Striatal DAT-SPECT texture beyond mean binding in major depressive disorder

Area of Science:

• Neuroimaging
• Psychiatry
• Radiomics

Background:

• Dopaminergic dysfunction is linked to major depressive disorder (MDD).
• Conventional dopamine transporter (DAT) imaging shows inconsistent findings.
• Mean binding metrics may miss spatially heterogeneous DAT uptake alterations.

Purpose of the Study:

• To investigate if low-dimensional texture signatures from striatal DAT-SPECT provide additional information beyond mean binding.
• To assess the association of texture metrics with depressive severity and treatment intensity.

Main Methods:

• Retrospective analysis of DAT-SPECT (¹²³I-ioflupane) in 223 MDD patients.
• Quantification of bilateral striatal mean binding and texture metrics.
• Texture features summarized into entropy/complexity and scale/run-length domains.
• Ordinal regression models adjusted for covariates tested associations with severity and treatment intensity proxy.

Main Results:

• Mean binding did not improve model fit for severity or treatment intensity.
• Adding texture domains significantly improved model fit for both severity (p=0.024) and treatment intensity (p=0.0048).
• Higher texture scores correlated with increased probability of severe depression and need for electroconvulsive therapy (ECT).

Conclusions:

• A two-domain texture summary of striatal DAT-SPECT offers incremental value over mean binding.
• Texture signatures are associated with depressive severity and treatment intensity in MDD.
• This approach may enhance understanding of DAT imaging in MDD.