BS 1 - Neuroradiology
1. To have a basic understanding of classification of white matter disorders.
2. To describe the typical imaging features of noninfectious, noninflammatory disorders.
3. To identify and describe the imaging features of brain infectious-inflammatory disorders.
MR imaging is highly sensitive for the detection of white matter signal abnormalities, which can be identified in 5-10% of the adult population. Evaluation of this focal white matter hyperintensities (WMHs) on MR imaging, particularly in young adults, is always challenging since clinical and imaging features are commonly non-specific. Although most of these signal abnormalities are incidental and age related, or secondary to different types of vascular disorders, they also may be caused by a wide variety of infectious, inflammatory, neoplastic, and demyelinating disorders. In this regard, the most common difficulty, by far, is to distinguish multiple sclerosis from acquired hypoxic/ischaemic small-vessel disease, due to the high prevalence of this last group of disorders even in young adults. While it is recognized that a combination of findings from clinical history, physical examination, and laboratory tests is commonly required to correctly establish a firm and clear aetiological diagnosis, a detailed analysis of different MR imaging features should also be considered essential, e.g. lesions shape, size, and distribution; contrast-uptake; associated structural lesions (microbleeds, infarctions, etc.). Knowledge of these features, will assist the diagnostic workup of patients presenting with WMHs, and should be considered a first step to take full advantage of the potential of MRI, and in doing so should result in a reduced chance of misdiagnoses and facilitate the correct diagnosis of sometimes treatable disorders.
1. To identify and describe the imaging appearance of malignant tumours.
2. To identify and describe the imaging features of benign tumours.
3. To have a basic knowledge of postsurgical evaluation of brain.
Neuroimaging techniques are essential tools for the diagnostic process and management of brain tumours. Early and accurate diagnosis is usually possible using various brain imaging techniques. Brain tumours are classified by cell origin and how the cells behave, from the least aggressive (benign) to the most aggressive (malignant). Malignant tumours can be divided into two categories: primary and metastatic. A malignant tumour usually grows rapidly and often invades or crowds healthy areas of the brain, where most benign brain tumours are characterised by slow growth. Based on analysis of all imaging features/imaging biomarkers/tumours are rated or graded by their level of malignancy. Many factors which determine tumour grade include how fast the tumour is growing, how much blood is supplying the tumour’s tissue, the presence of the tumour necrosis and peritumoural oedema leading to high intracranial pressure/mass effect. Brain tumours are one of the most challenging disorders encountered; however, experiences of numerous authors as well as my own affirm the highest efficacy in the diagnostic process using multiparametric MR imaging: DWI, PWI or MRS. Lecture will present most common brain tumours and selected imaging modalities to their detection as well as postoperative follow-up and/or tumour’s recurrence.
1. To learn about typical imaging features of haemorrhagic stroke.
2. To discuss current imaging techniques for evaluation of ischaemic stroke.
3. To have a basic knowledge of neuroradiological interventions - revascularisation in stroke.
Ischaemic stroke results from a sudden cessation of adequate amounts of blood reaching the brain. Imaging workup should be fast, readily available and reliable to detect early and subtle abnormal findings to suggest parenchymal hypoperfusion and, therefore, facilitate early diagnosis and intervention. Initial ischaemic stroke imaging using non-contrast CT has been effectively applied to exclude haemorrhage, estimate parenchymal abnormality and other intracranial pathologies that may mimic stroke. Even though non-contrast CT remains the mainstay of imaging, it has limited sensitivity in the acute setting of the ischaemic changes. Detection depends on the territory, time of the examination from onset of symptoms and experience of the interpreting radiologist. CT perfusion and angiography as a second step is a critical tool in increasing the accurate diagnosis. CT perfusion shows both the core of the infarct and the surrounding penumbra, the region which can be salvaged. CT angiography may be helpful to identify the thrombus within an intracranial vessel, establishing the stroke aetiology and also may guide treatment planning. MRI has significantly higher sensitivity and specificity in the diagnosis of hyperacute stage of ischaemic stroke. However, MRI is more time-consuming and less available than CT particularly in the emergency departments. Diffusion-weighted MR imaging shows infarct core within minutes following the onset of ischaemia. MR perfusion imaging also provides information almost similar to the CT perfusion. Treatment planning can be done under the guidance of the imaging findings and can be performed as various reperfusion techniques (intravenous or intra-arterial thrombolysis, mechanical thrombectomy, etc.).