Diffusion imaging studies of Huntington's disease: A meta-analysis

Background: Diffusion tensor imaging (DTI) could detect abnormal brain microstructural alterations. DTI studies of Huntington's Disease(HD) have yielded inconsistent results.

Objective: To integrate the existing DTI studies of HD and explore the validity of DTI to detect microstructural damages in HD brain via meta-analysis.

Methods: Systematic and comprehensive searches of the databases were performed for DTI studies of HD. The data from the studies that met our inclusion criteria were extracted and analyzed using the CMA2 software. Random effect models were utilized to minimize the potential between-study heterogeneity. One-way sensitivity analysis was conducted to test the robustness of the results.

Results: The meta-analysis included 140 pre-symptomatic HD (PreHD), 235 symptomatic HD (SymHD) patients and 302 controls, revealing significantly increased fractional anisotropy (FA) in the caudate, putamen, and globus pallidus, while decreased FA in the corpus callosum of both PreHD and SymHD patients compared with controls. In addition, significantly increased mean diffusivity (MD) was identified in the putamen and thalamus of both PreHD and SymHD patients, and in the caudate of SymHD patients, while no significant difference in MD in the caudate of PreHD patients. In the corpus callosum, there was a significant increase of radial diffusivity and axial diffusivity in SymHD patients compared with controls. Meta-regression showed gender-based difference in MD values of the caudate.

Conclusions: Our meta-analysis provides further evidence that DTI detects microstructural damage of both white matter and gray matter even in PreHD gene carriers. MD is less sensitive than FA in detecting structural changes in PreHD.