title: Simultaneous perfusion and permeability measurements using combined spin- and gradient-echo MRI.
abstract: The purpose of this study was to estimate magnetic resonance imaging-based brain perfusion parameters from combined multiecho spin-echo and gradient-echo acquisitions, to correct them for T₁₋, T₂₋, and T₂₋*-related contrast agent (CA) extravasation effects, and to simultaneously determine vascular permeability. Perfusion data were acquired using a combined multiecho spin- and gradient-echo (SAGE) echo-planar imaging sequence, which was corrected for CA extravasation effects using pharmacokinetic modeling. The presented method was validated in simulations and brain tumor patients, and compared with uncorrected single-echo and multiecho data. In the presence of CA extravasation, uncorrected single-echo data resulted in underestimated CA concentrations, leading to underestimated single-echo cerebral blood volume (CBV) and mean transit time (MTT). In contrast, uncorrected multiecho data resulted in overestimations of CA concentrations, CBV, and MTT. The correction of CA extravasation effects resulted in CBV and MTT estimates that were more consistent with the underlying tissue characteristics. Spin-echo perfusion data showed reduced large-vessel blooming effects, facilitating better distinction between increased CBV due to active tumor progression and elevated CBV due to the presence of cortical vessels in tumor proximity. Furthermore, extracted permeability parameters were in good agreement with elevated T1-weighted postcontrast signal values.
authors: Lucas Center, Department of Radiology, Stanford University, Stanford, California 94305-5488, USA.
authors: Heiko
authors: H
authors: Schmiedeskamp
authors: Jalal B
authors: JB
authors: Andre
authors: Matus
authors: M
authors: Straka
authors: Thomas
authors: T
authors: Christen
authors: Seema
authors: S
authors: Nagpal
authors: Lawrence
authors: L
authors: Recht
authors: Reena P
authors: RP
authors: Thomas
authors: Greg
authors: G
authors: Zaharchuk
authors: Roland
authors: R
authors: Bammer
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001812:Blood-Brain Barrier / Q000378:metabolism / Q000473:pathology; D001921:Brain / Q000098:blood supply* / Q000378:metabolism / Q000473:pathology*; D001932:Brain Neoplasms / Q000098:blood supply* / Q000378:metabolism / Q000473:pathology*; D002199:Capillary Permeability; D002560:Cerebrovascular Circulation; D003287:Contrast Media / Q000493:pharmacokinetics; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D008954:Models, Biological
chemical_list: D003287:Contrast Media