Comparison of mild and severe forms of hydrocephalus using diffusion tensor imaging in neonatal rats

Abstract

The three groups were significantly different (p<0.0001) in Evan’s ratios with HCPM rats (Mean+/-STD = 0.38 +/-0.07, Range: 0.31-0.48) slightly higher than controls (Mean+/-STD = 0.29+/-0.01, Range: 0.27-0.31, p=0.02) but lower than the HCPS group (Mean+/-STD=0.85 +/-0.04, Range=0.80-0.90, p<0.0001). Both FA and MD values were significantly different among the three groups in cortex, corpus callosum and internal capsule (ANOVA, p<0.05). Post-hoc comparisons showed that the HCPM group was not significantly different from the control group, while the HCPS group was significantly different (lower FA and higher MD, p<0.05) from the control group (with the exception of FA in the internal capsule) and the HCPM group. In the HCPM group, it was found that the MD values in the external capsule increased proportionally with ventricle size (R=0.94, p=0.016), while FA values in the internal capsule decreased with increasing ventricle size (R=-0.98, p=0.005). Conclusions Although the DTI measurements in the HCPM rats with mild ventriculomegaly were not significantly different from normal controls, the correlation between ventricle size and DTI values in this group suggested that different levels of abnormality in brain tissues can be detected with DTI during various stages of hydrocephalus. Our results demonstrate that DTI is potentially a sensitive biomarker for monitoring the progression of ventricle enlargement and may help to determine the optimal window for surgical intervention.