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AIM: The aim of the present study is to evaluate diffusion tensor tractography (DTT) as a tool for detecting diffuse axonal injury in patients of acute, mild, and moderate traumatic brain injury (TBI), using two diffusion variables: Fractional anisotropy (FA) and mean diffusivity (MD). The correlation of these indices with the severity of post-concussive symptoms was also assessed. MATERIALS AND METHODS: Nineteen patients with acute, mild, or moderate TBI and twelve age- and sex-matched healthy controls were recruited. Following Magnetic Resonance Imaging (MRI) on a 3.0-T scanner, DTT was performed using the 'fiber assignment by continuous tracking' (FACT) algorithm for fiber reconstruction. Appropriate statistical tools were used to see the difference in FA and MD values between the control and patient groups. In the latter group, the severity of post-concussive symptoms was assessed six months following trauma, using the Rivermead Postconcussion Symptoms Questionnaire (RPSQ). RESULTS: The patients displayed significant reduction in FA compared to the controls (P < 0.05) in several tracts, notably the corpus callosum, fornix, bilateral uncinate fasciculus, and bilateral superior thalamic radiations. Changes in MD were statistically significant in the left uncinate, inferior longitudinal fasciculus, and left posterior thalamic radiation. A strong correlation between these indices and the RPSQ scores was observed in several white matter tracts. CONCLUSION: Diffusion tensor imaging (DTI)-based quantitative analysis in acute, mild, and moderate TBI can identify axonal injury neuropathology, over and above that visualized on conventional MRI scans. Furthermore, the significant correlation observed between FA and MD indices and the severity of post-concussive symptoms could make it a useful predictor of the long-term outcome.
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OBJECTIVES: Chronic hepatitis C virus infection is associated with insulin resistance (IR), and both host and viral factors are important in its development. The association and the predictors of IR in chronic hepatitis B virus (CHBV) infection remain unclear. METHODS: A total of 69 CHBV-infected subjects were examined to study the relationship between histological findings and anthropometric and biochemical data, including IR determined by the homeostasis model assessment (HOMA-IR). To assess the influence of CHBV infection on IR independent of any effect of hepatic fibrosis, overweight, or sex we also compared fasting serum insulin, C-peptide, HOMA-IR, HOMA-beta (measure of beta-cell function) and C-peptide-insulin ratio (to distinguish impaired insulin degradation (low ratio) from insulin hypersecretion (normal ratio)) levels between the subset of 14 male normal weight (body mass index, BMI<23) CHBV patients with stage 0 or 1 hepatic fibrosis and 50 male normal weight healthy controls matched by age and anthropometry (BMI and waist circumference). RESULTS: A total of 31 (44.9%) CHBV-infected patients were overweight (BMI>23 kg/m(2)) and 18 (26.1%) were obese (BMI>25 kg/m(2)). IR was seen in 34 (49.3%) patients. BMI (Spearman's coefficient=-0.436; P<0.001) and serum triglyceride levels (Spearman's coefficient=-0.307; P=0.010) were univariate predictors of IR. In multiple linear regression analysis, only BMI (P<0.001) was an independent predictor of HOMA-IR. The subgroup of CHBV-infected patients and the controls had comparable levels of all markers of IR, including fasting glucose, insulin, C-peptide, and HOMA-IR. CONCLUSIONS: IR in CHBV-infected patients is a reflection of the host metabolic profile and CHBV infection is not in itself correlated with IR.
