急性缺血再灌注心肌磁共振成像实验研究

目的：通过MR灌注成保评价急性梗死心肌组织血流灌注特点。方法：采用结扎左前降支90min存灌注的方法建立为存灌注梗死心肌组，对6只犬行MRI灌注成保及延迟扫描，观察犬心肌缺血存灌注模型梗死心肌MRI特点。结果：犬心肌缺血存灌注梗死心肌MR灌注成保表现为灌注缺损区，延迟扫描表现为高信号。结论：MR灌注成保有助于评价心肌血流，诊断心肌缺血存灌注梗死心肌。     

^13N—NH3 PET及冠状动脉造影评价CD151基因转染对小型猪心肌梗死后血流灌注的影响

目的用^13N—NH,PET及冠状动脉造影共同评价CD151基因转染促小型猪心肌梗死后血运重建。方法结扎20头小型猪冠状动脉左前降支（LAD）,建立心肌梗死模型。对梗死区及梗死周围心肌直接注射CD151及绿色荧光蛋白（GFP）重组腺相关病毒（rAAV）进行基因转染。8周后用免疫组织化学方法分析心肌组织CD151蛋白的表达和心肌组织微血管密度,用^13N—NH,PET显像评价心肌血流灌注,用LAD造影评价侧枝循环的建立。采用SPSS11．0软件行配对t检验或方差分析（ANOVA）。结果CD151基因转染促进局部心肌组织CD151高表达并增加缺血区心肌组织微血管密度。rAAV—CD151组心肌血流灌注明显增加,心肌缺血总分值为10．82±2．36,明显小于rAAV—GFP组（19．33±1．67,t=5．86,P=0．002）。冠状动脉造影显示rAAV—CD151组缺血心肌的侧枝循环建立明显较rAAV—GFP组增加。结论CD151基因转染可以明显促进心肌梗死后血运重建、增加血流灌注。^13N—NH,PET及冠状动脉造影能直观地评价心肌血运重建。     

急性心肌梗死的CT灌注实验研究

目的　探讨CT灌注扫描检测急性心肌梗死病灶的可靠性 ;定量研究急性梗死灶伽玛(γ)曲线的参数特征 ,以期指导临床对于冠心病及心肌梗死的分析、诊断。方法　使用ImatronC 15 0型电子束CT(EBCT) ,灌注扫描程序 ,扫描对比剂流动模型 ,观察拟合的曲线以及在不同灌注量中的变化 ;选取 6只健康家犬 ,麻醉后经开胸手术 ,结扎左冠状动脉前降支和旋支分支 ,使左心侧壁部分梗死。通过EBCT灌注扫描 ,观察正常和梗死区的形态及其灌注曲线变化 ,分析正常和梗死区的曲线特征和各参数 ,经统计学处理 ,提出其差异和鉴别点。有 2只同时经单光子发射体层计算机(SPECT)扫描 ,所有标本经氯化三苯基四氮唑 (TTC)染色处理 ,与扫描图像比较 ,并通过光学显微镜和电子显微镜检查证实。结果　不同灌注量的模型扫描曲线上升斜率不同 ;犬心肌的正常灌注曲线为一上升稍快 ,继之平缓下降的γ 曲线 :其上升时间约 10～ 13s,上升CT值约 34～ 37HU ,峰值CT值约 70～ 81HU。而梗死心肌的上升时间延长 ,平均 19 9s左右 ,上升CT值和峰值CT值降低 ,平均分别为 2 0 0和 5 3 8HU ,与正常心肌比较差异有显著性意义 (P <0 0 5 )。结论　正常与梗死心肌的灌注曲线有显著性差异 ,CT灌注扫描能够检测、发现心肌梗死病灶     

13N-NH3心肌灌注显像评价兔心肌梗死模型缺血再灌注

目的　探讨兔心肌梗死模型缺血再灌注与梗死面积之间的关系。方法　完全闭塞 16只雄性新西兰大白兔冠状动脉左前降支 4 5min ,随机分为再灌注组 (n =8)和无再灌注组 (n =8) ,7～10d后行1 3N NH3PET CT心肌灌注显像 ,与三氯四氮唑 (TTC)染色梗死灶缺损百分比进行比较。HE染色评价梗死灶病理学改变。结果　TTC染色示无再灌注组、再灌注组实际梗死灶缺损百分比分别为 (2 5 7± 2 3) %、(2 1 5± 2 4 ) % (P =0 0 0 31)。1 3N NH3PET CT心肌灌注显像示 ,无再灌注组与再灌注组缺损百分比分别为 (2 4 6± 2 2 ) %和 (2 0 5± 2 5 ) % (P =0 0 0 37)。组内TTC染色与PET CT显像结果差异无显著性 (P >0 0 5 )。结论　1 3N NH3PET CT心肌灌注显像较TTC染色能更准确测定心肌梗死灶范围。     

慢性冬眠心肌动物模型的建立

 目的 建立理想的实验性猪慢性冬眠心肌动物模型.方法 体重8～10 kg幼猪开胸分离冠状动脉左前降支近段并置入C形缩窄环,饲养21周后行冠状动脉造影、99mTc-MIBI单光子发射型计算机断层心肌灌注显像、小剂量多巴酚丁胺负荷超声检查,最后取心肌组织行放射性微球测定心肌血流量、氯化-2,3,5-三苯基四氮唑检测梗死面积和透射电镜组织学检查.结果 冠状动脉造影显示左前降支近段完全或接近完全闭塞,闭塞端以远依靠侧枝循环供血.心肌灌注显示左前降支供血区心肌呈放射性稀疏.左前降支供血区域心肌符合已知的慢性冬眠心肌的病理生理学特征:静息状态下室壁增厚率明显下降[(8.2±3.2)% vs (41.3±6.3)%,P<0.01]并对多巴酚丁胺负荷呈明显双相反应,室壁平均心肌血流量和心内膜下心肌血流量显著降低[0.86±0.1 vs 1.05±0.06 ml/(min·g),P<0.05和0.71±0.06 vs 1.15±0.04 ml/(min·g),P<0.01],经检测未发现心肌坏死,透射电镜显示心内膜下心肌细胞肌小节减少,核周有大量小线粒体聚集,核内出现异染色质.结论 在幼猪冠脉左前降支近段置入C形缩窄环并饲养21周后,可成功建立慢性冬眠心肌动物模型,能为深入探讨冬眠心肌的病理机制提供实验基础.     

KDML-Ⅱ型激光对缺血心肌的灌注效应和组织学实验研究

目的 :研究缺血心肌的血液灌注后改善情况及打孔后 2月孔道周围心肌组织学变化。材料及方法 :心肌缺血模型通过结扎左冠状动脉前降支第一对角支开口下方及供应心尖部血管分支 ,造成左室前侧壁及心尖的心肌缺血或梗死。 12只健康杂种犬随机分为对照组和实验组。实验组采用国产ＫＤＭＬ Ⅱ型激光 (功率 2 0Ｗ ,连续脉冲 ,光纤直径 1ｍｍ)在缺血区打孔 10～ 15个 ,对照组不作处理。术日观察 2ｈ心电图及血流动力学变化 ;术后2月 ,开胸。实验组于心肌打孔处 ,对照组于缺血区穿刺抽取标本 ,经相应处理后 ,分别测定孔道周围微血管数量、心肌的胶原…     

心肌灌注显像对症状性冠状动脉心肌桥患者的临床应用价值

目的 探讨心肌灌注显像对症状性冠状动脉(以下简称冠脉)心肌桥患者的临床应用价值.方法 回顾性分析19例因胸痛、胸闷等症状行冠脉造影排除阻塞性冠脉狭窄,诊断为心肌桥并接受运动-静息99Tcm-甲氧基异丁基异腈(MIBI)心肌灌注显像的患者资料,分析心肌灌注显像结果,并与运动心电图、冠脉造影结果比较.应用Stata 7.0软件,对符合正态分布的计量资料行t检验比较,用χ2检验分析组间频数差别.结果 19例症状性心肌桥患者冠脉造影示收缩期冠脉狭窄程度为(65.4±22.1)%,18例为左前降支肌桥、1例为左前降支合并左回旋支肌桥.运动-静息心肌灌注显像示心肌缺血10例、正常9例,其中心肌缺血位于前壁和(或)心尖部8例、下壁1例、后侧壁和后间壁1例;心肌灌注显像诊断心肌缺血的阳性率为52.6%(10/19),明显高于运动心电图的21.1%(4/19)=4.07,P<0.05.19例心肌桥患者按Nobel分级法,Ⅰ级狭窄5例、Ⅲ级狭窄6例、Ⅲ级狭窄8例;Ⅰ级狭窄患者中1例心肌灌注显像心肌缺血阳性,Ⅱ级狭窄患者中2例阳性,Ⅲ级狭窄患者中7例阳性.心肌桥患者心肌灌注显像心肌缺血组收缩期冠脉狭窄明显高于心肌灌注显像正常组[(78.0±4.7)%与(52.8±6.7)%,t=3.06,P<0.01],2组肌桥长度差异无统计学意义[(15.1±2.1)mm与(11.8±1.0)mm,t=1.43,P>0.05].结论 运动-静息心肌灌注显像能有效评价症状性心肌桥患者所致心肌缺血,明确心肌桥与临床症状的关系及其临床意义.     

软组织肿瘤的多层螺旋CT、MR灌注成像初步研究

目的　探讨多层螺旋CT(MSCT)及MR灌注成像对软组织肿瘤的良恶性鉴别诊断价值。方法　分别对软组织肿瘤 2 6例 (良性 15例 ,恶性 11例 )行MSCT灌注成像、2 9例 (良性 17例 ,恶性 12例 )行MR灌注成像 ,通过灌注软件分析灌注参数在良恶性肿瘤中的差异。结果　MSCT灌注成像结果 :恶性组血流速度 (BF)为 (2 4 4 9± 14 4 9)ml·10 0mg-1·min-1,良性组BF为 (1 98± 1 19)ml·10 0mg-1·min-1;表面通透性 (PS)恶性组为 (14 6 4± 1 89)ml·10 0mg-1·min-1,良性组为 (2 4 0± 0 38)ml·10 0mg-1·min-1。良恶性软组织肿瘤间的BF、PS值差异具有显著性意义 (P值均 <0 0 5 ) ;血容量 (BV)、平均通过时间 (MTT)值差异则无显著性意义 (P值均 >0 0 5 )。MSCT灌注成像诊断软组织恶性肿瘤的灵敏度为 90 9% (10 / 11) ,特异度为 86 7% (13/ 15 ) ,准确度为 88 5 % (2 3/ 2 6 ) ,阳性预测值为 83 3% (10 /12 ) ,阴性预测值为 92 9% (13/ 14 )。MR灌注成像结果 :恶性组BF为 (0 11± 0 0 2 )ml·10 0mg-1·min-1,良性组为 (0 0 7± 0 0 1)ml·10 0mg-1·min-1;良、恶性软组织肿瘤之间的BF值差异具有显著性意义 (P<0 0 5 ) ;BV、MTT值差异则无显著性意义 (P >0 0 5 )。MR灌注成像诊断恶性肿瘤的灵敏度为 91     

心肌内注射碱性成纤维生长因子促进缺血心肌血管生成的实验研究

目的　探讨心肌内注射碱性成纤维生长因子 (bFGF)对急性心肌梗死血管生成的作用。方法　 2 4只健康杂种犬随机数字表法分成对照组和实验组 ,结扎冠状动脉左前降支第一对角支下0 5cm处。每组按 4个时间点 (术后第 1、3、10、17天 )分为 4个小组 ;实验组在梗死心肌区 5个位点注射bFGF 5 0mg 生理盐水共 15ml,对照组在相同部位注射生理盐水共 15ml。各组动物在处死前采用敏感编码 (SENSE)技术行MR电影和心肌灌注MR成像 ;电子显微镜观察新生血管生长 ;免疫组织化学方法检测微血管数量。结果　实验组左心室射血分数自第 10天明显增加 (第 10天 :对照组 2 4 0 9± 3 32、实验组 4 5 71± 6 2 7;第 17天 :对照组 31 4 6± 4 6 0、实验组 5 3 4 6± 5 2 4 ) (P <0 0 5 ) ;梗死心肌首过灌注呈低强化 ,延迟扫描信号强度高于正常心肌 ,曲线上升时间、峰值时间、曲线上升斜率、对比增强率低于正常心肌 ;第 17天时心肌梗死范围百分比显著变小 [对照组 (9 0 4± 1 5 9) %、实验组 (4 0 7± 1 2 0 ) % ](P <0 0 5 ) ;实验组微血管生长活跃 ,其数量除第 1天外余各个时间点实验组均比对照组明显增多 ,对照组与实验组分别为第 3天 :(92 3± 11 6 )个 /视野、(14 7 3± 11 6 )个 /视野 ;第 10天 :(12 5 0± 12     

正常猪及急性心肌梗死猪模型的左心室电机械标测

目的　采用电机械标测 (NOGA)系统标测左心室 ,明确梗死前、后心肌组织的电压及机械变化。方法　选取 10头体重为5 0～ 65kg的家猪 ,进行左心室造影及NOGA标测。其后 ,以冠状动脉内球囊将填塞物送入左前降支远端 ,造成急性心肌梗死模型 ,2h后再次进行左心室造影及标测。结果　梗死区心肌的单极电压 (UpV)及局段线性缩短率 (LLS)与梗死前相比显著降低 (UpV ,11.6mV± 2 .3mVvs 4.9mV± 1.2mV ,Ρ <0 .0 0 1;LLS ,13 .3± 2 .1vs 5 .9± 1.3 ,Ρ <0 .0 0 1)。结论　NOGA标测可明确区分正常与梗死心肌 ,并能同步反映心肌的电机械特性 ,为介入医师提供了一种新的诊疗策略     

Assessment of myocardial viability after myocardial infarction

Conclusions  The data presented above suggest that assessment of myocardial viability after MI, particularly in those patients with severe LV dysfunction, is important for the identification of those with the highest risk, in whom revascularization can be of clinical benefit. There is growing and consistent evidence that patients with relatively large areas of dysfunctional but viable myocardium after MI have improved function, symptoms, and survival with prompt revascularization compared with medical therapy alone. Most importantly, long-term survival with revascularization in these patients is comparable with that achieved with cardiac transplantation. There are several methods available to the clinician with which to investigate the presence of tissue viability, and the evidence suggests that the scintigraphic approaches are the most sensitive. These observations suggest that noninvasive investigation of the amount of ischemic myocardium should be an important component of the diagnostic evaluation of patients with severe LV dysfunction after MI. This approach will likely enhance the often difficult process of selecting patients with poor cardiac function in whom revascularization will likely improve both the quality and quantity of life.     

Nitrate-augmented myocardial imaging for assessment of myocardial viability

²⁰¹Tl myocardial perfusion imaging is presently done by several possible strategies. Stress/delayed redistribution, stress/redistribution/reinjection, and rest/redistribution imaging can be useful in the clinical assessment of myocardial viability. Unfortunately, the extent of myocardial viability may still be underestimated even by ²⁰¹Tl reinjection imaging, compared with ¹⁸F-fluorodeoxyglucose positron emission tomography. ^99mTc-labeled sestamibi imaging provides results similar to those of ²⁰¹Tl imaging in the detection of coronary artery disease, but several previous studies suggest that stress/rest ^99mTc-labeled sestamibi imaging significantly underestimates myocardial viability. Recently it has been reported that the administration of nitrates, before ²⁰¹Tl reinjection, improves detection of defect reversibility. Several studies also suggested that administration of nitrates before the injection of ^99mTc-labeled sestamibi significantly improved detection of reversibility with this agent, whereas additional studies showed further that this combination improves the predictive accuracy for recovery of left ventricular function and perfusion after coronary revascularization, compared with a standard rest ^99mTc-labeled sestamibi study. Nitrate administration before the injection of ²⁰¹Tl and ^99mTc-labeled sestamibi may thus be a potentially attractive alternative for the evaluation of myocardial viability. Although the available results are encouraging, further studies are needed to evaluate the clinical value of ²⁰¹Tl and ^99mTc-labeled sestamibi imaging, in combination with nitrates, for predicting recovery of left ventricular dysfunction.     

Acute myocardial infarction during adenosine myocardial perfusion imaging

Journal of Nuclear Cardiology -     

急性心肌梗死心肌血流再灌注评价技术

TIMIFlow作为评价再灌注的方法自20世纪80年代起就一直应用于临床。TIMIFrameCount是较TIMI血流分级更为客观、更具可重复性的联系性变量指标。TMBG和TMP从心肌微血管水平对再灌注进行评价。冠脉内多普勒血流频谱变化常作为造影过程中的附加检查指标评价血管再通及心肌再灌注。同时心肌声学造影、连续心电图ST段监测、核素心肌灌注显像和心肌增强磁共振成像作为无创性的评价方法也显示出其应用价值。     

Assessment of regional myocardial function by ECG-gated myocardial SPECT]

PURPOSES: Regional myocardial functional parameters were assessed by ECG-gated myocardial SPECT analysis in normal subjects and ischemic heart diseases. METHODS: Normal subjects (13 male and 10 female) and 51 patients with chronic ischemic heart disease underwent ECG-gated myocardial SPECT. A dose of 740 MBq of 99mTc-MIBI was injected at rest, and gated SPECT was performed 60 min later. Wall motion (WM) and systolic wall thickening (WT), % tracer uptake were evaluated by quantitative gated SPECT program (QGS). Regional parameters were obtained in the 16 segments based on the functional polar map. In the normal group, standard values were evaluated in the lateral, septal, anterior and inferior regions both in male and female subjects. In the ischemic heart disease group, sensitivity and specificity of these parameters were assessed in each segment. To estimate the ability of WM and WT in detecting regional dysfunction, decreased perfusion area, which was defined as < mean - 2SD by the normal profile, was used as a standard. The receiver operating characteristics (ROC) area analysis was also performed. RESULT: In the normal profile, % tracer uptake was decreased in the anterior segments of female group, no significant difference was observed between male and female in WM and WT. WM was decreased in the septum and increased in the lateral segment. WT didn't show any difference regional difference. Sensitivity and specificity of WM were 56%/91% in the anterior, 0%/100% in the septum, 43%/87% in the inferior, 31%/85% in the lateral. WT were 67%/93% in the septum, 67%/79% in the inferior, and 59%/81% in the septum. The area under ROC curve was WM 0.63, WT 0.85 (p < 0.005 between WM and WT) in the septum, in inferior WM 0.77, WT 0.80 (p = 0.57), in anterior WM 0.86, WT 0.87 (p = 0.095), in lateral WM 0.68, WT 0.78 (p = 0.037). CONCLUSION: In normal profile, the % tracer uptake in the anterior wall decreased in females, but WM and WT did not show significant difference in each region affected this influence. The septal WM was decreased in the normal profile and ability to diagnose regional function was also decreased compared with WT. Thus, we can conclude that WT is preferable for detecting septal functional abnormality.     

急性心肌梗死再灌注治疗前后心肌血流和代谢的变化及临床意义

目的　探讨急性心肌梗死患者行经皮冠状动脉腔内成形术 (PTCA)和支架术后心肌血流、脂肪酸代谢及糖代谢的变化及其临床意义。方法　 2 2例急性心肌梗死患者 ,于发病后 4周行延迟PTCA ,术前 (急性期 )及术后 (慢性期 )分别行2 0 1 Tl、1 2 3I β 甲基碘苯脂十五烷酸 (BMIPP)SPECT显像及1 8F 脱氧葡萄糖 (FDG)PET心肌显像。将左心室分成 13个节段 ,采用 4级评分法对2 0 1 Tl、1 2 3I BMIPP显像放射性分布进行视觉评价 ,两者得分差为2 0 1 Tl BMIPP不匹配。在血流减低部位 ,定量测定1 8F FDG摄取。慢性期复查冠状动脉造影。结果　急性期心肌血流 脂肪酸代谢不匹配的节段 ,1 8F FDG摄取率明显高于匹配节段 [(76 .5± 10 .6 ) %和 (4 5 .8± 8.6 ) % ,P <0 .0 1],慢性期两者无明显差异。冠状动脉非再狭窄患者其慢性期2 0 1 Tl BMIPP不匹配 (0 .2 5± 0 .4 2 )及1 8F FDG摄取率 [(5 2 .1± 8.1) % ]较急性期 [0 .36± 0 .5 1和 (72 .8± 9.8) % ]明显降低 (P均 <0 .0 1) ;冠状动脉再狭窄患者其慢性期与急性期比较 ,2 0 1 Tl BMIPP不匹配及1 8F FDG摄取率无明显变化。结论　观察急性心肌梗死PTCA前后心肌血流 脂肪酸代谢及糖代谢的变化 ,可间接预测PTCA后再狭窄。