Transient mitral regurgitation: an adjunctive sign of myocardial ischemia during dipyridamole-thallium imaging

A patient developed transient exacerbation of a mitral insufficiency murmur and a reversible posterior wall perfusion defect during dipyridamole-thallium imaging. Coronary angiography showed significant stenoses of both the right and the circumflex coronary arteries that supply the posterior papillary muscle. Cardiac auscultation for transient mitral incompetence, a sign of reversible papillary muscle dysfunction, is a simple and practical adjunctive test for myocardial ischemia during dipyridamole-thallium imaging. It may confirm that an isolated reversible posterior wall myocardial perfusion defect is truly ischemic in nature as opposed to an artifact resulting from attenuation by the diaphragm.     

Exercise myocardial perfusion scintigraphy is useful for evaluating myocardial ischemia even in the elderly

Pharmacologic stress testing is recommended to elderly patients as a valuable alternative to exercise testing. We examined whether exercise testing is as useful for evaluating myocardial ischemia in the elderly as in the young. The consecutive 1,508 patients who underwent exercise 201Tl single-photon emission computed tomography (SPECT) were divided into six age groups: 6-29 years (n = 56), 30-44 (n = 143), 45-54 (n = 311), 55-64 (n = 498), 65-74 (n = 402), and 75-88 (n = 98). Both heart rate and rate-pressure product at peak exercise were significantly lower in patients aged 75-88 than in the other five groups. The frequency of ischemic ST depression was higher in patients aged 75-88 than in those aged 6-74, although the difference was not significant. Moreover, the frequency of 201Tl transient defect was significantly higher in patients aged 75-88 than in those aged 6-74. On the other hand, the sensitivity of ischemic ST depression for 201Tl transient defect was similar among the six groups, but the specificity was significantly lower in patients aged 75-88 than in those aged 6-74. In conclusion, exercise 201Tl SPECT is useful for evaluating myocardial ischemia even in the elderly, but exercise electrocardiography has limitations such as lower specificity in the elderly than 201Tl SPECT.     

Dipyridamole test and myocardial scintigraphy with Tl-201 in the diagnosis of myocardial ischemic pathology

We studied 19 consecutive subjects affected by effort angina using following tests: ecg stress test, stress 201-Tl scan, coronary arteriography; 201-Tl scan, coronary arteriography, hemodynamic, echo 2 D, ecgraphic monitoring during Dipyridamole test (D). Basing on coronary arteriography results we divided patients; in the group A (10 patients with significant stenoses greater than or equal to 50%) stress ecg and scintigraphy were positive in 9 patients; Dipyridamole test induced angor and ecgraphic changes in 5 patients and in 4 left ventricle wall motion disorders, 201-Tl scan was positive in all 9 patients tested. In the group B (9 subjects with no significant stenosis) ecgraphic changes were observed in 2 subjects and 201-Tl scan was positive in 6 subjects; D induced in 2 cases angor, in 1 case ecgraphic changes, in 1 case left ventricle wall motion disorders and the same 201-Tl defects in 6 previously individualized patients. In both groups we observed at coronary arteriography during D identical findings in comparison with the immediately before performed. In our experience D infusion is confirmed as provocative test of ischemia. The same ischemic pattern observed at stress and Dipyridamole scintigraphy in patients with no significant coronary stenosis suggests as pathogenetic mechanism the regional lack of dilatory reserve.     

Comparison of SPECT bone scintigraphy with MRI for diagnosis of meniscal tears

BACKGROUND: Scintigraphy has been considered as competitive to MRI, but limited data are available on the accuracy of single photon emission tomography (SPECT) compared with MRI for the assessment of meniscal tears. Our objective was to assess the value of SPECT in comparison to MRI. METHODS: Between January 2003 and March 2004, sixteen patients were studied with both modalities and the accuracy rates of SPECT scan results, and MRI findings in the diagnosis of meniscal tears were compared. Arthroscopy was the gold standard. RESULTS: The respective sensitivity rate, specificity rate, and positive and negative predictive accuracies of MRI were 89%, 94%, 93%, and 79% and for SPECT those were 78%, 94%, 94%, and 88%. There was good agreement on the presence or absence of tears between two modalities (kappa statistic = 0.699). CONCLUSION: SPECT and MRI are both valuable imaging techniques. SPECT is a useful alternative when MRI is unavailable or unsuitable and it is beneficial when more possible accuracy is desired (such as when MRI results are either inconclusive or conflict with other clinical data).     

Comparison of scrotal scintigraphy and thermography for the diagnosis of varicocele

Varicocele is the most frequent cause of male subfertility. Several invasive and noninvasive techniques can be used to visualize scrotal phlebectasies. In this study sequential scintigraphy after intravenous injection of ^99mTc-albumin was compared with tele-thermography. The normal and pathological images are described. The more obvious the clinical condition, the more lesions were revealed by scintigraphy (29.6% in subfertile men suspected of having variococele; 76.9% in patients with first degree varicocele; and 100% in Grades II and III cases). In 55 cases (of a total of 76 cases explored by radioisotopic techniques), the comparison of the thermographic results with the scintigraphy results suggests that scrotal scintigraphy is less sensitive. However, there are more false positive thermographies expressed as a discordance with clinical examination, which indicates higher specificity of scintigraphy. In conclusion scrotal scintigraphy cannot be considered as the screening procedure of first choice for varicocele, but it can give complementary information, especially when thermographic results are at variance with the clinical examination.     

运动试验18F-FDG心肌代谢显像诊断心肌缺血

目的 探讨运动试验同时行^18F-脱氧葡萄糖（FDG）心肌代谢和^99Tc^m-甲氧基异丁基异腈（MIBI）心肌灌注显像判断心肌缺血的可行性和诊断价值.方法 26例既往无心肌梗死病史的确诊或怀疑冠心病患者,在运动试验高峰或出现终止指标时注射^99Tc^m-MIBI和^18F-FDG,进行心肌灌注和代谢显像,随后进行静息^99Tc^m-MIBI心肌灌注显像以及冠状动脉造影.比较运动^18F-FDG心肌代谢显像和^99Tc^m-MIBI心肌灌注显像及冠状动脉造影结果.结果 22例有1支及其以上冠状动脉狭窄≥50%的患者中,18例出现血流灌注异常,灵敏度为82%,20例患者有明显^18F-FDG摄取,灵敏度为91%,两者比较差异无显著性（x^2=1.497,P=0.338）.静息^99Tc^m-MIBI心肌灌注显像示完全（12例）或部分（3例）可逆性心肌灌注缺损（心肌缺血）的患者同时行运动试验^99Tc^m-MIBI心肌灌注、^18F-FDG心肌代谢显像,表现为血流灌注减低的心肌节段^18F-FDG摄取增加.与冠状动脉造影对比,22例患者共51个病变血管（管腔狭窄≥50%）支配的心肌节段中,运动试验^99Tc^m-MIBI心肌灌注显像发现了25个节段,灵敏度为49%,而运动^18F-FDG心肌代谢显像发现了34个节段,灵敏度为67%（x^2=7.30,P=0.008）.结论 运动试验引起心肌缺血可以进行^18F-FDG心肌代谢显像.且与单纯运动/静息心肌灌注显像比较,同时行运动试验^99Tc^m-MIBI心肌灌注和^18F-FDG心肌代谢显像对诊断局部缺血心肌节段有更高的准确性.     

Comparison of image reconstruction algorithms in myocardial perfusion scintigraphy

The purpose of this study was to compare the clinical utility of two image reconstruction algorithms in myocardial perfusion SPECT (single-photon emission computed tomography): filtered back-projection (FBP) and ordered subset expectation maximization (OSEM). A rest/stress one-day protocol with 99mTc-MIBI or tetrofosmin was performed on 102 consecutive patients who underwent coronary angiography. After SPECT data acquisition, images were reconstructed with FBP and OSEM algorithms. We assessed diagnostic performance (sensitivity, specificity and accuracy) in detecting coronary artery stenosis and evaluated regional tracer uptake with a 4-point scoring system. Although there were no significant differences in diagnostic performance between FBP and OSEM reconstruction, the OSEM method yielded higher uptake in the RCA area than the FBP method by reducing the count-loss artifact due to hepatic uptake of the tracers. In addition, regional uptake in the LCX area was significantly lower in the OSEM image than in the FBP image; this phenomenon was observed mainly in patients with coronary stenosis and/or infarction in the LCX territory. In conclusion, OSEM and FBP offered comparable diagnostic performance in stress myocardial perfusion SPECT. The OSEM method contributed to reduction of the count-loss artifact in inferior and posterior walls and to easy recognition of hypoperfusion in the LCX area.     

I-MIBG myocardial scintigraphy as a noninvasive screen for the diagnosis of coronary artery spasm

Background. It has been suggested that the sympathetic nervous system might play an important role in the development of coronary artery spasm. However, no cardiac imaging modality has been able to demonstrate abnormal sympathetic innervation in patients with coronary artery spasm. The purpose of this study was to assess the presence and location of abnormal sympathetic innervation using iodine 123-metaiodobenzylguanidine (¹²³I-MIBG) single photon emission computed tomography (SPECT) and to evaluate the clinical efficacy of ¹²³I-MIBG SPECT as a noninvasive screening test in patients with coronary artery spasm.Methods and Results. Coronary arteriography and a provocative test with intravenous administration of ergonovine maleate were performed in 26 patients (20 men, 6 women, mean age 48.2 ± 12.0 years, range 20 to 67 years) who were suspected of having a coronary artery spasm. The subjects were divided into 2 groups: group 1 (n = 18) comprised subjects with a positive provocative test result, and group 2 (n = 8) comprised subjects with negative provocative test results. Ten healthy subjects served as controls. No abnormal MIBG uptake was observed in the control subjects. Abnormal sympathetic nervous innervation using ¹²³I-MIBG SPECT was observed either as a reduced uptake or a defective pattern in the perfused areas in 13 of the 18 regions supplied by vessels of ergonovine-induced vasospasm. Normal sympathetic innervation, as evidenced by normal ¹²³I-MIBG uptake, was noted in all of the 60 segments of normal vessel territories. Reduced uptake of ¹²³I-MIBG was not detected in the perfused areas of 5 vasospasm-induced vessels (perfusion territory of left anterior descending coronary artery [LAD] and the right coronary artery [RCA] in 2 and 3 patients, respectively). The sensitivity and specificity of ¹²³I-MIBG for detection of coronary artery spasm were 72.2% (95% confidence interval [CI] 55 % to 89 %) and 100 %, respectively. The positive predictive and negative predictive values were 100% and 92.3% (95% CI 91% to 93%), respectively.Conclusion. ¹²³I-MIBG SPECT is a feasible method to evaluate noninvasively and localize the territories of coronary arteries with spasm. Invasive diagnostic coronary arteriography with ergonovine provocation test may be unnecessary for diagnosis of coronary artery spasm in patients with typical resting pain, negative exercise test or normal thallium perfusion scan results, but showing abnormalities in ¹²³I-MIBG SPECT.     

123I-MIBG myocardial scintigraphy as a noninvasive screen for the diagnosis of coronary artery spasm

Background  It has been suggested that the sympathetic nervous system might play an important role in the development of coronary artery spasm. However, no cardiac imaging modality has been able to demonstrate abnormal sympathetic innervation in patients with coronary artery spasm. The purpose of this study was to assess the presence and location of abnormal sympathetic innervation using iodine 123-metaiodobenzylguanidine (¹²³I-MIBG) single photon emission computed tomography (SPECT) and to evaluate the clinical efficacy of ¹²³I-MIBG SPECT as a noninvasive screening test in patients with coronary artery spasm. Methods and Results  Coronary arteriography and a provocative test with intravenous administration of ergonovine maleate were performed in 26 patients (20 men, 6 women, mean age 48.2±12.0 years, range 20 to 67 years) who were suspected of having a coronary artery spasm. The subjects were divided into 2 groups: group 1 (n=18) comprised subjects with negative provocative provocative test result, and group 2 (n=8) comprised subjects with negative provocative test results. Ten healthy subjects served as controls. No abnormal MIBG uptake was observed in the control subjects. Abnormal sympathetic nervous innervation using ¹²³I-MIBG SPECT was observed either as a reduced uptake or a defective pattern in the perfused areas in 13 of the 18 regions supplied by vessels of ergonovine-induced vasospasm. Normal sympathetic innervation, as evidenced by normal ¹²³I-MIBG uptake, was noted in all of the 60 segments of normal vessel territories. Reduced uptake of ¹²³I-MIBG was not detected in the perfused areas of 5 vasospasm-induced vessels (perfusion territory of left anterior descending coronary artery [LAD] and the right coronary artery [RCA] in 2 and 3 patients, respectively). The sensitivity and specificity of ¹²³I-MIBG for detection of coronary artery spasm were 72.2% (95% confidence interval, [CI] 55% to 89%) and 100%, respectively. The positive predictive and negative predictive values were 100% and 92.3% (95% CI 91% to 93%), respectively. Conclusion   ¹²³I-MIBG SPECT is a feasible method to evaluate noninvasively and localize the territories of coronary arteries with spasm. Invasive diagnostic coronary arteriography with ergonovine provocation test may be unnecessary for diagnosis of coronary artery spasm in patients with typical resting pain, negative exercise test or normal thallium perfusion scan results, but showing abnormalities in ¹²³I-MIBG SPECT. Presented in part at the European Association of Nuclear Medicine Congress, September 1996, Copenhagen, Denmark.     

Comparison of fractional myocardial mass,a vessel-specific myocardial mass-at-risk,with coronary angiographic scoring systems for predicting myocardial ischemia

AimsThe burden of coronary artery disease has been assessed by various semi-quantitative angiographic scores, which are frequently different each other. A non-invasive and quantitative modality may substitute angiographic sores for prognostic implication and decision of revascularization strategy. We compared fractional myocardial mass (FMM) with angiographic scores for predicting myocardial ischemia.MethodsIn this multicenter registry, 411 patients who underwent coronary computed tomography angiography (CCTA) were followed by invasive coronary angiography and fractional flow reserve (FFR) measurement. CCTA–derived %FMM with diameter stenosis≥70% (%FMM-70) or ≥50% (%FMM-50) were compared with 9 angiographic scores (APPROACH, Duke Jeopardy, BARI, CASS, SYNTAX, Jenkins, BCIS-1, Leaman, Modified Duke) and were tested regarding their performance for predicting FFR≤0.80.ResultsThe performance of %FMM-70 and %FMM-50 were similar to most angiographic scores (%FMM-70, c-statistics = 0.74; %FMM-50, 0.73; angiographic scores, 0.68–0.77). The frequency of FFR≤0.80 increased consistently according to %FMM-70, %FMM-50, and all angiographic scores (p < 0.001, all). The optimal cutoff of %FMM-50 and %FMM-70 for FFR≤0.80 were ≥36.3% and ≥8.7%, respectively. Using these cutoffs, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of %FMM-50 were 81%, 55%, 3%, 67%, 71%, and of %FMM-70 were 67%, 78%, 82%, 61%, 71%.Conclusion%FMM was comparable to angiographic scores for prediction of functional stenosis defined by FFR≤0.80. The integration of the severity of stenosis and the amount of subtended myocardium may improve the detection of the functional significance of vessel.     

Identification of residual ischemia in the occluded coronary artery irrigation area using myocardial perfusion scintigraphy

BACKGROUND: Inspite the indisputable significance of coronarography, the implications of a revealed stenosis--and how close it is to occlusion could vary in regard to its physiological importance. Myocardial perfusion scintigraphy (MPS) possiblity to prove and objectivise the presence of ischemia and myocardial viability within an occlusion found coronarographically is especially significant since it makes possible to the clinitian to choose an adequate therapy. CASE REPORT: We reported a 43-year-old male patient who had been hospitalized to another institution due to acute myocardial infarction (AMI) of posterolateral localisation. Following the acute AMI stage the ergometric test per Bruce protocole was performed, negative to ischemic heart disease, while multislice computed tomography showed no significant changes on the coronary arteries. The performed one-day-protocole MPS showed a massive area of residual ischemia within myocardial infarction (MI) type culprit lesion of the posterolateral zone starting from the subapical level to the basal cross-section. According to the MPS findings coronarography was indicated due to a revascularisation assessment. The performed coronarography revealed an occlusion of the circumflex coronary artery (CCA) right after the division of obtuse branch (OB) that presented discretely in the distal parts from the homo- and heterocolaterals. The distal portion of CCA presented discretely out off the right coronary artery (RCA). Echocardiography confirmed an ejection fraction of 50% with hypokinesia of inferior and posterior walls, as well as the septum, showing a mild reduction of the general contractility. Flows through confluences were well. A month after MI a percutane coronary intervention (PCI) was performed with the implantation of a drug-releasing stent (Taxus). Early after PCI (within two weeks) a control MPS was done to evaluate the effects of the therapy giving the normal findings of myocardial perfusion. CONCLUSION. Determination and identificantion of vivid but ischemic myocard of culprit lesion type in the occluded artery irrigation zone enable making choice of the best therapy for a patient.     

Dobutamine combined with low-level exercise for myocardial perfusion scintigraphy

Increased abdominal background activity is one of the limitations of dobutamine myocardial perfusion scintigraphy which may interfere with interpretation of the images. In this study, we evaluated the value of low-level exercise supplementation to dobutamine infusion in improving image quality. The control group (n = 32, Group A) received dobutamine alone, while the study group received dobutamine plus low-level exercise for the last 2 min of dobutamine administration (n = 26, Group B). One hundred and eleven MBq of 201Tl was injected 1 min before cessation of peak dose. The ratios of cardiac/hepatic (C/HEP), cardiac/subdiaphragmatic (C/INF) and cardiac/pulmonary (C/PUL) were calculated from anterior planar images taken immediately following the test. Cardiac/non-cardiac activity was also visually graded on a three-point scale. Visual evaluation showed improved cardiac/non-cardiac ratios as confirmed by significantly higher C/HEP and C/INF ratios for Group B (1.5+/-0.3 and 1.7+/-0.2, respectively) compared to corresponding values in Group A (1.2+/-0.4 and 1.4+/-0.4, respectively) (P<0.05). The cardiac/pulmonary (C/PUL) ratio was also higher for Group B (2.3+/-0.5) as compared to corresponding value in Group A (2.0+/-0.6, respectively), but this difference did not reach statistical significance (P > 0.05). No difference in the frequency of side effects and ECG changes were detected between the two groups (P > 0.05). Low-level exercise supplementation to dobutamine infusion for myocardial perfusion scintigraphy is a safe method and leads to a significant decrease in uptake by the areas adjacent to the heart, improving image quality.     

缺血修饰白蛋白诊断多柔比星心肌毒性价值实验室研究

目的探讨缺血修饰白蛋白(IMA)诊断多柔比星(DOX)心肌毒性的敏感性、准确性以及是否存在早期诊断价值。方法将SD大鼠分为对照组、DOX心肌损伤模型组、DOX心肌损伤加抗氧化剂谷胱甘肽(GSH)组,饲养大鼠,查大鼠血清IMA值变化。建立DOX心肌损伤大鼠模型,应用Western-blot方法观察IMA增高组、心肌酶谱组、肌钙蛋白(cTnT)组心肌细胞凋亡Caspase-3情况。结果对3组大鼠心肌组织凋亡指标Caspase-3含量进行分析,提示IMA增高时,立即停止DOX给药的大鼠心肌损伤较轻;DOX心肌毒性产生时,IMA增高,拮抗活性氧产物(ROS)产生,使IMA值下降,提示血清IMA生成与ROS有关。结论 IMA作为DOX心肌毒性反应的早期诊断指标具有初步实验室基础。     

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.     

The prevalence and the clinical characteristics of silent myocardial ischemia detected by stress thallium scintigraphy]

The prevalence of silent myocardial ischemia was retrospectively assessed in a group of 100 consecutive patients with angiographically proved coronary artery disease, and diagnostic ECG, by symptom-limited exercise thallium-201 scintigraphy. Twenty-four patients had no evidence of ischemia despite adequate exercise level. So among 76 patients with exercise induced ischemia, only 33 patients (43%) stopped exercise due to anginal pain (symptomatic ischemia: Group 3). And 43 patients with asymptomatic ischemia composed of 23 patients (30%) with ECG change (Group 2B) and 20 patients (26%) without ECG change (Group 2A). Patients background including the history of old myocardial infarction and diabetes mellitus, were similar among Group 2A, 2B, and Group 3. And our major observation was that the extent and severity of quantified SPECT perfusion defects was nearly identical between 3 groups Thus in this study group, there was a rather high prevalence rate of silent ischemia (57%) by exercise thallium-201 criteria. Patients with silent ischemia, associated with positive and negative exercise ECG findings, and those with exercise angina had similar background and comparable amount of jeopardized myocardium.     

动态心电图对无症状心肌缺血的诊断价值

动态心电图(Ambulatory electrocaroliogram,AECG)是监测冠心病(Coronary heart disease,CHD)心肌缺血,评估心肌缺血进展情况及评价疗效的一项简便、准确、实时、可重复的无创检查技术.无症状性心肌缺血(Silentmyocardial ischemic,SMI)指确有心肌缺血的客观检查证据,但无缺血性胸痛或与心肌缺血有关的主观症状,又称隐形冠心病.近年来,国内外对CHD患者无症状性心肌缺血(SMI)进行了广泛研究.笔者对100例CHD患者进行了AECG监测,以探讨CHD患者SMI的检出率、产生机制、昼夜规律,以及AECG对SMI的诊断价值.