Cardiovascular nuclear medicine 1976/'06: 30 years representation in clinical cardiology

Over the past 30 years, cardiovascular nuclear medicine has become an important diagnostic tool in patients with known and suspected coronary artery disease. Myocardial perfusion scintigraphy is indicated in: patients with suspected coronary artery disease and an intermediate likelihood of disease to detect myocardial ischemia, patients with a sustained myocardial infarction to assess myocardial viability, patients following revascularization for risk stratification, and coronary patients to assess prognosis. Gated SPECT myocardial perfusion imaging offers the potential of assessing left ventricular function and myocardial perfusion simultaneously. Information on left ventricular function and volumes significantly improves the diagnostic accuracy of myocardial perfusion imaging. The gated SPECT technique is a valuable tool for risk stratification because it offers the potential of assessing left ventricular function and volumes, which are both important prognostic parameters.     

Recent advances in nuclear cardiology

Nuclear cardiology is an essential part of functional, non-invasive, cardiac imaging. Significant advances have been made in nuclear cardiology since planar (201)thallium ((201)TI) scintigraphy was introduced for the evaluation of left ventricular (LV) perfusion nearly 40 years ago. The use of nuclear cardiology has been steadily increasing over the last 20 years with important steps being the introduction of (99m)technetium- ((99m)Tc)-labelled perfusion radiotracers, the change from only planar to now much more single photon emission computed tomography (SPECT) and positron emission tomography (PET), electrocardiogram gating of nuclear perfusion imaging, and finally introducing nuclear hybrid imaging using either SPECT or PET together with either computed tomography or magnetic resonance imaging. The indications have extended from nearly only coronary artery diseases to several non-coronary cardiac diseases. The advances in nuclear cardiology are discussed under the four headlines of: 1) myocardial perfusion, 2) cardiac performance including LV and right ventricular (RV) function, 3) myocardial metabolism, and 4) experimental nuclear cardiology.     

Radionuclide imaging of the heart

Nuclear cardiology is an established part of diagnosis and assessment of patients with possible heart disease, the two most common tests being myocardial perfusion imaging and radionuclide ventriculography. Myocardial perfusion imaging comprises approximately 75% of nuclear cardiology studies in the UK, and is used in diagnosis and management of coronary artery disease.     

核素心肌灌注断层显像诊断冠心病的临床应用

目的评估核素心肌灌注断层显像在冠心病（CAD）临床诊断中的价值。方法对30例冠心病和可疑冠心病患者进行^99m锝-甲氧基异丁基异晴（^99mTc-MIBI）心肌灌注断层显像，同时采用半定量方法分析患者左心室心肌血流灌注情况，其中15例患者行冠状动脉造影术（CAG）。结果心肌灌注断层显像冠心病和可疑冠心病患者检查的阳性率为46．7％。结论。^99mTc-MIBI心肌灌注断层显像是安全、无创伤、方便及费用低的检查方法，临床联合应用对冠心病的诊断、治疗和预后判断有重要的价值。     

硝酸甘油介入99mTc-MIBI心肌显像对存活心肌的评价

目的探讨含服硝酸甘油(NTG)介入99mTc甲氧基异丁基异晴(99mTc-M IB I)心肌断层显像在估测心肌存活中的价值。方法对66例不稳定型心绞痛患者按心电图无/有病理性Q波分为非合并陈旧性心肌梗死组(A组)和合并陈旧性心肌梗死组(B组),分别进行静息心肌显像,于次日再进行NTG介入99mTc-M IB I心肌显像,采集图像经计算机测定并进行对比分析。结果在66例594个心肌节段中,静息心肌显像有242个节段(40.7%)灌注异常,而经NTG介入后显像中有114个节段(47.1%)灌注得到改善。其中非合并陈旧心梗组改善率为56.6%,合并陈旧心梗组为31.6%,差异有统计学意义。结论NTG介入99mTc-M IB I心肌断层显像对存活心肌评价简便无创,客观准确,为不稳定心绞痛患者冠脉血管重建术前选择适应证及术后评价疗效提供了有力手段。     

Evaluation of myocardial perfusion using intravenous contrast echocardiography

The aim of the study was to assess the accuracy of rest myocardial contrast echocardiography (MCE) in detecting perfusion abnormalities after intravenous contrast administration in chronic coronary artery disease. In 21 patients (mean age 49 years) contrast agent was injected intravenously. ATL HDI 5000 ultrasound machine was used. Triggering every fifth cardiac cycle in end-systole apical 2-chamber, 3-chamber and 4-chamber views were used. All patients underwent thallium scintigraphy on the same day and coronary angiography was performed within 24 hours. Second harmonic imaging and power Doppler were used in assessing presence or absence of perfusion, localization and extent of perfusion defects, and their relation with wall motion. In the first group all the 13 patients after myocardial infarction had akinetic segments on echocardiography in accordance with the coronary occlusion detected by coronary angiography. In the second group none of the 8 patients without previous myocardial infarction had wall motion abnormality. Group I: dividing the left ventricle into 16 segments out of 208 segments 44 were akinetic. Perfusion defect was detected by MCE in 29 segments. In 12 segments with wall motion abnormality the normal myocardial perfusion was consistent with viable myocardium, 2 inferior akinetic segments could not be evaluated due to contrast attenuation and in one inferior segment MCE in contrast to the thallium scintigraphy showed no perfusion defect. Group II: good contrast effect was detected in all 128 segments except one inferior segment in which there was a fixed perfusion defect also by thallium scintigraphy and coronary angiography revealed occluded right coronary artery. In conclusion MCE and second harmonic triggered imaging is comparable with thallium scintigraphy in detecting fixed perfusion abnormalities. MCE may contribute to the detection of viable myocardium.     

The clinical use of nuclear exercise tests.

In the mid-1970s, after decades of clinical use, the utility of electrocardiographic exercise testing for the evaluation of patients with suspected ischemic heart disease was critically examined and questioned. Concurrent with this critique, two sophisticated, more expensive and powerful "nuclear" exercise tests were introduced sequentially for clinical use: myocardial perfusion imaging with thallium-201 and radionuclide ventriculography with technetium 99m. The published indications for the two tests are similar, and both have been shown to offer advantages over ECG stress testing in selected populations. However, few data are available regarding the comparative utility of thallium versus ventriculographic imaging. As part of a prospective study to assess the efficacy of cardiovascular nuclear medicine studies, we undertook the present analysis to assess the clinical evolution of these tests and to elucidate factors responsible for clinicians' choice for the often competing examinations. The study examined 213 consecutive patient referrals for thallium scintigraphy and 183 referrals for ventriculography, ranging from patients with no symptoms or highly non-specific chest pain syndromes (21% of referrals) to patients with proven coronary disease (28% of the referrals). Twenty-one percent of patients were referred to confirm the clinical impression that the patient did not have coronary disease, 40% to confirm its presence, and 37% to determine its severity. Analyses were undertaken to determine the factors that dictated a preference for thallium scintigraphy rather than ventriculography; only the physician's intent in testing and level of training were significant predictors for a particular nuclear test.     

Non-invasive imaging for the detection of coronary artery disease

Non-invasive coronary artery imaging is useful in patients with an intermediate level of risk of coronary artery disease because it avoids the health risks associated with invasive coronary angiography, the current gold standard. The conventional non-invasive imaging techniques of myocardial perfusion scintigraphy, stress echocardiography and MRI rely on ischaemia as a marker for coronary artery disease. The more recently introduced techniques of electron beam tomography and multi-slice CT use atherosclerosis as a marker for coronary artery disease. These techniques allow for earlier detection of coronary artery disease, but provide limited information with regard to treatment decisions.     

核素心肌灌注显像与冠状动脉造影的对比分析

目的评价核素心肌灌注显像诊断冠心病的准确性,分析核素心肌灌注显像与冠状动脉造影结果。方法分析近两年来核素心肌灌注显像检查及冠脉造影的患者46例,所有患者均进行了心肌灌注显像,负荷显像异常者于24h后再行静息心肌灌注显像。结果核素显像与冠状动脉造影结果不相符的患者共5例,核素心肌灌注断层显像阴性而冠状动脉造影阳性者1例,核素心肌灌注断层显像阳性而冠状动脉造影正常者4例。结论这两种检查方法有高度的一致性,但核素心肌灌注断层显像更具有优势。     

急性心肌梗死急诊介入治疗后心肌组织水平再灌注评价方法对比研究

目的 应用TIMI心肌灌注分级(TMPG)、单个导联ST段回落幅度(单导STR)、单个导联ST段最大偏移幅度(MaxSTE)三种方法评价急性心肌梗死(AMI)急诊经皮冠状动脉介入治疗(PCI)后心肌组织水平再灌注情况.方法 42例AMI患者急诊PCI后采用TMPG、单导STR、MaxSTE方法评价心肌组织水平再灌注情况,并于术后行99mTc-甲氧基异丁基异腈(MIBI)单光子发射型计算机体层摄影(SPECT)心肌灌注显像.结果 与99mTc-MIBI SPECT心肌灌注显像对比,TMPG灵敏度93.75%,特异度20.00%,准确度76.19%;单导STR灵敏度87.50%,特异度80.00%,准确度85.71%;MaxSTE灵敏度81.25%,特异度80.00%,准确度80.95%.单导STB、MaxSTE与99MTc-MIBI SPECT心肌灌注显像检查均存在一致性(P<0.05),且一致性良好;TMPG未显示与99MTc-MIBI SPECT心肌灌注显像检查存在一致性.结论 单导STR和MaxSTE可较好地评价AMI后心肌组织水平再灌注情况.     

The role and clinical value of thallium-201 myocardial scintigraphy in ischemic heart disease

To define the role and clinical value of thallium-201 myocardial scintigraphy in ischemic heart disease, 967 consecutive patients referred to our laboratory since 1985 were studied. The purpose of scintigraphy has changed from diagnosing myocardial ischemia to assessing myocardial viability with the progress of coronary angioplasty. At present, thallium-201 myocardial scintigraphy has become an indispensable noninvasive method for the management of patients with ischemic heart disease.     

动态心电图对心肌缺血诊断价值的研究进展

心肌缺血是冠状动脉血流减少导致心肌供氧供血不足的一种病症,临床依据患者是否存在胸痛症状将该病划分为两个类别,即有症状性心肌缺血、无症状性心肌缺血。在既往研究资料中表明,冠心病心肌缺血患者中,25%左右为有症状者,75%左右为无症状者;而在稳定性心绞痛患者中,无症状性心肌缺血者的占比区间为20%～60%;以此导致很多患者发病后,因不具备典型症状而大概率误诊、漏诊。现阶段临床多通过冠脉CT、冠脉造影、核素心肌灌注显像以及心电图运动平板试验等方式对心肌缺血进行诊断,但这些技术存在有创性、体制运动能力要求等弊端,难以普及;动态心电图因不具备上述弊端,且诊断信息更为充足成为一种使用频率较高的心肌缺血诊断方案。本文结合既往研究资料对动态心电图诊断心肌缺血的价值进行分析,旨在可以为相关人员提供参考。     

延迟经皮冠状动脉形成术及支架植入对老年急性心肌梗死患者的影响

目的探讨延迟经皮冠状动脉成形术(PTCA)及支架植入对有无梗死前心绞痛老年急性心肌梗死(AMI)患者心肌灌注和预后的近期影响.方法46例老年首次急性心肌梗死患者,按心肌梗死前有无心绞痛史分为无心绞痛组(17例)、有心绞痛组(29例),所有患者均在急性心肌梗死后15～30d行延迟PTCA及支架植入治疗.术前和术后6个月行心肌灌注断层显像(SPET)测定梗死区缺血程度;监测心肌酶谱变化;观察心律失常、心力衰竭、心源性休克发生率和再梗死率.结果有心绞痛组肌酸激酶MB同工酶(CK-MB)峰值低于无心绞痛组,有心绞痛组心肌缺损程度小于无心绞痛组,差异均有显著性(P＜0.05),急性心肌梗死延迟PTCA及支架植入6个月后观察,两组梗死区缺血程度均较术前有改善,有心绞痛组梗死区缺血程度较术前改善尤明显,差异有非常显著性(P＜0.01).有心绞痛组心律失常、心力衰竭、心源性休克和再梗死率有低于无心绞痛组的趋势(P＞0.05).结论心肌梗死前心绞痛对老年急性心肌梗死患者有心肌保护作用,而延迟PTCA及支架植入可明显提高有梗死前心绞痛老年急性心肌梗死患者的心肌灌注,并改善其近期预后.     

64排螺旋CT冠状动脉成像检查对心肌桥诊断的应用价值

目的：探讨64排螺旋CT冠状动脉成像（CTA）检查对心肌桥诊断的应用价值。方法：回顾性分析300例冠状动脉CTA患者,评估心肌桥的发生率、位置、长度、心肌厚度及壁冠状动脉近段和远段血管的形态。结果：心肌桥共检出82例（95段）,检出率为27．3％,发生在前降支中段73处,占79-3％（73／95）,心肌桥厚度为0．4-11．2mm,平均厚度为1．7mm,壁冠状动脉长度为13mm-52mm,平均22mm。结论：64排螺旋CT冠状动脉成像能清晰准确显示壁冠状动脉与心肌的解剖关系,对心肌桥的检出率高,是确诊心肌桥的首选检查方法。     

药物负荷脉冲多普勒组织成像早期诊断冠心病

目的联合使用脉冲组织多普勒成像（PW—TDI）和潘生丁负荷试验对左室局部纵向心肌的舒缩功能进行定量分析,为早期诊断冠心病提供可靠依据。方法选择冠心病患者77例,设正常对照组25例,均经冠状动脉造影证实。应用PW—TDI分别测量两组静息状态及潘生丁负荷状态下左室各壁基底段和中段Vs、Ve、Va及RIVRT。结果单纯应用脉冲多普勒组织成像,冠心病组Vs、Ve、e／a较对照组减低,R／VRT较对照组延长且有显著性差异（P〈0．05）,诊断冠心病敏感性79．3％、特异性71．6％。潘生丁负荷状态下,两组对应数据差异均明显增大（P〈0．01）,诊断冠心病敏感性81．8％、特异性87．1％。结论PW—DTI结合潘生丁负荷实验对冠心病的早期诊断有值得肯定的应用价值。     

Tc-99m DTPA scintigraphic findings in patients with postoperative complications of renal transplantation

Tc-99m DTPA scintigraphic findings in patients with postoperative complications of renal transplantation were presented. In acute tubular necrosis, excretion of the tracer was not observed though its perfusion was preserved. In acute rejection, perfusion was reversibly disturbed. In chronic rejection, perfusion was irreversibly disturbed. In renal infarction, multiple defects were observed. In renal vein thrombosis, similar pattern to acute tubular necrosis was found but RI venography was helpful. In lymphocele, perirenal photon deficiency was observed. In renal artery thrombosis, absence of the perfusion and total photon deficient were noted. Tc-99m DTPA renal scintigraphy is useful for diagnosis and follow up of the complications of transplanted kidneys.     

冠状动脉靶血管楔压测定法评价ST段抬商眭心肌梗死患者冠状动脉侧支循环形成对心肌存活程度的影响

目的 通过测定ST段抬高性心肌梗死（STEMI）患者急诊经皮冠状动脉介入治疗（PCI）后冠状动脉靶血管楔压的变化,并与正电子发射断层显像/X线计算机体层成像（PET-CT）心肌灌注显影进行对照,探讨冠状动脉靶血管楔压测定对心肌存活程度评价的临床意义.方法 33例接受了急诊PCI的初发STEMI患者,依据Rentrop冠状动脉侧支循环分级方法,将患者分为两组,冠状动脉侧支循环Rentrop 0级患者为第一组（23例）,Rentrop1～3级患者为第二组（10例）.评价梗死相关动脉PCI前及PCI后心肌梗死溶栓试验血流及心肌灌注分级,应用压力导丝观察冠状动脉楔压（Pcw）/平均主动脉压力（Pa）变化,于PCI后7d,所有患者接受PET-CT检测.结果 将PET-CT上18F-氟代脱氧葡萄糖（18F-FDG）摄取率与Pcw/Pa进行相关性分析发现,在第一组患者中两者呈负相关（r=-0.561,P=0.010）,但是在第二组患者中,两者无明显相关性（r=-0.262,P=0.464）.受试者工作特征曲线分析对应50％的18F-FDG摄取率的Pcw/Pa阈值为0.33（曲线下面积=0.667,敏感度42.1％,特异度92.9％）.结论 用Pcw/Pa评价未形成侧支循环的STEMI患者,测定梗死相关心肌的心肌存活具有较高的价值,但是对于已经形成侧支循环的STEMI患者而言则无确切价值.     

Utility of stress cardiography to identify myocardial ischemia

BACKGROUND: The dobutamine echocardiography takes more and more an important place in diagnosis, prognosis and therapeutics strategies of the coronary disease. AIM: We prospectively enrolled 130 consecutive patients followed for a coronary insufficiency METHODS: the aim of determinating the diagnostic value of the dobutamine echocardiography in the myocardial ischemia compared with the classic means as the exercise test and the myocardial scintigraphy. RESULTS: Our results are comparable to the data of the literature, the dobutamine echocardiography is more specific than the exercise test and the myocardial scintigraphy (96 %, 61% and 53 %), more sensitive than exercise test (75 % versus 47 %) but less sensitive than the myocardial scintigraphy (75 % versus 96 %). The stress echocardiography has the best diagnosis precision 87% against 72 % for the scintigraphy and 56 % for the exercise test. The dobutamine echocardiography is a very feasible, tolerated well exam and especially very reliable in term of detection of the coronary disease in the feminine population, with a sensibility at 66,7 %, a specificity at 100 % and a diagnostic precision at 92 %, also in patient with hypertension the stress echocardiography is much more specific and reliable than the exercise test (100 % vs 22 % and 93 % vs 54 %, respectively),and it's superior to the exercise test in the presence of electric signs of systolic excess load and to the myocardial scintigraphy in case of left ventricular hypertrophy. The dobutamine echocardiography can be considered as safety and reliable means of investigation of the coronary insufficiency .     

Women and cardiovascular disease

More women die of cardiovascular disease than men; in women, cardiovascular mortality is 1.5 times greater than cancer mortality. The pathophysiology of cardiovascular disease has female-specific aspects such as fragile coronary arteries and microvascular ischaemia. Women with acute coronary syndromes are more likely to present with atypical symptoms such as dyspnoea, nausea or fatigue. With regard to diagnostic tests in women, exercise ECG can be difficult to interpret and a normal coronary angiogram does not exclude coronary heart disease. Myocardial perfusion scintigraphy may be considered for high-risk women who are clinically suspected of having coronary heart disease and have a normal or inconclusive exercise ECG and angiogram. Women are less likely to be treated according to guidelines than men, and their prognosis after a myocardial infarction or a coronary intervention is worse. Female-specific aspects such as gestational hypertension and diabetes allow for early detection and treatment of women at risk for cardiovascular disease.     

Cardiolite (99m-Tc-isonitrile) SPECT studies in patients prior to coronary bypass surgery

The authors studied with 99m-Tc Cardiolite (methoxy-isobutyl-isonitrile) SPECT examination the effect of coronary bypass operation on the myocardial perfusion. One week before and 3 weeks after the operation examinations were performed first with dipyridamol loading and 24 hours later in rest. The regional perfusion of the myocardium was studied on the basis of transversal section-pictures of corrected axis position. In the examinations preceding the operation the global sensitivity of the method was found to be 100%. In the demonstration of the structures of the ramus descendens 95%, of the ramus circumflexus and of the right coronary artery 100% sensitivity was reached. In postoperative examinations following the bridging of the ramus descendens anterior the improvement of the perfusion of the corresponding ventricular segment was found in 15/20 during the loading and in 7/8 cases following the bridging of the ramus circumflexus and right coronary artery. Improving perfusion was demonstrated in 17/20 and in 6/8 cases in rest. On the basis of the results the authors consider their method suitable for the study of the regional blood perfusion and for the examination of the changes taking place upon coronary bypass operations.