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Dynamic planar scintigraphy for the rapid kinetic measurement of myocardial 123I-MIBG turnover can identify Lewy body disease.

ABSTRACT: BACKGROUND:Using two static scans for 123I-meta-iodobenzyl-guanidine (123I-MIBG) myocardial scintigraphy ignores the dynamic response from vesicular trapping in nerve terminals. Moreover, the long pause between scans is impractical for patients with Lewy body diseases (LBDs). Here, we optimized indices that capture norepinephrine kinetics, tested their diagnostic performance, and determined the differences in 123I-MIBG performance among disease groups. METHODS:We developed a new 30-min protocol for 123I-MIBG dynamic planar imaging for suspected LBD patients. Pharmacokinetic modelling of time-activity curves (TACs) was used to calculate three new indices: unidirectional uptake of 123I-MIBG to vesicular trapping (iUp), rate of myocardial 123I-MIBG loss (iLoss), and non-specific fractional distribution of 123I-MIBG in the interstitial space. We compared the performance of the new and existing indices with regard to discrimination of patients with or without LBDs. Subgroup analysis was performed to examine differences in 123I-MIBG turnover between patients in a dementia with Lewy bodies (DLB) group and two Parkinson's disease (PD) groups, one with and the other without REM sleep behaviour disorder (RBD). RESULTS:iLoss was highly discriminative, particularly for patients with low myocardial 123I-MIBG trapping, and the new indices outperformed existing ones. ROC analysis revealed that the AUC of iLoss (0.903) was significantly higher than that of early HMR (0.863), while comparable to that of delayed HMR (0.892). The RBD-positive PD group and the DLB group had higher turnover rates than the RBD-negative PD group, indicating a potential association between prognosis and iLoss. CONCLUSION:123I-MIBG turnover can be quantified in 30 min using a three-parameter model based on 123I-MIBG TACs. The discriminatory performance of the new model-based indices might help explain the neurotoxicity or neurodegeneration that occurs in LBD patients.

SUBMITTER: Kumakura Y

PROVIDER: S-EPMC8671580 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Iodine-123 metaiodobenzylguanidine (123I-MIBG) myocardial scintigraphy has been used to evaluate cardiac sympathetic denervation in Lewy body disease (LBD), including Parkinson's disease (PD) and dementia with Lewy bodies (DLB). The heart-to-mediastinum ratio (H/M) in PD and DLB is significantly lower than that in Parkinson's plus syndromes and Alzheimer's disease. Although this ratio is useful for distinguishing LBD from non-LBD, it fluctuates depending on the system performance of the gamma cameras. Therefore, a new, simple quantification method using 123I-MIBG uptake analysis is required for clinical study. The purpose of this study was to develop a new uptake index with a simple protocol to determine 123I-MIBG uptake on planar images.The 123I-MIBG input function was obtained from the input counts of the pulmonary artery (PA), which were assessed by analyzing the PA time-activity curves. The heart region of interest used for determining the H/M was used for calculating the uptake index, which was obtained by dividing the heart count by the input count.Forty-eight patients underwent 123I-MIBG chest angiography and planar imaging, after clinical feature assessment and tracer injection. The H/M and 123I-MIBG uptake index were calculated and correlated with clinical features. Values for LBD were significantly lower than those for non-LBD in all analyses (P<0.001). The overlapping ranges between non-LBD and LBD were 2.15 to 2.49 in the H/M method, and 1.04 to 1.22% in the uptake index method. The diagnostic accuracy of the uptake index (area under the curve (AUC), 0.98; sensitivity, 96%; specificity, 91%; positive predictive value (PPV), 90%; negative predictive value (NPV), 93%; and accuracy, 92%) was approximately equal to that of the H/M (AUC, 0.95; sensitivity, 93%; specificity, 91%; PPV, 90%; NPV, 93%; and accuracy, 92%) for discriminating patients with LBD and non-LBD.A simple uptake index method was developed using 123I-MIBG planar imaging and the input counts determined by analyzing chest radioisotope angiography images of the PA. The diagnostic accuracy of the uptake index was approximately equal to that of the H/M for discriminating patients with LBD and non-LBD.

Project description:Chronic heart failure (CHF) results in both increased cardiac sympathetic activity and myocardial inflammation. The aim of this study was to identify the relationship between severity of heart failure (i.e., NT-proBNP and LVEF), cardiac sympathetic activity (123I-mIBG scintigraphy), and measures of inflammation in subjects with stable, optimally treated CHF. In addition, the predictive value for cardiac events (i.e., ventricular arrhythmia, progression of CHF and cardiac death) of 123I-mIBG parameters and these inflammatory markers was evaluated.Fifty-five CHF patients (age 66.3 ± 8.0 years, 78% male, LVEF 22.4 ± 6.3) referred for cardiac 123I-mIBG imaging were included. At 15 minutes (early) and 4 hours (late) after i.v. administration of 123I-mIBG (185 MBq), planar images were acquired. Early Heart/Mediastinum (H/M) ratio, late H/M ratio, and 123I-mIBG washout (WO) were calculated. NT-proBNP and markers of inflammation (i.e., C-reactive protein (CRP), IL-1?, IL-6, IL-8, IL-10, IL-12p40, tumor necrosis factor-? (TNF-?), soluble (s)E-selectin, myeloperoxidase (MPO), plasminogen activator inhibitor-1 (PAI-1), tPA, tumor necrosis factor receptor (TNFR) 1 and 2, and interferon (IFN) ? and ?) were measured in blood plasma samples, taken just before 123I-mIBG administration.Mean early H/M ratio was 2.12 ± 0.39, late H/M ratio was 1.84 ± 0.40, and 123I-mIBG WO was 13.0 ± 10.9. LVEF was the only independent predictor of late H/M ratio (adjusted R 2 = 0.100, p = 0.011). NT-proBNP was an independent predictor of 123I-mIBG WO (adjusted R 2 = 0.090, p = 0.015). CRP, IL12p40, TNF-?, sE-selectin, MPO, PAI-1, tPA, and TNFR2 were not related to late H/M ratio and 123I-mIBG WO. During a median follow-up of 34 months (2-58 months), 13 patients experienced a cardiac event [ventricular arrhythmia (4), progression of CHF (4), and cardiac death (5)]. Univariate Cox regression analysis showed that the risk of a cardiac event was associated with CRP (HR 1.047 [1.013-1.081]), NT-proBNP (HR 1.141 [1.011-1.288]), MPO (HR 0.998 [0.996-1.000]), and late H/M ratio (HR 0.182 [0.035-0.946]). Multivariate Cox regression analysis showed that only CRP, NT-proBNP, MPO, and IL-12p40 were predictors of a cardiac event.Inflammation and cardiac sympathetic activity seem not to be related in stable CHF patients. This is corroborated by the finding that they both provide prognostic information in this specific CHF population. The current findings should be regarded as insightful but preliminary.

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Dynamic planar scintigraphy for the rapid kinetic measurement of myocardial 123I-MIBG turnover can identify Lewy body disease.

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