Head Ultrasound Scans
Detection of Germinal Matrix-Intraventricular Haemorrhage and Periventricular Leukomalacia

Reviewed by Carl Kuschel

June
2005

Associated Risk Factors	Timing of IVH	Diagnosis
Indications for USS	Grading System	Other Information

Intracranial haemorrhage (ICH) can affect newborns of all gestational ages and often is clinically ‘silent’. Germinal matrix haemorrhage and intraventricular haemorrhage (GM-IVH) is most common in the premature population.

Estimates of frequency have changed over the last 20 years. Currently, large series report a 15% prevalence in infants <32 weeks.

National Women's data for the period 2001-2003 indicates an incidence of 10.0% for GM-IVH in infants<32 weeks. Those most at risk were infants <28 weeks gestation. Grade 3 and 4 GM-IVH was seen in 2.9% of infants<32 weeks, with a higher incidence (15.5%) in infants <26 weeks gestation.

The incidence of periventricular leukomalacia (PVLM) in infants <32 weeks at National Women's over the same period of time was 1%.

Routine screening for GM-IVH is performed in infants <30 weeks or <1250g at birth.

Associated Risk Factors

SGA status of newborn
Maternal pre-eclampsia
Asphyxia
Male gender

Outborn infant
Antepartum haemorrhage
Base deficit >10

Timing of IVH

Most haemorrhage occurs within the first three days of life.
"Late" haemorrhage (i.e., after three days of age) may be associated with pneumothorax and its restriction of venous return to the heart.

Diagnosis

GM-IVH is reliably diagnosed with ultrasonography.
Parenchymal injury (ischaemia, petechial haemorrhage, haemorrhagic infarct) can be diagnosed with ultrasonography, but with less sensitivity.
Parenchymal ischaemia, without haemorrhage, may not be evident even with transducers of high frequency and very good equipment.
MRI is more sensitive but currently impractical as a routine investigation in preterm infants.
CT scanning is more sensitive than ultrasonography in cases where extra axial (subdural, subarachnoid) or posterior fossa haemorrhage is suspected.

Indications for Cerebral Ultrasound Scan

Routine screening for GM-IVH should be performed in infants <30 weeks or <1250g at birth.
- Some more mature or larger infants will have cranial ultrasound scans performed because of clinical suspicion of GM-IVH.
- The first scan should be performed at 4-5 days of age, by which time most cases of GM-IVH will have occurred.
- Discussion with parent(s) regarding prognosis/follow up can be conducted by the admitting team.
Ultrasonograms can always be obtained when clinical signs and/or symptoms suggest that intracranial haemorrhage has occurred, regardless of the baby’s age.
A second ultrasound scan should be done at one month of age, looking at resolution of previous GM-IVH, evidence of parenchymal injury, and for evidence of periventricular leukomalacia (PVLM).
A "discharge" head ultrasound scan should be done at "term" (36 weeks is often chosen as the most appropriate time) or at discharge from the nursery.
- In infants <30 weeks, this should be done at the same time as the screening renal ultrasound scan for nephrocalcinosis.
Be aware that ultrasound is not a sensitive method of detecting cortical or brainstem injury as seen with neonatal encephalopathy, or for detecting evidence of cerebrovascular events or collections outside the brain.
- In infants suspected of other pathologies, MRI or CT should be considered.

Grading Systems

GM-IVH

I	Germinal layer (subependymal haemorrhage)
II	Intraventricular haemorrhage - no dilatation (<97th percentile)
III	Intraventricular haemorrhage with dilatation
IV	Intraparenchymal haemorrhage

Periventricular Leucomalacia

without cysts	echogenic periventricular margins (flare)
cystic	multiple small periventricular cysts
porencephaly	large intraparenchymal cysts

Other Information

Research protocols may require variations on a grading system; grading should follow the requirement of the protocols.
The ultrasonographers describe abnormalities in detail on their reports.
Be aware that transverse measurements of lateral ventricles from the midline will be influenced by the size of the cavum septum pellucidum, a normal midline structure in preterm infants. Scans should be reviewed with the Radiologist at conferences in NICU.

Head Ultrasound Scans Detection of Germinal Matrix-Intraventricular Haemorrhage and Periventricular Leukomalacia