Yong-An Chung

Effect of Chronic Deep Brain Stimulation of the Subthalamic Nucleus for Frontal Lobe Epilepsy: Subtraction SPECT Analysis

Objectives: Experimental data and case reports of patients with intractable epilepsy treated with deep brain stimulation (DBS) of the subthalamic nucleus (STN) suggest a considerable anticonvulsant effect. However, no satisfactory mechanisms of action have yet been elucidated. We investigated the putative therapeutic mechanisms of DBS from cerebral perfusion changes as measured by subtracting the SPECT image of the pre-DBS period from that of the chronic post-DBS state. Methods: Two patients who had previous resective surgery on their right frontal cortices with or without anterior callosotomy were selected for DBS of the STN. Both of them showed frequent bilateral asymmetric tonic seizures (left > right) with rare drop attacks, and 1 patient’s seizure frequency was more than 15/month during the pre-DBS period. They had both taken more than four antiepileptic agents for more than 10 years. After video-EEG monitoring, the irritative zones of the brain were delineated. The regional cerebral blood flow (rCBF) changes between the two SPECT images (pre-DBS and post-DBS after at least 6 months) were analyzed by SPECT subtraction with the volumetric MRI coregistration method using Analyze 5.0 software. Results: After chronic STN DBS (18 months, case 1; 6 months, case 2), both patients experienced markedly reduced seizure frequencies (86.7% reduction in patient 1, 88.6% in patient 2). In patient 1, the increased rCBF was observed in the right frontal areas (dorsolateral and inferior frontal area), which corresponded to the irritative zones as confirmed by previous EEG recording. Unexpectedly, there was definite hyperperfusion in the right superior and inferior temporal areas as well as rCBF increase in the right superior frontal area (SMA) in patient 2. Conclusions: We demonstrated that the cerebral perfusion increase in the irritative zones of epilepsy patients is associated with favorable seizure reduction after STN DBS in 2 cases of frontal lobe epilepsy. Although the exact mechanism remains unknown, our findings suggest that the perfusion changes after STN DBS in frontal lobe epilepsy patients are quite different from those in subjects with Parkinson’s disease. Our preliminary data suggest the clinical relevance of subtraction SPECT imaging in assessing the postprocedural outcome as well as the characteristics of SPECT perfusion patterns in other epilepsy syndromes.

Cardiac [123I]metaiodobenzylguanidine scintigraphy for vascular Parkinsonism

The purpose of our study was to prospectively evaluate cardiac [123I]metaiodobenzylguanidine (MIBG) uptake in patients with cerebrovascular disease (CVD) who develop clinical symptoms of vascular Parkinsonism (VP). A total of 19 consecutive patients who developed Parkinsonism during the course of their CVD were enrolled in the study; 16 age‐matched subjects, and 30 patients with Parkinsons disease (PD) were also evaluated with cardiac MIBG uptake. MIBG uptake was assessed using the ratio of the heart to the upper mediastinum (H/M) according to planar scintigraphic data. The mean H/M ratio was significantly higher in patients with VP than in those with PD (2.28 ± 0.41 vs. 1.27 ± 0.13; P < 0.001). MIBG uptake did not differ between VP and controls (2.46 ± 0.33; P > 0.05). Our findings suggest that myocardial postganglionic sympathetic dysfunction found in PD is absent in most patients with VP. MIBG single photon emission computed tomography imaging may be useful to help distinguish between PD and VP patients in clinical practice.

Combined use of 123I-metaiodobenzylguanidine (MIBG) scintigraphy and dopamine transporter (DAT) positron emission tomography (PET) predicts prognosis in drug-induced Parkinsonism (DIP): A 2-year follow-up study

DIP is a heterogeneous clinical syndrome; some patients develop persistent and worsening of parkinsonian symptoms after discontinuation of the offending drug, or Parkinsons disease (PD) reappears later after a full remission from DIP. However, it is difficult to predict the prognosis in patients with DIP. Herein, we evaluated whether the combined use of (18)F-N-(3-fluoropropyl)-2 beta-carbon ethoxy-3beta-(4-iodophenyl) nortropane (FP-CIT) PET and cardiac MIBG scintigraphy can be used to help distinguish the prognosis in patients with DIP. Among 20 patients enrolled, 16 showed normal DAT uptake and normal myocardial sympathetic innervation. After withdrawal of the suspected drugs, the patients experienced a clinical remission of parkinsonian motor symptoms within 3 months and did not experience any new movement symptoms after at least 2 years of follow-up. Two patients with a moderate decrease in DAT uptake and impaired sympathetic denervation showed worsening of motor manifestations 3 months after discontinuation of the drugs. Another two patients with normal DAT uptake and decreased MIBG uptake, presented full remission of motor symptoms within 2 months after discontinuation of the drugs. However, these two patients eventually developed parkinsonism within 2 years of the follow-up period. The follow-up scans revealed severe decreased DAT uptake in the putamen and similar ranges of cardiac sympathetic denervation. The results suggest that the combined use of these techniques can predict the prognosis of DIP and suggest a proper therapeutic plan for DIP.

Temporal Changes in Functional Magnetic Resonance Imaging Activation of Heterosexual Couples for Visual Stimuli of Loved Partners

Objective Previous neuroimaging studies on romantic love have focused on determining how the visual stimuli that serve as a representation of loved ones induce the neural activation patterns of romantic love. The purpose of this study was to investigate the temporal changes in romantic love over a period of 6 months and their correlated neurophysiological changes. Methods Five heterosexual couples (n=10, mean age 21.1±1.97) who started dating not less than 100 days previously were recruited to measure their blood oxygen level dependent (BOLD) signals using functional magnetic resonance imaging (fMRI) while showing them pictures of their loved ones and their previously identified, opposite-sex friends. Subsequently, the subjects were scanned under the same experimental conditions to assess possible changes in their brain activities after 180 days. Results We found that their Passionate Love Score (PLS) values (M: 118.6±9.1, F: 120.2±7.0) were significantly reduced after 6 months (M: 110.8±4.0, F: 106.2±3.0). Furthermore, significantly increased activations were found in the cingulate gyri, inferior frontal gyri, supramarginal gyri, etc., after 6 months, whereas the head and tail of the right caudate nucleus were deactivated, which is indicative of the inhibition of expression and sensory neglect. Conclusion These findings suggest that dynamic neural processes in the cortical-subcortical regions are involved in temporal changes in romantic love.

Decreased striatal dopamine transporter binding in a patient with extrapontine myelinolysis

We describe the case of a 61‐year‐old woman who developed extrapontine myelinolysis (EPM) with parkinsonism. Decreased striatal dopamine transporter binding assessed by [123I]N‐(3‐iodopropen‐2‐yl)‐2β‐carbomethoxy‐3β‐(4‐chlorophenyl) tropane and single photon emission computed tomography ([123I]IPT) SPECT) were observed in the patient, suggesting that osmotic injury causes the demyelination of nigrostriatal dopaminergic neurons and that such injury may be involved in the pathogenesis of EPM with parkinsonism.

Changes in cerebral blood flow after cognitive behavior therapy in patients with panic disorder: a SPECT study

Aim Inconsistent results continue to be reported in studies that examine the neural correlates of cognitive behavioral therapy (CBT) in patients with panic disorder. We examined the changes in regional cerebral blood flow (rCBF) associated with the alleviation of anxiety by CBT in panic patients. Methods The change in rCBF and clinical symptoms before and after CBT were assessed using single photon emission computed tomography and various clinical measures were analyzed. Results Fourteen subjects who completed CBT showed significant improvements in symptoms on clinical measures, including the Panic and Agoraphobic Scale and the Anxiety Sensitivity Index-Revised. After CBT, increased rCBF was detected in the left postcentral gyrus (BA 43), left precentral gyrus (BA 4), and left inferior frontal gyrus (BA 9 and BA 47), whereas decreased rCBF was detected in the left pons. Correlation analysis of the association between the changes in rCBF and changes in each clinical measure did not show significant results. Conclusion We found changes in the rCBF associated with the successful completion of CBT. The present findings may help clarify the effects of CBT on changes in brain activity in panic disorder.

Novel use of gamma correction for precise 99mTc-HDP pinhole bone scan diagnosis and classification of knee occult fractures

ObjectiveThe aim of this study was to introduce gamma correction pinhole bone scan (GCPBS) to depict specific signs of knee occult fractures (OF) on 99mTc-hydroxydiphosphonate (HDP) scan.Materials and MethodsThirty-six cases of six different types of knee OF in 27 consecutive patients (male = 20, female = 7, and age = 18–86xa0years) were enrolled. The diagnosis was made on the basis of a history of acute or subacute knee trauma, local pain, tenderness, cutaneous injury, negative conventional radiography, and positive magnetic resonance imaging (MRI). Because of the impracticability of histological verification of individual OF, MRI was utilized as a gold standard of diagnosis and classification. All patients had 99mTc-HDP bone scanning and supplementary GCPBS. GCPBS signs were correlated and compared with those of MRI. The efficacy of gamma correction of ordinary parallel collimator and pinhole collimator scans were collated.ResultsGamma correction pinhole bone scan depicted the signs characteristic of six different types of OF. They were well defined stuffed globular tracer uptake in geographic I fractures (nu2009=u20099), block-like uptake in geographic II fractures (nu2009=u20097), simple or branching linear uptake in linear cancellous fractures (nu2009=u20094), compression in impacted fractures (nu2009=u20092), stippled-serpentine uptake in reticular fractures (nu2009=u200911), and irregular subcortical uptake in osteochondral fractures (nu2009=u20093). All fractures were equally well or more distinctly depicted on GCPBS than on MRI except geographic II fracture, the details of which were not appreciated on GCPBS. Parallel collimator scan also yielded to gamma correction, but the results were inferior to those of the pinhole scan.ConclusionsGamma correction pinhole bone scan can depict the specific diagnostic signs in six different types of knee occult fractures. The specific diagnostic capability along with the lower cost and wider global availability of bone scanning would make GCPBS an effective alternative.

Orthostatic hypotension, non-dipping and striatal dopamine in Parkinson disease.

Orthostatic hypotension and non-dipping are relatively common autonomic dysfunctions in patients with Parkinson disease (PD). These abnormalities have been thought to occur independently of striatal dopaminergic depletion; however, only little preliminary information is available. In this study, we investigated the association of neurocirculatory changes with striatal dopamine transporter status in 69 patients with early PD. Seventeen patients had orthostatic hypotension and 55 patients were non-dippers. A comparison between cases with and without orthostatic hypotension was insignificant for striatal dopamine transporter uptake. These insignificances continued in a comparison of dippers and non-dippers. These results suggest that sympathetic noradrenergic dysfunctions in PD are independent of striatal dopamine transporter depletion.

No evidence of perfusion abnormalities in the basal ganglia of a patient with generalized chorea-ballism and polycythaemia vera: analysis using subtraction SPECT co-registered to MRI

Polycythaemia vera is a well-known cause of symptomatic chorea, however, the pathophysiology of this correlation remains unclear. We report on a patient with generalized chorea-ballism associated with polycythaemia vera, and we present the findings of 99mTc-hexamethylpropylene amine oxime (HMPAO) SPECT done in both the choreic state and the non-choreic state. The SPECT during both the choreic and the non-choreic states did not reveal any definite perfusion changes in specific regions of the brain, as compared with 6 age-matched controls. In addition, the subtraction SPECT co-registered to MRI (SISCOM) analysis did not show any difference in cerebral blood flow during the choreic and non-choreic states. This result suggests that the basic mechanism of chorea associated with polycythaemia vera does not appear to be associated with a reduction in cerebral perfusion to a specific cerebral area, such as the basal ganglia or its thalamocortical connections.

Assessment of cerebrovascular reserve before and after STA-MCA bypass surgery by SPECT and SPM analysis.

Objective The purpose of this study was to objectively assess the efficacy of superficial temporal artery to middle cerebral artery (STA-MCA) bypass surgery using Technetium (Tc)-99m-ethyl cysteinate dimer (ECD) single photon emission computed tomography (SPECT) in patients who underwent STA-MCA bypass surgery. Materials and Methods Brain perfusion SPECT images obtained at baseline and after the administration of acetazolamide were reconstructed using statistical parametric mapping in 23 patients, both before and after STA-MCA bypass surgery. The clinical outcomes of the surgery were also recorded and compared with the hemodynamic changes. A voxel with an uncorrected p-value of less than 0.001 was considered to be statistically significant. Results SPECT images of the territory supplied by the bypass graft showed an increase in both cerebrovascular flow and reserve at baseline, and the increase was significantly higher following the administration of acetazolamide. All patients showed improvement of clinical symptoms and increased blood flow to the left temporal, parietal, and frontal cortices as well as the thalamus. Conclusion Brain SPECT effectively and objectively demonstrated the improved outcomes of STA-MCA bypass surgery, and thus may be used in postoperative analyses.