Jonas Bause1,2, Philipp Ehses1,3, Christian Mirkes1,3, G Shajan1, Klaus Scheffler1,3, Rolf Pohmann1. 1. Max Planck Institute for Biological Cybernetics, High-Field Magnetic Resonance Center, Tübingen, Germany. 2. Graduate Training Center of Neuronal Sciences, International Max Planck Research School, University of Tübingen, Tübingen, Germany. 3. Department of Biomedical Magnetic Resonance, University of Tübingen, Tübingen, Germany.
Abstract
PURPOSE: The feasibility of multislice pulsed arterial spin labeling (PASL) of the human brain at 9.4 T was investigated. To demonstrate the potential of arterial spin labeling (ASL) at this field strength, quantitative, functional, and high-resolution (1.05 × 1.05 × 2 mm(3)) ASL experiments were performed. METHODS: PASL was implemented using a numerically optimized adiabatic inversion pulse and presaturation scheme. Quantitative measurements were performed at 3 T and 9.4 T and evaluated on a voxel-by-voxel basis. In a functional experiment, activation maps obtained with a conventional blood-oxygen-level-dependent (BOLD)-weighted sequence were compared with a functional ASL (fASL) measurement. RESULTS: Quantitative measurements revealed a 23% lower perfusion in gray matter and 17% lower perfusion in white matter at 9.4 T compared with 3 T. Furthermore almost identical transit delays and bolus durations were found at both field strengths whereas the calculated voxel volume corrected signal-to-noise ratio was 1.9 times higher at 9.4 T. This result was confirmed by the high-resolution experiment. The functional experiment yielded comparable activation maps for the fASL and BOLD measurements. CONCLUSION: Although PASL at ultrahigh field strengths is limited by high specific absorption rate, functional and quantitative perfusion-weighted images showing a high degree of detail can be obtained.
PURPOSE: The feasibility of multislice pulsed arterial spin labeling (PASL) of the human brain at 9.4 T was investigated. To demonstrate the potential of arterial spin labeling (ASL) at this field strength, quantitative, functional, and high-resolution (1.05 × 1.05 × 2 mm(3)) ASL experiments were performed. METHODS: PASL was implemented using a numerically optimized adiabatic inversion pulse and presaturation scheme. Quantitative measurements were performed at 3 T and 9.4 T and evaluated on a voxel-by-voxel basis. In a functional experiment, activation maps obtained with a conventional blood-oxygen-level-dependent (BOLD)-weighted sequence were compared with a functional ASL (fASL) measurement. RESULTS: Quantitative measurements revealed a 23% lower perfusion in gray matter and 17% lower perfusion in white matter at 9.4 T compared with 3 T. Furthermore almost identical transit delays and bolus durations were found at both field strengths whereas the calculated voxel volume corrected signal-to-noise ratio was 1.9 times higher at 9.4 T. This result was confirmed by the high-resolution experiment. The functional experiment yielded comparable activation maps for the fASL and BOLD measurements. CONCLUSION: Although PASL at ultrahigh field strengths is limited by high specific absorption rate, functional and quantitative perfusion-weighted images showing a high degree of detail can be obtained.
Authors: Fabian Zimmer; Kieran O'Brien; Steffen Bollmann; Josef Pfeuffer; Keith Heberlein; Markus Barth Journal: MAGMA Date: 2016-04-15 Impact factor: 2.310
Authors: Laurentius Huber; Desmond H Y Tse; Christopher J Wiggins; Kâmil Uludağ; Sriranga Kashyap; David C Jangraw; Peter A Bandettini; Benedikt A Poser; Dimo Ivanov Journal: Neuroimage Date: 2018-06-08 Impact factor: 6.556