Non-Gaussian diffusion MR imaging of glioma: comparisons of multiple diffusion parameters and correlation with histologic grade and MIB-1 (Ki-67 labeling) index

INTRODUCTION

This study was conducted to compare the association of Gaussian and non-Gaussian magnetic resonance imaging (MRI)-derived parameters with histologic grade and MIB-1 (Ki-67 labeling) index (MI) in brain glioma.

METHODS

Sixty-five patients with pathologically confirmed glioma, who underwent diffusion-weighted MRI with 2 b values (0, 1000 s/mm(2)) and 22 b values (≤5000 s/mm(2)), respectively, were divided into three groups of grade II (n = 35), grade III (n = 8), and grade IV (n = 22). Comparisons by two groups were made for apparent diffusion coefficient (ADC), slow diffusion coefficient (Dslow), distributed diffusion coefficient (DDC), and heterogeneity index α. Analyses of receiver operating characteristic (ROC) curve were performed to maximize the area under the curve (AUC) for differentiating grade III + IV (high-grade glioma, HGG) from grade II (low-grade glioma, LGG) and grade IV (glioblastoma multiforme, GBM) from grade II + III (other grade glioma, OGG). Correlations with MI were analyzed for the MRI parameters.

RESULTS

On tumor regions, the values of ADC, Dslow, DDC, and α were significantly higher in grade II [(1.37 ± 0.29, 0.70 ± 0.11, 1.39 ± 0.34) (×10(-3) mm(2)/s) and 0.88 ± 0.05, respectively] than in grade III [(0.99 ± 0.13, 0.55 ± 0.07, 1.04 ± 0.20) (×10(-3) mm(2)/s) and 0.80 ± 0.03, respectively] and grade IV [(1.03 ± 0.14, 0.50 ± 0.05, 1.02 ± 0.16) (×10(-3) mm(2)/s) and 0.76 ± 0.04, respectively] (all P < 0.001). The parameter α showed the highest AUCs of 0.950 and 0.922 in discriminating HGG from LGG and GBM from OGG, respectively. Significant correlations with histologic grade and MI were observed for the MRI parameters.

CONCLUSION

The non-Gaussian MRI-derived parameters α and Dslow are superior to ADC in glioma grading, which are comparable with ADC as reliable biomarkers in noninvasively predicting the proliferation level of glioma malignancy.

Investigation of association between female genital tract diseases and Schistosomiasis japonica infection

With the support of WHO/TDR, a case-control study was undertaken to explore the association between female genital tract manifestation and Schistosomiasis japonica. Two thousand one hundred and six women aged 18-50 in a township with schistosomiasis japonica infection rate of >15% were surveyed using modified Kato-Katz method qualitatively and quantitatively. Two hundred and forty four women with schistosomiasis japonica were selected as experimental group and 236 matched healthy women as control group. Sixty nine items including cervix smear and the S. japonicum circulating antigen in intrauterine lavage were investigated. The results showed that physically, menstrual disorder and shorter stature and lighter weight of the first newborn occurred more frequently in the experimental group than that in control group. As for female genital tract manifestation, there were more cases with chronic cervicitis and uterine enlargement in the experimental group than that in the control group. Schistosome circulating antigen was detected in intrauterine lavage from 13 cases with schistosomiasis by ELISA. No evidence was found to show that female genital tract diseases be directly caused by S. japonicum, but the findings emerging from this survey merit further study.