Myocardial Uptake Of 123I-MIBG Research Articles

Impact of age on myocardial uptake of 123I-mIBG in older adult subjects without coronary heart disease

BackgroundThe purpose of this study was to examine the relationship between myocardial uptake of 123I-mIBG and age in older normal adult subjects. Methods94 subjects (age 29-82, mean 58.5) without coronary heart disease were studied. All subjects underwent early and delayed planar and 4-hour SPECT 123I-mIBG imaging. 123I-mIBG uptake was quantified as heart/mediastinum ratio on planar images (H/Mp) and on SPECT images (H/Ms) reconstructed by filtered backprojection, ordered subsets-expectation maximization (OSEM), and OSEM with compensation for collimator septal penetration (DSP). Relationships between age and 123I-mIBG uptake were examined by correlation analysis, t-tests, and analysis of variance. ResultsThere was no significant correlation between age and H/Mp, reflecting comparable increases in activity in the two regions of interest with age. Results on SPECT analyses were comparable, with no significant correlation between age and H/Ms. Using DSP, 123I-mIBG H/Ms was significantly higher in subjects ≥70 of age compared with younger subjects. ConclusionsBoth cardiac and background uptake of 123I-mIBG increase with age in older subjects without coronary heart disease, resulting in stability of H/M results (planar and SPECT). This study suggests that prognostic analyses of quantitative 123I-mIBG uptake in patients with heart disease do not require adjustment for patient age.

123I-MIBG Scintigraphy as a Powerful Tool to Plan an Implantable Cardioverter Defibrillator and to Assess Cardiac Resynchronization Therapy in Heart Failure Patients

Iodine-123-metaiodobenzylguanidine (123I-MIBG) scintigraphy is a nuclear medicine technique which describes the functional status of the cardiac sympathetic nervous system. It is well known that an autonomic dysfunction is present in heart failure setting as a neuronal uptake of norepinephrine is impaired in the failing myocardium. Reduction in sympathetic nervous function in the heart, measured by reduced myocardial uptake of 123I-MIBG, is an indicator of poor prognosis for heart failure patients. The aim of this paper was to investigate the role of 123I-MIBG scintigraphy in evaluating the need of implantable cardioverter defibrillator (ICD) and the response to cardiac resynchronization therapy (CRT) in heart failure patients. For this purpose scientific literature data on these topics were reviewed. Based on literature data, 123I-MIBG scintigraphy seems to be a useful tool to assess which patients may benefit most from an ICD implantation to reduce the risk of ventricular arrhythmia or sudden cardiac death. Furthermore, 123I-MIBG scintigraphy seems to predict which patients will response to CRT with an improvement in left ventricular function.

Takotsubo syndrome in a patient after renal transplantation

SummaryBackgroundTakotsubo syndrome (TTS) is a transient cardiomyopathy of unknown origin, clinically manifesting as acute coronary syndrome (ACS). This syndrome mainly occurs in postmenopausal women and has a temporary relationship with emotional or physical stress.Case ReportTTS occurred in 46-year-old female patient on the first day after renal transplantation. The predominant symptoms were connected with ACS, performed with low grade troponin elevation and characteristic shape of left ventricle depicted in echocardiography. Taking into consideration the risk of the development of contrast-induced nephropathy, coronary angiography (CA) was delayed; myocardial perfusion scintigraphy and iodine-123 metaiodobenzylguanidine (123I-mIBG) myocardial uptake were performed to confirm the clinical suspicion. Myocardial perfusion scintigraphy (MPS) performed in rest condition showed normal perfusion but myocardial uptake of 123I-mIBG was impaired. Within 6 months after surgery, full recovery of all biochemical and functional parameters of the left ventricle were observed. At that time CA was done, depicting normal coronary arteries.ConclusionsTTS could be diagnosed by the use of non-nephrotoxic tests – 123I-mIBG myocardial scintigraphy, MPS and echocardiography.

Hepatocyte growth factor levels are associated with the results of 123I-metaiodobenzylguanidine myocardial scintigraphy in patients with type 2 diabetes mellitus

Elevated hepatocyte growth factor (HGF) levels and cardiovascular autonomic dysfunction are associated with a high mortality rate in patients with type 2 diabetes mellitus. We tested the hypothesis that elevated HGF is associated with insulin resistance and cardiovascular autonomic dysfunction in patients with type 2 diabetes mellitus not receiving insulin treatment. The study group consisted of 21 type 2 diabetes mellitus patients with high HGF levels (>0.26 ng/mL, 58 ± 5 years old, high-HGF group). The control group consisted of 25 type 2 diabetes mellitus patients with normal HGF levels (≤0.26 ng/mL, 58 ± 9 years old, normal-HGF group). Cardiovascular autonomic function was assessed by baroreflex sensitivity, heart rate variability, plasma norepinephrine concentrations, and cardiac 123I-metaiodobenzylguanidine (MIBG) scintigraphy. Early and delayed 123I-MIBG myocardial uptake values were lower (P < .005 and P < .01, respectively) and the percentage of washout rate of 123I-MIBG was higher (P < .001) in the high-HGF group than in the normal-HGF group. The fasting plasma insulin concentrations (P < .0001) and the homeostasis model assessment index values (P < .0001) were higher in the high-HGF group than in the normal-HGF group. Multiple regression analysis revealed that the level of HGF was independently predicted by the homeostasis model assessment index values and the myocardial uptake of 123I-MIBG at the delayed phase. Our results demonstrate that high levels of HGF are associated with depressed cardiovascular autonomic function and insulin resistance in patients with type 2 diabetes mellitus.

Hypoadiponectinemia in type 2 diabetes mellitus in men is associated with sympathetic overactivity as evaluated by cardiac 123I-metaiodobenzylguanidine scintigraphy

Hypoadiponectinemia is associated with insulin resistance. However, there is very limited information about the relationship between plasma adiponectin and cardiac autonomic nervous function. We tested the hypothesis that hypoadiponectinemia is associated with cardiac sympathetic overactivity in patients with type 2 diabetes mellitus. Thirty-three male type 2 diabetic patients not on insulin treatment were classified into a hypoadiponectinemia group (plasma adiponectin concentration, <4.0 μg/mL; age, 58.6 ± 8.6 years [mean ± SD]; n = 14) and an age-matched normoadiponectinemia group (serum adiponectin concentration, ≥4.0 μg/mL; age, 58.2 ± 8.1 years; n = 19). In each patient, baroreflex sensitivity, heart rate variability, plasma norepinephrine concentration, and cardiac 123I-metaiodobenzylguanidine (MIBG) scintigraphic findings were assessed. Compared with the normoadiponectinemia group, the hypoadiponectinemia group had a higher body mass index ( P < .01), higher plasma concentrations of glucose and insulin ( P < .05 and P < .01, respectively), higher homeostasis model assessment of insulin resistance (HOMA-IR) values ( P < .005), higher plasma triglyceride levels ( P < .05), and lower plasma high-density lipoprotein cholesterol levels ( P < .05). In the hypoadiponectinemia group, the autonomic function measurements included a lower baroreflex sensitivity ( P< .05) and a lower delayed myocardial uptake of 123I-MIBG ( P < .01) with a higher washout rate ( P < .05). Multiple regression analysis revealed that the plasma adiponectin level was independently associated with HOMA-IR (F = 9.916) and the percent washout rate of 123I-MIBG (F = 5.985). Our results suggest that in middle-aged men with type 2 diabetes mellitus, hypoadiponectinemia is associated with cardiac sympathetic overactivity as determined by 123I-MIBG scintigraphy.

Brain natriuretic peptide and cardiac autonomic function in type 2 diabetic patients

The present study tested the hypothesis that increased plasma brain natriuretic peptide (BNP) levels are related to cardiac autonomic dysfunction in type 2 diabetic patients. A total of 32 consecutive Japanese patients with type 2 diabetes were assigned to either a high-BNP (≥18 pg/ml) group ( n = 12; age 57 ± 13 years, mean ± S.D.) or a normal-BNP (<18 pg/ml) group ( n = 20; 59 ± 10 years). No patient had any overt structural heart disease. Cardiac autonomic function was assessed by measurements of baroreflex sensitivity (BRS), heart rate variability (HRV) and cardiac 123I-metaiodobenzylguanidine (MIBG) scintigraphic findings. BRS was lower ( p < 0.005) in the high-BNP group than in the normal-BNP group. However, the components of HRV, and the early and delayed myocardial uptake of 123I-MIBG and percentage washout rate of 123I-MIBG were not significantly different between the groups. The plasma level of BNP negatively correlated with BRS ( r = 0.35, p = 0.049). These findings suggest that increased plasma BNP levels were related to cardiac reflex parasympathetic dysfunction in our Japanese type 2 diabetic patients.

High-sensitivity C-reactive protein is associated with insulin resistance and cardiovascular autonomic dysfunction in type 2 diabetic patients

We tested the hypothesis that elevated levels of plasma high-sensitivity C-reactive protein (HSCRP) are associated with insulin resistance/hyperinsulinemia and cardiovascular autonomic dysfunction in type 2 diabetic patients without insulin treatment. The study group consisted of 17 type 2 diabetic patients with high HSCRP (0.3-1.0 mg/dL; age, 59 ± 8 years, mean ± SD; high HSCRP group). The control group consisted of 18 age-matched type 2 diabetic patients with low HSCRP (<0.3 mg/dL; 59 ± 7 years; low HSCRP group). Cardiovascular autonomic function was assessed by baroreflex sensitivity, heart rate variability, plasma norepinephrine concentration, and cardiac metaiodobenzylguanidine (MIBG) labeled with iodine 123 scintigraphic findings. Baroreflex sensitivity was lower in the high HSCRP group than in the low HSCRP group ( P < .05). Early and delayed 123I-MIBG myocardial uptake values were lower ( P < .05 and P < .005, respectively) and the percent washout rate of 123I-MIBG was higher ( P < .01) in the high HSCRP group than in the low HSCRP group. Fasting plasma insulin concentration ( P < .01) and the homeostasis model assessment index ( P < .01) were higher in the high HSCRP group than in the low HSCRP group. Multiple regression analysis revealed that the level of HSCRP was independently predicted by fasting plasma insulin concentration and myocardial uptake of 123I-MIBG at a delayed phase. Our results suggest that high levels of HSCRP are associated with depressed cardiovascular autonomic function and hyperinsulinemia and that fasting plasma insulin concentration and myocardial uptake of 123I-MIBG at a delayed phase are independent predictors of HSCRP level in our Japanese patients with type 2 diabetes mellitus.

Microalbuminuria, cardiovascular autonomic dysfunction, and insulin resistance in patients with type 2 diabetes mellitus

Urinary albumin excretion/microalbuminuria and cardiovascular autonomic dysfunction are associated with high mortality in type 2 diabetic patients. We tested the hypothesis that the presence of microalbuminuria would correlate with cardiovascular autonomic dysfunction and insulin resistance in type 2 diabetic patients. The study group consisted of 15 Japanese patients with type 2 diabetes and microalbuminuria (age: 56 ± 10 years, mean ± SD). The control group consisted of 19 age-matched patients with normalbuminuria (56 ± 7 years). Cardiovascular autonomic function was assessed by baroreflex sensitivity (BRS), heart rate variability, plasma norepinephrine concentration, and cardiac 123I-metaiodobenzylguanidine (MIBG) scintigraphy. BRS was lower in the microalbuminuria group than in the normalbuminuria group ( P < .05). Early and delayed 123I-MIBG myocardial uptake values were lower ( P < .05 and P < .005, respectively) and the percent washout rate of 123I-MIBG was higher ( P < .0005) in the microalbuminuria group than in the normalbuminuria group. Fasting plasma glucose ( P < .05) and insulin concentrations ( P < .05), and the homeostasis model assessment (HOMA) index ( P < .01) were higher in the microalbuminuria group than in the normalbuminuria group. Multiple regression analysis showed that urinary albumin excretion was independently predicted by the myocardial uptake of 123I-MIBG at delayed phase, fasting plasma insulin concentration, and the HOMA index. Our results indicate that the presence of microalbuminuria in our Japanese patients with type 2 diabetes is characterized by depressed cardiovascular autonomic function and insulin resistance, and that the myocardial uptake of 123I-MIBG at delayed phase, fasting plasma insulin, and HOMA index are independent predictors of urinary albumin excretion.

Effect of essential hypertension on cardiac autonomic function in type 2 diabetic patients

OBJECTIVESThe aim of this study was to examine the effects of essential hypertension on cardiac autonomic function in type 2 diabetic patients.BACKGROUNDHypertension is common in type 2 diabetic patients and is associated with a high mortality. However, the combined effects of type 2 diabetes and essential hypertension on cardiac autonomic function have not been fully elucidated.METHODSThirty-three patients with type 2 diabetes were assigned to a hypertensive diabetic group (n = 15; age: 56 ± 8 years, mean ± SD) or an age-matched normotensive diabetic group (n = 18, 56 ± 6 years). Cardiac autonomic function was assessed by baroreflex sensitivity (BRS), heart rate variability (HRV), plasma norepinephrine concentration and cardiac 123I-metaiodobenzylguanidine (MIBG) scintigraphic findings.RESULTSBaroreflex sensitivity was lower in the hypertensive diabetic group than it was in the normotensive diabetic group (p < 0.05). The early and delayed myocardial uptake of 123I-MIBG was lower (p < 0.01 and p < 0.05, respectively), and the percent washout rate of 123I-MIBG was higher (p < 0.05) in the hypertensive diabetic group. However, the high frequency (HF) power and the ratio of low frequency (LF) power to HF power (LF/HF) of HRV and plasma norepinephrine concentration were not significantly different. The homeostasis model assessment index was higher in the hypertensive diabetic group than it was in the normotensive diabetic group (p < 0.01).CONCLUSIONSOur results indicate that essential hypertension acts synergistically with type 2 diabetes to depress cardiac reflex vagal and sympathetic function, and the results also suggest that insulin resistance may play a pathogenic role in these processes.

Measurement of myocardial accumulation of 123I-metaiodobenzylguanidine for studying cardiac autonomic neuropathy in diabetes mellitus.

The association of myocardial 123I-metaiodobenzylguanidine (MIBG) accumulation and autonomic neuropathy, as well as factors known to affect autonomic nervous function, were studied in a group of 12 diabetic patients representing different degrees of autonomic failure. The early myocardial uptake phase of 123I-MIBG was measured by calculating the peak net influx rate for the first 30 min after the 123I-MIBG injection and by single photon emission computed tomography (SPECT) imaging 1 h after the injection. The retainment of 123I-MIBG in the myocardium was measured using SPECT imaging 6 h after the injection, and myocardial uptake and the myocardium/liver uptake ratio were calculated. The 6-h myocardium/liver uptake ratio of 123I-MIBG was significantly (p < 0.05) lower in the diabetic patients with clinically evident autonomic neuropathy compared with those without autonomic neuropathy. Greater body mass index was associated with lower peak net influx rate and 1-h myocardial uptake of 123I-MIBG, and greater diastolic blood pressure was associated with lower 1-h myocardial uptake of 123I-MIBG, whether or not the patients had diabetic autonomic neuropathy. In conclusion, reduction in the 6-h myocardium/liver uptake ratio of 123I-MIBG is related to diabetic autonomic neuropathy. Because the early 123I-MIBG accumulation in myocardium is reduced in diabetic patients with greater body mass index and diastolic blood pressure, irrespective of autonomic neuropathy, our results encourage the use of the late myocardial accumulation of 123I-MIBG for studying sympathetic neuropathy in the diabetic heart.

Reduced myocardial 123I-metaiodobenzylguanidine uptake in newly diagnosed IDDM patients.

123I-labeled metaiodobenzylguanidine (123I-MIBG) scintigraphy is a novel technique for the assessment of cardiac sympathetic dysinnervation. To evaluate defects of the cardiac autonomic nervous system at the onset of IDDM, this technique together with conventional electrocardiogram (ECG)-based cardiac reflex tests and measurement of the QT interval was applied to 22 newly diagnosed metabolically stabilized IDDM patients without myocardial perfusion abnormalities (99mTc-labeled methoxyisobutylisonitrile scintigraphy) and 9 matched control subjects. Seventeen diabetic patients (77%), but none of the control subjects, were observed to have a reduced global myocardial uptake of 123I-MIBG. In contrast, only two diabetic patients (9%) demonstrated an ECG-based cardiac autonomic neuropathy (two or more of five age-related cardiac reflex tests abnormal) (P < 0.001). In newly diagnosed IDDM patients, the uptake of 123I-MIBG was reduced more in the posterior myocardial region compared with the lateral and apical region (P < 0.01, P = 0.03). The septal myocardial region exhibited a smaller uptake than the lateral myocardial region (P = 0.02). The maximum/minimum 30:15 ratio correlated with the global, anterior, lateral, and septal myocardial uptake of 123I-MIBG (P < 0.05, P < 0.05, P < 0.01, P < 0.05). A correlation between global and regional myocardial 123I-MIBG uptake and HbA1c or QT interval was not observed. Newly diagnosed metabolically stabilized IDDM patients without myocardial perfusion defects show evidence of cardiac sympathetic dysinnervation, as indicated by a reduction of 123I-MIBG uptake, at a significant higher proportion than ECG-based cardiac autonomic neuropathy. Furthermore, they present with regional differences of myocardial 123I-MIBG uptake.

Influence of drugs on the myocardial uptake of 123I-MIBG

Influence of drugs on the myocardial uptake of 123I-MIBG

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.