M Fahlström1, A Lewén2, P Enblad2, E-M Larsson2, J Wikström2. 1. From the Departments of Surgical Sciences (M.F., E.-M.L., J.W.) and Neuroscience (A.L., P.E.), Uppsala University, Uppsala, Sweden. Markus.Fahlstrom@radiol.uu.se. 2. From the Departments of Surgical Sciences (M.F., E.-M.L., J.W.) and Neuroscience (A.L., P.E.), Uppsala University, Uppsala, Sweden.
Abstract
BACKGROUND AND PURPOSE: Arterial spin-labeling-derived CBF values may be affected by arterial transit time artefacts. Thus, our aim was to assess to what extent arterial spin-labeling-derived CBF and cerebrovascular reserve capacity values in major vascular regions are overestimated due to the arterial transit time artifacts in patients with Moyamoya disease. MATERIALS AND METHODS: Eight patients with Moyamoya disease were included before or after revascularization surgery. CBF maps were acquired using a 3D pseudocontinuous arterial spin-labeling sequence, before and 5, 15, and 25 minutes after an IV acetazolamide injection and were registered to each patient's 3D-T1-weighted images. Vascular regions were defined by spatial normalization to a Montreal Neurological Institute-based vascular regional template. The arterial transit time artifacts were defined as voxels with high signal intensity corresponding to the right tail of the histogram for a given vascular region, with the cutoff selected by visual inspection. Arterial transit time artifact maps were created and applied as masks to exclude arterial transit time artifacts on CBF maps, to create corrected CBF maps. The cerebrovascular reserve capacity was calculated as CBF after acetazolamide injection relative to CBF at baseline for corrected and uncorrected CBF values, respectively. RESULTS: A total of 16 examinations were analyzed. Arterial transit time artifacts were present mostly in the MCA, whereas the posterior cerebral artery was generally unaffected. The largest differences between corrected and uncorrected CBF and cerebrovascular reserve capacity values, reported as patient group average ratio and percentage point difference, respectively, were 0.978 (95% CI, 0.968-0.988) and 1.8 percentage points (95% CI, 0.3-3.2 percentage points). Both were found in the left MCA, 15 and 5 minutes post-acetazolamide injection, respectively. CONCLUSIONS: Arterial transit time artifacts have negligible overestimation effects on calculated vascular region-based CBF and cerebrovascular reserve capacity values derived from single-delay 3D pseudocontinuous arterial spin-labeling.
BACKGROUND AND PURPOSE: Arterial spin-labeling-derived CBF values may be affected by arterial transit time artefacts. Thus, our aim was to assess to what extent arterial spin-labeling-derived CBF and cerebrovascular reserve capacity values in major vascular regions are overestimated due to the arterial transit time artifacts in patients with Moyamoya disease. MATERIALS AND METHODS: Eight patients with Moyamoya disease were included before or after revascularization surgery. CBF maps were acquired using a 3D pseudocontinuous arterial spin-labeling sequence, before and 5, 15, and 25 minutes after an IV acetazolamide injection and were registered to each patient's 3D-T1-weighted images. Vascular regions were defined by spatial normalization to a Montreal Neurological Institute-based vascular regional template. The arterial transit time artifacts were defined as voxels with high signal intensity corresponding to the right tail of the histogram for a given vascular region, with the cutoff selected by visual inspection. Arterial transit time artifact maps were created and applied as masks to exclude arterial transit time artifacts on CBF maps, to create corrected CBF maps. The cerebrovascular reserve capacity was calculated as CBF after acetazolamide injection relative to CBF at baseline for corrected and uncorrected CBF values, respectively. RESULTS: A total of 16 examinations were analyzed. Arterial transit time artifacts were present mostly in the MCA, whereas the posterior cerebral artery was generally unaffected. The largest differences between corrected and uncorrected CBF and cerebrovascular reserve capacity values, reported as patient group average ratio and percentage point difference, respectively, were 0.978 (95% CI, 0.968-0.988) and 1.8 percentage points (95% CI, 0.3-3.2 percentage points). Both were found in the left MCA, 15 and 5 minutes post-acetazolamide injection, respectively. CONCLUSIONS: Arterial transit time artifacts have negligible overestimation effects on calculated vascular region-based CBF and cerebrovascular reserve capacity values derived from single-delay 3D pseudocontinuous arterial spin-labeling.
Authors: Manus J Donahue; Eric Achten; Petrice M Cogswell; Frank-Erik De Leeuw; Colin P Derdeyn; Rick M Dijkhuizen; Audrey P Fan; Rashid Ghaznawi; Jeremy J Heit; M Arfan Ikram; Peter Jezzard; Lori C Jordan; Eric Jouvent; Linda Knutsson; Richard Leigh; David S Liebeskind; Weili Lin; Thomas W Okell; Adnan I Qureshi; Charlotte J Stagg; Matthias Jp van Osch; Peter Cm van Zijl; Jennifer M Watchmaker; Max Wintermark; Ona Wu; Greg Zaharchuk; Jinyuan Zhou; Jeroen Hendrikse Journal: J Cereb Blood Flow Metab Date: 2017-08-17 Impact factor: 6.200
Authors: Audrey P Fan; Jia Guo; Mohammad M Khalighi; Praveen K Gulaka; Bin Shen; Jun Hyung Park; Harsh Gandhi; Dawn Holley; Omar Rutledge; Prachi Singh; Tom Haywood; Gary K Steinberg; Frederick T Chin; Greg Zaharchuk Journal: Stroke Date: 2017-08-01 Impact factor: 7.914