Diffusion tensor imaging of fetal spinal cord: feasibility and gestational‐age‐related changes

• Published in: Ultrasound in obstetrics & gynecology 2023-08, Vol.62 (2), p.241-247
• Main Authors: Corroenne, R., Grevent, D., Mahallati, H., Gauchard, G., Bussieres, L., Ville, Y., Salomon, L. J.
• Format: Article
• Language: English
• Subjects: Anisotropy; Central nervous system; Correlation analysis; Diffusion coefficient; diffusion tensor imaging; Diffusion Tensor Imaging - methods; DTI; Feasibility Studies; Female; fetal MRI; Fetuses; Gynecology; Humans; Image processing; Image reconstruction; Magnetic resonance imaging; Mathematical analysis; Medical imaging; Moisture content; Myelination; Neuroimaging; Obstetrics; Parameters; Patients; Pregnancy; Prospective Studies; Spinal cord; Spinal Cord - diagnostic imaging; Spinal Cord - pathology; Spine; Spine (lumbar); Substantia alba; Tensors; Thorax; Water content; White Matter
• ISSN: 0960-7692; 1469-0705
• DOI: 10.1002/uog.26208

ABSTRACT Objectives Diffusion tensor imaging (DTI) of the fetal brain is a relatively new technique that allows evaluation of white matter tracts of the central nervous system throughout pregnancy, as well as in certain pathological conditions. The objectives of this study were to evaluate the feasibility of DTI of the spinal cord in utero and to examine gestational‐age (GA)‐related changes in DTI parameters during pregnancy. Methods This was a prospective study conducted between December 2021 and June 2022 in the LUMIERE Platform, Necker–Enfants Malades Hospital, Paris, France, as part of the LUMIERE SUR LE FETUS trial. Women with a pregnancy between 18 and 36 weeks of gestation without fetal or maternal abnormality were eligible for inclusion. Sagittal diffusion‐weighted scans of the fetal spine were acquired, without sedation, using a 1.5‐Tesla magnetic resonance imaging scanner. The imaging parameters were as follows: 15 non‐collinear direction diffusion‐weighted magnetic‐pulsed gradients with a b‐value 700 s/mm2 and one B0 image without diffusion‐weighting; slice thickness, 3 mm; field of view (FOV), 36 mm; phase FOV, 1.00; voxel size, 4.5 × 2.8 × 3 mm3; number of slices, 7–10; repetition time, 2800 ms; echo time, minimum; and total acquisition time, 2.3 min. DTI parameters, including fractional anisotropy (FA) and apparent diffusion coefficient (ADC), were extracted at the cervical, upper thoracic, lower thoracic and lumbar levels of the spinal cord. Cases with motion degradation and those with aberrant reconstruction of the spinal cord on tractography were excluded. Pearson's correlation analysis was performed to evaluate GA‐related changes of DTI parameters during pregnancy. Results During the study period, 42 pregnant women were included at a median GA of 29.3 (range, 22.0–35.7) weeks. Five (11.9%) patients were not included in the analysis because of fetal movement. Two (4.8%) patients with aberrant tractography reconstruction were also excluded from analysis. Acquisition of DTI parameters was feasible in all remaining cases (35/35). Increasing GA correlated with increasing FA averaged over the entire fetal spinal cord (r, 0.37; P