Krombach Gabriele A, Wendland Michael F, Higgins Charles B, Saeed Maythem
Department of Radiology, University of California San Francisco, 505 Parnassus Ave, L308, San Francisco, CA 94143-0628, USA.
Radiology. 2002 Nov;225(2):479-86. doi: 10.1148/radiol.2252011512.
To (a) assess the value of a blood pool magnetic resonance (MR) imaging contrast agent (Clariscan) for characterizing microvascular injury in ischemically injured rat myocardium and (b) compare the extent of microvascular injury at Clariscan-enhanced MR imaging with infarction and areas at risk seen with histochemical staining.
Twenty rats underwent 45 minutes of coronary artery occlusion and 3 hours of reperfusion. Sequential T1-weighted spin-echo MR images were acquired in 10 rats to assess leakage of Clariscan into myocardium over time. Ten other rats underwent the same duration of occlusion and reperfusion (3 hours) so that the extent of microvascular injury in the entire heart could be measured and correlated with infarction and area at risk at necropsy. The Student t test and Bland-Altman method were used for data analysis.
Clariscan improved visualization of regions with transmural and nontransmural microvascular injury. Accumulation of Clariscan was best reflected by the mean ratios of signal intensity in injured myocardium to that in normal myocardium measured before (0.98 +/- 0.01 [standard error of the mean]) and after (1.34 +/- 0.04) injection. At 15 minutes after injection, the size of the enhanced region remained constant over the course of observation. The mean size of the hyperenhanced region (44% of the left ventricle +/- 2) was significantly (P <.001) larger than the mean size of true infarction at necropsy (29% +/- 3) but smaller than the mean size of the area at risk (50% +/- 2).
Clariscan has potential for estimating the spatial extent of microvascular injury in ischemically injured myocardium and may be useful as a marker of microvascular injury after thrombolytic therapy.
(a)评估血池磁共振（MR）成像造影剂（Clariscan）在表征缺血性损伤大鼠心肌微血管损伤方面的价值，(b)比较Clariscan增强MR成像时微血管损伤的范围与梗死范围以及组织化学染色显示的危险区域。
20只大鼠经历45分钟冠状动脉闭塞和3小时再灌注。对10只大鼠采集连续的T1加权自旋回波MR图像，以评估随时间推移Clariscan向心肌的渗漏情况。另外10只大鼠经历相同时长的闭塞和再灌注（3小时），以便测量整个心脏微血管损伤的范围，并将其与尸检时的梗死范围和危险区域相关联。采用Student t检验和Bland-Altman方法进行数据分析。
Clariscan改善了透壁和非透壁微血管损伤区域的可视化。Clariscan的蓄积情况通过测量注射前（0.98±0.01[平均标准误差]）和注射后（1.34±0.04）损伤心肌与正常心肌信号强度的平均比值得到最佳反映。注射后15分钟，增强区域的大小在观察过程中保持恒定。高增强区域的平均大小（左心室的44%±2）显著大于尸检时真正梗死的平均大小（29%±3）（P<.001），但小于危险区域的平均大小（50%±2）。
Clariscan有潜力估计缺血性损伤心肌中微血管损伤的空间范围，可能作为溶栓治疗后微血管损伤的标志物。
