Combined diffusion tensor imaging and transverse relaxometry in early-onset bipolar disorder

Area of Science:

• Neuroimaging
• Neuroscience
• Pediatric Psychiatry

Background:

• Transverse relaxation time (T2) imaging assesses membrane fluidity, impacting cellular functions.
• Bipolar disorder (BD) is a complex psychiatric condition affecting individuals from a young age.
• Previous research indicates potential white matter abnormalities in pediatric BD.

Purpose of the Study:

• To investigate T2 abnormalities in the white matter of children with unmodified DSM-IV-TR bipolar disorder (BD).
• To examine the cingulate-paracingulate (CPC) white matter region in pediatric BD.
• To explore potential differences in T2 values between individuals with BD and healthy controls.

Main Methods:

• Magnetic resonance imaging (MRI) at 1.5 Tesla was performed on 21 children/adolescents with BD and 16 healthy controls.
• Region-of-interest analysis was used to compare T2 values in the bilateral CPC white matter.
• Post hoc diffusion tensor imaging (DTI) analysis was conducted on a subset of participants.

Main Results:

• Significantly decreased T2 values were observed in the right CPC white matter of subjects with BD compared to controls.
• A hemispheric difference was noted in the BD group, with lower T2 on the right compared to the left CPC.
• DTI analysis revealed reduced fractional anisotropy and increased diffusivity on the left, and increased trace and decreased T2 on the right in subjects with BD.

Conclusions:

• The observed T2 differences in pediatric BD likely reflect alterations in cerebral blood flow, not changes in membrane fluidity.
• Findings suggest potential myelin damage on the left CPC white matter in early-onset BD, alongside blood flow changes.
• Further prospective studies with larger cohorts are needed to validate these findings and explore their clinical relevance.