CRANIAL ULTRASOUND
(ULTRASOUND OF BRAIN)


A cranial ultrasound is a scan of the structures of the brain. It enables us to examine normal brain structures, anomalies in the development of the brain, inflammation of the brain, brain tumours, haemorrhaging (bleeding) in the brain and hypoxic-ischaemic changes to the brain. It is carried out by using ultrasound waves that are reflected off of different brain structures after entering through the large fontanelle (“soft spot”). The large fontanelle constitutes an “acoustic window”, a window through which the ultrasound waves can penetrate to the brain structures. Frequencies between 5 Mhz and 7.5 MHz are used for the cranial ultrasound examination. Higher frequencies permit a higher resolution of details.

Cranial ultrasounds on newborns and infants, as opposed to other brain scans (e.g. CT, MR) can be carried out frequently, at any time, without the need for anaesthesia or sedation. The examination is safe and reliable, it can be done quickly, and up until now there is no proof of any adverse effects. It can be carried out on newborns even when they are in an incubator or in bed without disrupting intensive care conditions.

The examination is usually done through the large fontanelle. The child lies on her back, her head is supported by pillows or she lies in the arms of the examiner. A contact medium (hydrogel) improves the transmission of ultrasound waves. Gel is spread on the skin over the large fontanelle. A probe (transducer) is placed in the middle of the large fontanelle and is moved at different angles and in different directions to show specific views/sections of the brain. Since the results of an initial cranial ultrasound scan can be similar for various pathological conditions and some physiological changes in the brain, in addition to good quality equipment, the timing and frequency of scans as well as the experience and knowledge of the diagnostician are particularly important for a valid and full interpretation of a scan.

Indications for cranial ultrasound scanning in newborns and infants:

  • prematurity (especially gestational age of less than 35 weeks)

  • neurological disorders of the newborn or infant, convulsions

  • high-risk (“neurorisk”) factors during birth (e.g. asphyxiation, intrauterine growth retardation, respiratory distress syndrome, perinatal infection, newborns of diabetic mothers or mothers with gestational diabetes, hemorrhagic diathesis, traumatic delivery etc.)

  • head circumference inappropriate for age (macrocephaly or microcephaly)

  • facial asymmetry or other irregularities

  • newborns with spina bifida (meningomyelocele)

  • infections of the central nervous system

  • head injuries

  • symptoms or signs of increased intracranial pressure in infants

  • conditions after intracranial neurosurgical operations in infants.