脑出血早期血肿扩大机制的CT densitometry研究

Intracerebral hemorrhage is a devastating neurological disorder that accounts for 20-30% of stroke in China. Early hematoma enlargement which is defined as hematoma expnasion of greater than 30% on the 24 hour follow-up CT scan, was seen in approximately one third of patients with intracerebral hemorrhage. Previous research suggested that early hematoma enlargement is an important cause of neurological deterioration and poor functional outcome in patients with intracerebral hemorrhage. It is an independent predictor of poor functional outcome at 3 months. The exact mechanism of early hematoma enlargement is unclear. There is no effective treatment after intracerebral hemorrhage. There is no perfect animal models that could accurately similate the intracerebral hemorrhage pathophysiology. Current understanding of mechanisms of hematoma enlargement are mainly based on neuroimaging research of patients with intracerebral hemorrhage. The most accepted mechanism for hematoma enlargement was continued bleeding or rebleeding. Recent research suggested that osmotic pressue induced dilution of hematoma may also contribute to hematoma enlargement. Rebleeding or continued bleeding may lead to increased or unchanged mean CT density within the hematoma. In contrast, osmotic pressure induced hematoma dilation may lead to decreased mean hematoma density. We set up to investigate the mechanism of early hematoma enlargement by CT densitometry. Baseline CT scan was performed within 6 hours after onset of symptoms. Follow-up CT was obtained 24 hours after onset of symptoms. The CT source images were registered before calculation. The hematoma volume and perihematoma edema volume were measured with Analyze software. The CT densitometry of hematoma and edema were perfromed by using Analyze software. Our study may shed light on the mechanism of early hematoma enlargement and provides new therapeutic targets for intracerebral hemorrhage.

脑出血患者中有超过三分之一的患者出现早期血肿扩大。研究表明早期血肿扩大是造成脑出血患者神经功能恶化的重要原因。血肿扩大可导致患者神经功能缺失加重和预后不良。目前脑出血早期血肿扩大的机制还不清楚，也没有有效地治疗方法。目前多数学者认为脑出血早期血肿扩大是由于持续出血或再出血所致。有研究表明，血肿高渗状态和血肿周围水分子的进入也有可能导致血肿扩大。如果血肿扩大是继续出血所致，第二次血肿的平均密度与第一次血肿相比，平均密度不变或有轻度增加。如果由于血肿稀释所致血肿扩大，血肿平均密度将降低。本研究通过对脑出血患者6小时内及24小时行CT扫描，通过自主研发Matlab编程进行CT图像的配准，由Analyze软件精确测量血肿体积变化和血肿密度的动态变化，从而为阐明脑出血早期血肿扩大的机制奠定基础，为脑出血的治疗提供新的靶点。

脑出血患者中有超过三分之一的患者出现早期血肿扩大。早期血肿扩大是造成脑出血患者神经功能缺失加重和预后不良的重要原因。目前脑出血早期血肿扩大的机制还不清楚。早期血肿扩大的准确预测也非常困难。故对早期血肿扩大机制和预测方法的研究对于我们找到攻克该疾病的靶点有着重要的作用。本研究自主研发了Matlab程序测量血肿密度动态变化，通过Analyze 软件精确测量血肿体积变化，从而为阐明脑出血早期血肿扩大的机制奠定基础，为脑出血的治疗提供新的靶点。本研究取得了几项重要成果，包括（1）在国际上首次提出了可以通过CT densitometry实现早期血肿扩大预测的新征象，并命名为Blend Sign。通过多元逻辑回归分析显示，基线CT扫描的时间，初始血肿体积，以及基线CT扫描混合征(Blend sign)都是早期血肿扩大的独立预测因子。Blend Sign预测血肿扩大的敏感性、特异性、阳性预测值和阴性预测值分别为39.3%，95.5%，82.7%，和74.1%。(2)对脑出血早期血肿扩大的机制提出了新的见解：阐明了脑出血破入脑室在早期血肿扩大的作用。并提出了迟发性脑室出血的现象。（3）在本研究进行过程中，在脑血管扫描方案上，自主研发基于单源CT的双能剪影成像方案，该方案可广泛用于改善脑出血患者血管成像质量。（4）通过Matlab编程建立了脑血管疾病的脑灌注压监测的拟合函数，为实现脑出血患者个体化的脑灌注压监测和分析奠定了基础。（5）通过8阶Fourier函数拟合该技术实现了脑血流速度数字化模型，为实现脑出血患者血流动力学个体化研究提供了途径。

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