Postganglionic Sudomotor Dysfunction and Brain Glucose Hypometabolism in Patients with Multiple System Atrophy.

BACKGROUND: Sudomotor dysfunction is common in patients with multiple system atrophy (MSA). Postganglionic sudomotor dysfunction in MSA, which can be assessed using quantitative sudomotor axon reflex testing (QSART), results from the degeneration of preganglionic sympathetic neurons and direct loss of postganglionic fibers. OBJECTIVE: We investigate whether abnormal QSART responses in patients with MSA are associated with disease severity. METHODS: In this retrospective study, patients with probable MSA who underwent both 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) and autonomic function tests were included. Autonomic function test results were integrated divided into three sub-scores, including sudomotor, cardiovagal, and adrenergic sub-scores. The sudomotor sub-score represented postganglionic sudomotor function. Unified Multiple System Atrophy Rating Scale (UMSARS) Part I, Part II, and sum of Part I and II scores (Part I + II) to reflect disease severity and 18F-FDG-PET/CT results were collected. RESULTS: Of 74 patients with MSA, 62.2%demonstrated abnormal QSART results. The UMSARS Part I + II score was significantly higher in the abnormal QSART group than in the normal QSART group (p = 0.037). In the regression analysis, both UMSARS Part I (ß= 1.185, p = 0.013) and Part II (ß= 1.266, p = 0.021) scores were significantly associated with the sudomotor sub-score. On 18F-FDG-PET/CT, the abnormal QSART group exhibited more severely decreased metabolic activity in the cerebellum and basal ganglia in patients with MSA-P and MSA-C, respectively. The sudomotor sub-score was significantly associated with regional metabolism in these areas. CONCLUSION: Patients with MSA and postganglionic sudomotor dysfunction may have worse disease severity and greater neuropathological burden than those without.

[Cardiac sympathetic innervation imaging with myocardial MIBG scintigraphy]. / Studio dell'innervazione cardiaca mediante scintigrafia miocardica con MIBG.

Metaiodobenzylguanidine (MIBG) was developed initially as a tracer for oncological imaging; when labeled with 123 I or 131 I, it may detect APUDomas, such as pheochromocytomas and paragangliomas. In the last years, MIBG has found an important role also in neurology and cardiology, as cardiac innervation tracer. Actually, MIBG cardiac imaging is a universally accepted method to estimate cardiac sympathetic innervations. This review covers the role of MIBG cardiac imaging in Parkinson disease and parkinsonisms, from the pathophysiological premises for cardiac denervation to new emerging data.

Imaging of carotid canal sympathetic plexus schwannoma.

One case report of a schwannoma involving the sympathetic plexus in the carotid canal has been reported previously. This article presents 2 additional cases of this rare entity with associated clinical and unique radiographic findings. All patients presented with diplopia among other symptoms, and they had enhancing masses that smoothly expanded the carotid canal on cross-sectional imaging. Comparison with the index case and differential diagnosis of more common pathologies in this area are discussed.

Association of visual hallucinations with reduction of MIBG cardiac uptake in Parkinson's disease.

BACKGROUND: Postganglionic cardiac sympathetic denervation is evident in patients with Parkinson's disease (PD) and iodine-123 metaiodobenzylguanidine ((123)I-MIBG) cardiac scintigraphy has proven to be a useful tool for diagnosis of PD. OBJECTIVE: To elucidate the factors associated with severity of cardiac sympathetic nerve dysfunction in PD patients. METHODS: We investigated 95 PD patients hospitalized in the Department of Neurology at Tottori University Hospital. (123)I-MIBG cardiac scintigraphy was performed on each patient and the early and delayed heart to mediastinum (H/M) ratios and washout rate (WR) of (123)I-MIBG cardiac scintigraphy were calculated. Independent predictive variables for parameters of (123)I-MIBG cardiac scintigraphy were analyzed by multivariate regression analysis. RESULTS: Multivariate regression analysis revealed that the presence of visual hallucinations (VH) and the patient's age at the time of evaluation independently predicted the early or delayed H/M ratio. Analysis of covariance, adjusted for the age of the patients as covariates, revealed that the early and delayed H/M ratios of PD patients with VH but no dementia, as well as PD patients with dementia were significantly lower than the ratios in PD patients with no VH or dementia. CONCLUSION: Cardiac sympathetic dysfunction may be associated with the presence of VH in PD patients.

[123 I-MIBG myocardial sympathetic innervation scintigraphy and Parkinson's disease. Preliminary results]. / Gammagrafía miocárdica de inervación con 123 I-MIBG y enfermedad de Parkinson. Resultados preliminares.

OBJECTIVES: Cardiac sympathetic function in patients with Parkinson's disease (PD) is significantly impaired. Cardiac scintigraphy with 123I-metaiodobenzylguanidine (123I-MIBG) is used to assess cardiac sympathetic function. METHODS: A total of 29 consecutive patients with PD and 10 control subjects without neurological disease were studied. Myocardial imaging with 123I-MIBG was performed to evaluate cardiac sympathetic function. Early and delayed images of the anterior view were obtained at 15 min. and 4 h. after injection of 123I-MIBG, respectively. 123I-MIBG uptake was quantified qualitatively and semiquantitatively by calculating a heart-to-mediastinum (H/M) ratio. RESULTS: The heart/mediastinum ratio was markedly reduced in patients with PD (I to IV on the Hoehn and Yahr scale) when compared to the control subjects (p < 0.05). This finding was independent of the length and severity of the disease or the pharmacological treatment of the patients. None of the control subjects showed decrease in myocardial 123I-MIBG uptake. CONCLUSIONS: Our findings indicate that a decrease in myocardial accumulation of 123I-MIBG was observed in the early stages of PD. This suggests that the measurement of 123I-MIBG may help the early diagnosis of PD, and can be used to detect cardiac autonomic dysfunction, especially in patients without typical signs and symptoms.

Differentiation of Parkinson's disease and multiple system atrophy in early disease stages by means of I-123-MIBG-SPECT.

BACKGROUND: Differential diagnosis between idiopathic Parkinson's disease (PD) and multiple system atrophy (MSA) is often difficult in early disease stages. Since MSA is misdiagnosed as PD in more than 20% of the early stages, there is need for methods refining the differentiation of the two disease entities. In PD postganglionic involvement of the autonomic nervous system (ANS) predominates whereas in MSA the ANS is mainly affected in its preganglionic structures. The functional integrity of postganglionic cardiac sympathetic neurons can be investigated using I-123-metaiodobenzylguanidine-single photon emission computed tomography (MIBG-SPECT). OBJECTIVES: We investigated whether I-123-MIBG-SPECT allows to differentiate between early stages of PD and MSA in patients not yet requiring L-dopa therapy. METHODS: Thirty patients (10 PD and 20 MSA patients) underwent MIBG-SPECT and evaluation of heart rate variability (HRV). Patients on any medication interfering with MIBG-accumulation were excluded from the study. Cardiac perfusion was evaluated by myocardial scintigraphy. RESULTS: The median cardiac MIBG uptake was significantly decreased in PD as well as MSA patients compared to controls (P<0.001). However, in the PD group MIBG uptake was significantly lower than in MSA (P=0.03). Even in PD patients without clinical signs of autonomic failure, MIBG uptake was significantly lower than in MSA patients (P=0.03). Analysis of heart rate parameters did not differentiate between PD and MSA patients. The median coefficient of variation was significantly smaller in PD and MSA patients compared to control subjects. CONCLUSIONS: Our study shows that MIBG-SPECT identifies autonomic cardiac dysfunction in very early stages of both, PD and MSA. More importantly, the technique facilitates differentiation of MSA and PD in the early stages. The different pathology with prominent peripheral, postganglionic sympathetic dysfunction in PD and primarily central and preganglionic lesions in MSA accounts for a lower MIBG uptake in PD compared to MSA patients.

[Markedly decreased cardiac uptake with 123I-MIBG scintigraphy in a case of pure progressive autonomic failure].

A 70-year-old man with about 25 years' history of autonomic nervous system disturbances including orthostatic hypotension is presented. He had had no extrapyramidal and cerebellar signs, and was diagnosed as having pure progressive autonomic failure. His cardiac imaging with 123I labeled MIBG (metaiodobenzylguanidine) showed extremely diminished uptake, but the imaging with 201-thallium showed a normal cardiac uptake. Those results indicate non-cardiac disease-associated (neurogenic) postganglionic sympathetic fiber abnormality innervating the heart. Also, adrenomedullary imaging with 123I labeled MIBG showed no adrenal image, which suggests the possibility that there should be dysfunction in the adrenal medulla of this patient. This imaging study is thought to be useful for evaluating autonomic nervous system function in neurologic diseases.