D2 receptor imaging in neonates using I-123 iodobenzamide brain SPECT.

Area of Science:

• Neonatal neurology
• Neuroimaging
• Biochemical markers

Background:

• Hypoxic-ischemic injury in neonates can lead to severe neurodevelopmental impairments, including cerebral palsy.
• Damage to the striatum is often associated with the dyskinetic form of cerebral palsy.
• Early detection of brain injury and its impact on neurochemistry is crucial for intervention.

Purpose of the Study:

• To evaluate the viability of dopamine D2 receptors in the perinatal period using I-123 iodobenzamide brain SPECT.
• To correlate D2 receptor viability with early neurologic status in neonates following hypoxic-ischemic events.

Main Methods:

• 12 full-term neonates with hypoxic-ischemic events underwent I-123 iodobenzamide brain SPECT one week after birth.
• SPECT imaging was performed one hour after intravenous injection of I-123 iodobenzamide.
• Brain magnetic resonance imaging (T2 weighted) was acquired on the same day for comparison.

Main Results:

• I-123 iodobenzamide concentrated in the striatum, with striatum:cerebellum activity ratios ranging from 1.28 to 2.25.
• A trend towards decreased striatum:cerebellum ratios was observed with increasing severity of hypoxic-ischemic events.
• Striatal hypersignal on MRI was noted in only two neonates, highlighting SPECT's potential for detecting biochemical changes.

Conclusions:

• I-123 iodobenzamide is a viable imaging agent for use in the neonatal period.
• The study demonstrates the biochemical maturation of D2 receptors as early as one week postpartum.
• Perinatal hypoxic-ischemic events appear to have a deleterious effect on D2 receptor function.