Moon Won-Jin, Na Dong Gyu, Ryoo Jae Wook, Roh Hong Gee, Byun Hong Sik, Chon Yong Hwan, Chung Eun Chul
Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Korean J Radiol. 2005 Apr-Jun;6(2):75-81. doi: 10.3348/kjr.2005.6.2.75.
The aim of this study was to investigate the relationship between the diffusion and perfusion parameters in hyperacute infarction, and we wanted to determine the viability threshold for the ischemic penumbra using diffusion- and perfusion-weighted imaging (DWI and PWI, respectively).
Both DWI and PWI were performed within six hours from the onset of symptoms for 12 patients who had suffered from acute stroke. Three regions of interest (ROIs) were identified: ROI 1 was the initial lesion on DWI; ROI 2 was the DWI/PWI mismatch area (the penumbra) that progressed onward to the infarct; and ROI 3 was the mismatch area that recovered to normal on the follow-up scans. The ratios of apparent diffusion coefficient (ADC), the relative cerebral blood volume (rCBV), and the time to peak (TTP) were calculated as the lesions' ROIs divided by the contralateral mirror ROIs, and these values were then correlated with each other. The viability threshold was determined by using the receiver operating characteristic (ROC) curves.
For all three ROIs, the ADC ratios had significant linear correlation with the TTP ratios (p < 0.001), but not with the rCBV ratios (p = 0.280). There was no significant difference for the ADC and rCBV ratios within the ROIs. The mean TTP ratio/TTP delay between the penumbras' two ROIs showed a significant statistical difference (p < 0.001). The cutoff value between ROI 2 and ROI 3, as the viability threshold, was a TTP ratio of 1.29 (with a sensitivity and specificity of 86% and 73%, respectively) and a TTP delay of 7.8 sec (with a sensitivity and specificity of 84% and 72%, respectively).
Determining the viability thresholds for the TTP ratio/delay on the PWI may be helpful for selecting those patients who would benefit from the various therapeutic interventions that can be used during the acute phase of ischemic stroke.
本研究旨在探讨超急性梗死中扩散与灌注参数之间的关系，并使用扩散加权成像（DWI）和灌注加权成像（PWI）分别确定缺血半暗带的存活阈值。
对12例急性脑卒中患者在症状发作后6小时内进行DWI和PWI检查。确定了三个感兴趣区域（ROI）：ROI 1是DWI上的初始病变；ROI 2是DWI/PWI不匹配区域（半暗带），该区域随后进展为梗死；ROI 3是在随访扫描中恢复正常的不匹配区域。表观扩散系数（ADC）、相对脑血容量（rCBV）和达峰时间（TTP）的比值通过将病变的ROI除以对侧镜像ROI来计算，然后将这些值相互关联。使用受试者操作特征（ROC）曲线确定存活阈值。
对于所有三个ROI，ADC比值与TTP比值具有显著的线性相关性（p < 0.001），但与rCBV比值无相关性（p = 0.280）。ROI内的ADC和rCBV比值无显著差异。两个半暗带ROI之间的平均TTP比值/TTP延迟显示出显著的统计学差异（p < 0.001）。作为存活阈值，ROI 2和ROI 3之间的临界值为TTP比值1.29（敏感性和特异性分别为86%和73%）和TTP延迟7.8秒（敏感性和特异性分别为84%和72%）。
确定PWI上TTP比值/延迟的存活阈值可能有助于选择那些在缺血性脑卒中急性期可从各种治疗干预中获益的患者。
