Review Arterial Spin Labeling (ASL) for the clinical radiologist Review the concept of perfusion imaging Describe how ASL works Consider the advantages and disadvantages of the technique Discuss the clinical applications of ASL

Perfusion of blood into tissues to provide oxygen and nutrients is a fundamental physiological process. Patterns of hypo- and hyper-perfusion are seen in a myriad of pathological processes. Current modalities of perfusion imaging in clinical use include Positron Emission Tomography (PET), Single Photon Emission Computed Tomography (SPECT), Perfusion Computed Tomography (PCT) and MRI dynamic susceptibility contrast (DCT). Perfusion imaging Can be utilised to access the haemodynamics in all body systems, detecting abnormalities in tissue perfusion before anatomical changes can be observed. Can add important functional...

Arterial Spin Labeling (ASL) An MRI technique, which utilizes radiofrequency labeled arterial blood water protons as an endogenous tracer. The major benefit is the avoidance of ionizing radiation and intravenous contrast agents. Since its development in 1992 improvements in labeling approaches and image processing have broadened potential clinical applications. Involves a preparation component where blood is ‘labeled’ in the feeding vasculature in different magnetic states to create control and labeled images. Following a ‘post-labeling delay’ to allow the blood to reach the parenchyma the acquisition...

ASL imaging is a recognized research tool, which is gaining clinical validity has clinical applications in cerebrovascular disease, Alzheimer’s disease, brain tumours and seizure disorders has particular potential advantages where repeated studies are required

Professor Alan Coulthard is a Professor of Neuroradiology at the University of Queensland, Head of the UQ Discipline of Medical Imaging and Senior Staff Specialist in the Department of Medical Imaging at the Royal Brisbane and Women’s Hospital. His qualifications include BMedSci, MBBS, FRCSEd, FRCR and FRANZCR. Dr Madeleine McGuiness is a Senior House Officer at the Royal Brisbane and Women’s Hospital. Her qualifications include MBBS and BSc. She is applying for the 2012 intake into the Radiology training program. Dr Annah Lane is a...

1. Zaharchuk G, Bammer R, Straka M, Shankaranarayan A, Alsop D, Fischbein NJ, Atlas S, Moseley ME. Arterial Spin-Label Imaging in patients with normal bolus perfusion-weighted MR Imaging findings: Pilot identification of the Borderzone sign. Radiology. 2009 Sep;252(3):797-807 2. Pollock JM, Tan H, Kraft RA, Whitlow CT, Burdette JH, Maldjian JA. Arterial Spin-Labeled MR Perfusion Imaging: Clinical Applications. Magn Reson Imaging Clin N Am. 2009; 17; 315-338 Alsop DC. ASL Perfusion Imaging: Concepts and Applications 3. Wintermark M, Sessay M et al. Comparative Overview of...