Quantitative perfusion measurements using pulsed arterial spin labeling: effects of large region-of-interest analysis.

Journal article

PURPOSE: To study arterial spin labeling (ASL) MRI techniques and to investigate various problematic issues that still hinder the accurate and robust quantitative analysis of ASL data. MATERIALS AND METHODS: A pulsed-ASL (PASL) sequence was implemented on a 3-T imaging system and a protocol was developed for the measurement of perfusion based on fitting to a standard kinetic model. Both numerical simulations and multi-inversion time MRI data were analyzed. The effect of fitting a kinetic curve to a large region of interest (ROI) with a distribution of arterial transit times was compared to a pixel-by-pixel (PBP) method. RESULTS: It was found that a significant underestimation of perfusion of approximately 17+/-6% (P<0.001) occurs in gray matter, when comparing an ROI with a PBP analysis over a group of 12 healthy subjects. CONCLUSION: Analysis of ASL data based on a large ROI may suffer from inaccuracies arising from a distribution of transit times, implying that averaging of ASL kinetic data over such regions should therefore be avoided. When possible, a PBP fit should be performed.

Authors: Figueiredo, P; Clare, S; Jezzard, P

• Publication status: Published
• Journal: Journal of magnetic resonance imaging : JMRI
• Volume: 21
• Issue: 6
• Pages: 676-682
• Publication date: 2005-06-01
• DOI: 10.1002/jmri.20329
• EISSN: 1522-2586
• ISSN: 1053-1807
• Language: English
• Keywords: Male; Magnetic Resonance Imaging; Models, Theoretical; Adult; Female; Image Processing, Computer-Assisted; Cerebrovascular Circulation; Spin Labels; Humans; Computer Simulation