title: Assessment of vessel permeability by combining dynamic contrast-enhanced and arterial spin labeling MRI.
abstract: The forward volumetric transfer constant (K(trans)), a physiological parameter extracted from dynamic contrast-enhanced (DCE) MRI, is weighted by vessel permeability and tissue blood flow. The permeability × surface area product per unit mass of tissue (PS) in brain tumors was estimated in this study by combining the blood flow obtained through pseudo-continuous arterial spin labeling (PCASL) and K(trans) obtained through DCE MRI. An analytical analysis and a numerical simulation were conducted to understand how errors in the flow and K(trans) estimates would propagate to the resulting PS. Fourteen pediatric patients with brain tumors were scanned on a clinical 3-T MRI scanner. PCASL perfusion imaging was performed using a three-dimensional (3D) fast-spin-echo readout module to determine blood flow. DCE imaging was performed using a 3D spoiled gradient-echo sequence, and the K(trans) map was obtained with the extended Tofts model. The numerical analysis demonstrated that the uncertainty of PS was predominantly dependent on that of K(trans) and was relatively insensitive to the flow. The average PS values of the whole tumors ranged from 0.006 to 0.217 min(-1), with a mean of 0.050 min(-1) among the patients. The mean K(trans) value was 18% lower than the PS value, with a maximum discrepancy of 25%. When the parametric maps were compared on a voxel-by-voxel basis, the discrepancies between PS and K(trans) appeared to be heterogeneous within the tumors. The PS values could be more than two-fold higher than the K(trans) values for voxels with high K(trans) levels. This study proposes a method that is easy to implement in clinical practice and has the potential to improve the quantification of the microvascular properties of brain tumors.
authors.affiliation: Department of Medical Imaging and Radiological Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.|Department of Imaging Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX, USA.
authors.forename: Ho-Ling
authors.initials: HL
authors.lastname: Liu
authors.affiliation: Department of Medical Imaging and Radiological Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
authors.forename: Ting-Ting
authors.initials: TT
authors.lastname: Chang
authors.affiliation: Department of Medical Imaging and Radiological Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.|Department of Radiology, Taipei Medical University/Shuang-Ho Hospital, New Taipei City, Taiwan.
authors.forename: Feng-Xian
authors.initials: FX
authors.lastname: Yan
authors.affiliation: Department of Medical Imaging and Radiological Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
authors.forename: Cheng-He
authors.initials: CH
authors.lastname: Li
authors.affiliation: Department of Medical Imaging and Radiological Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
authors.forename: Yu-Shi
authors.initials: YS
authors.lastname: Lin
authors.affiliation: Department of Medical Imaging and Intervention, Chang Gung Memorial Hospital at Keelong, Linkou Medical Center, Taiwan.|College of Medicine, Chang Gung University, Taoyuan, Taiwan.
authors.forename: Alex M
authors.initials: AM
authors.lastname: Wong
mesh_terms: D000293:Adolescent; D001783:Blood Flow Velocity; D001810:Blood Volume; D001811:Blood Volume Determination; D001932:Brain Neoplasms / Q000098:blood supply / Q000473:pathology / Q000503:physiopathology*; D002199:Capillary Permeability; D002536:Cerebral Arteries / Q000473:pathology / Q000503:physiopathology*; D002560:Cerebrovascular Circulation; D002648:Child; D002675:Child, Preschool; D003287:Contrast Media / Q000493:pharmacokinetics; D005240:Feasibility Studies; D005260:Female; D019786:Gadolinium DTPA / Q000493:pharmacokinetics*; D006801:Humans; D007089:Image Enhancement; D007090:Image Interpretation, Computer-Assisted; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013113:Spin Labels
chemical_list: D003287:Contrast Media; D013113:Spin Labels; D019786:Gadolinium DTPA
keywords: MRI; arterial spin labeling (ASL); dynamic contrast enhanced (DCE); forward volumetric transfer constant (Ktrans); permeability