Motion corrected fetal body magnetic resonance imaging provides reliable 3D lung volumes in normal and abnormal fetuses

Abstract

Objectives To calculate 3D‐segmented total lung volume (TLV) in fetuses with thoracic anomalies using deformable slice‐to‐volume registration (DSVR) with comparison to 2D‐manual segmentation. To establish a normogram of TLV calculated by DSVR in healthy control fetuses. Methods A pilot study at a single regional fetal medicine referral centre included 16 magnetic resonance imaging (MRI) datasets of fetuses (22–32 weeks gestational age). Diagnosis was CDH (n = 6), CPAM (n = 2), and healthy controls (n = 8). Deformable slice‐to‐volume registration was used for reconstruction of 3D isotropic (0.85 mm) volumes of the fetal body followed by semi‐automated lung segmentation. 3D TLV were compared to traditional 2D‐based volumetry. Abnormal cases referenced to a normogram produced from 100 normal fetuses whose TLV was calculated by DSVR only. Results Deformable slice‐to‐volume registration‐derived TLV values have high correlation with the 2D‐based measurements but with a consistently lower volume; bias −1.44 cm3 [95% limits: −2.6 to −0.3] with improved resolution to exclude hilar structures even in cases of motion corruption or very low lung volumes. Conclusions Deformable slice‐to‐volume registration for fetal lung MRI aids analysis of motion corrupted scans and does not suffer from the interpolation error inherent to 2D‐segmentation. It increases information content of acquired data in terms of visualising organs in 3D space and quantification of volumes, which may improve counselling and surgical planning.

The Necessity of Magnetic Resonance Imaging in Congenital Diaphragmatic Hernia

“…The 3D segmentation of the fetal lung also begins to show its value, as underlined in recent studies such as Davidson et al [27] and Uss et al [28]. It is well known that fetal movements during MRI scans can greatly reduce the image quality and make accurate volume measurements a great challenge.…”

Assessment of the fetal lungs in utero

“… 12 3D MRI-derived lung volumes have been evaluated as a prognostic marker for pulmonary hypoplasia in CDH 13 , 14 and are used in clinical practice; however, validation in other high-risk groups is limited and confined to the research setting. 15 , 16 Recent advances in image acquisition such as fast single-shot, accelerated MRI sequences and postprocessing techniques such as DSVR 17 now yield reconstructed high-resolution motion-corrected 3D volumes from multiple stacks of slices affected by nonrigid motion ( Figure 1 ). DSVR oversamples the region of interest in which a single stack is selected as a template and iteratively aligns the reconstructed volume to each individual slice in a common coordinate space thereby accounting for unpredictable motion.…”

“…This technique has been used in uncomplicated pregnancies, 20 those at high risk of preterm birth, 21 and fetuses with CDH. 14

Figure 1 3T images of low-risk fetus at 30 weeks before and after applying DSVR 17 18 DSVR: Deformabale slice-to-volume registration.

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3D black blood cardiovascular magnetic resonance atlases of congenital aortic arch anomalies and the normal fetal heart: application to automated multi-label segmentation

“…For instance, the existing various implementations of 3D SVR reconstruction methods [ 3 , 4 , 7 ] already showed to improve information content of CMR for the fetal heart [ 1 ] as well as the other body organs [ 8 ]. In addition to visual inspection, the reconstructed 3D CMR images are also used for volume rendering as well as biometry [ 6 ] and segmentation for quantitative analysis [ 9 ].…”

“…Fig 9. An example of label propagation error in one of the testing datasets that required manual refinement: incorrect azygous vein segmentation…”