Antenatal thymus volumes in fetuses that delivered &lt;32 weeks' gestation: An MRI pilot study

Story, Lisa; Zhang, Tong; Uus, Alena; Hutter, Jana; Egloff, Alexia; Gibbons, Deena L.; Ho, Alison; Al-Adnani, Mudher; Knight, Caroline; Theodoulou, Iakovos; Deprez, Maria; Seed, Paul; Tribe, Rachel M.; Shennan, Andrew; Rutherford, Mary

doi:10.1111/aogs.13983

Cited by 22 publications

(21 citation statements)

References 29 publications

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“…Coefficients > 0.75 were accepted as an indicator of good reliability [29]. Intra-observer reliability for MRIderived TV was confirmed previously between two expert operators (AE and LS), ICC = 0.964, P<=0.0001) [21].…”

Section: Thymic Measurementssupporting

confidence: 59%

“…All segmentations were undertaken by one operator (LS). Good inter observer variability had previously been confirmed with a further operator (AE) [21].…”

Section: Mri Scansmentioning

confidence: 76%

“…Intra-and inter-observer variability of MRI-derived TV had previously been ascertained [21]. Pearson correlation coefficients (PCC) (r) were then used to compare US-derived measurements with the 3D MRI-derived TV.…”

Section: Discussionmentioning

confidence: 99%

“…However, the technique is time-consuming [17], limited by both acoustic shadowing and movement artefact [18] and has poor inter-observer reliability [19]. MRI is less sensitive to fetal lie and increased maternal habitus, and slice-tovolume reconstruction methods can account for unpredictable fetal motion [20] providing a more accurate representation of true fetal thymic size [21]. Fetal thymus volume (TV) has been successfully measured on fetal magnetic resonance imaging (MRI) in both normal and growth-restricted fetuses [22] and those at high risk of preterm birth [21].…”

Section: Introductionmentioning

confidence: 99%

“…MRI is less sensitive to fetal lie and increased maternal habitus, and slice-tovolume reconstruction methods can account for unpredictable fetal motion [20] providing a more accurate representation of true fetal thymic size [21]. Fetal thymus volume (TV) has been successfully measured on fetal magnetic resonance imaging (MRI) in both normal and growth-restricted fetuses [22] and those at high risk of preterm birth [21]. However, the cost of MRI in comparison to conventional ultrasound may preclude its use in routine clinical practice.…”

Section: Introductionmentioning

confidence: 99%

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Assessment of the fetal thymus gland: Comparing MRI-acquired thymus volumes with 2D ultrasound measurements

Myers

Hutter

Matthew

et al. 2021

European Journal of Obstetrics & Gynecology and Reproductiv

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Objectives: The fetal thymus gland has been shown to involute in response to intrauterine infection, and therefore could be used as a non-invasive marker of fetal compartment infection. The objective of this study was to evaluate how accurately 2D ultrasound-derived measurements of the fetal thymus reflect the 3D volume of the gland derived from motion corrected MRI images. Study design: A retrospective study was performed using paired ultrasound and MRI datasets from the iFIND project (http://www.ifindproject.com). To obtain 3D volumetry of the thymus gland, T2weighted single shot turbo spin echo (ssTSE) sequences of the fetal thorax were acquired. Thymus volumes were manually segmented from deformable slice-to-volume reconstructed images. To obtain 2D ultrasound measurements, previously stored fetal cine loops were used and measurements obtained at the 3-vessel-view (3VV) and 3-vessel-trachea view (3VT): anterior-posterior diameter (APD), intrathoracic diameter (ITD), transverse diameter (TD), perimeter and 3-vessel-edge (3VE). Inter-observer and intra-observer reliability (ICC) was calculated for both MRI and ultrasound measurements. Pearson correlation coefficients (PCC) were used to compare 2D-parameters with acceptable ICC to TV. Results: 38 participants were identified. Adequate visualisation was possible on 37 MRI scans and 31 ultrasound scans. Of the 30 datasets where both MRI and ultrasound data were available, MRI had good interobserver reliability (ICC 0.964) and all ultrasound 3VV 2D-parameters and 3VT 3VE had acceptable ICC (>0.75). Four 2D parameters were reflective of the 3D thymus volume: 3VV TD r = 0.540 (P = 0.002); 3VV perimeter r = 0.446 (P = 0.013); 3VV APD r = 0.435 (P = 0.110) and 3VT TD r = 0.544 (P = 0.002). Conclusions: MRI appeared superior to ultrasound for visualization of the thymus gland and reproducibility of measurements. Three 2D US parameters, 3VV TD, perimeter and 3VT APD, correlated well with TV. Therefore, these represent a more accurate reflection of the true size of the gland than other 2D measurements, where MRI is not available.

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Section: Thymic Measurementssupporting

confidence: 59%

“…All segmentations were undertaken by one operator (LS). Good inter observer variability had previously been confirmed with a further operator (AE) [21].…”

Section: Mri Scansmentioning

confidence: 76%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Assessment of the fetal thymus gland: Comparing MRI-acquired thymus volumes with 2D ultrasound measurements

Myers

Hutter

Matthew

et al. 2021

European Journal of Obstetrics & Gynecology and Reproductiv

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Multi‐modal MRI reveals changes in placental function following preterm premature rupture of membranes

Hutter

Slator

Zampieri

et al. 2022

Magnetic Resonance in Med

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Purpose: Preterm premature rupture of membranes complicates up to 40% of premature deliveries. Fetal infection may occur in the absence of maternal symptoms, delaying diagnosis and increasing morbidity and mortality. A noninvasive antenatal assessment of early signs of placental inflammation is therefore urgently required.Methods: Sixteen women with preterm premature rupture of membranes < 34 weeks gestation and 60 women with uncomplicated pregnancies were prospectively recruited. A modified diffusion-weighted spin-echo single shot EPI sequence with a diffusion preparation acquiring 264 unique parameter combinations in < 9 min was obtained on a clinical 3 Tesla MRI scanner. The data was fitted to a 2-compartment T * 2 -intravoxel incoherent motion model comprising fast and slowly circulating fluid pools to obtain quantitative information on perfusion, density, and tissue composition. Z values were calculated, and correlation with time from between the rupture of membranes and the scan, gestational age at delivery, and time between scan and delivery assessed. Results: Placental T *2 was significantly reduced in preterm premature rupture of membranes, and the 2-compartmental model demonstrated that this decline is mainly linked to the perfusion component observed in the placental parenchyma. Multi-modal MRI measurement of placental function is linked to gestational age at delivery and time from membrane rupture. Conclusion:More complex models and data acquisition can potentially improve fitting of the underlying etiology of preterm birth compared with individual single-contrast models and contribute to additional insights in the future. This will need validation in larger cohorts. A multi-modal MRI acquisition between rupture of the membranes and delivery can be used to measure placental function and is linked to gestational age at delivery.

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Characterizing T1 in the fetal brain and placenta over gestational age at 0.55T

Aviles Verdera,

Tomi‐Tricot,

Story

et al. 2024

Magnetic Resonance in Med

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PurposeT1 mapping and T1‐weighted contrasts have a complimentary but currently under utilized role in fetal MRI. Emerging clinical low field scanners are ideally suited for fetal T1 mapping. The advantages are lower T1 values which results in higher efficiency and reduced field inhomogeneities resulting in a decreased requirement for specialist tools. In addition the increased bore size associated with low field scanners provides improved patient comfort and accessibility. This study aims to demonstrate the feasibility of fetal brain T1 mapping at 0.55T.MethodsAn efficient slice‐shuffling inversion‐recovery echo‐planar imaging (EPI)‐based T1‐mapping and postprocessing was demonstrated for the fetal brain at 0.55T in a cohort of 38 fetal MRI scans. Robustness analysis was performed and placental measurements were taken for validation.ResultsHigh‐quality T1 maps allowing the investigation of subregions in the brain were obtained and significant correlation with gestational age was demonstrated for fetal brain T1 maps () as well as regions‐of‐interest in the deep gray matter and white matter.ConclusionsEfficient, quantitative T1 mapping in the fetal brain was demonstrated on a clinical 0.55T MRI scanner, providing foundations for both future research and clinical applications including low‐field specific T1‐weighted acquisitions.

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Antenatal thymus volumes in fetuses that delivered <32 weeks' gestation: An MRI pilot study

Abstract: This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Cited by 22 publications

References 29 publications

Assessment of the fetal thymus gland: Comparing MRI-acquired thymus volumes with 2D ultrasound measurements

Assessment of the fetal thymus gland: Comparing MRI-acquired thymus volumes with 2D ultrasound measurements

Multi‐modal MRI reveals changes in placental function following preterm premature rupture of membranes

Characterizing T1 in the fetal brain and placenta over gestational age at 0.55T

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