. Some of them, especially at neonatal period, manifest with acute encephalopathy and a life-threatening episode of metabolic decompensation, whereas later-onset disorders have a more manageable clinical course with variable outcomes.

Basal Ganglia and Thalamic Lesions

A wide variety of diseases may involve the basal ganglia and thalami, and neuroimaging plays a major role in their diagnosis. The causes of abnormalities in deep gray structures in adults may be broadly classified as toxic, acquired metabolic disorders, inflammatory and infectious diseases, vascular and neoplasms, and many of them represent emergencies and must be promptly reported.