transfontanelar

Transfontanelar is a medical term used to describe approaches that access the brain through a fontanel, the soft spot on an infant’s skull where the sutures have not yet closed. The most common application is transfontanelar ultrasound, which uses the open anterior fontanel as an acoustic window to visualize brain structures in newborns and young infants.

In transfontanelar ultrasound, a curvilinear or linear ultrasound transducer is placed on the fontanel to obtain real-time images of the neonatal brain. It is a bedside, noninvasive, radiation-free modality that can be repeated as needed. Indications include evaluation of intraventricular hemorrhage, hydrocephalus, congential brain malformations, periventricular leukomalacia, intracranial infections, and assessment of cerebral blood flow or development in premature infants.

Advantages include safety, portability, and the ability to perform rapid assessments in the NICU without sedation or transport. Limitations involve a relatively limited field of view and lower resolution compared with MRI or CT, particularly for posterior fossa structures or subtle cortical abnormalities. The quality of imaging depends on the presence of an adequate acoustic window, which may be reduced as the fontanel closes with age.

Beyond imaging, the term transfontanelar can describe any procedure or examination conducted through the fontanel, though in clinical practice its primary association is with transfontanelar ultrasound for neonatal brain assessment. Related concepts include neonatal neuroimaging and neonatal cranial ultrasound.