| Objective: To assess the value of diffusion weighted imaging(DWI) with high b value in predicting the grade of cerebral gliomas.Methods:Thirty-six patients with histologically proved brain gliomas(23 high-grade and 13 low-grade gliomas) underwent routine MR imaging and DWI with low(600 s/mm2), moderate(1000 s/mm2) and high(3000 s/mm2) b values. The DWI appearances of the gliomas were analysed. The signal intensity(SI) values, apparent diffusion coefficient (ADC) values, SI ratio and ADC ratio(the tumor solid portion SI or ADC value/the corresponding normal contralateral-hemisphere white matter SI or ADC value, namely rSI or rADC) were obtained with varied b values.Results: (1) with a high b value, most(91.3%) of high-grade gliomas show hyperintensity, while most(92.3%) of the low-grade gliomas show hypointensity. (2) With a same b value, the mean rSI of the high-grade gliomas was significantly higher than that of the low-grade gliomas (P<0.0001), while the mean ADC value and rADC value of the high-grade gliomas were significantly lower than those of the low-grade gliomas (P<0.0001). The differences of rSI and rADC values between of high-and low-grade gliomas were greatest with a high b value. (3) There were statistically differences(P<0.0001) in the mean rSI and the mean rADC values of the high-grade gliomas between high b value and moderate b value, as well as between high b value and low b value. There was statistically difference(P<0.0001) in the mean rSI of the low-grade gliomas between high b value and moderate b value, as well as between high b value and low b value.Conclusion: DWI with a high b value is more useful than those with low or moderate b values in preoperative grading the brain gliomas at 3 T. Objective: To evaluate the diagnostic value of susceptibility weighted imaging(SWI) for cerebral gliomas at 3.0 T.Methods: Thirty-two patients with histologically proved cerebral gliomas(20 high-grade and 12 low-grade gliomas) underwent conventional MR imaging (T2WI,T1FLAIR,T2FLAIR,contrasted T1FLAIR) and SWI. The parameters were following:TR 60 ms,TE 6 ms, FA 20°, slice thickness=2 mm, matrixsize=320×384, NEX=0.75. we got a minimum intensity Projection(MIP) of the Pre-enhanced SWI images(SWI-MinP) by the adw4.4 workstation Software. All SWI images were reviewed independently by two radiologists who did not know the surgical or pathological results, including: Identifying blood products venous vasculature, calcification, necrosis and solid portion in gliomas, and the intratumoral susceptibility signals(ITSS) on SWI were graded.Results: Varying drgrees of intratumoral multiple patchy or linear like low intense signals were presented in 12 of 20 cases of high grade gliomas and intratumoral hemorrhge and vasculature was observed on pathology. In 12 cases of low grade glioma no obvious low intense signal was noted in 6, and mixed dots, linier low intense signals were noted in 5, which were confirmed by pathology to be intratumoral blood vessels; a small amount of patchy low intense signals were observed in 1 and this was confirmed pathologically to be intratumoral hemorrhage. Hypointensity(dotlike or linier) on SWI of WHO Grade 2 tumors indicates vascular structure and that on SWI of higher grade tumors indicates both vascular and hemorrhagic lesions in almost equal numbers. Mean grading scores of ITSS in the tumor were higher for high-grade gliomas than for low-grade gliomas(Z=-3.308, P<0.01). The degree of ITSS showed a correlation with the classification of gliomas(r=0.616, P<0.0001).Conclusion: SWI call be used as a complementary sequence for gliomas imaging, which offers more complete and detailed information combining with others sequence, SWI may be useful in preoperative grading the brain gliomas at 3.0 T.
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