20 research outputs found
Anatomy-Aware Self-supervised Fetal MRI Synthesis from Unpaired Ultrasound Images
Fetal brain magnetic resonance imaging (MRI) offers exquisite images of the
developing brain but is not suitable for anomaly screening. For this ultrasound
(US) is employed. While expert sonographers are adept at reading US images, MR
images are much easier for non-experts to interpret. Hence in this paper we
seek to produce images with MRI-like appearance directly from clinical US
images. Our own clinical motivation is to seek a way to communicate US findings
to patients or clinical professionals unfamiliar with US, but in medical image
analysis such a capability is potentially useful, for instance, for US-MRI
registration or fusion. Our model is self-supervised and end-to-end trainable.
Specifically, based on an assumption that the US and MRI data share a similar
anatomical latent space, we first utilise an extractor to determine shared
latent features, which are then used for data synthesis. Since paired data was
unavailable for our study (and rare in practice), we propose to enforce the
distributions to be similar instead of employing pixel-wise constraints, by
adversarial learning in both the image domain and latent space. Furthermore, we
propose an adversarial structural constraint to regularise the anatomical
structures between the two modalities during the synthesis. A cross-modal
attention scheme is proposed to leverage non-local spatial correlations. The
feasibility of the approach to produce realistic looking MR images is
demonstrated quantitatively and with a qualitative evaluation compared to real
fetal MR images.Comment: MICCAI-MLMI 201
Expanding the FANCO/RAD51C associated phenotype: Cleft lip and palate and lobar holoprosencephaly, two rare findings in Fanconi anemia
Fanconi anemia is a rare chromosome instability disorder with a highly variable phenotype. In the antenatal and neonatal periods, the diagnosis is usually suggested by the presence of typical congenital abnormalities such as intrauterine growth retardation, microcephaly and radial ray defects. We report a newborn female with a prenatal diagnosis of Fanconi anemia, complementation group O (FANCO). Antenatal ultrasounds identified symmetrical intrauterine growth retardation, complex heart defect as well as brain anomalies, overlapping fingers and cleft lip and palate. Imperforate anus was detected after birth. Compound heterozygous RAD51C variants c. [571+5G > A]; [c.935G > A] were detected by prenatal whole exome sequencing and cellular hypersensitivity to DNA interstrand crosslinking agents (DEB, MMC) was confirmed after birth. With only one previously described homozygous RAD51C variant to date, our findings expand the phenotypic spectrum of FANCO and suggest it should be part of the antenatal differential diagnosis for trisomy 13 and 18, due to the presence of atypical findings such as cleft lip and palate, holoprosencephaly, growth restriction and overlapping fingers. © 2018 Elsevier Masson SAS
Fusion imaging in brain structure measurements on a fetus phantom, combining real‐time ultrasound with magnetic resonance imaging
Objectives: To assess synchronisation of MRI and US in measuring foetus phantom head structures; inter-method, intra- and inter-observer differences on biparietal diameter (BPD), head diameter, anterio-posterior head diameter (HAP) and lateral ventricle structures (VS). Methods: Fusion Imaging (FI) has been performed by combining MRI and US simultaneously. Axial scans of 1.5 Tesla MRI on a foetus phantom were acquired and uploaded on a US machine (EPIQ 7G, Philips). A PercuNav US tracker allowed the system to recognise and display the position of the transducer. A fetal phantom tracker was used as a phantom reference. Real-time US of the phantom head was performed by synchronising the uploaded MRI images using different landmarks. Synchronisation has been assessed by taking measurements after rotating the US probe by 90. Measurements were taken by three different observers twice. Differences in measurements between MRI and US, inter-, intra-observer differences in all measurements were assessed. Results: BPD, HAP and VS measurements before rotation were 0.13 ± 0.06 cm, 0.46 ± 0.09 cm and 0.4 ± 0.23 cm (width) and mean 0.6 ± 0.25 cm (length) larger at MRI than at US using any number of landmarks. After US probe rotation VS were 0.3 ± 0.24 cm in width and 0.3 ± 0.27 cm in length. Intra- and inter-observer differences in all measurements were small. Conclusions: FI showed good synchronisation in measurements. BPD, HAP and VS were larger at MRI than US, likely a result of the way images are generated. Intra-, inter-observer differences between measurements were small. This can be important when reporting geometric measures from FI