The goal of this educational exhibit is to use a graphical and image heavy Powerpoint presentation to familiarize the reader with the background necessary to understand common clinical ASL-PWI imaging techniques along with displaying a pictorial assay of different normal and abnormal ASL perfusion findings within the field of Pediatric Neuroradiology. To introduce our topic, we will briefly discuss the physiology of cerebral blood flow and how it is measured with and without an exogenous tracer. Next, to serve as an overview, we will show the general ASL experiment, namely, labeling, post label delay, and readout. Following, we will discuss each of the above components, beginning with showing the different main labeling methods, CASL, PCASL, and PASL. Finally, the concept of post label delay will be illustrated respective to each of the main labeling methods. In the second section, we will discuss the image acquisition component by first describing and illustrating two common readout methods, such as 2D-EPI and 3D-GRASE methods along with their advantages and disadvantages. Additionally, we will illustrate the process of background suppression along with its significance. Finally, we will review the process of obtaining perfusion weighted images through the subtraction between tagged and control images. The third section will illustrate an assortment of clinical examples beginning with showing normal physiological hyper- and hypoperfusion and newborn perfusion characteristics. Following, we will highlight a spectrum of clinical cases including: moyamoya, HIE, medullary infarct with luxury perfusion, arteriovenous malformation, PRES, infections (intracerebral abscess, toxoplasmosis, cerebellitis), characteristics of headache, intracranial tumors (juvenile astrocytoma, hemangioblastoma, ATRT, and choroid plexus papilloma), cortical dysplasia, tuberous sclerosis with seizures, and variations presentations of methotrexate toxicity. Lastly, we will discuss cerebral blood reserve imaging utilizing acetazolamide challenge. All cases will contain pertinent clinical information and images from other sequences/modalities that aid in the diagnosis of disease.
SPR 2019 Annual Meeting & Postgraduate Course
Arterial Spin Labeling,