[Value of intravoxel incoherent motion diffusion weighted imaging in evaluating the microstructure changes in white matter hyperintensities].

Objective: To investigate the value of intravoxel incoherent motion diffusion weighted imaging (IVIM DWI) in evaluating microstructure changes in elderly white matter hyperintensities (WMH) patients and to analyze the correlation between IVIM parameters and severity grading and cognitive scores. Methods: Sixty-two WMH patients in Zhejiang Hospital were collected from December 2014 to March 2018 and underwent conventional magnetic resonance (MR) plain scan and diffusion weighted imaging with different b values. The age was 60-92(74±10) years with 37 males, 25 females. The severity of WMH was assessed by T(2) fluid attenuated inversion recovery (FLAIR) sequence and Fazekas score,which were divided into two subgroups. Slow diffusion coefficient (D), fast diffusion coefficient (D(*)) and perfusion fraction (f) from IVIM parameters of double exponential model were compared between regions of WMH (deep WMH (DWMH) and periventricular WMH (PWMH)) and surrounding normal white matter (NWM).The Shapiro-Wilk test was used for normality tests, Kruskal-Wallis tests and Dwass-Steel-Critchlow-Fligner (DSCF) procedure were used for the comparison among these parameters. Furthermore, Wilcoxon two-sample test was used for the comparisons between different severity. Pearson correlation analysis was performed to determine whether these D, D(*), f values were correlated with the mini mental state examination (MMSE) scores. Results: D(D)WMH (0.83(0.72,0.99)×10(-3) mm(2)/s), D(PWMH)((1.13±0.25)×10(-3) mm(2)/s) were significantly higher than D(NWM) ((0.71±0.05)×10(-3) mm(2)/s)(P<0.01). f (DWMH) ((8.94%(7.46%,11.67%)), f (PWMH)(8.34%(6.73%,9.96%)) were significantly higher than f (NWM)(6.71%±1.72%)(P<0.01).D in DWMH were significantly lower than that in PWMH(P<0.01), there's no statistically difference between other groups. D in severe WMH (both DWMH and PWMH) were significantly higher than that in mild WMH (P=0.000 1, P=0.04). Only f in PWMH were positively associated with the MMSE scores (r=0.326 5,P<0.05). Conclusions: IVIM DWI can noninvasively assess the variation of microstructure diffusion and perfusion in WMH in one sequence,which may objectively reflect the severity of these lesions. This method has important clinical significance for better assessment and management of this disease.

[Comparison of simple canalith repositioning treatment and medication therapeutic alliance in the management of canalithiasis associated with benign paroxysmal positional vertigo of the horizontal semicircular canal].

Objective:To compare the therapeutic efficacy and the recurrence rate between the simple repositioning method and the reposition manoeuvre plus medication in the treatment of horizontal semicircular canal otolith benign paroxysmal positional vertigo (HSC-BPPV). Method:Sixty-two patients diagnosed with otolith HSC-BPPV by roll maneuver test were randomly divided into canalith repositioning group (32 patients) and reposition plus drug treatment group (30 patients). Patients in the canalith repositioning group were treated only with Barbecue reposition maneuver; patients in the reposition plus drug treatment group were treated firstly with Barbecue reposition maneuver and then were given Alprostadil, Cinepazide and Betahistine drug treatment. Both groups were evaluated after 7 days and 28 days treatment, and the recurrence rate was analyzed after 3 months. Result:After 7 days of the treatment , the recovery rate of the two groups was 62.5% and 73.3%, respectively. There's no significant difference between the two groups. However, the total effective power of the reposition plus drug treatment group was 96.7%, which was significantly higher than that of the canalith repositioning group (75.0%) (χ²=5.858, P<0.05). There were 8 patients in the canalith repositioning group showed changes of BBPV types after treatment, while only 1 patient in the reposition plus drug treatment group showed lesion changes. The difference was statistically significant (χ²=4.061, P<0.05). After 28 days of the treatment, the recovery rate and the total effective power of the two groups was 100%, respectively. There is no statistical difference in the total effective rate between the two groups. After 3 months follow-up, 2 patients in the canalith repositioning group (6.25%) and in the reposition plus drug treatment group (6.67%) showed BBPV recurrence, and no significant difference in the recurrence rate was found between the two groups (P>0.05). Conclusion:The repositioning maneuver is the preferred method for treating HSC BPPV. Canalith reposition maneuver plus medication has no obvious effect on the recovery rate and the recurrence rate, it only increases the effective rate and reduces the changes of the BBPV types.

QSAR-based toxicity classification and prediction for single and mixed aromatic compounds.

Quantitative structure-activity relationships (QSARs) based on the octanol/water partition coefficient were employed to predict acute toxicities of 36 substituted aromatic compounds and their mixtures. In this study, the model developed by Verhaar et al. was modified and used to calculate octano/water partition coefficients of chemical mixtures. To validate the model, acute toxicities of these chemicals were measured to Vibrio fischeri in terms of EC50. The results indicated that the obtained QSAR models could be used to predict toxicities of samples consi sting of these substituted aromatic compounds, individually or in combinations. The obtained equations were proved to be robust enough by using the leave-one-out test method. By classifying these chemicals into two groups, polar and non-polar, the toxicities of chemical mixtures within each group can be predicted accurately from their calculated partition coefficients.