Application Of CT Perfusion Imaging In The Evaluation Of The Effects Of Brain Metastases With Radiation Therapy

Objective To investigate the value of CT perfusion imaging in the evaluation of the effects of brain metastases with radiation therapy.Methods Both conventional and perfusion CT were performed in 20 patients with brain metastases before and after whole radiotherapy respectively.Then the TDC curves were obstained ,and cerebral blood flow (CBF) maps,cerebral blood volume (CBV) maps and time to peak (TTP) maps were generated.The CBF,CBV and TTP of the reagion of interest (ROI) were measured on the perfusion maps,and then the relative CBF(rCBF),relative CBV(rCBV),relative TTP(rTTP) and the relative MTT(rMTT) were calculated.The CT perfusion parameters of the parenchymatous tissue of brain metastases and the normal brain tissue before and after radiotherapy were compared.Tne effects of radiotherapy of the brain metastases with different perfusion parameters and with different pathologic sources were compared,too.Results The rCBF,rCBV of most brain metastases before radiation therapy were increased significantly, the values were 5.27±2.09,3.24±1.07 respectively.The rMTT was increased and the rTTP was decreased a little,the values were 1.54±0.46 and 0.85±0.25 respectively.A few brain metastases which were small (D<15.0mm) has no significant showing on the perfusion maps.The tumors of 2 cases had no significant change,but the tumors'volume of other 18 cases decreased to a greater or lesser degree.The CBF,rCBF,rCBV of the parenchymatous tissue of tumors decreased significantly.The differences of the rMTT,rTTP of the parenchymatous tissue of tumors before and after radiotherapy were not significant,the same to the CBF,CBV of normal white matter and normal grey matter.The effects of the brain metastases with radiation...