title: Arterial input functions (AIFs) measured directly from arteries with low and standard doses of contrast agent, and AIFs derived from reference tissues.
abstract: Measurements of arterial input function (AIF) can have large systematic errors at standard contrast agent doses in dynamic contrast enhanced MRI (DCE-MRI). We compared measured AIFs from low dose (AIFLD) and standard dose (AIFSD) contrast agent injections, as well as the AIF derived from a muscle reference tissue and artery (AIFref). Twenty-two prostate cancer patients underwent DCE-MRI. Data were acquired on a 3T scanner using an mDixon sequence. Gadobenate dimeglumine was injected twice, at doses of 0.015 and 0.085 mmol/kg. Directly measured AIFs were fitted with empirical mathematical models (EMMs) and compared to the AIF derived from a muscle reference tissue (AIFref). EMMs accurately fitted the AIFs. The 1st and 2nd pass peaks were visualized in AIFLD, but not in AIFSD, thus the peak and shape of AIFSD could not be accurately measured directly. The average scaling factor between AIFSD and AIFLD in the washout phase was only 56% of the contrast dose ratio (~6:1). The shape and magnitude of AIFref closely approximated that of AIFLD after empirically determined dose-dependent normalization. This suggests that AIFref may be a good approximation of the local AIF.
authors.affiliation: Department of Radiology, University of Chicago, Chicago, IL 60637.
authors.forename: Shiyang
authors.initials: S
authors.lastname: Wang
authors.affiliation: Department of Radiology, University of Chicago, Chicago, IL 60637.
authors.forename: Xiaobing
authors.initials: X
authors.lastname: Fan
authors.affiliation: Department of Radiology, University of Chicago, Chicago, IL 60637.
authors.forename: Milica
authors.initials: M
authors.lastname: Medved
authors.affiliation: Department of Radiology, University of Chicago, Chicago, IL 60637.
authors.forename: Federico D
authors.initials: FD
authors.lastname: Pineda
authors.affiliation: Department of Radiology, University of Chicago, Chicago, IL 60637.
authors.forename: Ambereen
authors.initials: A
authors.lastname: Yousuf
authors.affiliation: Department of Radiology, University of Chicago, Chicago, IL 60637.
authors.forename: Aytekin
authors.initials: A
authors.lastname: Oto
authors.affiliation: Department of Radiology, University of Chicago, Chicago, IL 60637. Electronic address: gskarczm@uchicago.edu.
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Karczmar
mesh_terms: D000328:Adult; D000368:Aged; D003198:Computer Simulation; D003287:Contrast Media / Q000008:administration & dosage / Q000493:pharmacokinetics; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D018810:Magnetic Resonance Angiography / Q000379:methods* / Q000592:standards; D008297:Male; D008536:Meglumine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D008954:Models, Biological; D009389:Neovascularization, Pathologic / Q000150:complications / Q000378:metabolism* / Q000473:pathology*; D009942:Organometallic Compounds / Q000008:administration & dosage / Q000493:pharmacokinetics*; D011471:Prostatic Neoplasms / Q000150:complications / Q000378:metabolism* / Q000473:pathology*; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013113:Spin Labels
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; D013113:Spin Labels; C064572:gadobenic acid; D008536:Meglumine
keywords: Arterial input function (AIF); Contrast agent dose; Dynamic contrast enhanced MRI (DCE-MRI) of prostate cancer; Empirical mathematical model (EMM); First pass peak; Reference tissue method