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目的探讨光声成像(photoacoustic tomography,PAT)定量评估大鼠急性心肌缺血损伤程度的可行性。方法将72只SD大鼠随机分为实验组和对照组。实验组36只,采用结扎SD大鼠左前降支,按结扎前和结扎后的不同时间(0,5,30,60,90和120 min)点再分为6小组,每小组6只;对照组36只,采用仅穿线不打结,按穿线前和穿线后的不同时间(0,5,30,60,90和120min)点再分为6小组,每小组6只。在不同时间点描记心电图并采血检测血清学指标,当心脏停跳后立即获取左心室前壁缺血区域PAT图象,提取分析PAT图象的灰度值。实验后摘除心脏做病理学检查。结果实验组心电图结扎后ST段抬高值≥0.1 mV,与对照组比较,差异具有非常显著意义(P<0.01);实验组血清学指标和病理学指标都随着造模时间延长而逐渐增加,而对照组无明显变化,两组比较差异具有显著意义(P<0.05);实验组PAT图象的灰度值逐渐减小,而对照组的灰度值无明显变化,两组比较差别具有显著意义(P<0.05)。相关性分析显示实验组的PAT图像灰度值与血清学指标及病理学指标均存在相关关系,呈负相关(P<0.05)。结论研究结果表明PAT定量评估心肌急性缺血损伤程度是可行的。
Objective To investigate the feasibility of using photoacoustic tomography (PAT) to quantitatively assess the severity of acute myocardial ischemia in rats. Methods 72 SD rats were randomly divided into experimental group and control group. Thirty-six rats in experimental group were divided into 6 groups (6 in each group) by ligation of the left anterior descending branch of SD rats at different time points (0, 5, 30, 60, 90 and 120 min) Group 36, using only threading without knot, according to threading before and after threading at different times (0,5,30,60,90 and 120min) points and then divided into 6 groups, 6 per group. At different time points, electrocardiogram was traced and blood was taken to detect serological indexes. PAT images of ischemic area of anterior wall of left ventricle were acquired immediately after cardiac arrest, and gray values of PAT images were extracted and analyzed. After the experiment, the heart was removed for pathological examination. Results Compared with the control group, the ST segment elevation in the experimental group after electrocardiogram ligation was significant (P <0.01). Serum and pathological parameters of the experimental group increased gradually with the increase of the modeling time , While there was no significant change in the control group, the difference between the two groups was significant (P <0.05); the gray value of the PAT image in the experimental group decreased gradually, while the gray value of the control group had no significant change, the difference between the two groups was Significant (P <0.05). Correlation analysis showed that there was a negative correlation between the grayscale values of PAT images and the serological and pathological parameters (P <0.05). Conclusion The results show that PAT quantitative assessment of acute myocardial ischemia and injury is feasible.