The detection of spina bifida at 11–13+6 weeks' gestation

Abstract

Prenatal detection of spina bifida during a 12-week ultrasound can be a complex diagnosis. Spina bifida is a condition characterised by failure of the neural tube to form during embryological development, and the early manifestations in the head and spine may be detected on ultrasound. A good understanding of the characteristic intracranial ultrasound signs within the first trimester, such as the intracranial translucency, cisterna magna and aqueduct of Sylvius will allow for greater awareness and detection of spina bifida at this gestation. Other markers such as biparietal diameter, transverse abdominal diameter, brain stem to occiput bone and frontomaxillary facial angle have been shown to greatly increase the detection of such a condition. Recent advances in technology such as 3D sonography and transvaginal scanning have greatly increased visualisation and provided greater confidence in detection. At present, there is no formal direction put forward from major ultrasound bodies for the detection, at this gestation; however, bodies such as ISUOG have created awareness. Future developments suggest that the visualisation of the intracranial translucency and aqueduct of Sylvius will become a standard practice while scanning at this gestation.