3D-MRI Investigation On Fetal Surface Malformations Vs.2d-MRI And 3D-US

Objective: To investigate the clinical value of three dimensional magnetic resonance imaging (3D-MRI) in displaying the normal and abnormal structure of fetal surface malformations.Methods: 68 pregnant women were examined by conventional prenatal US (Ultrasonography) and MRI, 36 fetus (gestational age ranged from 18.2~38 weeks, with a mean of 26.4 weeks) with surface malformations were conformed by follow-up results and autopsy. Fetal MRI was performed by a 1.5T GE superconducting MR scanner within 2 days after US examinations. A three-plane rapid localizer acquisition was performed to ensure proper positioning of the coil and patient. From the localizer acquisition, conventional axial, sagittal and coronal single-shot fast spin-echo T2-weighted sequences (SSFSE) and thick-slab heavy T2WI with SSFSE were performed, 3D-MRI with three dimensional fast image employing steady-state acquisition (3D-FIESTA) were acquired. Volume rendering (VR), muti-planar reconstruction (MPR), transparent mode and MR virtual endoscopy (MRVE) were employed in image post-processing on workstation. The results from 2D- MR, 3D-MRI and US images were compared with each other as well as the autopsy and follow-up results.Results: A total of 42 fetal surface malformations were identified by autopsy and follow-up after birth, including cleft lip and palate (with the number of cases n=6), outgrowth of face (n=1), micromandible (n=1), flat nose (n=2), microtia (n=1) ,hemangioma of face (n=2), microcephalia (n=5), parabiotic twins (n=1),teratoma (n=3), varus feet (n=4), short limbs deformity (n=3), urachal diverticulum (n=1), limb posture abnormalities (n=4), upper forearm absent (n=3), oligodactylia (n=3), absence of palm (n=2). The sensitivity, specificity, accuracy were 90.5%/69.1%/95.1%, 100%/100%/99.8%, 99.3%/97.7%/99.5%. There are obvious statistical difference for sensitivity and accuracy of 2D-MRI and 3D-MRI, and unobvious statistical difference for sensitivity ,specificity, and accuracy of 3D-MRI and 3D-US."one stop"3D-FIESTA was not affected by the complex superficial curvature changes, and could clearly demonstrate the surface features, three dimensional patterns and spatial positions of the fetus like photoes, VR images can directly demonstrate the fetal surface structures such as cheek, ear, the alae and bridge of the nose, nostril, lower mandible, labia oris, enitalia, umbilical cord, and extremity etc, MPR (multiple-planar mode) could demonstrate the region of interest from various directions.Conclusions: 3D-MRI is better than conventional 2D-MRI in displaying fetal normal surface structure and malformations, and it has lager fov and higher soft tissue resolution than US. The 3D fetal MR imaging can be used as a complementary strategy to US in diagnosing fetal surface malformations...