探讨双源CT灌注成像对缺血性脑卒中半暗带的诊断价值

Exploring the Diagnostic Value of Dual Source CT Perfusion Imaging in the Penumbra of Ischemic Stroke

摘要: 目的：缺血性脑卒中半暗带的精准识别是指导临床溶栓、取栓治疗和改善预后的重要环节，双源CT成像(computed tomography perfusion imaging, CTPI)可以更早发现责任病灶的位置，快速区分缺血性脑卒中核心梗死区和半暗带，准确评价灌注情况，给溶栓等治疗决策提供重要的依据，提高诊断效率和准确性。方法：选取96例急性脑梗死患者的全脑CT灌注结果，根据发病时间把96例临床诊断急性脑梗死患者分为I组(6小时至24小时)和II组(24小时至72小时)。双源CT对两组患侧和健侧进行平扫，分析两组患侧和健侧CTP的主要参数(CBF、CBV、MTT、TTP)并计算与健侧对称部位的比值得出相对参数值(rTTP、rCBF、rCBV、rMTT)以及分析梗死病灶核心区和半暗带的CTP参数情况；依据美国国立卫生研究院卒中量表(NIHSS)依次对照评价两组患者的神经功能缺失程度。结果：I组(6-24小时)：缺血半暗带CBF、CBV较健侧显著降低，MTT、TTP显著延长(P < 0.05)；梗死灶核心仅有CBF、CBV显著下降(P < 0.05)，而参数MTT、TTP的值无明显变化(P > 0.05)。梗死灶核心与缺血半暗带相比，rCBF、rCBV、rMTT三个指标上的差异均具有统计学意义(P < 0.05)，rTTP无差异(P > 0.05)；NIHSS评分与rCBF呈负相关(P < 0.05)。II组(24~72小时)：缺血半暗带及梗死灶核心CBF、CBV均较健侧显著降低，MTT、TTP显著延长(P < 0.05)。梗死灶核心与缺血半暗带相比，rCBF、rMTT、rTTP差异显著(P < 0.05)，rCBV无差异(P > 0.05)；NIHSS评分与rCBV呈负相关(P < 0.05)。结论：双源CT灌注成像(DSCTP)依靠快速扫描、高时空分辨率、低辐射剂量的特性，可以准确得到脑组织血流动力学参数，实现缺血性脑卒中半暗带和不可逆梗死灶的量化区分。它用CBF、CBV、MTT等参数阈值准确地找到半暗带的范围，给临床溶栓、取栓治疗的适应症选择提供客观的依据，有效地降低出血转化的风险，也可以动态地评价治疗的效果，对改善患者的预后有重要的指导意义。

Abstract: Objective: The precise identification of the ischemic penumbra in ischemic stroke is a crucial step in guiding clinical thrombolytic and thrombectomy treatments and improving prognosis. Dual-source CT perfusion imaging (CTPI) can detect the location of the responsible lesion earlier, quickly distinguish the core infarction area and the ischemic penumbra in ischemic stroke, accurately evaluate the perfusion status, and provide important basis for treatment decisions such as thrombolysis, thereby enhancing diagnostic efficiency and accuracy. Methods: The full-brain CT perfusion results of 82 patients with acute cerebral infarction were selected. According to the onset time, the 82 patients diagnosed with acute cerebral infarction were divided into Group I (6 to 24 hours) and Group II (24 to 72 hours). Dual-source CT plain scans were performed on the affected and unaffected sides of both groups. The main parameters of CTP (CBF, CBV, MTT, TTP) of the affected and unaffected sides of both groups were analyzed, and the ratios to the symmetrical parts of the unaffected side were calculated to obtain the relative parameter values (rTTP, rCBF, rCBV, rMTT), as well as the CTP-derived parameters of the infarction core region and the ischemic penumbra area.The National Institutes of Health Stroke Scale (NIHSS) served as the tool to gauge the level of neurological deficits in the two groups. Results: Group I (6-24 hours): The CBF and CBV in the ischemic penumbra were significantly lower than those in the unaffected side, and MTT and TTP were significantly prolonged (P < 0.05). In the core infarction area, only CBF and CBV were significantly decreased (P < 0.05), while the values of parameters MTT and TTP did not change significantly (P > 0.05). Compared with the ischemic penumbra, the core infarction area showed significant differences in rCBF, rCBV, and rMTT (P < 0.05), but no difference in rTTP (P > 0.05); NIHSS score was negatively correlated with rCBF (P < 0.05). Group II (24-72 hours): The CBF and CBV in the ischemic penumbra and the core infarction area were significantly lower than those in the unaffected side, and MTT and TTP were significantly prolonged (P < 0.05). Compared with the ischemic penumbra, the core infarction area showed significant differences in rCBF, rMTT, and rTTP (P < 0.05), but no difference in rCBV (P > 0.05); NIHSS score was negatively correlated with rCBV (P < 0.05). Conclusion: Dual-source CT perfusion imaging (DSCTP), relying on its characteristics of rapid scanning, high spatiotemporal resolution, and low radiation dose, can accurately obtain hemodynamic parameters of brain tissue and quantitatively distinguish the ischemic penumbra and irreversible infarction area in ischemic stroke. It can accurately identify the range of the ischemic penumbra using parameter thresholds such as CBF, CBV, and MTT, providing an objective basis for the selection of indications for clinical thrombolytic and thrombectomy treatments, effectively reducing the risk of hemorrhagic transformation, and also dynamically evaluating the treatment effect, which is of great guiding significance for improving the prognosis of patients.