Ruoh-Fang Yen

Network modulation by the subthalamic nucleus in the treatment of Parkinson's disease.

Deep brain stimulation of the subthalamic nucleus (STN DBS) has become an accepted tool for the treatment of Parkinsons disease (PD). Although the precise mechanism of action of this intervention is unknown, its effectiveness has been attributed to the modulation of pathological network activity. We examined this notion using positron emission tomography (PET) to quantify stimulation-induced changes in the expression of a PD-related covariance pattern (PDRP) of regional metabolism. These metabolic changes were also compared with those observed in a similar cohort of patients undergoing STN lesioning. We found that PDRP activity declined significantly (P < 0.02) with STN stimulation. The degree of network modulation with DBS did not differ from that measured following lesioning (P = 0.58). Statistical parametric mapping (SPM) revealed that metabolic reductions in the internal globus pallidus (GPi) and caudal midbrain were common to both STN interventions (P < 0.01), although declines in GPi were more pronounced with lesion. By contrast, elevations in posterior parietal metabolism were common to the two procedures, albeit more pronounced with stimulation. These findings indicate that suppression of abnormal network activity is a feature of both STN stimulation and lesioning. Nonetheless, these two interventions may differ metabolically at a regional level.

Detection of recurrent or persistent nasopharyngeal carcinomas after radiotherapy with 18-fluoro-2-deoxyglucose positron emission tomography and comparison with computed tomography.

PURPOSE The effectiveness of positron emission tomography (PET) with 1 8-fluoro-2-deoxyglucose (FDG) for detecting suspected recurrence of nasopharyngeal carcinomas (NPC) was evaluated and compared with computed tomography (CT). PATIENTS AND METHODS FDG-PET studies were performed on 36 NPC patients 4 months after radiotherapy. The images were interpreted visually and quantitatively by calculating standardized uptake values (SUVs). RESULTS The sensitivity, specificity, and accuracy of visually interpreted FDG-PET images, for differentiation of recurrent or persistent NPC from benign lesions, were 100%, 96%, and 97%, respectively. Cases with recurrent or persistent NPC (1.6 to 5.8) had significantly higher SUVs than cases with benign lesions (0.8 to 1.5). The sensitivity, specificity, and accuracy of CT for detecting recurrent or persistent NPC were 72%, 88%, and 83%, respectively. CONCLUSION FDG-PET is a better tool than CT for the detection of recurrent or persistent NPC. Either visual interpretation or SUV can be used to differentiate benign lesions from recurrent or persistent NPC.

Metabolic changes following subthalamotomy for advanced Parkinson's disease.

We studied 6 advanced‐stage Parkinsons disease patients with [18F] fluorodeoxyglucose/positron emission tomography before and 3 months after unilateral ablation of the subthalamic nucleus performed with microelectrode mapping. Operative changes in glucose metabolism were assessed by comparing baseline and postoperative scans. We also quantified operative changes in the activity of an abnormal Parkinsons disease‐related metabolic network that we had identified in previous [18F] fluorodeoxyglucose/positron emission tomography studies. Following unilateral subthalamic nucleus ablation, a highly significant reduction in glucose utilization was present in the midbrain ipsilateral to the lesion site, most pronounced in the vicinity of the substantia nigra pars reticularis. Significant metabolic reductions were also present in the ipsilateral internal globus pallidus, ventral thalamus, and pons. Operative changes in Parkinsons disease network activity differed significantly for the lesioned and unlesioned hemispheres. In the lesioned hemisphere, network activity declined significantly following surgery, but was unaltered in the contralateral, unlesioned hemisphere. These results suggest that subthalamotomy reduces basal ganglia output through internal globus pallidus/substantia nigra pars reticularis and also influences downstream neural activity in the pons and ventral thalamus. This procedure also reduces the activity of abnormal Parkinsons disease‐related metabolic brain networks, suggesting a widespread modulation of motor circuitry.

131I-6β-Iodomethyl-19-Norcholesterol SPECT/CT for Primary Aldosteronism Patients with Inconclusive Adrenal Venous Sampling and CT Results

The 2 main causes of primary aldosteronism (PA) are aldosterone-producing adenoma (APA) and idiopathic adrenal hyperplasia (IAH). Dexamethasone-suppression 131I-6β-iodomethyl-19-norcholesterol (NP-59) adrenal scintigraphy can assess the functioning of the adrenal cortex. This study evaluated the diagnostic usefulness of NP-59 SPECT/CT in differentiating APA from IAH and in predicting postadrenalectomy clinical outcome for PA patients who had inconclusive adrenal venous sampling (AVS) and CT results. Methods: We retrospectively reviewed the 31 adrenal lesions of 27 patients (age range, 33–71 y; mean age ± SD, 50.4 ± 10.9 y) who had been clinically confirmed (by saline infusion and captopril tests) to have PA, had inconclusive CT and AVS test results, and had undergone NP-59 imaging before adrenalectomy. The accuracy of NP-59 imaging was determined by comparison with histopathologic findings. Results: NP-59 SPECT/CT gave us 18 true-positive, 3 false-positive, 6 true-negative, and 4 false-negative results. Compared with planar imaging, SPECT/CT significantly improved diagnostic accuracy and prognostic predicting ability (P = 0.0390 and P = 0.0141, respectively). The NP-59 results were negative for 7 of the 23 patients with unilateral adrenal lesions, and none of these 7 patients had shown postsurgical clinical improvement. Conclusion: NP-59 SPECT/CT is an effective imaging tool for differentiating APA from IAH in PA patients whose CT and AVS results are inconclusive. Our results suggest that patients with presurgically negative NP-59 results should be treated medically and that noninvasive NP-59 SPECT/CT may be suited for use as the first lateralization modality after CT in patients with clinically confirmed PA.

Association of Kidney Function With Residual Hypertension After Treatment of Aldosterone-Producing Adenoma

BACKGROUND Autonomous secretion of aldosterone in patients with primary aldosteronism increases glomerular filtration rate and causes kidney damage. The influence of a mild decrease in kidney function on residual hypertension after adrenalectomy is unexplored. STUDY DESIGN Nonconcurrent prospective study. SETTING & PARTICIPANTS The study was based on the Taiwan Primary Aldosteronism Investigation (TAIPAI) database. 150 patients (61 men; overall mean age, 47.2 +/- 11.6 years) with a diagnosis of aldosterone-producing adenoma had undergone unilateral adrenalectomy at National Taiwan University Hospital from July 1999 to January 2007. PREDICTOR Presurgery estimated glomerular filtration rate (eGFR). OUTCOMES & MEASUREMENTS Residual hypertension after adrenalectomy, defined either as less than 75% of recorded blood pressure measurements with systolic blood pressure less than 140 mm Hg and diastolic blood pressure less than 90 mm Hg or requiring antihypertensive medications during the first year after surgery. RESULTS Before surgery, 27 (18%), 72 (48%), and 51 (34%) patients had moderately to severely decreased (<60 mL/min/1.73 m(2)), mildly decreased (60 <or= eGFR < 90 mL/min/1.73 m(2)), or nondecreased eGFR (>or=90 mL/min/1.73 m(2)), respectively. After surgery, 16 (59.3%), 29 (40.3%), and 10 (19.3%) patients in each category had postsurgery residual hypertension. Compared with patients without decreased eGFR before surgery, adjusted odds ratios for postsurgery residual hypertension were 2.7 (95% confidence interval, 1.03 to 7.0; P = 0.04) and 2.8 (95% confidence interval, 1.05 to 9.3) for mildly and moderately to severely decreased eGFR, respectively. LIMITATIONS Arbitrary definition for residual hypertension. CONCLUSIONS Two-thirds of patients with aldosterone-producing adenoma were cured of hypertension by means of unilateral adrenalectomy. Kidney function impairment, even mild, appears to be associated with a high incidence of postsurgery residual hypertension.

Lack of independent relationship between plasma adiponectin, leptin levels and bone density in nondiabetic female adolescents

objectives  Adiponectin has been implicated in the pathophysiology of metabolic syndrome and coronary artery disease in humans. Whether adiponectin is related to bone mineralization remains unclear in adults as well as in adolescents. In this study, we aimed to determine the relationship between plasma adiponectin, leptin concentrations and bone density, including total‐body bone mineral density (BMD) and bone mineral content (BMC) in adolescence.

Kidney impairment in primary aldosteronism

BACKGROUND Kidney impairment is noted in primary aldosteronism (PA), and probably initiated by glomerular hyperfiltration. METHODS A prospectively defined survey was conducted on 602 patients who were suspected of PA in the multiple-center Taiwan Primary Aldosteronism Investigation (TAIPAI) database. Estimated glomerular filtration rate (eGFR) was calculated and followed up at 1 yr after treatment. RESULTS The diagnosis of PA was confirmed in 330 patients. Among them 17% of these patients had kidney impairment (eGFR<60 ml/min/1.73 m²). Patients with PA had a higher prevalence of estimated hyperfiltration than those with essential hypertension (EH) (14.5% vs. 7.0%, p=0.005). The eGFR independently predicted PA (OR, 1.017) in the propensity-adjusted multivariate logistic model. In PA, plasma renin activity and lower serum potassium (p=0.018) was correlated with kidney impairment (p=0.001), while this relationship was not significant in patients with EH. Either unilateral adrenalectomy or treatment of spironolactone for PA patients caused a decrease of eGFR (p<0.001). Pre-operative hypokalemia (p=0.013) and the long latency of hypertension (p=0.016) could enhance the significant decrease of eGFR after adrenalectomy. CONCLUSIONS Patients with aldosteronism had relative estimated hyperfiltration than patients with EH. Calculation of eGFR may increase the specificity in identifying patients with PA. Our findings demonstrate the correlation of serum potassium and renin with estimated hyperfiltration in PA and their relationship to kidney damage. These results provide a high priority for future renal protective strategies and methods for the early diagnosis and prompt treatment of PA.

Using 18-fluoro-2-deoxyglucose positron emission tomography in detecting infectious endocarditis/endoarteritis : a preliminary report

RATIONALE AND OBJECTIVES We evaluated the effectiveness of positron emission tomography (PET) with 18-fluoro-2-deoxyglucose (FDG) in the detection of infectious endocarditis/endoarteritis. MATERIALS AND METHODS For this study, we recruited 6 patients (4 women, 2 men; age range, 35 - 78 years; mean age, 55.8 +/- 16.8 years) who were clinically diagnosed as having infective endocarditis/endoarteritis by their echocardiographic findings and by Duke criteria. RESULTS For all 6 patients, we also found increased FDG uptakes in the corresponding areas detected in echocardiography. CONCLUSION FDG-PET appears to be a promising tool in diagnosing infective endocarditis/endoarteritis, and further prospective studies on a large scale to fully exploit the usefulness of FDG-PET for infective endocarditis/endoarteritis are needed.

Treatment of advanced Parkinson's disease by subthalamotomy: One‐year results

We studied effects on parkinsonian features at 6 and 12 months in 12 patients who underwent unilateral ablation of subthalamic nucleus (STN). Microelectrode mapping was used, and a lesion was created in the STN using thermal coagulation and confirmed with magnetic resonance imaging. At 6 months postoperatively, improvements were seen in several areas: 1) Unified Parkinsons Disease Rating Scales II and III (UPDRS II and III) scores, 30% in off period, 38% in on period; 2) Schwab and England Scale (S&E) score, 21%; and 3) on dyskinesia, 85%. Contralateral rigidity, bradykinesia, UPDRS II and III scores, and S&E scores remained improved at 12 months. Daily dosage of levodopa requirement was reduced by 42%. Axial motor features, gait, postural stability, off period tremor, and motor fluctuation improved at 6 and 12 months but showed a decline in benefits at 18 months. Complications include 3 cases of hemiballism, of whom 2 patients recovered spontaneously but 1 died from aspiration pneumonia. One patient had asymptomatic hematoma, and 2 suffered transient postural asymmetries. We conclude that unilateral subthalamotomy results in moderate improvement in all aspects of parkinsonian features, allows reduction in the dose of levodopa required, and ameliorates drug‐induced complications throughout 12‐month assessments.

The diagnostic and prognostic effectiveness of F-18 sodium fluoride PET-CT in detecting bone metastases for hepatocellular carcinoma patients.

BackgroundThe aim of this prospective study is to evaluate the diagnostic and prognostic usefulness of F-18 sodium fluoride (NaF) positron emission tomography-computed tomography (PET-CT) relative to Tc-99m methylene diphosphonate (MDP) planar bone scintigraphy with no CT (BS) for hepatocellular carcinoma (HCC) patients with suspicious bone metastasis. MethodsBoth Tc-99m MDP BS and F-18 NaF PET-CT were performed for 34 consecutive Taiwanese HCC patients (five female and 29 male; mean age, 61.0±12.0 years) within a time span of 1 month (mean: 11.3±10.4 days). The accuracies of BS and PET-CT were determined by comparing their results with the finalized clinical data in a lesion-by-lesion manner. ResultsAccording to the pathological and/or follow-up results, the accuracy for detecting metastatic bone lesions by Tc-99m MDP BS is 75.4% and that by F-18 NaF PET-CT is 95.7%, respectively. F-18 NaF PET-CT is significantly more accurate than Tc-99m MDP BS (P=0.0001). Furthermore, there is a significant correlation between the presence of F-18 NaF PET-CT-positive bone lesions and the survival time of HCC patients. On the other hand, the diagnostic results from BS are not correlated with the survival time of these HCC patients. ConclusionF-18 NaF using PET-CT system has significantly better sensitivity and specificity than conventional Tc-99m MDP BS in detecting metastatic HCC bone lesions that are predominantly osteolytic. The diagnostic result of PET-CT also serves as a more effective prognostic indictor for HCC patients.