Kau Thomas, Birnbacher Robert, Schwärzler Peter, Habernig Sandra, Deutschmann Hannes, Boltshauser Eugen
Institute of Radiology, Villach General Hospital, Nikolaigasse 43, 9500 Villach, Austria.
Department of Pediatrics, Villach General Hospital, Villach, Austria.
Cerebellum Ataxias. 2019 Mar 5;6:4. doi: 10.1186/s40673-019-0098-1. eCollection 2019.
Fetal magnetic resonance imaging (MRI), mainly performed at standard field strength, plays a role in the classification of posterior fossa malformations. In the context of early second-trimester screening, upward rotation of the cerebellar vermis per se is usually compatible with a more favorable outcome than Dandy-Walker malformation and profound vermian hypoplasia. Delayed fenestration of Blake's pouch may either mimic vermian hypoplasia by compression or be associated with it in individual cases. To increase specificity, there is a growing interest in the use of high-field MRI which is believed to be safe as long as the specific absorption rate is kept within accepted limits. We aim to illustrate its added value during the second and third trimester.
In the first case, fetal MRI at 1.5 Tesla was performed at 21 and 27 weeks' gestation with sonographic follow up postnataly. In the second case, 3 Tesla MR images were acquired at 21 and 34 weeks' gestation as well as in the neonatal period.
This pictorial case vignette supports the suggestion that mid-gestational MRI at 3 Tesla has the potential to exclude pronounced vermian hypoplasia with higher confidence than at 1.5 Tesla. However, the discrimination of mild hypoplasia from slight deformation of the cerebellar vermis will likely remain challenging.
胎儿磁共振成像（MRI）主要在标准场强下进行，在小脑后窝畸形的分类中发挥作用。在孕中期早期筛查的背景下，小脑蚓部本身向上旋转通常比Dandy-Walker畸形和严重蚓部发育不全的预后更有利。Blake囊延迟开窗可能通过压迫模拟蚓部发育不全，或在个别情况下与之相关。为了提高特异性，人们对使用高场MRI的兴趣日益增加，只要比吸收率保持在可接受范围内，高场MRI被认为是安全的。我们旨在说明其在孕中期和孕晚期的附加价值。
第一例在孕21周和27周时进行了1.5特斯拉的胎儿MRI检查，并在产后进行超声随访。第二例在孕21周和34周以及新生儿期采集了3特斯拉的MR图像。
本病例图片支持以下观点，即孕中期3特斯拉MRI比1.5特斯拉MRI更有信心排除明显的蚓部发育不全。然而，区分轻度发育不全和小脑蚓部的轻微变形可能仍然具有挑战性。
