Agarwal Smriti, Matys Tomasz, Marrapu S Tulasi, Scoffings Daniel J, Mitchell Jennifer, Jones P Simon, Baron Jean-Claude, Warburton Elizabeth A
Clinical Neurosciences, University of Cambridge , Cambridge , UK.
Department of Radiology, Addenbrooke's Hospital , Cambridge , UK.
Front Neurol. 2015 Apr 9;6:70. doi: 10.3389/fneur.2015.00070. eCollection 2015.
CT-based perfusion and collateral imaging is increasingly used in the assessment of patients with acute stroke. Time of stroke onset is a critical factor in determining eligibility for and benefit from thrombolysis. Animal studies predict that the volume of ischemic penumbra decreases with time. Here, we evaluate if CT is able to detect a relationship between perfusion or collateral status, as assessed by CT, and time since stroke onset.
We studied 53 consecutive patients with proximal vessel occlusions, mean (SD) age of 71.3 (14.9) years, at a mean (SD) of 125.2 (55.3) minutes from onset, using whole-brain CT perfusion (CTp) imaging. Penumbra was defined using voxel-based thresholds for cerebral blood flow (CBF) and mean transit time (MTT); core was defined by cerebral blood volume (CBV). Normalized penumbra fraction was calculated as Penumbra volume/(Penumbra volume + Core volume) for both CBF and MTT (PenCBF and PenMTT, respectively). Collaterals were assessed on CT angiography (CTA). CTp ASPECTS score was applied visually, lower scores indicating larger lesions. ASPECTS ratios were calculated corresponding to penumbra fractions.
Both PenCBF and PenMTT showed decremental trends with increasing time since onset (Kendall's tau-b = -0.196, p = 0.055, and -0.187, p = 0.068, respectively). The CBF/CBV ASPECTS ratio, which showed a relationship to PenCBF (Kendall's tau-b = 0.190, p = 0.070), decreased with increasing time since onset (Kendall's tau-b = -0.265, p = 0.006). Collateral response did not relate to time (Kendall's tau-b = -0.039, p = 0.724).
Even within 4.5 h since stroke onset, a decremental relationship between penumbra and time, but not between collateral status and time, may be detected using perfusion CT imaging. The trends that we demonstrate merit evaluation in larger datasets to confirm our results, which may have potential wider applications, e.g., in the setting of strokes of unknown onset time.
基于CT的灌注和侧支循环成像在急性卒中患者评估中的应用日益广泛。卒中发病时间是决定是否适合溶栓以及能否从溶栓中获益的关键因素。动物研究预测，缺血半暗带体积会随时间减小。在此，我们评估CT能否检测到通过CT评估的灌注或侧支循环状态与卒中发病后的时间之间的关系。
我们对53例连续的近端血管闭塞患者进行了研究，这些患者的平均（标准差）年龄为71.3（14.9）岁，发病后平均（标准差）时间为125.2（55.3）分钟，采用全脑CT灌注（CTp）成像。半暗带通过基于体素的脑血流量（CBF）和平均通过时间（MTT）阈值来定义；梗死核心通过脑血容量（CBV）来定义。计算CBF和MTT的标准化半暗带分数，分别为半暗带体积/（半暗带体积 + 梗死核心体积）（分别为PenCBF和PenMTT）。在CT血管造影（CTA）上评估侧支循环。通过视觉应用CTp ASPECTS评分，分数越低表明病变越大。计算与半暗带分数对应的ASPECTS比值。
PenCBF和PenMTT均显示出自发病以来随时间增加呈递减趋势（肯德尔tau - b分别为 - 0.196，p = 0.055，以及 - 0.187，p = 0.068）。与PenCBF相关的CBF/CBV ASPECTS比值（肯德尔tau - b = 0.190，p = 0.070）自发病以来随时间增加而降低（肯德尔tau - b = - 0.265，p = 0.006）。侧支循环反应与时间无关（肯德尔tau - b = - 0.039，p = 0.724）。
即使在卒中发病后4.5小时内，使用灌注CT成像可能检测到半暗带与时间之间存在递减关系，但侧支循环状态与时间之间不存在这种关系。我们所展示的这些趋势值得在更大的数据集中进行评估以证实我们的结果，这些结果可能具有更广泛的潜在应用，例如在发病时间不明的卒中情况下。
