ABSTRACT
Objective To investigate the value of MR intravoxel incoherent motion (IVIM)imaging and dynamic susceptibility contrast-enhanced(DSC)perfusion imaging in astrocytoma grading.Methods 22 patients with high grade astrocytoma and 28 patients with low grade astrocytoma underwent conventional MRI and IVIM,DSC scanning before operation.Parameters of IVIM included standard diffusion coefficient(ADCstandard ),slow diffusion coefficient(D),fast diffusion coefficient(D? ),fractional perfusion-related volume (f)values,and parameters of DSC included relative blood volume(rCBV),relative blood flow(rCBF)values of tumor solid part were measured quantitatively.The values between the two groups were compared by two samples t-test.By using ROC curve to evaluate the diagnostic efficacy of using IVIM and DSC alone or jointly.Results The ADCstandard ,D,rCBV,rCBF values of tumor solid part had significant differences between the groups(P<0.01).The D? and f values were no significant differences (P=0.130,P=0.379).The area under the ROC curve of the values showed that ADCstandard (0.823),D(0.854),rCBV(0.858),rCBF(0.871),D+rCBV(0.952),D+rCBF(0.953).Conclusion The D,rCBV,rCBF values are helpful to determine the grade of astrocytomas.The use of IVIM in combination with DSC may improve the diagnostic accuracy of astrocytoma grading.
ABSTRACT
The purpose of this study was to quantitatively analyze the relationship between three dimensional arterial spin labeling (3D-ASL) and dynamic susceptibility contrast-enhanced perfusion weighted imaging (DSC-PWI) in ischemic stroke patients. Thirty patients with ischemic stroke were included in this study. All subjects underwent routine magnetic resonance imaging scanning, diffusion weighted imaging (DWI), magnetic resonance angiography (MRA), 3D-ASL and DSC-PWI on a 3.0T MR scanner. Regions of interest (ROIs) were drawn on the cerebral blood flow (CBF) maps (derived from ASL) and multi-parametric DSC perfusion maps, and then, the absolute and relative values of ASL-CBF, DSC-derived CBF, and DSC-derived mean transit time (MTT) were calculated. The relationships between ASL and DSC parameters were analyzed using Pearson's correlation analysis. Receiver operative characteristic (ROC) curves were performed to define the thresholds of relative value of ASL-CBF (rASL) that could best predict DSC-CBF reduction and MTT prolongation. Relative ASL better correlated with CBF and MTT in the anterior circulation with the Pearson correlation coefficients (R) values being 0.611 (P<0.001) and-0.610 (P<0.001) respectively. ROC curves demonstrated that when rASL ≤0.585, the sensitivity, specificity and accuracy for predicting ROIs with rCBF<0.9 were 92.3%, 63.6% and 76.6% respectively. When rASL ≤0.952, the sensitivity, specificity and accuracy for predicting ROIs rMTT>1.0 were 75.7%, 89.2% and 87.8% respectively. ASL-CBF map has better linear correlations with DSC-derived parameters (DSC-CBF and MTT) in anterior circulation in ischemic stroke patients. Additionally, when rASL is lower than 0.585, it could predict DSC-CBF decrease with moderate accuracy. If rASL values range from 0.585 to 0.952, we just speculate the prolonged MTT.
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Humans , Brain Ischemia , Metabolism , Magnetic Resonance Angiography , Retrospective Studies , Stroke , MetabolismABSTRACT
Objective To evaluate the value of dynamic susceptibility contrast-enhanced MR imaging (DSC)in evaluation of brain tumor after operation.Methods 41 cases with brain tumors verified histologically,including 8 cases of high-grade gliomas,16 of low-grade gliomas,7 of metastases and 10 of meningiomas underwent DSC examination.All the cases at 3.0T MR unit.All primitive data were sent to ADW4.3 workstation for post-processing.The mean maximal rCBV and rCBF ratios of tumors,1 cm and 2 cm regions of peri-tumor were obtained respectively.The relativity of MR perfusion parameters(rCBV and rCBF)between diferent tumors were statistically evaluated by using Pearson correlative analysis.Results In the solid region of tumors,rCBV and rCBF were statistically significant differences (P<0.05)between low-grade gliomas and the other three groups of tumors; in 1 cm region of peri-tumor between high-grade gliomas and the other three groups,and between low-grade gliomas and metastases,between the solid region and both regions of 1 cm and 2 cm peri-tumors at the same tumor were all of statistically significant differences(P<0.05),between 1 cm and 2 cm region of peri-tumors at high-grade gliomas and metastases,the rCBV and rCBF were also of statistically significant differences.Pearson correlative analysis showed that there were significant positive correlations between the mean maximal rCBV and rCBF ratios at the same region in the same tumor's group.Conclusion DSC is very valuable in evaluation of the histopathological grade and the differentiation of brain tumor.