Evidence of small vessel disease in patients with transient global amnesia based on the peak width of skeletonized mean diffusivity.

Background and purpose: The peak width of skeletonized mean diffusivity (PSMD) is a novel marker of small vessel disease. In this study, we aimed to investigate the presence of small vessel disease in patients with transient global amnesia (TGA) using the PSMD.

Materials and methods: We enrolled 75 patients newly diagnosed with TGA and included 65 age-and sex-matched healthy controls. Diffusion tensor imaging (DTI) was performed using a 3T magnetic resonance imaging scanner. We measured the PSMD based on DTI using the FSL program. This measure was compared between patients with TGA and healthy controls. Additionally, we conducted a correlation analysis to explore the relationship between PSMD and clinical factors.

Results: A significant difference in the PSMD between patients with TGA and healthy controls was observed. Patients with TGA exhibited higher a PSMD compared to healthy controls (2.297±0.232 vs. 2.188±0.216 ×10^-4 mm²/s, p=0.005). Additionally, patients with TGA but without any vascular risk factors, such as diabetes, hypertension or dyslipidemia, also exhibited higher a PSMD compared to healthy controls (2.278±0.253 vs. 2.188±0.216 ×10^-4 mm²/s, p=0.036). The PSMD positively correlated with age (r=0.248, p=0.032); however, it was not associated with duration of amnesia.

Conclusions: This finding underscores the feasibility of using PSMD as a marker for detecting small vessel diseases in patients with neurological disorders. Furthermore, our study also implies the presence of small vessel disease may be present in patients with TGA.

Abbreviations: TGA=transient global amnesia; TIA= transient ischemic attack; PSMD= peak width of skeletonized mean diffusivity; DTI= diffusion tensor imaging.