title: In vivo intravoxel incoherent motion measurements in the human placenta using echo-planar imaging at 0.5 T.
abstract: This paper presents the first in vivo measurements of intravoxel incoherent motion in the human placenta, obtained using the pulsed gradient spin echo (PGSE) sequence. The aims of this study were two-fold. The first was to provide an initial estimate of the values of the IVIM parameters in this organ, which are currently unknown. The second aim was then to use these results to optimize the sequence timings for future studies. The moving blood fraction (f), diffusion coefficient (D), and pseudo-diffusion coefficient (D*) were measured. The average value of f was 26 +/- 6 % (mean +/- SD), D was 1.7 +/- 0.5 x 10(-3) mm2/sec, and D* was 57 +/- 41 x 10(-3) mm2/sec. For the optimized values of b, the expected percentage uncertainty in the fitted values of f, D, and D* for the placenta were sigmaf/f = 14.9%, sigmaD/D = 14.3%, sigmaD*/D* = 44.9%, for an image signal-to-noise of 20:1, and a total imaging time of 800 sec.
authors.affiliation: Magnetic Resonance Centre, School of Physics and Astronomy, University of Nottingham, UK.
authors.forename: R J
authors.initials: RJ
authors.lastname: Moore
authors.forename: B
authors.initials: B
authors.lastname: Issa
authors.forename: P
authors.initials: P
authors.lastname: Tokarczuk
authors.forename: K R
authors.initials: KR
authors.lastname: Duncan
authors.forename: P
authors.initials: P
authors.lastname: Boulby
authors.forename: P N
authors.initials: PN
authors.lastname: Baker
authors.forename: R W
authors.initials: RW
authors.lastname: Bowtell
authors.forename: B S
authors.initials: BS
authors.lastname: Worthington
authors.forename: I R
authors.initials: IR
authors.lastname: Johnson
authors.forename: P A
authors.initials: PA
authors.lastname: Gowland
mesh_terms: D000704:Analysis of Variance; D016477:Artifacts; D017352:Echo-Planar Imaging / Q000295:instrumentation / Q000379:methods* / Q000706:statistics & numerical data; D005260:Female; D005324:Fetal Movement; D006801:Humans; D009068:Movement; D010920:Placenta / Q000033:anatomy & histology*; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third; D012016:Reference Values; D013997:Time Factors