Department of Radiology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210029, China.
Chin Med J (Engl). 2013 Jan;126(2):311-7.
A new lacunar infarction model was recently established in beagle dogs through proximal middle cerebral artery (MCA) occlusion by thrombus. This study aimed to characterize the model by multimodal magnetic resonance imaging (MRI) and to investigate its potential role for the future stroke research.
The left proximal MCA was embolized with an autologous thrombus in six beagles. Diffusion-weighted imaging (DWI) and T2-weighted imaging (T2WI) were performed every half hour during the first six hours after occlusion, followed by three time points at 12 hours, 24 hours, and one week. Perfusion-weighted imaging (PWI) and magnetic resonance angiography (MRA) were carried out at six hours, 24 hours and one week. The PWI-DWI mismatch ratio was defined as (PWI-DWI)/DWI ischemic volume.
Lacunar infarcts induced by MCA occlusion were located in the left caudate nucleus and internal capsule. All the lesions could be detected within two hours by DWI. Lesion volume on DWI increased in a time dependent manner, from (87.19 ± 67.16) mm(3) at one hour up to (368.98 ± 217.05) mm(3) at 24 hours (P = 0.009), while that on PWI gradually decreased from (7315.00 ± 2054.38) mm(3) at six hours to (4900.33 ± 1319.71) mm(3) at 24 hours and (3334.33 ± 1195.11) mm(3) at one week (P = 0.002). The mismatch ratio was 41.93 ± 22.75 at six hours after ischemia, showing "extensive mismatch", and decreased to 18.10 ± 13.74 at 24 hours (P = 0.002). No MCA recanalization was observed within 24 hours after MCA occlusion.
Lacunar infarction induced by proximal MCA occlusion could be detected early by DWI and was characterized by extensive PWI-DWI mismatch. Multimodal MRI is useful to demonstrate the natural evolution of PWI-DWI mismatch. This ischemic model could be further used for investigating early thrombolysis in lacunar stroke showing extensive mismatch.
最近通过血栓形成阻塞近端大脑中动脉 (MCA) 成功建立了一种新的腔隙性梗死模型。本研究旨在通过多模态磁共振成像 (MRI) 对该模型进行特征描述，并探讨其在未来脑卒中研究中的潜在作用。
将 6 只比格犬的左侧 MCA 近端用自体血栓栓塞。在闭塞后最初的 6 小时内每半小时进行一次弥散加权成像 (DWI) 和 T2 加权成像 (T2WI)，随后在 12 小时、24 小时和 1 周时进行 3 个时间点的检查。在 6 小时、24 小时和 1 周时进行灌注加权成像 (PWI) 和磁共振血管造影 (MRA)。将 PWI-DWI 不匹配率定义为 (PWI-DWI)/DWI 缺血体积。
MCA 闭塞引起的腔隙性梗死位于左侧尾状核和内囊。所有病变在 2 小时内通过 DWI 即可检测到。DWI 上的病变体积随时间呈依赖性增加，从 1 小时时的 (87.19 ± 67.16)mm3 增加至 24 小时时的 (368.98 ± 217.05)mm3（P = 0.009），而 PWI 上的病变体积则从 6 小时时的 (7315.00 ± 2054.38)mm3 逐渐减少至 24 小时时的 (4900.33 ± 1319.71)mm3 和 1 周时的 (3334.33 ± 1195.11)mm3（P = 0.002）。缺血后 6 小时的不匹配率为 41.93 ± 22.75，表现为“广泛不匹配”，并在 24 小时时降至 18.10 ± 13.74（P = 0.002）。MCA 闭塞后 24 小时内未见 MCA 再通。
DWI 可早期检测到近端 MCA 闭塞引起的腔隙性梗死，并表现为广泛的 PWI-DWI 不匹配。多模态 MRI 可用于显示 PWI-DWI 不匹配的自然演变。该缺血模型可进一步用于研究表现出广泛不匹配的腔隙性脑卒中的早期溶栓治疗。
