Article

Comparison of parameters of (123)I-metaiodobenzylguanidine scintigraphy for differential diagnosis in patients with parkinsonism: correlation with clinical features.

Department of Neurology, Tokyo Women's Medical University, Kawada-cho, Shinjuku-ku, Tokyo, Japan.
Annals of Nuclear Medicine (Impact Factor: 1.41). 04/2011; 25(7):478-85. DOI: 10.1007/s12149-011-0490-2
Source: PubMed

ABSTRACT The purpose of this study was to estimate the diagnostic accuracy of (123)I-metaiodobenzylguanidine (MIBG) scintigraphy to diagnose Lewy body disease (LBD), including Parkinson's disease (PD) and dementia with Lewy bodies, and to clarify the relationship between MIBG parameters and the clinical findings.
One hundred-and-forty-four patients with parkinsonism without diabetes mellitus or a history of cardiac disease were retrospectively selected in the study. Clinical diagnosis was confirmed by follow-up during more than 6 months by neurologists. All patients underwent MIBG imaging at 15 min (initial) and 4 h (delayed) after the tracer injection, and clinical features such as Hoehn and Yahr (H-Y) classification or symptoms specific to parkinsonism were also investigated. The heart to mediastinum ratio (H/M) and the washout ratio (WR) of MIBG were calculated, and correlation with the clinical features was analyzed.
Ninety-seven and 47 patients were diagnosed as LBD and Parkinson's syndrome (PS), respectively. Initial and delayed H/M were significantly lower and WR was significantly higher in LBD than in PS (p < 0.0001). The initial H/M was independently correlated with tremor (F value 10.45), hesitation (F = 4.49), and hallucinations (F = 5.09) (p < 0.0001). The sensitivity and specificity for the diagnosis of LBD were 64.9 and 87.2% with initial H/M, 78.4 and 68.1% with delayed H/M, and 80.4 and 61.7% with WR, respectively. Using multivariate analysis, initial H/M (F = 39.33) and tremor (F = 10.46) were independently correlated to the diagnosis of LBD (r = 0.562, p < 0.0001) among the MIBG and various clinical parameters.
The initial H/M was the most useful of the 3 different parameters of MIBG for the diagnosis of LBD, but had low sensitivity. WR and delayed H/M had no incremental value to initial H/M for the diagnosis of PD. Careful long-term follow-up is needed for patients with parkinsonism who are clinically diagnosed as LBD with normal initial H/M, or diagnosed as no LBD with low initial H/M.

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    ABSTRACT: OBJECTIVES: Iodine-123 metaiodobenzylguanidine ((123)I-MIBG) myocardial scintigraphy provides useful diagnostic information in differentiating Parkinson's disease (PD) from other neurological diseases. Moreover, a number of studies have reported that (123)I-MIBG imaging provides powerful diagnostic and prognostic information in congestive heart failure (HF) patients. The aim of the present study was to investigate the cardiovascular predictive value of cardiac (123)I-MIBG imaging in patients with PD. METHODS: Seventy-eight patients with PD were retrospectively studied. All patients underwent (123)I-MIBG imaging at 30 min (early) and 240 min (delayed) after the tracer injection, and clinical parameters were also investigated. RESULTS: During a mean follow-up of 27 ± 12 months, 5 patients required hospitalization for HF. There were no occurrences of myocardial infarction, fatal arrhythmia or sudden death. There was no significant coronary artery stenosis, significant valvular heart disease, or cardiomyopathy in the HF patients. The left ventricular ejection fraction (LVEF) was normal in the HF patients. (123)I-MIBG delayed heart to mediastinal ratio (delayed H/M) was lower and washout rate (WR) was higher in HF patients than non-HF patients (1.62 ± 0.21 vs. 1.34 ± 0.08, p = 0.019; 31.9 ± 5.5 vs. 38.2 ± 3.3, p = 0.005, respectively). Both WR and delayed H/M did not correlate with Hoehn and Yahr stage. The WR showed a weak negative correlation with delayed H/M (R = -0.357, p < 0.001) upon simple linear regression analysis. A multivariate Cox regression analysis revealed that WR and delayed H/M were independently associated with HF (p = 0.014, p = 0.029, respectively). Kaplan-Meier analysis revealed that patients with abnormal WR (>37 %) and delayed H/M (<1.48) had a higher incidence of HF than those with normal WR and delayed H/M (p = 0.014, p = 0.04, respectively). CONCLUSIONS: WR showed stronger predictive power than delayed H/M in Kaplan-Meier analysis. WR has more useful cardiovascular predictive value than delayed H/M in Japanese patients with PD. Further studies are needed to clarify the significance of abnormal MIBG uptake in PD patients.
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