[Current events in fetal magnetic resonance].
The challenge of fetal imaging is crucial in France because of the law allowing termination of pregnancy (TOP) until the end of pregnancy. Fetal MRI is an imaging tool always used after ultrasonography (US). Its indications are pertinent only in relation with a prenatal center. Fetal MRI raises parental anxiety to take into account before and during the examination. To date, cerebral indications are predominant. Fetal brain maturation can be followed with MRI (gyration and myelination) but the optimal moment of a fetal MRI depends on the suspected pathology: the analysis of gyration is possible only by 28 WG, as before this time, the brain surface is smooth; in contrast, the posterior fossa demonstrates a definitive morphology since 20 WG. The ventriculomegaly is the most frequent call sign and includes various entities. MRI can disclose associated abnormalities (heterotopia, gyration, white matter, median line), which can suggest diagnosis and pronosis. A cystic pouch of the posterior fossa must lead to a careful analysis of cerebellum and brainstem to approach the diagnosis. Extracerebral indications become progressively larger and fetal MRI is a useful complementary tool after US to study tumors, particularly cervicothoracic masses. MRI can help to assess the level of bowel obstruction but multiple stenosis and post-stenotic bowel is difficult to evaluate. Fetal MRI can help to evaluate bilateral important pyelocalicial dilatation.
Adamsbaum
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C
université Paris Descartes, Paris, France. svp.radio@svp.aphp.fr
Mezzetta
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L
Hornoy
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P
D001921:Brain / Q000002:abnormalities*; D002552:Cerebral Ventricles / Q000002:abnormalities; D003388:Cranial Fossa, Posterior / Q000002:abnormalities*; D005260:Female; D005333:Fetus / Q000002:abnormalities*; D006801:Humans; D007415:Intestinal Obstruction / Q000175:diagnosis; D008279:Magnetic Resonance Imaging; D009369:Neoplasms / Q000175:diagnosis*; D011237:Predictive Value of Tests; D011247:Pregnancy; D011296:Prenatal Diagnosis; D011704:Pyelonephritis / Q000175:diagnosis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016216:Ultrasonography, Prenatal / Q000379:methods