Influence of specific activity on myocardial uptake of 123I-mIBG in rats

Heart and lung uptake of 123I-mIBG was studied in rats 1 h after injection as a function of specific activity (mCi mg-1) and the total loading dose (microgram kg-1) of labelled compound. Absolute lung uptake of the tracer was dependent upon specific activity, declining as the loading dose increased from 0.15 to 4300 micrograms kg-1. Uptake in the total heart was constant at 2.1% up to about 12 micrograms kg-1, at which point the heart uptake also began to decline as the loading dose increased. Myocardial uptake of 123I-mIBG, therefore, appears saturable in the rat and subject to competitive binding and/or displacement with increasing amounts of non-labelled compound.     

Impact of body mass index on cardiac adrenergic derangement in heart failure patients: a 123I-mIBG imaging study

European Journal of Nuclear Medicine and Molecular Imaging - To assess the impact of body mass index (BMI) on cardiac adrenergic derangement, measured by iodine-123 meta-iodobenzylguanidine...     

Influence of myocardial region of interest definition on quantitative analysis of planar 123I-mIBG images

Purpose

In planar ¹²³I-mIBG myocardial imaging, definition of the heart region of interest (ROI) is a critical step in quantifying uptake. The present study evaluated the impact of changes in heart ROI size on quantitative results in subjects with good and poor uptake.

Methods

Reference irregular whole-heart and square upper mediastinum ROIs were defined visually on 531 planar ¹²³I-mIBG images. Based on the reference heart ROI, an automated program created two other ROIs: one larger (+1 pixel) and one smaller (?1 pixel), the stated numbers representing the spacing intervals between each epicardial boundary pixel. Two additional smaller ROIs (?2 and ?3 pixels) were drawn for the 100 images (19 %) with a heart/mediastinum (H/M) ratio ≤1.30. The number of pixels, the counts per pixel, and the H/M ratio for each heart ROI were calculated and compared to that in the reference ROI. Washout rate and changes as a function of ROI size were also calculated for 110 subjects who had both early and late images.

Results

The mean changes in heart ROI size ranged from +19.0 % for the +1 pixel to ?44.4 % for the ?3 pixels ROI. For the +1 and ?1 pixel ROIs, mean relative counts per pixel changes were ?1.2 % and +0.7 %, respectively, with corresponding ranges of change in the H/M ratio of ?0.12 to +0.05 and ?0.05 to +0.11. For scans with H/M ratio ≤1.30, mean relative counts per pixel changes were 0, 0, ?0.7 %, and ?1.4 % for the four ROIs, with range of change in the H/M ratio from ?0.13 to +0.05. Mean washout rates were almost identical for the reference ROIs (45.0 %) and the +1 pixel and ?1 pixel heart ROIs (44.9 % and 45.1 %, respectively).

Conclusion

Significant changes in the size of the best visually defined heart ROI produce minimal, clinically inconsequential changes in the H/M ratio and washout rate, even in subjects with significantly reduced myocardial uptake of ¹²³I-mIBG.     

I-123 labeled hexadecenoic acid in comparison with Thallium-201 for myocardial imaging in coronary heart disease

The imaging properties of ¹²³I-16-iodo-9-hexadecenoic acid (¹²³I-HA), a terminally iodinated 17-carbon atom fatty acid analogue, were compared with Thallium-201 (²⁰¹Tl). Because of its shorter half-life, favourable photon-energy and rapid myocardial turnover rate, ¹²³I-HA possesses potential advantages in the study of regional myocardial perfusion and metabolism. Twelve patients with documented coronary artery disease (CAD) were studied; eight patients sustained an acute myocardial infarction, four patients suffered from unstable angina. Visually assessed, a similar distribution pattern and comparable imaging quality was demonstrated with both radionuclides. The scintigraphic results were also correlated with coronary arteriographic findings. A good relationship was found between the perfusion defects and the location of the coronary artery lesions in the patients with acute myocardial infarction.We conclude that ¹²³I-HA is comparable to ²⁰¹Tl in detecting areas of reduced myocardial perfusion in patients with CAD with the advantage of studying myocardial metabolism.     

Glucose tolerance and myocardial F-18 fluorodeoxyglucose uptake in normal regions in coronary heart disease patients

To elucidate the relation between glucose tolerance and myocardial uptake of F-18 fluorodeoxyglucose (FDG), FDG-PET with 75 g oral glucose loading was performed on 43 coronary artery disease patients (twice in 2 patients). The patients were divided into 4 groups based on the blood glucose level (BS) and the insulinogenic index (II): group 1, normal (n = 9); group 2, impaired glucose tolerance (IGT, n = 12); group 3, mild diabetes mellitus (DM) (II > 0.4, n = 12); and group 4, severe DM (II < 0.4, n = 12). Percent (%) dose uptake of FDG in the normal regions of the myocardium was not significantly different in groups 1,2, and 3, but it was much lower in group 4 than in groups 1 and 2. In groups 2,3, and 4, % dose uptake showed a definite negative correlation with BS 60 min after glucose loading (r = -0.450, p < 0.05), and a close positive correlation with II (r = 0.363, p < 0.05). These findings indicate that myocardial FDG uptake in normal regions is not greatly impaired in patients with IGT or mild DM. Myocardial viability can be assessed by oral glucose loading in patients with IGT and mild DM as well as in patients with normal glucose tolerance.     

年龄对冠心病患者植入生物涂层可降解支架预后的影响

目的 探讨老年(≥65岁)冠心病患者植入生物涂层可降解支架(BP-SES)术后1年净不良临床事件(NACCE)的发生情况.方法 回顾性分析I-LOVE-IT 2研究中植入生物涂层可降解支架的患者资料.入选2012年10月-2013年6月沈阳军区总医院住院期间在冠心病手术中行生物涂层可降解支架植入治疗的老年患者1829例,其中老年组(年龄≥65岁)627例,非老年组(年龄<65岁)1202例.主要观察终点为12个月的靶病变失败率(TLF),次级终点为NACCE发生率,包括全因死亡、心肌梗死、卒中和严重出血(BARC≥3型),并对其进行多因素回归分析.结果 两组在BMI、糖尿病、高血压、高脂血症、冠心病家族史、吸烟史、既往卒中病史、外周血管病病史、稳定型心绞痛等方面的基线情况差异有统计学意义(P<0.05).老年组与非老年组在NACCE发生率(10.0%vs.5.2%,P<0.01)、全因死亡(2.7%vs.0.7%,P<0.01)、心肌梗死(5.6%vs.3.5%,P=0.03)、支架内血栓(1.9%vs.0.5%,P<0.01)、卒中(2.2%vs.0.8%,P=0.01)差异有统计学意义.多因素回归分析结果 显示为NACCE(OR=1.904,95%CI 1.304~2.781,P=0.001)的独立预测因素.结论 老年冠心病(≥65岁)植入生物涂层可降解支架患者,术后1年NACCE发生率明显增加,且老年为其独立的预测因素.     

Absent myocardial I-123 BMIPP uptake in a family

A 72-year-old woman with hypertension showed no sign of myocardial accumulation of¹²³I-BMIPP, and²⁰¹Tl and¹²³I-MIBG scintigraphy demonstrated normal findings. Electrocardiography showed left axis deviation with inverted T waves in leads I, aV_L, V_2–6 and QT prolongation. Coronary arteriography, two dimensional echo cardiography and laboratory data showed no abnormality. Her 66-year-old sister with non-insulin-dependent diabetes mellitus also had no myocardial BMIPP uptake, but had normal²⁰¹Tl finding. ECG and chest film findings were normal. Laboratory data indicated slightly high fasted blood glucose, triglyceride and total cholesterol. Four sons of a 72-year-old woman also underwent BMIPP scintigraphy. No BMIPP uptake was also observed in her 2nd son (49 years old) and his electrocardiogram showed QT prolongation. Since these rare findings indicating no myocardial BMIPP uptake were seen in a family, we suspected that a hereditary myocardial metabolic abnormality accounted for them.     

Impact of aging on cardiac sympathetic innervation measured by <Superscript>123</Superscript>I-mIBG imaging in patients with systolic heart failure

Purpose

Sympathetic nervous system (SNS) hyperactivity is a salient characteristic of chronic heart failure (HF) and contributes to the progression of the disease. Iodine-123 meta-iodobenzylguanidine (¹²³I-mIBG) imaging has been successfully used to assess cardiac SNS activity in HF patients and to predict prognosis. Importantly, SNS hyperactivity characterizes also physiological ageing, and there is conflicting evidence on cardiac ¹²³I-mIBG uptake in healthy elderly subjects compared to adults. However, little data are available on the impact of ageing on cardiac sympathetic nerve activity assessed by ¹²³I-mIBG scintigraphy, in patients with HF.

Methods and results

We studied 180 HF patients (age?=?66.1?±?10.5 years [yrs]), left ventricular ejection fraction (LVEF?=?30.6?±?6.3 %) undergoing cardiac ¹²³I-mIBG imaging. Early and late heart to mediastinum (H/M) ratios and washout rate were calculated in all patients. Demographic, clinical, and echocardiographic data were also collected. Our study population consisted of 53 patients aged >75 years (age?=?77.7?±?4.0 year), 67 patients aged 62–72 years (age?=?67.9?±?3.2 years) and 60 patients aged ≤61 year (age?=?53.9?±?5.6 years). In elderly patients, both early and late H/M ratios were significantly lower compared to younger patients (p?<?0.05). By multivariate analysis, H/M ratios (both early and late) and washout rate were significantly correlated with LVEF and age.

Conclusions

Our data indicate that, in a population of HF patients, there is an independent age-related effect on cardiac SNS innervation assessed by ¹²³I-mIBG imaging. This finding suggests that cardiac ¹²³I-mIBG uptake in patients with HF might be affected by patient age.

     

门控心肌灌注SPECT在冠心病方面的应用进展

门控心肌灌注SPECT能同时获得心肌血流灌注情况和左心室功能参数,是目前核素心脏检查中常用的方法。此法可重复性强,在临床应用广泛,为冠心病患者的诊断、危险度分层、心肌活力评价、治疗、预后及疗效的评价提供了可靠的依据。     

Influence of drugs on myocardial iodine-123 metaiodobenzylguanidine uptake in rabbit myocardium

About 15 years ago, iodine-123 metaiodobenzylguanidine (MIBG) myocardial imaging was introduced for the evaluation of myocardial sympathetic nerve function. Two uptake mechanisms for MIBG have so far been identified: uptake type I, a saturable, energy-dependent mechanism, and uptake type II, a non-saturable, energy-independent mechanism. We incubated isolated rabbit myocardial tissue samples with ¹²³I-MIBG in order to assess the uptake characteristics and the influence of varying incubation conditions. Furthermore, we examined the effects of several drugs and uptake inhibitors on the myocardial uptake of MIBG. The in vitro myocardial uptake of MIBG reached a steady plateau at 23.87%±3.63% after 1 h, i.e. a concentration gradient of 10, in a thermo-independent manner within a concentration range from 1.5 to 1500 μM. This indicates an unsaturable uptake process in the tested concentrations. Pre-incubation with the following drugs caused a significant inhibitory effect on myocardial MIBG uptake: haloperidol, levomepromazine, metoprolol, labetalol and clomipramine. According to our findings, the uptake mechanism seems to be an unspecific process, but the concentration gradient of 10 makes passive diffusion unlikely. Further studies with uptake-II-blocking substances as well as with isolated myocardial cells will be needed to clarify the nature of the myocardial MIBG uptake mechanism. Received 1 September and in revised form 18 November 1999     

Influence of drugs on myocardial iodine-123 metaiodobenzylguanidine uptake in rabbit myocardium

About 15 years ago, iodine-123 metaiodobenzylguanidine (MIBG) myocardial imaging was introduced for the evaluation of myocardial sympathetic nerve function. Two uptake mechanisms for MIBG have so far been identified: uptake type I, a saturable, energy-dependent mechanism, and uptake type II, a non-saturable, energy-independent mechanism. We incubated isolated rabbit myocardial tissue samples with 123I-MIBG in order to assess the uptake characteristics and the influence of varying incubation conditions. Furthermore, we examined the effects of several drugs and uptake inhibitors on the myocardial uptake of MIBG. The in vitro myocardial uptake of MIBG reached a steady plateau at 23.87%+/-3.63% after 1 h, i.e. a concentration gradient of 10, in a thermo-independent manner within a concentration range from 1.5 to 1500 microM. This indicates an unsaturable uptake process in the tested concentrations. Preincubation with the following drugs caused a significant inhibitory effect on myocardial MIBG uptake: haloperidol, levomepromazine, metoprolol, labetalol and clomipramine. According to our findings, the uptake mechanism seems to be an unspecific process, but the concentration gradient of 10 makes passive diffusion unlikely. Further studies with uptake-II-blocking substances as well as with isolated myocardial cells will be needed to clarify the nature of the myocardial MIBG uptake mechanism.     

Improved detection of coronary artery disease by estimated myocardial thallium uptake

Myocardial thallium uptake has been assessed at the time of thallium scanning in a group of 50 male patients undergoing coronary arteriography and 10 young healthy volunteers. The net thallium dose injected was obtained by counting the dose prior to injection using the gamma camera and counting the syringe and IV cannula after injection. Significantly higher levels of myocardial thallium uptake were obtained in both the volunteers and patients with normal coronary anatomy (1.36% +/- 0.32%, n = 10 and 0.93% +/- 0.26%, n = 9, respectively) compared to patients with single, double or triple vessel coronary artery disease (0.63% +/- 0.19%, n = 11; 0.70% +/- 0.20%, n = 15; 0.67 +/- 0.18, n = 15, respectively). Exercise tests were positive in 46% of patients with coronary artery disease with an overall predictive accuracy of 56%. Thallium scans were positive in 68% of patients at a specificity of 89%. If the range of myocardial thallium uptake from the patients with normal coronary arteries is used to define a lower limit of normal, then the sensitivity of the thallium scan with thallium uptake is 90% with a predictive accuracy of 90% in the detection of significant coronary artery disease in this group of patients. Thus, estimation of total % thallium uptake is a simple index which yields useful diagnostic clinical information.     

Improved detection of coronary artery disease by estimated myocardial thallium uptake

Myocardial thallium uptake has been assessed at the time of thallium scanning in a group of 50 male patients undeergoing coronary arteriography and 10 young healthy volunteers. The net thallium dose injected was obtained by counting the dose prior to injection using the gamma camera and counting the syringe and IV cannula after injection. Significantly higher levels of myocardial thallium uptake were obtained in both the volunteers and patients with normal coronary anatomy (1.36%±0.32%, n=10 and 0.93%±0.26%, n=9, respectively) compared to patients with single, double or triple vessel coronary artery disease (0.63%±0.19%, n=11; 0.70%±0.20%, n=15; 0.67±0.18, n=15, respectively). Exercise tests were positive in 46% of patients with coronary artery disease with an overall predictive accuracy of 56%. Thallium scans were positive in 68% of patients at a specificity of 89%. If the range of myocardial thallium uptake from the patients with normal coronary arteries is used to define a lower limit of normal, then the sensitivity of the thallium scan with thallium uptake is 90% with a predictive accuracy of 90% in the detection of significant coronary artery disease in this group of patients. Thus, estimation of total % thallium uptake is a simple index which yields useful diagnostic clinical information.     

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.     

冠脉内支架在冠脉病变中的应用价值

目的 探讨支架在冠脉病变治疗中的应用价值。方法对１９例冠心病患者植入冠脉支架,冠脉造影示Ａ型病变１例,Ｂ型１３例及Ｃ型５例。支架樾入用于预防ＰＴＣＡ后再狭窄１４例,治疗ＰＴＣＡ急性并发症（内膜撕裂和急性闭塞）５例。樾主支架２０个,其中前降支１０个,回旋支２个,右冠８个。结果 术后冠脉扩张效果满意,无残余狭窄。无一例发生急性和亚急性心脏事件,临床症状均明显改善。结论支架植入对复杂冠脉病变和急性冠脉并     

99Tcm-NOET门控心肌灌注SPECT评价冠心病的价值

目的评价99Tcm--双（N-乙氧基,N-乙基-二硫代氨基甲酸酯）氮化锝（99Tcm-NOET）静息门控断层心肌灌注显像对冠心病患者的诊断价值。方法疑诊为冠心病的45例患者注射925MBq 99Tcm-NOET后1h用SPECT行静息门控心肌灌注显像,获得舒张未期容积（EDV）、收缩未期容积（ESV）、左室射血分数（LVEF）等心功能参数和舒张末期容积灌注、局部射血分数、局部室壁活动和室壁增厚度4个靶心图。所有患者在1周内行冠状动脉造影,将冠状动脉狭窄≥50％定为病变血管。根据冠状动脉造影结果将其分为心肌梗死组、心肌缺血组和对照组三组。结果99Tcm-NOET静息门控SPECT诊断冠心病的灵敏度和特异度分别为68．42％和83．33％。心肌梗死组的心功能参数[EDV=（129．32±9．14）ml,ESV=（80．97±9．49）ml,LVEF=（40．15±3．28）％】与对照组【EDV=（80．91±3．12）ml,ESV=（30．12±1．79）ml,LVEF=（63．51±1．04）％]相比,统计学差异有显著性（EDV：F=22．103,ESV：F=32．277,LVEF：F=42．60：4,均为P〈0．01）,心肌缺血组的心功能参数[（EDV=（70．83±3．46）ml,ESV=（25．13±2．85）ml,LVEF=（65．55±2．62）％1与对照组相比,统计学差异无显著性意义。心肌梗死组左室心肌共分为460个节段,其中209个节段局部灌注、局部射血分数、局部室壁活动和室壁增厚度4个靶心图均异常。局部灌注异常的节段共328个节段,伴有局部射血分数、局部室壁活动和室壁增厚度异常分别有250个、240个和276个节段。局部灌注异常的节段与局部射血分数、局部室壁活动和室壁增厚度异常的节段不完全匹配。结论99Tcm-NOET静息门控心肌灌注显像对冠心病的诊断有较大临床应用价值,所获得的整体心室功能参数在心肌梗死的评价中有优越性,但对心肌缺血的诊断价值不大。心肌梗死中存在有不少的局部灌注与心肌?     

Significance of I-123 metaiodobenzylguanidine (123I-MIBG) lung activity in subjects with heart failure in comparison to healthy control subjects

Background

Little is known concerning the significance of lung activity of the sympathetic neuronal imaging agent ¹²³I-MIBG in heart failure patients and healthy subjects.

Methods

¹²³I-MIBG activity was assessed in lung, heart, and mediastinum regions of interest on early and late planar images in 951 heart failure patients and 94 controls. Cox regression analyses were performed to identify factors associated with outcome events during a median 17 month follow-up.

Results

Heart failure subjects with pulmonary disease had significantly reduced late lung-to-mediastinum (L/M) ratios compared to heart failure subjects without pulmonary disease. Late L/M ratio was greater in heart failure subjects without outcome events than either subjects with events or healthy controls. L/M ratio was an independent predictor of all-cause mortality. Subjects with combined favorable prognosis L/M ratio ≥ 1.7 and heart-to-mediastinum ratio (H/M) ≥ 1.6 had a significantly lower 2-year mortality (2.0%) than subjects with unfavorable L/M ratio < 1.7 and H/M ratio < 1.6 (17.7% 2-year mortality, P < .0008).

Conclusions

Increased ¹²³I-MIBG lung activity in heart failure subjects, compared to controls, is associated with a relatively low risk of adverse events, including all-cause mortality. L/M ratio may, therefore, be useful to provide incremental prognostic information on ¹²³I-MIBG imaging.     

Myocardial scintigraphy with I-123 heptadecanoic acid as a test for coronary heart disease

We have evaluated 123I-heptadecanoic acid for myocardial scintigraphy in the diagnosis of coronary heart disease by comparing the results obtained with it in subject groups with high and low probabilities of disease. We conclude that although some patients in the former group can be identified, the test is neither sufficiently sensitive nor specific for routine clinical use.     

Myocardial scintigraphy with I-123 heptadecanoic acid as a test for coronary heart disease

We have evaluated ¹²³I-heptadecanoic acid for myocardial scintigraphy in the diagnosis of coronary heart disease by comparing the results obtained with it in subject groups with high and low probabilities of disease. We conclude that although some patients in the former group can be identified, the test is neither sufficiently sensitive nor specific for routine clinical use.     

Iodine 123-labeled metaiodobenzylguanidine imaging in heart disease

Scintigraphic images of myocardial iodine 123-labeled metaiodobenzylguanidine (MIBG) reflect the relative distribution of adrenergic neurodensity and function in the myocardium. In patients with hypertrophic cardiomyopathy or after infarction, MIBG uptake in hypertrophied myocardium and the infarct-related myocardium was found to be decreased in comparison to blood flow distribution, delineated with thallium 201. Most intriguingly, semiquantitative measurements in patients with congestive heart failure demonstrated reduced myocardial MIBG uptake. This reduction correlated directly with indexes of left ventricular function. Decreases in neuronal density, dysfunction of adrenergic neurons, or chronically elevated circulating norepinephrine levels may account for this diminished myocardial uptake, which, as demonstrated in a pilot study of 90 patients with congestive heart failure, was found to be of predictive value for survival.