The hemodynamics of late-onset intrauterine growth restriction by MRI

Zhu, Meng; Milligan, Natasha; Keating, Sarah; Windrim, Rory; Keunen, Johannes; Thakur, Varsha; Öhman, Annika; Portnoy, Sharon; Sled, John G.; Kelly, Edmond; Yoo, Shi Joon; Gross-Wortmann, Lars; Jaeggi, Edgar; Macgowan, Christopher K.; Kingdom, John; Seed, Mike

doi:10.1016/j.ajog.2015.10.004

Cited by 131 publications

(130 citation statements)

References 46 publications

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“…The similarity in relaxation properties is encouraging, as it supports the findings of studies which used adultderived calibrations to perform fetal/neonatal oximetry (e.g. [2,3]). As the first characterization of the MRI properties of fetal blood at 1.5 Tesla, this work represents a key step in the adaptation of non-invasive vascular oximetry techniques towards a fetal population.…”

Section: Resultssupporting

confidence: 70%

“…The feasibility of relaxometry measurements in human fetal vessels using magnetization prepared, motion corrected, fast imaging techniques has recently been demonstrated [2,3]. As such, the potential for accurate, non-invasive estimation of fetal blood cO 2 is now within reach.…”

Section: Introductionmentioning

confidence: 99%

“…The remaining terms in Eq. [3], which describe the transverse relaxation rate of blood in the absence of deoxyhemoglobin induced field inhomogeneities were unchanged. Application of the J-C model to blood data requires adopting a model of uniformly magnetized, randomly distributed spheres for blood [10,26,27].…”

Section: Biophysical Modelsmentioning

confidence: 99%

“…For the T 2 fits the RMSD increased by 1.5% and 2.2%, respectively. Furthermore, the use of Hct in place of f ery in Equations [1] and [3] results in simpler, more direct relationships between the relaxation rate and the hematocrit -the parameter of clinical relevance. Based on these observations, Hct, rather than f ery , is used throughout this work.…”

Section: Biophysical Modelsmentioning

confidence: 99%

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Relaxation properties of human umbilical cord blood at 1.5 Tesla

et al. 2016

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Purpose-To characterize the MRI relaxation properties of human umbilical cord blood at 1.5 Tesla.Methods-Relaxometry measurements were performed on cord blood specimens (N=88, derived from 6 caesarean deliveries) spanning a broad range of hematocrits (Hct=0.19-0.76) and oxygen saturations (sO 2 =4-100%), to characterize the dependence of T 1 and T 2 on these blood properties.Adult blood data (N = 31 specimens, derived from two volunteers) were similarly studied to validate our experimental methods by comparison with existing literature. Using biophysical models previously developed for adult blood, new model parameters were estimated, which relate Hct and sO 2 to the observed cord blood relaxation times.Results-Fitted biophysical models explained more than 90% of the variation in T 1 and T 2 . In general, T 2 relaxation times of cord blood were longer (by up to 35%) than those of adult blood, while T 1 relaxation times were slightly shorter (by up to 10%).Conclusion-The models and fitted parameters presented here can be used for calibration of future MRI investigations of fetal and neonatal blood physiology. This study is an important step in facilitating accurate, non-invasive assessments of fetal blood oxygen content, a valuable diagnostic parameter in the identification and treatment of fetal hypoxia.

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Section: Resultssupporting

confidence: 70%

Section: Introductionmentioning

confidence: 99%

Section: Biophysical Modelsmentioning

confidence: 99%

Section: Biophysical Modelsmentioning

confidence: 99%

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Relaxation properties of human umbilical cord blood at 1.5 Tesla

et al. 2016

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“…Although malnutrition contributes to fetal growth restriction in many developing countries (18), placental insufficiency is the major cause of low birth weight within the Western world (19). Placental hypoxia that occurs in response to placental insufficiency alters fetal oxygen delivery resulting in intrauterine growth restriction ( IUGR ) (20). Rook et al recently utilized a rat model of prenatal hypoxia to examine the role of muscle SNA in the fetal origins of hypertension.…”

Section: The Sympathetic Nervous System and The Developmental Programmentioning

confidence: 99%

Developmental Programming of Hypertension

et al. 2016

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Placental MRI Predicts Fetal Oxygenation and Growth Rates in Sheep and Human Pregnancy

et al. 2022

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Magnetic resonance imaging (MRI) assessment of fetal blood oxygen saturation (SO 2 ) can transform the clinical management of high-risk pregnancies affected by fetal growth restriction (FGR). Here, a novel MRI method assesses the feasibility of identifying normally grown and FGR fetuses in sheep and is then applied to humans. MRI scans are performed in pregnant ewes at 110 and 140 days (term = 150d) gestation and in pregnant women at 28 +3 ± 2 +5 weeks to measure feto-placental SO 2 . Birth weight is collected and, in sheep, fetal blood SO 2 is measured with a blood gas analyzer (BGA). Fetal arterial SO 2 measured by BGA predicts fetal birth weight in sheep and distinguishes between fetuses that are normally grown, small for gestational age, and FGR. MRI feto-placental SO 2 in late gestation is related to fetal blood SO 2 measured by BGA and body weight. In sheep, MRI feto-placental SO 2 in mid-gestation is related to fetal SO 2 later in gestation. MRI feto-placental SO 2 distinguishes between normally grown and FGR fetuses, as well as distinguishing FGR fetuses with and without normal Doppler in humans. Thus, a multi-compartment placental MRI model detects low placental SO 2 and distinguishes between small hypoxemic fetuses and normally grown fetuses.

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The hemodynamics of late-onset intrauterine growth restriction by MRI

Cited by 131 publications

References 46 publications

Relaxation properties of human umbilical cord blood at 1.5 Tesla

Relaxation properties of human umbilical cord blood at 1.5 Tesla

Developmental Programming of Hypertension

Placental MRI Predicts Fetal Oxygenation and Growth Rates in Sheep and Human Pregnancy

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