The Quantitative Evaluation Of Peritumoral Brain Edema By Multislice CT Perfusion Imaging

PartⅠ:The cerebral hemodynamics study by using multislice CT perfusion imaging in normal adultPurpose:To explore the application of multislice CT perfusion imaging(MSCTPI) depicts cerebral hemodynamics in normal adult.Materials and Methods:Routine CT was performed in 26 normal adults,then MSCTPI study was made by selecting the basal ganglia slice and its adjacent slice. The contrast material was bolus injected through antecubital vein,while two layers of dynamic scans were performed for 40 seconds.These dynamic images were processed with the CT perfusion software package.Cerebral blood flow(CBF),cerebral blood volume(CBV),and permeability surface(PS) were measured within the specific regions of interest(ROI) of the brain,and quantitative analysis was performed.Results:A gradient of perfusion between gray matter and white matter was showed on MSCTPI in normal adults.CBF,CBV,and PS were(31.35±5.63) ml.100ml~1·min~1, (42.19±6.27)ml·1000ml~1,(1.41±0.36)0.5ml·100m~1·min~1,respectively in the gray matter,(21.51±2.24)ml·100ml~1min~1,(30.94±3.14)ml·1000ml~1,(1.18±0.27)0.5ml·100 ml~1·min~1,respectively in the white matter,and(27.73±4.87)ml·100ml~1·min~1, (39.37±5.78)ml·1000ml~1,(1.28±0.41)0.5ml·100ml~1·min~1,respectively in basal ganglia.CBF,CBV of gray matter were significantly higher than that of white matter(P＜0.05),while no significant difference was recorded among PS of gray matter and white matter.Conclusion:MSCTPI provided a new imaging method for measuring the cerebral hemodynamics.PartⅡ:The quantitative evaluation of peritumoral brain edema by multislice CT perfusion imagingPurpose:To evaluate the potential of CTP in diagnosing of brain tumors and defining the tumor boundary by analysing the parameters obtained from peritumoral edema.Materials and Methods:Sixty-two patients with brain tumors underwent routine, perfusion CT imaging.Except for six patients with metastases and were confirmed by clinic,all patients were confirmed by pathology.The peritumoral low-attenuation region was divided into two regions to allow investigation of whether cerebral blood flow(CBF),cerebral blood volume(CBV),and permeability surface(PS) varies with distance of from the enhancing portion of the tumor.The immediate peritumoral area was defined to be within a 1 cm distance from the outer enhancing tumor margin;the distant peritumoral region was defined as greater than 1 cm from the enhancing portion of the tumor.Comparisons of CBF,CBV,and PS were done among distant peritumoral region,immediate peritumoral region,and contrallateral normal white matter.CBF,CBV and PS obtained from the peritumoral regions among intracranial diseases were compared by using the one-way ANOVA.The two-way ANOVA was used to determine if there was a significant difference in the cranial tumors among different peritumoral regions.All the statistical data were displayed as x±s,a P value of less than 0.05 indicated a statistically significant difference.Results:Peritumoral edema of all cranial tumors demonstrated hypointensity in the MIP imaging.CBF,CBV in immediate peritumoral edema of brain tumors were significantly lower than that of contrallateral normal white matter(P＜0.05).PS in immediate peritumoral edema of high-grade gliomas and malignant meningioma were significantly higher than that of contrallateral normal white matter(P＜0.05).PS in immediate peritumoral edema of low-grade gliomas,metastases,benign meningiomas and hemangiopericytoma were not significantly different from that of contrallateral normal white matter(P＞0.05).CBF,CBV and PS of immediate peritumoral edema were prominently significant for differentiating high-grade gliomas,malignant meningioma from low-grade gliomas,metastases,benign meningiomas and hemangiopericytoma(P＜0.05),while no significant difference was recorded among CBF,CBV and PS in immediate peritumoral of high-grade gliomas,malignant meningioma and in distant peripheral edema of all tumors(P＞0.05).As for high-grade glioma and malignant meningioma,the CBF,CBV and PS of immediate peritumoral edema were higher than that of distant edema(P＜0.05).The CBF,CBV and PS in immediate,distant peritumoral edema of low-grade glioma and hemangiopericytoma could not distinguish from each other(P＞0.05).The CBF,CBV of immediate peripheral edema in patients with metastases and benign meningioma were significantly lower than those of distant peripheral edema(P＜0.05),while the PS was no significantly difference(P＞0.05).Conclusion:The CBF,CBV and PS in immediate perifocal edema enable distinction high-grade glioma,malignant meningioma from metastasis,benign meningioma and hemangiopericytoma.However,it could not reliably distinguish high-grade glioma and malignant meningioma from peritumoral edema.CBF,CBV and PS of immediate peritumoral edema are higher than that of distant edema in high-grade glioma and malignant meningioma,which are contrary in low-grade glioma,metastasis,benign meningioma and hemangiopericytoma.CTP can demonstrates tumor infiltration early and accurately,which is quite valuable in clinic.The term "perienhancing region" can better describe the region of abnormal signal intensity surrounding the tumoral core.