彩色室壁动力技术小剂量多巴酚丁胺负荷试验检测冬眠心肌与病理学检查对比的实验研究

目的: 探讨彩色室壁动力技术(CK)小剂量多巴酚丁胺超声心动图负荷试验(CK-DSE) 检测冬眠心肌(HM)的价值.材料和方法: 22只犬结扎冠状动脉造成实验性心肌缺血损伤的动物模型.应用CK-DSE检测动物模型的心肌梗塞区心内膜运动幅度/非梗塞区心内膜运动幅度比值(AMI/ANMI),与病理组织切片显示冬眠心肌面积/梗塞区总面积的比值(ATAM/ATIM)进行对比分析.结果: 本实验成功地建立11只实验性心肌缺血损伤的动物模型,CK-DSE检测冬眠心肌的敏感性、特异性和准确性分别为90%、80%和83%.CK-DSE检测AMI/ANMI比值,与ATAM/ATIM具有较好的相关关系(r=0.75).结论: CK-DSE能准确地检出心肌梗死后存活的冬眠心肌,是定量检测梗塞区内冬眠心肌的较好方法.     

心肌灌注/代谢显像评价干细胞移植后犬受损心肌的修复能力

目的 采用核素心肌灌注(MPI)/代谢(MMI)显像评价犬心肌梗死自体骨髓干细胞移植后受损心肌的修复能力.方法 选取杂种犬12条,按动物编号法随机分为移植组(单号)及对照组(双号)各6条.通过手术间断阻断左前降支(LAD)下1/3循环90 min,建立犬心肌梗死模型.将诱导分化的骨髓间质干细胞自体移植到移植组动物梗死区,通过核素MPI和MMI、组织病理、免疫组织化学等技术评价干细胞移植治疗后6周和10周的效果.采用SPSS 10.0软件进行统计学处理.结果 (1)3条犬死亡,其中对照组2条.其余9条犬结扎冠状动脉24-48 h后的心电图、9～12 h后静脉血清心肌酶谱、5～7 d后MPI符合心肌梗死改变.(2)细胞移植后5～7 d MPI/MMI发现对照组心肌梗死节段数及梗死区存活心肌节段数分别为20及8个节段,移植组分别为25及10个节段,2组差异无统计学意义(t=0.389,P＞0.05).(3)ANOVA分析结果示,移植组有存活心肌的节段数在细胞移植10周与移植后5～7 d MPI/MMI比较差异有统计学意义(F=5.879,P＜0.05);无存活心肌的节段数细胞移植6周及10周MPI/MMI差异均无统计学意义(F=0.376,P＞0.05).对照组细胞移植后5～7 d、6周和10周的MPI/MMI所示梗死心肌节段数差异无统计学意义(F=0.212,0.005,0.316,P均＞0.05).(4)细胞移植5～7 d及10周后对照组与移植组的MPI所示左心室射血分数(LVEF)的变化值分别为(5.50±2.69)%及(16.20±2.93)%,2组之间差异有统计学意义(t=13.563,P＜0.01).结论 MPI/MMI不仅可以确定心肌梗死的部位、范围、程度及梗死心肌是否存活,还可以反映骨髓干细胞移植后的细胞存活及生长状况.     

高原心脏病心力衰竭机制探讨

高原心脏病(high altitude heart disease,HAHD)是慢性高原病的一种临床类型,为海拔3 000m以上地区移居人群多发病。本文旨在探讨高原心脏病左室损伤机制及冬眠心肌(hibernating myocardium,HM)在损伤中的作用,评价冬眠心肌在高原心脏病心力衰竭中的作用。作者选择34名HAHD患者进行了经胸壁小剂量多巴酚丁胺负荷超声试验,观察左室局部心肌收缩功能及心功能指标。结果轻中度心衰患者左室心肌对逐渐增加剂量的多巴酚丁胺     

99锝m N-2-巯基吡啶-N-氧化物与99锝m-甲氧基异丁基异腈对犬急性心肌梗死模型的对照研究

目的 在正常和心肌梗死犬模型上,研究99TcmN-2-巯基吡啶-N-氧化物(99TcmN-MPO)的药物代谢动力学特征、生物学分布特征和对急性心肌梗死的诊断能力,并与传统示踪剂99锝m-甲氧基异丁基异腈(99Tcm-MIBI)进行对比研究.方法 正常杂种犬12只.静脉注射99TcmN-MPO,于不同时间点(30 s及1、2、3、4、5、10、20、30、40、60和90 min)静脉分别采血1 ml,经γ探测器测量其放射活性;注药后10、20、30、60、90及120 min行全身SPECT显像,并于不同器官上各取同样大小的ROI,测量其放射性计数进行定量研究.每只犬均注射相同剂量的99TcmMIBI,进行相同的实验作为对照.介入学方法构建犬急性心肌梗死模型,24 h后,静脉注入99TcmN-MPO(5只)和99Tcm-MIBI(5只),并于注药后30、60min进行心肌SPECT显像.结果 在静脉注射90 min内,99TcmN-MPO和99Tcm-MIBI均表现为快速的血液清除.两种示踪剂的初始注射剂量均为370 MBq.注射后1 min,每毫克血浆的放射活性小于初始注射剂量的50%[99TcmN-MPO为(35.77±6.31)%ID/mg;99Tcm-MIBI为(34.46±6.83)%ID/mg],30 min时＜5%[99TcmN-MPO:(3.11±1.44)%ID/mg;99Tcm-MIBI:(2.93±0.39)%ID/mg].99TcmN-MPO在心脏的浓聚明显,且存留时间很长,由于其在肝脏清除的速度较快,因此可获得良好的心/肝摄取比值,注射后10 min为0.54±0.06,30 min为1.02±0.06,60 min上升到1.38±0.06.相比之下,99Tcm-MIBI的心/肝摄取比值上升较为缓慢(注射后10 min为0.46±0.03,30 min为0.63±0.03,60 min为0.62±0.12).犬心肌梗死后SPECT心肌断层扫描显示,在注射99TcmN-MPO 30 min后,心脏与肝脏分界清楚,可清楚显示心肌缺血、梗死灌注缺损区域、范围和程度;而99Tcm-MIBI注射后60 min,心脏和肝脏的分界依然不清,尤其是肝脏的高放射性对心脏下壁和左心室壁的影响很大,对心脏左心室壁的心肌梗死灌注缺损区域的显示不佳.结论 99TcmN-MPO具有心肌摄取量较高,肝脏代谢快的特点,是一种具有广阔临床应用前景的SPECT心肌灌注成像显像剂.

Abstract：

Objective The purpose of the present study is to compare the pharmacokinetic and biodistribution properties of 99Tcm N-mercaptopyridine-N-oxide (99 Tcm N-MPO) with 99 Tcm-sestamibi (99 Tcm-MIBI) in normal dogs, and to investigate the potential of 99TcmN-MPO as a myocardial perfusion agent in canines with acute myocardial infarction. Methods Twelve healthy mongrel dogs were injected intravenously with 99TcmN-MPO (n = 6) or 99Tcm-MIBI (n = 6). Tracer kinetics in body fluids were determined by collecting blood of 1 ml via a femoral vein catheter at 30 s, 1,2,3,4,5, 10, 20, 30, 40, 60and 90 min post-injection (p. i.). The collected blood samples were weighed and counted for radioactivity in a γ-counter. Anterior and posterior planar γ-camera images were collected at 10, 20, 30, 60, 90, and 120 min after injection, with organ uptake quantified by region-of-interest (ROIs) analysis. For comparison, 99Tcm-MIBI was also evaluated in the same twelve dogs. Canine infarct models were set up by micro-invasive interventional embolization. SPECT images in the canine infarct model were collected 24 hours after myocardial infarction at 30 min and 60 min after the administration of 99Tcm N-MPO (n = 5) or 99Tcm-MIBI (n = 5). Results Both of 99Tcm N-MPO and 99Tcm-M1BI had a rapid blood clearance with less than 50% of initial radioactivity remaining at 1 min [99TcmN-MPO: (35. 77 ± 6. 31)% ID/mg ,99Tcm-MIBI (34. 46 ± 6. 83) % ID/mg] and less than 5% at 30 min p. i. [99Tcm N-MPO(3. 11 ± 1.44) % ID/mg,99Tcm-MIBI (2.93 ±0. 39)% ID/mg] . After injection, 99TcmN-MPO showed significant accumulation in the myocardium and prolonged retention. This rapid liver clearance of 99TcmN-MPO led to favorable heart-to-liver ratios, reaching values of 0. 54 ±0. 06 at 10 min, 1.02 ±0. 06 at 30 min, and 1.38 ±0. 06 at 60 min p. i.In contrast, the heart/liver ratio of 99Tcm-MIBI remained low at all time points (0. 46 ± 0. 03 at 10 min,0. 63 ±0. 03 at 30 min, and 0. 62 ± 0. 12 at 60 min p. i.). SPECT imaging studies in canines with acute myocardial infarction indicated that good visualization of the left ventricular wall and perfusion defects could be achieved at 30 min after administration of 99TcmN-MPO, but not 99Tcm-MIBI. Conclusion The combination of high heart uptake and rapid liver clearance makes 99TcmN-MPO a promising new radiotracer for myocardial perfusion imaging.     

心肌梗死延迟增强三维与二维MR成像对比研究

Objective To prospectively evaluate the correlation between a single breath-hold three-dimensional (3 D) and several breath-hold two-dimensional (2D) delayed enhancement MR imaging sequences in the assessment of myocardial infarction size and the differences on image quality. Methods Fifteen patients with myocardial infarction underwent MR scan by using a single breath-hold 3D inversion-recovery fast low-angle shot (FLASH) sequence and several breath-hold 2D turbo-FLASH as the reference standard. Paired-samples t test was used to compare the ratio of the infarction areas in two sequences. Two-way ANOVA was used to assess the contrast-to-noise ratio (CNR) on 3D,2D magnitude-reconstructed and 2D phase-sensitive (PS) images. P value less than 0.05 was considered to indicate a significant difference. Meanwhile subjective visual evaluation was also performed to compare the image quality. Results The infarction ratio determined by 3D MR imaging 31.28% was no significant difference with that of 2D MR imaging 30.91% and had a good correlation (t = -0.505,P =0.621,r =0.990). The CNR was significantly higher in 3D and 2D magnitude-reconstructed groups than in 2D-PS group (3D and 2D magnitude-reconstructed images, 2D P5 image, 43.43±20.67 and 34.10±14.29, 7.59±2.59, respectively) (F = 24.376, P < 0.01). However, the contrast between normal and infracted myocardium was the highest in 2D-PS group with subjective visual evaluation (scores of 3D, 2D magnitude-reconstructed and 2D-PS images, 2.33, 2.13 and 2.73, respectively). On the other hand, the background noise on 2D-PS images was the highest in 3 groups (scores of 3 D, 2 D magnitude-reconstructed and 2 D-PS images, 2.67, 2.53 and 1.20, respectively). Conclusion The myocardial infarction ratio obtained with 3D MR imaging sequence is accurate, and the image quality is good.     

浸泡性体温过低对犬心功能的影响

目的 探讨浸泡性低温过低对犬心功能的影响.方法 4只健康杂种犬置于(6±1)℃的冷水中全身浸泡致发生室颤.用多道生理记录仪测定犬心功能指标,心电图仪测定心电图,透射电镜观察室颤犬心肌组织变化.结果 随着动物体温下降,犬左心室内压值(LVSP)、左心室内压最大上升/下降速率(±dp/dtmax)明显下降,Q-T间期延长,可见低温性J波,出现室颤.结论 体温过低可导致心功能下降,Q-T间期延长和低温J波的出现预示室颤发生.

Abstract：

Objective To investigate the effect of cold water immersion on the cardiac function of dogs. Methods Four healthy dogs were immersed in cold water at ( 6 ± 1 ) ℃ until the onset of ventricular fibrillation. Electrocardiogram was recorded with Cardiofax, cardiac function was monitored with the polygraph system, and changes in the structure of myocardium were observed with the transmission electron microscope.Results With the decrease in the body temperature of animals, marked changes in the decrease of the left ventricular pressure peak value (LVSP) and isovolumetric contraction of maximal ascending/descending velocity ( ± dp/dtmax) could be noted. When high -grade hypothermia occurred, J wave was found with a prolonged Q-T duration, and subsequently, there came the rapid ventricular arrhythmia. Conclusions Hypothermia could induce the decrease in the canine cardiac function, moreover, the prolongation of Q-T and the appearance of J wave might predict the occurrence of ventricular fibrillation.     

Low-dose dobutamine gated single-photon emission tomography: comparison with stress echocardiography

Perfusion scintigraphy provides important information regarding the presence of viable tissue after myocardial infarction. Defects of moderate severity, however, may represent viable myocardium, necrotic tissue or a mixture of both. In this study the presence or absence of inotropic response in the infarcted area was assessed by low-dose dobutamine tetrofosmin gated single-photon emission tomography (LDD gated SPET). Results were compared with those obtained with stress echocardiography (SE). Twenty-five patients with acute myocardial infarction were studied. Gated SPET myocardial perfusion imaging was performed 60 min after the injection of technetium-99m tetrofosmin (925 MBq) at rest using a triple-headed camera equipped with focussing collimators (Cardiofocal). Two consecutive acquisitions were performed according to a ”fast” gated SPET protocol (3×20 stops, 9 s/stop, 64×64 pixel matrix, zoom 1.23) with the subjects remaining in the same position. The first acquisition was obtained at rest; the second acquisition was obtained under infusion of 10 μg kg^–1 min^–1 dobutamine. The severity of regional dysfunction, wall thickening severity (WT_sev), was assessed and quantified using a method based on circumferential profile analysis. SE was performed at rest and during infusion of 5 and 10 μg kg^–1 min^–1 dobutamine. Two patients could not be analysed because of disturbing gastro-intestinal activity on the perfusion study. Under dobutamine 11 patients presented a significant change in WT_sev (three showed normalisation, five an improvement and three a deterioration), while in 12 patients the WT_sev score remained unchanged. The overall concordance between LDD gated SPET and SE was 83%. In patients with perfusion defects of moderate severity the concordance was 90% (9/10). It may be concluded that functional changes in infarcted areas induced by dobutamine can be detected with gated SPET. Good agreement was observed between LDD gated SPET and SE for the identification of inotropic reserve in infarcted areas. Received 5 September and in revised form 22 November 1999     

T2 mapping技术监测缺血再灌注后心肌水肿动态改变:动物实验研究

目的 探究T2 mapping技术对心肌缺血/再灌注(I/R)后心肌水肿长期动态改变的监测作用.方法 对7只恒河猴进行I/R手术.所有动物于术前、术后7 d、30 d及90 d接受一系列心脏磁共振(CMR)检查.扫描序列包括T2 mapping、电影及钆对比剂延迟强化序列.将心肌分为梗死区、过渡区和远端心肌,测量不同区...     

心肌梗死患者左室局域舒张功能的运动幅度成像

目的探索冠心病患者左心室舒张各期局部心肌运动幅度成像特点及其评价左心室局域舒张功能的可能性。方法对54例前壁心肌梗死病人(M I组)和78例正常对照者(NOR组)左室心肌进行组织多普勒成像检查。记录心尖二腔动态图像,应用运动幅度成像描记技术获取左室各阶段心肌同步幅度曲线,测量等容舒张期(IR)、快速充盈期(RF)、缓慢充盈期(SF)、心房收缩期(AC)局部心肌速度变化幅度,对两组结果进行对比分析。结果在整个舒张期,正常对照组从前壁心尖、中间到心底部,幅度呈正值逐渐减小的梯度变化。M I组梯度变化规律消失,梗死区域幅度为负值。在等容舒张期,正常组为一个较平缓的下降波97.44%(76/78)。M I组则有50%(27/54)为下降波(P<0.05)。在快速充盈期,对照组有97.44%(76/78)为快速下降的波;M I组梗死区域运动幅度为负值(P<0.001)。在缓慢充盈期,正常组多数为靠近基线的水平波;而在M I组,无明显的水平波段(P<0.05)。结论局部心肌缺血梗死导致主动舒张期的局部心肌运动幅度显著异常。运动幅度成像能敏感、直观、无创地定量评价左心室局域舒张功能。     

兔缺血心肌组织PTEN及VEGF的表达和血管生成关系的研究

目的 研究家兔急性心肌梗死(AMI)后梗死边缘区心肌组织10号染色体上缺失的磷酸酶与张力蛋白同源物基因(PTEN)及血管内皮生成因子(VEGF)的表达与血管生成的关系.方法 20只日本大耳白兔,随机分为AMI组(n=15)和假手术(SH)组(n=5),AMI组又分为术后AMI 1、2、4周组,每组5只.AMI组结扎左冠状动脉回旋支建立AMI模型,SH组回旋支仅穿线不结扎血管.Ⅷ因子免疫组化测定梗死边缘区毛细血管密度,免疫组化及QRT-PCR检测梗死边缘区心肌VEGF的表达,Western blotting及QRT-PCR检测梗死边缘区心肌PTEN的表达.结果 AMI组梗死边缘区心肌组织VEGF的表达较SH组明显减少(P<0.01),PTEN的表达明显高于SH组(P<0.01).AMI 4周时梗死边缘区心肌组织的毛细血管密度(45.4±10.0/mm2)与SH组(103.2±13.3/mm2)比较明显减少(P<0.01).PTEN蛋白及mRNA表达与VEGF表达之间均呈负相关(r=-0.990,P<0.05;r=-0.994,P<0.01).结论 AMI后心肌组织中PTEN的表达增加抑制了VEGF水平,从而使梗死边缘区心肌组织的血管生成减少;抑制PTEN的表达可能改善缺血心肌的血液灌注.     

Selective intracoronary injection of sestamibi to detect myocardial viability: Prediction of perfusion and contractile recovery after percutaneous transluminal coronary angioplasty

BACKGROUND: The main limitation of myocardial single photon emission computed tomography (SPECT) in detecting hibernating myocardium is the poor delivery of radiotracers in hypoperfused areas supplied by severely stenotic coronary arteries. Increasing local availability of radiotracers by intracoronary injection might represent an attractive solution. The hypothesis that the intracoronary administration of sestamibi could improve myocardial SPECT accuracy in detecting hibernating myocardium was addressed in this pilot study. METHODS AND RESULTS: Seven patients with prior myocardial infarction and severe stenosis of the infarct-related artery underwent myocardial SPECT after intracoronary injection of technetium 99m sestamibi immediately before percutaneous transluminal coronary angioplasty (PTCA). Wall motion and perfusion were evaluated, before and 1 month after PTCA, by 2-dimensional echocardiography and rest-redistribution thallium 201 SPECT. A "low-flow area" was identified on the pre-PTCA Tl-201 SPECT image as the area with less than 50% of maximum radiotracer uptake. Changes in wall motion and perfusion in the low-flow area were compared with results of intracoronary sestamibi imaging. On a pixel-by-pixel analysis, intracoronary sestamibi predicted perfusion recovery within the low-flow area with a 91% sensitivity, a 78% specificity, and an 82% overall accuracy. Only in the 5 patients with an extent of sestamibi uptake greater than one third of the low-flow area was an improved regional and global left ventricular wall motion observed after PTCA (wall motion score index decreased from 1.95 +/- 0.28 to 1.60 +/- 0.34, P =.007; left ventricular ejection fraction increased from 42% +/- 7% to 49% +/- 7%, P =.001; asynergic segments in the low-flow area decreased from 3.6 +/- 0.9 to 1.8 +/- 1.5, P =.021). CONCLUSIONS: In patients with prior myocardial infarction and severe stenosis of the infarct-related artery, sestamibi uptake after intracoronary administration identified viable myocardium that was undetected after rest-redistribution thallium SPECT but capable of clinically significant contractile improvement after revascularization.     

多巴酚丁胺~(99m)Tc-MIBI心肌断层显像对检测心肌梗塞后残余心肌缺血的价值

目的：评价多巴酚丁胺９９ｍＴｃ－甲氧基异丁基异晴心肌断层显像（Ｄｏｂｕ－ＥＣＴ）检测心肌梗塞后残余心肌缺血的价值。材料与方法：６２例心肌梗塞患者在行冠状动脉造影时进行多巴酚丁胺心肌断层显像检查。结果：Ｄｏｂｕ－ＥＣＴ对心肌梗塞后残余心肌缺血检出率为７７％，高于多巴酚丁胺心电图负荷试验（Ｄｏｂｕ－ＥＣＧ）。无论是１支，还是２支或３支血管病变，Ｄｏｂｕ－ＥＣＴ对心肌梗塞后残余心肌缺血的检出率均高于Ｄｏｂｕ－ＥＣＧ（５６％，４％；８６％，２７％；１００％，４７％；Ｐ＜０．０１）。２１例急性心肌梗塞行溶栓治疗患者残余心肌缺血率为６７％，低于未行溶栓治疗患者（７２％）或陈旧性心肌梗塞患者（９４％），但差异无显著性。Ｄｏｂｕ－ＥＣＴ对非梗塞区心肌缺血的检出率为５６％。结论：多巴酚丁胺９９ｍＴｃ－甲氧基异丁基异晴心肌显像能够识别心肌梗塞后有无残余心肌缺血及其部位和范围。     

Regional 11C-hydroxyephedrine retention in hibernating myocardium: chronic inhomogeneity of sympathetic innervation in the absence of infarction.

We have previously shown that ex vivo counting of (131)I-metaiodobenzylguanidine can identify regional reductions in sympathetic norepinephrine uptake in pigs with hibernating myocardium. However, nonneuronal uptake limited relative differences between regions and would preclude accurate assessment with conventional imaging. We therefore hypothesized that the superior specificity of the positron-emitting isotope (11)C-hydroxyephedrine (HED) would facilitate the imaging of regional differences, and we designed this study to determine whether altered uptake of norepinephrine by sympathetic nerves in viable, dysfunctional myocardium can be imaged in vivo and to determine the temporal progression and stability of sympathetic dysinnervation in hibernating myocardium. METHODS: Pigs (n = 15) were chronically instrumented with a 1.5-mm stenosis of the left anterior descending coronary artery, a procedure that we have previously shown to produce viable chronically dysfunctional myocardium with reduced resting flow, or hibernating myocardium, after 3 mo. Physiologic studies and HED PET were performed 1-5 mo later with the animals in the closed-chest sedated state. One animal with a myocardial infarct was analyzed separately. RESULTS: After 3 mo, anterior hypokinesis developed (wall thickening, 32% +/- 4% vs. 60% +/- 4%, P < 0.001), with reductions in resting flow (subendocardial flow, 0.81 +/- 0.11 vs. 1.20 +/- 0.18 mL/min/g, P < 0.05) and a critical reduction in subendocardial flow reserve (subendocardial adenosine flow, 0.53 +/- 0.20 vs. 3.96 +/- 0.43 mL/min/g, P < 0.001). Extensive defects in HED uptake were found for hibernating myocardium, with regional retention approximately 50% lower than that in normally perfused remote myocardium (0.035 +/- 0.002 vs. 0.066 +/- 0.002 min(-1), P < 0.001). Relative HED uptake (left anterior descending coronary artery/remote) was lower in chronically instrumented animals than in control animals (n = 4, P < 0.001) and animals studied 1 mo after instrumentation (n = 2, P < 0.05). The regional reduction in sympathetic nerve function was persistent and unaltered for at least 2 mo after the development of hibernating myocardium. CONCLUSION: Hibernating myocardium is associated with persistent reductions in regional uptake of norepinephrine by sympathetic nerves. The inhomogeneity in sympathetic innervation in viable dysfunctional myocardium is similar to that occurring after myocardial infarction and may contribute to arrhythmic death in patients with ischemic cardiomyopathy.     

Diagnostic utility of myocardial imaging using 123I-labeled beta-methyl-iodophenyl pentadecanoic acid in ischemic heart disease]

We evaluated the myocardial metabolism in the acute and subacute phases of myocardial infarction or unstable angina using 123I-labeled beta-methyl-iodophenyl pentadecanoic acid (BMIPP). We then compared those findings with (1) myocardial perfusion images obtained with 201TlCl and (2) the regional and global left ventricular function determined by left ventriculography. Thirty-one patients were examined, consisting of 16 with acute myocardial infarction (6.8 +/- 2.6 days after onset), 8 with subacute myocardial infarction (35 +/- 3.0 days after onset) and 7 with unstable angina. The BMIPP images showed a larger uptake-defect than 201TlCl images in the patients in the acute or subacute phase of myocardial infarction. This finding was especially remarkable in the acute phase after successful coronary revascularization therapy. Moreover, in such cases, the myocardial BMIPP uptake improved to the same degree as 201TlCl one month later. The decrease in myocardial uptake of BMIPP agreed well with the decrease in regional wall motion in the acute and subacute phases of myocardial infarction. In contrast, the myocardial perfusion of 201TlCl did not always agree with the regional wall motion in stunned or hibernating myocardium, where BMIPP showed an uptake-defect in the acute phase but improved in the subacute phase. Thus, BMIPP is surmised to be able to depict fatty acid metabolism in in vivo myocardial imaging.     

冬眠心肌动物模型的制备及其MRI表现的实验研究

目的 探讨采用不全结扎法建立兔冬眠心肌模型的可行性以及心脏磁共振成像(CMRI)对冬眠心肌的诊断价值.材料与方法 健康新西兰大白兔15只,开胸对其左冠状动脉前降支近段进行不全结扎以造成冠状动脉狭窄,在术后相应时间采用不同序列行CMRI检查,将CMRI结果 与心肌病理进行对比,评价动物模型建立的成功率以及冬眠心肌的CMRI表现.结果 观察15只兔的CMRI及病理结果 ,其中有10只兔符合冬眠心肌动物模型改变,动物模型制备成功率为66.7%.对10只符合冬眠心肌的兔CMRI分析表明,动态灌注扫描表现为病变节段心肌灌注降低,延迟增强扫描均未见明显延迟强化灶;电影磁共振成像(cine-MRI)表现为节段性室壁运动减弱,室壁增厚度降低;常规CMRI T1、T2扫描均未见明显异常改变.结论 不全结扎法建立兔冬眠心肌模型具有较好的仿真性,且简单、经济、易行,是冬眠心肌动物模型建立的一种较好的方法,同时CMRI是一种评价冬眠心肌的行之有效的检查方法.     

The usefulness of 123I-BMIPP myocardial SPECT in diagnosis for silent myocardial ischemia induced by vasospasm

This study was designed to evaluate the clinical usefulness of 123I-BMIPP myocardial SPECT in patients with silent myocardial ischemia induced by vasospasm. Ultrasonic echocardiography (UCG), Holter electrocardiogram recording (Holter ECG), exercise 201Tl myocardial SPECT (EX-Tl) and rest 123I-BMIPP myocardial SPECT (BMIPP) were performed in 8 patients with asymptomatic vasospasm without history of myocardial infarction. The sensitivity of each modality in detecting coronary artery spasm was 37.5% (3 of 8 cases) for UCG, 37.5% (3 of 8 cases) in Holter ECG, 25.0% (2 of 8 cases) in Ex-Tl, 62.5% (5 of 8 cases) on initial BMIPP images and 75.0% (6 of 8 cases) on delayed BMIPP images. Severity of regional left ventricular wall motion abnormality in UCG correlated with the severity of regionally decreased tracer uptake in BMIPP. The washout rate of BMIPP was 18.7 +/- 2.4 in normal controls, 32.4 +/- 5.9 in asymptomatic vasospasm, and 38.2 +/- 4.0 in asymptomatic vasospasm with abnormal left ventricular wall motion. It was suggested that 123I-BMIPP myocardial SPECT might be useful for assessing asymptomatic vasospasm.     

Usefulness of early tetrofosmin myocardial SPECT during subacute period to estimate salvaged myocardium in patients with acute myocardial infarction--comparing with tetrofosmin myocardial SPECT during chronic period and evaluating regional wall motion using QGS method

To evaluate salvaged myocardium of acute myocardial infarction (AMI), we performed rest 99mTc-tetrofosmin (TF) SPECT with rest Tl and Tc-pyrophosphate (PYP) dual SPECT within 10 days after admission in 19 patients with initial AMI, who all were reperfused successfully and without restenosis. TF SPECT was obtained at 15 minutes (E) after tracer injection, 4 hours later (D), and 5 months later (FU). We calculated the regional uptake score (RUS) of infarcted area estimated by Tc-PYP uptake and defined RUS(FU) of TF(FU) as salvaged myocardium, and then regarded RUS/RUS(FU) x 100 (%) as subacute predicted value of salvaged myocardium. Furthermore, we regarded the improvement of wall motion estimated by QGS method as the guidepost of myocardial viability. The subacute predicted value of TF(E) was 85 +/- 25%, which was significantly higher than 61 +/- 28% of Tl and 36 +/- 24% of TF(D) (p < 0.01). Sensitivity and specificity of myocardial viability based on the improvement of wall motion SPECT image were 78% and 73% for Tl, 90% and 87% for TF(E) and 52% and 87% for TF(D). TF myocardial early imaging in subacute period was useful to detect salvaged myocardium.