OP04 * QUANTITATIVE MEASUREMENT OF BLOOD FLOW IN PAEDIATRIC BRAIN TUMOURS - A COMPARATIVE STUDY OF DYNAMIC SUSCEPTIBILITY CONTRAST AND MULTI-TIMEPOINT ARTERIAL SPIN LABEL IMAGING

Abstract

INTRODUCTION: Arterial spin labeling (ASL) is a MR technique that allows for noninvasive quantification of cerebral blood flow (CBF). This technique, predominately used in research, has seen significant technical developments in the last few years that have led to more clinical applications. Currently, the main MR method used to provide perfusion measures in brain tumours is dynamic susceptibility contrast (DSC). DSC traces the signal changes caused by the transit of a bolus of gadolinium contrast agent. ASL has the advantage of not requiring bolus injection of contrast. We have performed a comparative study of DSC and multi-timepoint ASL in paediatric brain tumours (PBT). METHOD: Data from a total of 19 PBT patients (mean age: 9 ± 5 years; 10 females, 9 males) were included in the analyses for this study. Data used were from first presentation scans performed before any surgical intervention. Comparisons of the quantitative measures of CBF and blood arrival time between the two techniques were carried out to test the feasibility of ASL to provide useful quantification measures of CBF in PBT. RESULTS: DSC measurements of tumour blood flow showed a significant decrease in flow in comparison with normal brain, but this is not seen with ASL. There was a strong correlation between ASL and DSC measures of blood flow in normal brain (r = 0.65, p = 0.009), but not in tumour blood flow (r = 0.33, p = 0.2). CONCLUSION: This study demonstrates the feasibility and potential utility of ASL as a non-invasive technique for measuring blood flow in PBT. However, there is a discrepancy between ASL and DSC measures, that may be due to leakage of gadolinium contrast, reflecting the abnormal characteristics of tumour blood vessels in PBT.