Cardiac 123I-MIBG Research Articles

The use of Cardiac 123I-mIBG Scintigraphy in Clinical Practice: The Necessity to Standardize!

Cardiac adrenergic imaging has a great potential in a wide variety of clinical applications. Cardiac 123I-meta-iodobenzylguanidine (123I-mIBG) scintigraphy has a key role to assess chronic heart failure (CHF) by risk stratifying patients for cardiac events. The mIBG is a norepinephrine (NE) analogue that can evaluate cardiac sympathetic activity by assessing the down expression of β-adrenergic receptor (β-AR) in CHF. Furthermore, 123I-mIBG scintigraphy in combination with other parameters of left ventricular function can be used to identify the best responder for implantable cardiac devices, as well as to assess oncological cardiotoxicity. Despite its usefulness, 123I-mIBG scintigraphy is not widely performed because of the lack of standardization between different institutions. Thus, standardization and validation may contribute to its acceptance in clinical setting.

Cardiac parasympathetic dysfunction in the early phase of Parkinson's disease.

Cardiac parasympathetic function is strongly affected by aging. Although sympathetic dysfunction has been well documented in Parkinson's disease (PD), cardiac parasympathetic dysfunction has not been well studied. The objective of this study was to clarify the development of cardiac parasympathetic dysfunction in the early phase of PD and to explore the age-corrected correlation between cardiac parasympathetic dysfunction and cardiac sympathetic dysfunction. We reviewed 25 healthy controls and 56 patients with idiopathic PD of Hoehn and Yahr stages I-III. We evaluated cardiac parasympathetic function using the Valsalva ratio, the baroreflex sensitivity (BRS) and the coefficient of variation of RR intervals in the resting state (resting-CVRR) and during deep breathing (DB-CVRR). In addition, we measured cardiac 123I-metaiodobenzylguanidine (MIBG) uptake to investigate the relationship between cardiac sympathetic and parasympathetic dysfunction in PD. Compared with healthy controls, patients with PD showed significantly decreased cardiac parasympathetic parameters (resting-CVRR 2.8±1.3 vs. 1.7±0.6%, p<0.001; DB-CVRR 5.8±2.3 vs. 3.8±1.7%, p<0.001; Valsalva ratio 1.52±0.26 vs. 1.34±0.17, p<0.01; BRS 10.6±9.5 vs. 5.0±5.4ms/mmHg, p<0.01). In particular, resting-CVRR and DB-CVRR were significantly decreased in the early phase of PD. In age-corrected analyses, none of the parasympathetic indices correlated with the delayed cardiac 123I-MIBG uptake. These observations indicate that cardiac parasympathetic dysfunction occurs in the early phase of PD, but not necessarily in parallel with cardiac sympathetic dysfunction.

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

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. We studied 180 HF patients (age = 66.1 ± 10.5years [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 >75years (age = 77.7 ± 4.0year), 67 patients aged 62-72years (age = 67.9 ± 3.2years) and 60 patients aged ≤61year (age = 53.9 ± 5.6years). 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. 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.

176-01: Radiofrequency cardiac denervation: scintigraphic evaluation of the effectiveness

Purpose: The aim of the study was to evaluate the role of radionuclide imaging with 123I-metaiodbenzilguanidine (123I-MIBG) in assessing of the cardiac radiofrequency denervation effectiveness. Methods and Materials: In this study were enrolled 32 patients with mitral valve (MV) disease: 21 patients with long-standing persistent atrial fibrillation, who was undergone MV surgery and the «Maze» procedure (Maze+ group) and 11 patients with sinus rhythm and with MV surgery without the «Maze» procedure (Maze- group). All patients underwent cardiac 123I-MIBG imaging prior and 10 days after surgery. The early and delayed heart-to-mediastinum ratio (HMR) and the washout rate (WR) were performed. Local denervation was evaluated on polar map images using the 17-segment model of left ventricle (LV). In addition, we determined the levels of norepinephrine, metanephrine, normetanephrine in plasma, obtained intraoperatively from the coronary sinus (CS) and the ascending aorta (Ao) before and after the main stage of the surgery. All patients were intraoperatively intake of histological material (left atrial appendage) to determine the distribution density of nerve endings in the myocardium. Results: In patients with AF the early HMR and delayed HMR prior surgery were significantly lower compared to patients with SR (p < 0.01). The washout rate of 123I-MIBG prior surgery in patients with AF was greater compared to patients with SR (p < 0.01). The HMR after surgery was significantly lower vs baseline in both groups (early HMR: 1,78 ± 0,17 vs 1,56 ± 0,19; p < 0,01 and 2,12 ± 0,25 vs 1,79 ± 0,18; p < 0,01; delayed HMR: 1,69 ± 0,21 vs 1,47 ± 0,19; p < 0,01 and 2,0 ± 0,22 vs 1,74 ± 0,19; p < 0,01). The WR after surgery was significantly increased vs baseline in both groups (27,3% ± 14,03% vs 35,0% ± 14,18%; p < 0,01 and 17,1% ± 13,7% vs 31% ± 16,15%; p < 0,01). After surgery sympathetic activity defect was increased only in the Maze+ group (12,7% ± 7,3% and 25,4% ± 8,5%; p < 0,01). The correlations between the cardiac 123I-MIBG parameters and the levels of norepinephrine, metanephrine, normetanephrine in plasma were examined. Cardiac 123I-MIBG parameters had significant correlations with transcardiac gradients (CS-Ao) of the norepinephrine and normetanephrine. Cardiac 123I-MIBG parameters had significant correlations with the distribution density of nerve endings in the myocardium. Conclusion: Results of this study indicated that the more sympathetic innervation abnormality prior surgery was observed in patients with AF. In patients who had undergone MV surgery without the «Maze» procedure, there were no significant changes in sympathetic activity defect in the early stage. The MV surgery itself doesn't influence the regional cardiac sympathetic activity. The evaluation of the cardiac nervous activity using 123I-MIBG scintigraphy may be a promising tool to determine of effectiveness of the cardiac radiofrequency denervation. The study was supported by a grant from the Russian Science Foundation № 15-15-10016.

PR Prolongation Is Correlated with Reduced Cardiac 123I-MIBG Uptake in Parkinson’s Disease (P6.374)

PR Prolongation Is Correlated with Reduced Cardiac 123I-MIBG Uptake in Parkinson’s Disease (P6.374)

(123)I-Meta-iodobenzylguanidine Sympathetic Imaging: Standardization and Application to Neurological Diseases.

123I-meta-iodobenzylguanidine (MIBG) has become widely applied in Japan since its introduction to clinical cardiology and neurology practice in the 1990s. Neurological studies found decreased cardiac uptake of 123I-MIBG in Lewy-body diseases including Parkinson's disease and dementia with Lewy bodies. Thus, cardiac MIBG uptake is now considered a biomarker of Lewy body diseases. Although scintigraphic images of 123I-MIBG can be visually interpreted, an average count ratio of heart-to-mediastinum (H/M) has commonly served as a semi-quantitative marker of sympathetic activity. Since H/M ratios significantly vary according to acquisition and processing conditions, quality control should be appropriate, and quantitation should be standardized. The threshold H/M ratio for differentiating Lewy-body disease is 2.0-2.1, and was based on standardized H/M ratios to comparable values of medium-energy collimators. Parkinson's disease can be separated from various types of parkinsonian syndromes using cardiac 123I-MIBG, whereas activity is decreased on images of Lewy-body diseases using both 123I-ioflupane for the striatum and 123I-MIBG. Despite being a simple index, the H/M ratio of 123I-MIBG uptake is reproducible and can serve as an effective tool to support a diagnosis of Lewy-body diseases in neurological practice.

Is There an Incremental Prognostic Value of Evaluating Left Ventricular Dyssynchrony by Gated SPECT in Patients with Systolic Heart Failure and Altered Myocardial Sympathetic Innervation as Evaluated by Cardiac I-123 mIBG Imaging?

Background: Altered myocardial sympathetic innervation activity (AMSI) is known to be present in systolic heart failure patients (SHF) and recently SPECT imaging using I-123 mIBG heart to mediastinum (H/M) ratio <1.6 has been shown to predict MACE in the ADMIRE-HF trial. Left ventricular mechanical dyssynchrony (LVMD) is known to be present in a substantial number of SHF patients and has been studied mainly to guide CRT therapy. Recently gated SPECT has shown promise to provide an accurate assessment of LVMD. It remains unclear how the combination of AMSI and LVMD collectively affect clinical outcomes and other cardiovascular parameters. Objectives: The objectives are to examine the clinical characteristics and incremental prognostic value for MACE of LVMD determined by SPECT in SHF patients with or without abnormal cardiac MIBG uptake (H/M ratio < 1.6). Methods: Out of 30 SHF patients who participated from our institution in the ADMIRE-HF trial studying MIBG based AMSI, we included 22 patients with abnormal MIBG H/M ratio of <1.6. We performed gated SPECT LVMD analysis on these patients using the Emory Cardiac Toolbox. The 2 SPECT variables for LVMD assessed were histogram bandwidth and phase standard deviation both of which assess the extent of dispersion of LV activation during contraction as a marker of LVMD. Patients were followed up for a mean period of 6 years. The primary end point was mortality from any cause and secondary end point was heart failure admission or myocardial infarction or ICD shock. Results: 2 Groups were defined: Group A: n = 17 with H/M MIBG ratio < 1.6 and +LVMD and Group B, n = 5 H/M MIBG ratio < 1.6 and −LVMD. Baseline characteristics, cardiac risk factors and medications were comparable between both groups. LVEF was lower and RBBB was less common in Group A. There was no statistical difference in achievement of primary or secondary end points in the two groups including death heart failure readmissions, ICD shocks or MI. Conclusions: In our pilot study, we did not find definitive value of adding SPECT based LVMD to abnormal cardiac MIBG imaging in SHF patients with regards to predicting outcomes. Although our sample size is too small to make any definitive conclusions, it is possible that LVMD works independently through different pathways in the progression of SHF and hence may not necessarily add incremental value to AMSI determination using MIBG.

Prognostic value of cardiac 123I-MIBG scintigraphy in patients with heart failure

Prognostic value of cardiac 123I-MIBG scintigraphy in patients with heart failure

Abstract 10858: Significant Association Between Washout Ratio of Renal 123i-metaiodobenzylguanidine and Muscle Sympathetic Nerve Activity in Patients With Hypertension

Background: Simplicity HTN-3 trial showed the negative result for renal denervation (RDN) in patient with resistant hypertension. One of limitations was that no appreciate evaluation of renal sympathetic nerve activity (RSNA) was applied before and after RDN. 123I-MIBG has been used to assess the cardiac sympathetic nerve activity. However, it remains unclear whether 123I-MIBG in kidney would reflect sympathetic nerve activity. In this study, we investigated the relationship renal 123I- MIBG and muscle sympathetic nerve activity (MSNA). Methods: 31 hypertensive patients were included in this study. MSNA was recorded from the peroneal nerve to evaluate direct sympathetic nerve activity to peripheral vascular bed. Images of 123I-MIBG were taken using the low-medium-energy general purpose collimator. An 111MBq dose of 123I-MIBG was injected intravenously at rest for the MIBG study. 123I-MIBG planar and SPECT studies were performed at 20min (early) and 3hr (delayed) after injection. In the planar study, a region of interest (ROI) was set over the heart and a rectangular ROI on the upper third of the mediastium and kidney cortex. The early and delayed heart-to-mediastinum average count ratios (H/M) and kidney-to-mediastinum average count ratios (K/M) were calculated. Washout rate (WR) of heart and kidney were also calculated. Results: Average systolic and diastolic blood pressure was 118±18/67±15 mmHg. Average estimated glomerular filtration rate was 71.5±22.4 ml/min/1.73m2 that was not related to renal 123I-MIBG. As expected, MSNA had significant negative relationship with delayed H/M in cardiac 123I-MIBG image (r=-0.37, p&lt;0.01) and positive relationship with WR of cardiac 123I-MIBG (r=0.45, p&lt;0.01). With regard to kidney, WR of 123I-MIBG of each left and right renal MIBG showed a significant correlation with MSNA (right kidney: r=0.56, p&lt;0.01, left kidney: r=0.60, p&lt;0.01, respectively), but not with early and delayed K/M in renal 123I-MIBG. Conclusions: Our study showed that WR of renal 123I-MIBG was associated with MSNA, indicating that WR of renal 123I-MIBG might reflect RSNA. These results suggest that renal 123I-MIBG might be available to assess sympathetic nerve activity as well as MSNA.

PR Prolongation and Cardiac 123I-MIBG Uptake Reduction in Parkinson's Disease

Background: Cardiac ¹²³I-metaiodobenzylguanidine scintigraphy (MIBG) previously demonstrated an uptake reduction in patients with Parkinson's disease (PD). However, epidemiologic research showed that electrocardiography (ECG) abnormalities occurred prior to motor signs in PD. Here we investigated whether the electrical conduction system of the heart was impaired in PD. Methods: Clinical features, ECG and MIBG parameters were analyzed in 191 patients with PD, 42 with multiple system atrophy (MSA) and 124 normal controls (NL). Results: The PR interval was significantly longer in patients with PD than in NL. The PR interval was significantly negatively correlated with early and delayed heart-to-mediastinum ratios in MIBG scintigraphy in PD and MSA patients. In 19 PD patients with PR prolongation, 17 patients also had abnormal MIBG findings, and the other 2 showed normal MIBG. Conclusions: The PR prolongation must show some sympathetic system abnormality because it is mainly controlled by the sympathetic nervous system. PR prolongation supports the objective biomarker value of MIBG for PD diagnosis.

Quantitative correlation between cardiac MIBG uptake and remaining axons in the cardiac sympathetic nerve in Lewy body disease

ObjectivesReduced cardiac meta-iodobenzylguanidine (MIBG) uptake and loss of cardiac sympathetic axons, as its possible anatomical substrate, were both recognised in Lewy body disease (LBD), while their direct correlation has so...

Correlation of cardiac 123I-MIBG imaging with conventional markers of the heart failure

Summary Objectives: Quantitative values of cardiac iodine-123 metaiodobenzylguanidine (123I-MIBG) global and regional adrenergic innervation showed promising results in predicting clinical course of heart failure. Nevertheless data is lacking how global and regional cardiac 123I-MIBG imaging parameters correlate with patient’s clinical data and conventional heart failure markers. Patients and methods: Eighty-six patientswith class II-IVNewYorkHeartAssociation (NYHA) heart failure were investigated. Patients underwent early and late cardiac 123I-MIBG planar and single photon emission computed tomography (SPECT) scanning. Global and regional cardiac 123I-MIBG scores were calculated and compared to conventional heart failure markers (left ventricular ejection fraction (LVEF), B-type natriuretic peptide (BNP) and maximum rate of oxygen consumption (VO2 max)), followed by NYHA functional class clinical assessment at the time of investigation. Results: Weak statistically significant correlation was noted between LVEF and global and regional cardiac adrenergic denervation scores, between BNP and VO2 max and global cardiac adrenergic denervation scores. Global and regional cardiac adrenergic denervation scores significantly differed within LVEF ranges. Global cardiac adrenergic denervation scores significantly differed within BNP levels and NYHA functional class. Conclusions: Conventional cardiac heart failure markers had weak correlation with global and regional cardiac 123I-MIBG imaging parameters. Cardiac 123I-MIBG imaging markers differed significantly depending on LVEF and BNP levels, and NYHA functional class.

123I-MIBG Cardiac Imaging: Acquisition Protocols and Correction Methods for Quantitative Evaluation

Cardiac sympathetic imaging with 123I-MIBG offers unique insights into heart failure and neurodegenerative disease. Because of the diffuse nature of impairment, quantitative evaluation is indispensable, and the heart-to-mediastinum ratio is widely accepted as a valuable index. However, estimation of this index is highly dependent on acquisition protocol, especially collimator choice. A low-energy high-resolution collimator having thin septa is often used for 123I-MIBG imaging, and high-energy photons emitted from 123I readily penetrate the thin septa. The heart-to-mediastinum ratios are affected by accumulation in the lung and liver and are underestimated to various degrees. Medium-energy collimators having thick septa are less susceptible to septal penetration and are expected to offer a better indicator of cardiac sympathetic function. This review will provide an overview of the physics of 123I imaging and discuss acquisition protocols and correction methods for quantitative evaluation of cardiac 123I-MIBG imaging with special reference to the effect of septal penetration.

Heart failure patients with B1-adrenoreceptor polymorphisms have augmented carvedilol response as detected by cardiac I123-MIBG scintigraphy

B1-adrenergic receptor is the target of most endogenous catecholamines and B-blockers agents, and has critical role in heart failure (HF) progression and treatment [1]. Current guidelines for HF management have been recommended the use of B-blocker agents, such as metoprolol, bisoprolol and carvedilol, which act as blocking B1-adrenoceptors. Carvedilol therapy has been showed to improve cardiac sympathetic activity, as indicated by imaging with 123iodine-metaiodobenzylguanidine (123I-MIBG), a norepinephrine analog radiotracer [2].

Prognostic value of cardiac iodine-123 metaiodobenzylguanidine imaging in patients with indications for cardiac resynchronization therapy

Background. The aim of our study was to assess the cardiac 123I-MIBG imaging predictive value on the clinical outcome in HF patients with wide QRS complexes and compare its power in different treatment groups. Materials and methods. We have prospectively investigated 67 heart failure patients with the New York Heart Association (NYHA) functional class II–IV, wide QRS complexes (&gt;120 milliseconds), reduced left ventricular ejection fraction (LV EF) eligible for CRT. 123I-MIBG planar and single photon emission computed tomography (SPECT) scans were performed in a supine position with calculation of early and late heart-to-mediastinum (H/M) ratios, washout ratio (WR), summed defect scores and scores difference from SPECT acquisition. All patients were then divided in two groups according to their clinical status – 36 patients underwent implantation of CRT, and 31 patients were continued with OMT. Initial conventional heart failure markers and NYHA were assessed at the time of 123I-MIBG imaging and 6 months later. Comparisons of two groups were done applying the Student’s t-test, and if samples were small, the Fisher’s exact test was used. NYHA groups were compared applying the ANOVA single factor analysis. ROC curve analysis was performed to establish cut off values for predictors of response. Results. Cardiac 123I-MIBG imaging data differed insignificantly, presenting a similar cardiac adrenergic innervation status in both groups. In the CRT group, NYHA and LV EF indicated more pronounced signs of HF. For all patients, NYHA IV patients had significantly larger LV diameter, smaller EF, larger BNP levels, lower late H/M values and larger denervation score difference. Responders to therapy (both groups) had significantly higher early H/M ratio – 2.35 ± 0.41 than non-responders – 2.00 ± 0.44 (p = 0.004), and late H/M ratio – 2.11 ± 0.44 for responders and 1.72 ± 0.54 for non-responders (p = 0.005). There were no significant differences in regional cardiac 123I-MIBG data for responders and non-responders. Conclusions. Cardiac 123I-MIBG imaging has valuable prognostic power predicting clinical outcomes of HF patients with wide QRS complexes, despite the chosen type of treatment, with better outcomes for patients with early H/M ratio 2.00 and late H/M ratio above 1.77.

The utility of ADMIRE-HF risk score in predicting serious arrhythmic events in heart failure patients: Incremental prognostic benefit of cardiac 123I-mIBG scintigraphy

BackgroundA minority of heart failure (HF) patients who undergo implantable cardioverter defibrillator (ICD) implantation for primary prevention of sudden cardiac death (SCD) receive device therapy. Whether the addition of mIBG scintigraphy to conventional markers of arrhythmic risk can provide incremental risk stratification in HF patients has not been investigated. MethodsWe identified 778 patients from the ADMIRE-HF study with LVEF < 35% and class II or III HF symptoms who did not have an ICD at the time of enrollment. Patients were followed up prospectively (median = 17 months) for occurrence of arrhythmic events (ArE). Heart-to-mediastinum ratio (HMR) was determined as a measure of relative myocardial sympathetic nerve activity at baseline using 123I-mIBG. The primary endpoint was the first occurrence of ArE: a composite of SCD, appropriate ICD therapy, resuscitated cardiac arrest or sustained ventricular tachycardia. Multivariate regression was used to determine independent predictors of ArE and to derive a risk score for ArE prediction. The score was used to group patients according to their risk for ArE. Integrated discrimination improvement (IDI) was used to quantify improvement in risk assessment with addition of HMR. ResultsArE occurred in 54 patients (6.9%). ArE predictors were: HMR < 1.6 (HR 3.5, 95% CI [1.52-8], P = .02), LVEF < 25% (HR 2.0, 95% CI [1.28-3.05], P = .04) and SBP < 120 (HR 1.2, 95% CI [1.03-1.39], P = .02). Event rates in the low-, intermediate-, and high risk groups were 2, 10 and 16%, respectively (P = .001). The score significantly improved risk prediction (IDI = 45%, P 0.03). Conclusion123I-mIBG significantly provides incremental risk stratification for ArE in HF patients.

Cardiac 123I-MIBG uptake in de novo Brazilian patients with Parkinson's disease without clinically defined dysautonomia.

Myocardial scintigraphy with meta-iodo-benzyl-guanidine (123I cMIBG) has been studied in Parkinson's disease (PD), especially in Asian countries, but not in Latin America. Most of these studies include individuals with PD associated to a defined dysautonomia. Our goal is to report the cardiac sympathetic neurotransmission in de novo Brazilian patients with sporadic PD, without clinically defined dysautonomia. We evaluated retrospectively a series of 21 consecutive cases with PD without symptoms or signs of dysautonomia assessed by the standard bedside tests. This number was reduced to 14 with the application of exclusion criteria. 123I cMIBG SPECT up-take was low or absent in all of them and the heart/mediastinum ratio was low in 12 of 14. We concluded that 123I cMIBG has been able to identify cardiac sympathetic neurotransmission disorder in Brazilian de novo PD patients without clinically defined dysautonomia.

123I-MIBG cardiac uptake, smell identification and 123I-FP-CIT SPECT in the differential diagnosis between vascular parkinsonism and Parkinson's disease

Vascular parkinsonism (VP) may occur as a distinct clinicopathological entity but the comorbid presence of vascular damage in Parkinson's disease (PD) is very frequent too. This differential diagnosis has therapeutic and prognostic implications but remains challenging as the usefulness of a number of supporting tools is still controversial. ObjectiveTo ascertain the clinical value of cardiac 123I-meta-iodobenzylguanidine (123I-MIBG) SPECT, olfactory function and 123I-FP-CIT SPECT as supporting tools in the differential diagnosis between VP and PD. MethodsCross-sectional study of 15 consecutive patients with suspected VP, 15 PD patients and 9 healthy subjects. Cardiac 123I-MIBG SPECT (heart-to-mediastinum ratio) and olfactory testing (University of Pennsylvania Smell Identification Test-UPSIT) were performed in all of them. 123I-FP-CIT SPECT was performed in VP-suspected patients. ResultsHeart-to-mediatinum ratio was significant lower in suspected VP (mean 1.45) and PD (mean 1.16) compared to control group (mean 1.69) (p = 0.017 and p < 0.0001). VP patients presented a higher ratio than PD patients (p = 0.001). Control group presented a significant higher UPSIT score (mean 30.71) when compared to both VP (mean 18.33) and PD (mean 15.29) (p = 0.001 for both groups). Those VP with a cardiac 123I-MIBG non suggestive of PD were more likely to have a higher UPSIT score (p = 0.006). 123I-FP-CIT SPECT imaging was heterogeneous (7/15 VP normal, 3/15 abnormal suggestive of PD and 5/15 abnormal but atypical for PD). ConclusionsThe use of cardiac 123I-MIBG SPECT and to a lesser extent UPSIT could assist the differential diagnosis between VP and PD in subjects in which the diagnosis remains uncertain despite 123I-FP-CIT SPECT imaging.

Resting perfusion MPI-SPECT combined with cardiac 123I-mIBG sympathetic innervation imaging improves prediction of arrhythmic events in non-ischemic cardiomyopathy patients: Sub-study from the ADMIRE-HF trial

BackgroundDelayed Iodine-123 meta-iodobenzylguanidine heart/mediastinum (H/M) uptake ratio predicted arrhythmic events in patients with heart failure (HF) and significant left ventricular dysfunction in ADMIRE-HF. We tested the hypothesis that resting perfusion defects on MPI-SPECT, representing scar, would further risk stratify patients beyond H/M ratio in the prediction of ventricular arrhythmic events in both ischemic (ICM) and non-ischemic cardiomyopathy (NICM) patients. MethodsPatients from the ADMIRE-HF database were classified as ICM and NICM and were stratified by delayed H/M ratio (<1.6/≥1.6) and by summed rest score (SRS) (≤8/>8) on MPI-SPECT. The entire cohort was also classified as high risk (H/M <1.6, SRS >8) and low risk (H/M ≥1.6, SRS ≤8). Scores were from visual interpretation of individual and derived consensus (average) reads per ASNC guidelines. ResultsThere were 612 (66%) ICM and 317 (34%) NICM patients. ICM patients had higher mean SRS than NICM patients (25 ± 13 vs 12 ± 10). Sixty-three arrhythmic events occurred over a median follow-up of 17 months. SRS had incremental predictive value among NICM patients with low H/M ratio (<1.6). There was no risk stratification in patients with ICM. Multivariable analysis for NICM with H/M ratio <1.6 demonstrated SRS score >8 as the only independent predictor of arrhythmic events (hazard ratio 3.3, 95% CI 1.1-9.8, P = .03). Patients classified in high-risk subgroup had statistically significant increased risk of arrhythmic events (hazard ratio 2.080, 95% CI 1.112-3.894, P = .022). There was only one event in low-risk subgroup with a trend towards lower risk of arrhythmic events (P = .07). ConclusionResting perfusion defects provide independent risk stratification in addition to Iodine-123 meta-iodobenzylguanidine sympathetic innervation imaging in predicting arrhythmic events in patients with NICM and HF. High and potentially low-risk groups for arrhythmic events can be identified based on the severity of resting perfusion defect score and H/M ratio.

Systemic blood pressure profile correlates with cardiac 123I-MIBG uptake in patients with Parkinson's disease

Purpose: To examine the correlation between the systemic blood pressure profile and cardiac 123I-metaiodobenzylguanidine (MIBG) uptake in patients with Parkinson's disease (PD).