| Summary: | 碩士 === 國立陽明大學 === 放射醫學科學研究所 === 93 === Hemodynamic parameters namely relative cerebral blood volume (rCBV), relative cerebral blood flow (rCBF), relative mean transit time (rMTT), and delay time (Td) are assessed using dynamic susceptibility contrast MRI (DSC-MRI). There are many algorithms for these parameters. The aim of this study is to use scatter plots to analysis the accuracy of the parameters calculated using these algorithms.
Eight methods were used to estimate rCBV, including three types of integration of the concentration-time curves using different time windows, the summations of tissue impulse responses from standard, circular and oscillation singular value decomposition (sSVD, cSVD and oSVD) and two curve fitting techniques. rCBF and Td were obtained using three kinds of SVD techniques; besides, rMTT was calculated as rCBV/rCBF. Scatter plots were used to observe the relations between different parameters and cerebrovascular diseases.
rCBV values calculated using cSVD and oSVD were identical. Both values were equal to the whole areas under the concentration-time curve were divided by the arterial input function areas. Moreover, these rCBV approximated to the rCBV calculated by signal-time curve fitting. rCBF with cSVD and oSVD wouldn’t be underestimated by delay effect and were good for relative quantity. The scatter plots of rMTT and Td were useful in stroke staging.
cSVD calculation is time efficient. Further, good rCBF and rCBV values are obtained at the same time, so cSVD might be applied in the clinical. The combination of rMTT and Td would help not only diagnose illness but also differentiate stage.
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