The utility of MRI for measuring hematocrit in fetal anemia

Xu, Jiawei; Duan, An Qi; Marini, Davide; Lim, Jessie Mei; Keunen, Johannes; Portnoy, Sharon; Sled, John G.; McCrindle, Brian W.; Kingdom, John; Macgowan, Christopher K.; Seed, Mike

doi:10.1016/j.ajog.2019.07.016

Cited by 26 publications

(25 citation statements)

References 22 publications

(29 reference statements)

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“…The pulse sequence design used for humans (variable

τ

180 ; 2013–2014), has since evolved and therefore differs from that of our recent work in humans (Xu et al . 2019) and that used in the sheep (consistent

τ

180 ; 2017).…”

Section: Methodsmentioning

confidence: 88%

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Normal human and sheep fetal vessel oxygen saturations by T2 magnetic resonance imaging

Saini

Darby

Portnoy

et al. 2020

The Journal of Physiology

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Human fetal Doppler ultrasound and invasive blood gas measurements obtained by cordocentesis or at the time of delivery reveal similarities with sheep (an extensively used model for human fetal cardiovascular physiology). r Oxygen saturation (SO 2) measurements in human fetuses have been limited to the umbilical and scalp vessels, providing little information about normal regional SO 2 differences in the fetus. r Blood T2 MRI relaxometry presents a non-invasive measure of SO 2 in the major fetal vessels. r This study presents the first in vivo validation of fetal vessel T2 oximetry against the in vitro T2-SO 2 relationship using catheterized sheep fetuses and compares the normal SO 2 in the major vessels between the human and sheep fetal circulations. r Human fetal vessel SO 2 by T2 MRI confirms many similarities with the sheep fetal circulation and is able to demonstrate regional differences in SO 2 ; in particular the significantly higher SO 2 in the left versus right heart.

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“…The pulse sequence design used for humans (variable

τ

180 ; 2013–2014), has since evolved and therefore differs from that of our recent work in humans (Xu et al . 2019) and that used in the sheep (consistent

τ

180 ; 2017).…”

Section: Methodsmentioning

confidence: 88%

“…Moving forward, we recommend future studies to use a fixed

τ

180 below 25 ms, similar to our updated technique in the sheep in this paper and that recently applied to anaemic human fetuses (Xu et al . 2019).…”

Section: Discussionmentioning

confidence: 99%

Normal human and sheep fetal vessel oxygen saturations by T2 magnetic resonance imaging

Saini

Darby

Portnoy

et al. 2020

The Journal of Physiology

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“…Moreover, MCA‐PSV may be falsely reassuring in approximately 5% of alpha‐thalassemia patients with moderate‐to‐severe anemia . The feasibility of measuring fetal hematocrit using a combination of T1 and T2 relaxometry measurements has been demonstrated in fetuses with a range of causes of fetal anemia, revealing that measurement of the fetal hematocrit by magnetic resonance relaxometry is comparable with the gold standard fetal blood sampling . Fetal hematocrit measured by MRI is more specific and has a significantly higher positive predictive value than Doppler ultrasound for the detection of moderate‐to‐severe fetal anemia over a wide range of hematocrit levels and gestational ages .…”

Section: Fetal Anemia and The Need For Invasive Umbilical Cord Samplimentioning

confidence: 99%

“…The feasibility of measuring fetal hematocrit using a combination of T1 and T2 relaxometry measurements has been demonstrated in fetuses with a range of causes of fetal anemia, revealing that measurement of the fetal hematocrit by magnetic resonance relaxometry is comparable with the gold standard fetal blood sampling . Fetal hematocrit measured by MRI is more specific and has a significantly higher positive predictive value than Doppler ultrasound for the detection of moderate‐to‐severe fetal anemia over a wide range of hematocrit levels and gestational ages . In estimating hematocrit, noninvasive magnetic resonance relaxometry provides a more direct assessment of the severity of fetal anemia compared with the measurement of a MCA PSV, which is a physiological response to anemia .…”

Section: Fetal Anemia and The Need For Invasive Umbilical Cord Samplimentioning

confidence: 99%

“…Fetal hematocrit measured by MRI is more specific and has a significantly higher positive predictive value than Doppler ultrasound for the detection of moderate‐to‐severe fetal anemia over a wide range of hematocrit levels and gestational ages . In estimating hematocrit, noninvasive magnetic resonance relaxometry provides a more direct assessment of the severity of fetal anemia compared with the measurement of a MCA PSV, which is a physiological response to anemia . Based on a comparison of hematocrit measured by MRI with direct blood sampling and MCA‐PSV in 23 fetuses, it has been suggested that the application of fetal MRI could improve clinical care by limiting unnecessary invasive umbilical cord blood samples in fetuses with elevated MCA PSV …”

Section: Fetal Anemia and The Need For Invasive Umbilical Cord Samplimentioning

confidence: 99%

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Current and future role of fetal cardiovascular MRI in the setting of fetal cardiac interventions

Marini

Sun

et al. 2019

Prenatal Diagnosis

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Over recent years, technical developments resulting in the feasibility of fetal cardiovascular magnetic resonance (CMR) have provided a new diagnostic tool for studying the human fetal heart and circulation. During the same period, we have witnessed the arrival of several minimally invasive fetal cardiac interventions (FCI) as a possible form of treatment in selected congenital heart diseases (CHDs). The role of fetal CMR in the planning and monitoring of FCI is not yet clear. Indeed, high-quality fetal CMR is not available or routinely offered at most centers caring for patients with prenatally detected CHD. However, in theory, fetal CMR could have much to offer in the setting of FCI by providing complementary anatomic and physiologic information relating to the specific intervention under consideration. Similarly, fetal CMR may be useful as an alternative imaging modality when ultrasound is hampered by technical limitations, for example, in the setting of oligohydramnios and in late gestation. In this review, we summarize current experience of the use of fetal CMR in the diagnosis and monitoring of fetuses with cardiopathies in the setting of a range of invasive in utero cardiac and vascular interventions and medical treatments and speculate about future directions for this versatile imaging medium.

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An efficient and combined placental ‐ADC acquisition in pregnancies with and without pre‐eclampsia

Hutter

Jackson

et al. 2021

Magnetic Resonance in Med

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Purpose To provide a new approach to jointly assess microstructural and molecular properties of the human placenta in vivo fast and efficiently and to present initial evidence in cohorts of healthy pregnancies and those affected by pre‐eclampsia. Methods Slice and diffusion preparation shuffling, built on the previously proposed ZEBRA method, is presented as a robust and fast way to obtain T1 and apparent diffusivity coefficient (ADC) values. Joint modeling and evaluation is performed on a cohort of healthy and pre‐eclamptic participants at 3T. Results The datasets show the ability to obtain robust and fast T1‐ADC measurements. Significant decay over gestation in T1 (−11 ms/week, P<.05) and a trend toward significance in ADC (−0.23 mm/s2/week, P = .08) values can be observed in a control cohort. Values for the pre‐eclamptic pregnancies show a negative trend for both ADC and T1. Conclusions The presented sequence allows the simultaneous acquisition of 2 of the most promising quantitative parameters to study placental insufficiency—identified individually as relevant in previous studies—in under 2 minutes. This allows dynamic assessment of physiological processes, reduced inconsistency in spatial comparisons due to reduced motion artefacts and opens novel avenues for analysis. Initial results in pre‐eclamptic placentas, with depicted changes in both ADC and T1, illustrate its potential to identify cases of placental insufficiency. Future work will focus on expanding the field‐of‐view using multi‐band acceleration techniques and the expansion to larger and more diverse patient groups.

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The utility of MRI for measuring hematocrit in fetal anemia

Cited by 26 publications

References 22 publications

Normal human and sheep fetal vessel oxygen saturations by T2 magnetic resonance imaging

Normal human and sheep fetal vessel oxygen saturations by T2 magnetic resonance imaging

Current and future role of fetal cardiovascular MRI in the setting of fetal cardiac interventions

An efficient and combined placental ‐ADC acquisition in pregnancies with and without pre‐eclampsia

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