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Titolo:
IN-VIVO PERFUSION MEASUREMENTS IN THE HUMAN PLACENTA USING ECHO-PLANAR IMAGING AT 0.5 T
Autore:
GOWLAND PA; FRANCIS S; DUNCAN KR; FREEMAN AJ; ISSA B; MOORE RJ; BOWTELL RW; BAKER PN; JOHNSON IR; WORTHINGTON BS;
Indirizzi:
UNIV NOTTINGHAM,MAGNET RESONANCE CTR NOTTINGHAM NG7 2RD ENGLAND UNIV NOTTINGHAM,ACAD RADIOL NOTTINGHAM NG7 2RD ENGLAND CITY HOSP,MAGNET RESONANCE CTR,DEPT PHYS OBSTET & GYNAECOL NOTTINGHAMENGLAND
Titolo Testata:
Magnetic resonance in medicine
fascicolo: 3, volume: 40, anno: 1998,
pagine: 467 - 473
SICI:
0740-3194(1998)40:3<467:IPMITH>2.0.ZU;2-F
Fonte:
ISI
Lingua:
ENG
Soggetto:
NUCLEAR MAGNETIC-RESONANCE; INVERSION;
Keywords:
PLACENTA; PERFUSION; FETUS; OPTIMIZATION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
14
Recensione:
Indirizzi per estratti:
Citazione:
P.A. Gowland et al., "IN-VIVO PERFUSION MEASUREMENTS IN THE HUMAN PLACENTA USING ECHO-PLANAR IMAGING AT 0.5 T", Magnetic resonance in medicine, 40(3), 1998, pp. 467-473

Abstract

This paper presents the first in vivo measurements of perfusion in the human placenta from 20 weeks gestational age until term, using the non-selective/selective inversion recovery echo-planar imaging sequence, in which data is alternately acquired following a selective and non-selective inversion pulse. Twenty pairs of images were collected, two each at the following inversion times: 20, 310, 610, 910, 1110, 1410, 1910, 2810, 3310, and 4510 ms with the sequence being repeated with a repetition time (TR) of 10 s, The results of these measurements were used to suggest the optimum sequence for future work in terms of the signal to noise ratio in the measured perfusion rate in a given measurement time. The sequence was also analyzed to determine the expected variability in the measurements. In normal pregnancies the average value of perfusion rate was found to be 176 (standard error = +/-24) ml/100 mg/min, (n = 16, standard deviation = 96 ml/100 mg/min), The expected variability in the measured parameters due to signal to noise ratio considerations alone was calculated to be 71%, For a maximum scanning time of 400 s, the optimum sequence for measuring placental perfusion was found to require 8 repetitions at each of 10 inversion times which were geometrically spaced (given by a(o), a(o)r, a(o)r(2), a(o)r(3),...), with a(o) = 850 ms, r = 1.073 and TR = 5 s, giving a pixel variability of 38%, Other timing schemes are recommended for measuring perfusion in other anatomical regions with different values of perfusion rateand longitudinal relaxation time.

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Documento generato il 02/12/20 alle ore 17:58:01