Altered White Matter Microstructure and Cerebral Spontaneous Activity in Early Neurosyphilis Without Human Immunodeficiency Virus Infection.

Objective: To investigate white matter microstructure and spontaneous cerebral activity in early neurosyphilis using tract-based spatial statistics and amplitude of low-frequency fluctuation (ALFF).

Methods: Twenty patients with early neurosyphilis and 20 matched healthy controls underwent diffusion tensor imaging and resting-state blood oxygen level-dependent imaging. Neuropsychological tests were performed before each magnetic resonance imaging. Fractional anisotropy (FA), mean diffusivity (MD), and ALFF values were compared between the 2 groups. Diffusion tensor imaging-derived metrics and ALFF values were correlated with the neuropsychiatric and laboratory indices.

Results: Tract-based spatial statistics revealed decreased FA and increased MD values in early neurosyphilis, affecting regions such as the forceps minor, bilateral cingulum (hippocampus), left inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, corticospinal tract, right cingulum (cingulate gyrus), and anterior thalamic radiation. Decreased FA and increased MD values were observed in nonoverlapping fibers. Moreover, reduced ALFF values were observed in the left precuneus, superior frontal cortex, and right inferior parietal cortex in early neurosyphilis. In addition, the FA, MD, and ALFF values were significantly correlated with specific clinical data and questionnaires.

Conclusion: Disrupted white matter microstructural integrity and spontaneous brain activity were observed in early neurosyphilis using advanced magnetic resonance imaging. Analysis of subtle cerebral structures and functions is potentially helpful for understanding the neural basis of neurosyphilis. Future longitudinal studies with larger sample sizes are warranted.