Search

Arterial Spin Labelling technique is a non-invasive magnetic resonance imaging technique used for Cerebral Blood Flow. ASL does not require gadolinium contrast reducing the risk of nephrogenic systemic fibrosis in patients with renal dysfunction.Due to the non-invasive nature 3D ASL was well accepted as an alternative method for estimating Cerebral Blood Flow Perfusion in patients with renal insufficiency and paediatric patients. ASL technique consists of two set of acquisitions, one with labelled protons and other with control acquisition. Labelled images are acquired after a particular post labelling delay (PLD). A control image is also acquired without the adiabatic inversion pulse and labelled image is subtracted from the control images for CBF signal. Absolute quantification of CBF depends on lot of hardware and software processings and are prone to artefacts. ASL artefacts can occur during the various stages of acquisition. Major artefacts can be classified into three subgroups 1. Artefacts arising during labelling(inversion) 2. Artefacts arising during transit of blood protons 3. Artefacts arising during readout. Acquisition of 3D ASL along with conventional MRI sequences in 3T MRI Scanner (GE Discovery 750W) using 3D pulse continuous ASL technique. CBF maps were generated using Readyview software in Advantage workstation. Average scan time was 4.5 to 5 minutes. Acquisitions were repeated after altering the parameters when artefacts were observed. It is really a challenging task to obtain a good quality ASL maps free from artefacts for clinical diagnostic purpose.A sound knowledge of various types of ASL artefacts and technical parameters are essential to maintain the quality of ASL maps. The main objective was to study and evaluate the artefacts that can be raised due to improper parameter settings and patient related issues. Most of the related artefacts can be tackled by proper positioning and awareness. A thorough knowledge of common imaging artifacts will help the correct interpretation of perfusion maps. [ABSTRACT FROM AUTHOR]