Comparison of Count Normalization Methods for Statistical Parametric Mapping Analysis Using a Digital Brain Phantom Obtained from Fluorodeoxyglucose-positron Emission Tomography

Objective(s): Alternative normalization methods were proposed to solve the biased information of SPM in the study of neurodegenerative disease. The objective of this study was to determine the most suitable count normalization method for SPM analysis of a neurodegenerative disease based on the results of different count normalization methods applied on a prepared digital phantom similar to one obtained using fluorodeoxyglucose-positron emission tomography (FDG-PET) data of a brain with a known neurodegenerative condition.Methods: Digital brain phantoms, mimicking mild and intermediate neurodegenerative disease conditions, were prepared from the FDG-PET data of 11 healthy subjects. SPM analysis was performed on these simulations using different count normalization methods. Results: In the slight-decrease phantom simulation, the Yakushev method correctly visualized wider areas of slightly decreased metabolism with the smallest artifacts of increased metabolism. Other count normalization methods were unable to identify this slightly decreases and produced more artifacts. The intermediate-decreased areas were well visualized by all methods. The areas surrounding the grey matter with the slight decreases were not visualized withthe GM and VOI count normalization methods but with the Andersson. The Yakushev method well visualized these areas. Artifacts were present in all methods. When the number of reference area extraction was increased, the Andersson method better-captured the areas with decreased metabolism and reduced the artifacts of increased metabolism. In the Yakushev method, increasing the threshold for the reference area extraction reduced such artifacts.Conclusion: The Yakushev method is the most suitable count normalization method for the SPM analysis of neurodegenerative disease

Dose Reduction and Image Quality Optimization of Pediatric Chest Radiography Using a Tungsten Filter

The use of diagnostic radiology in pediatric patients has increased, and various positive effects have been reported, including methods to reduce radiation doses in children. Research has been conducted to preserve image quality while reducing exposure and doses in pediatric patients. This study aimed to measure four different filters to identify an optimized filter for pediatric patients. The experiment was conducted using four types of filters, including aluminum, copper, molybdenum, and tungsten. The optimal filter thickness was verified using a histogram to visually evaluate the spectrum by filter thickness, effective dose on a pediatric phantom, entrance skin dose, organ absorbed dose using the PC-based Monte Carlo (PCXMC) program version 2.0 simulation, figure of merit (FOM), and image quality. As a result of measuring the spectrum according to the tube voltage and the four types of filters, dose reduction and contrast improvement effects were obtained with a 0.05 mm tungsten filter. Additionally, effective entrance skin and organ absorbed dose decreased with the said filter. The aluminum, copper, and molybdenum filters demonstrated that the effective dose scarcely decreased even when the thickness was increased; meanwhile, the effective dose decreased when the tungsten filter was 0.05 mm. The FOM with a 0.05 mm tungsten increased by 91% in the lung field and 39% in the mediastinal field. The entrance skin and organ absorbed dose in pediatric patients can be reduced by removing low-energy photons that fail in image formation using a tungsten filter

Common and distinct clinical features in adult patients with anti-aminoacyl-tRNA synthetase antibodies: heterogeneity within the syndrome.

OBJECTIVE: To identify similarities and differences in the clinical features of adult Japanese patients with individual anti-aminoacyl-tRNA synthetase antibodies (anti-ARS Abs). METHODS: This was a retrospective analysis of 166 adult Japanese patients with anti-ARS Abs detected by immunoprecipitation assays. These patients had visited Kanazawa University Hospital or collaborating medical centers from 2003 to 2009. RESULTS: Anti-ARS Ab specificity included anti-Jo-1 (36%), anti-EJ (23%), anti-PL-7 (18%), anti-PL-12 (11%), anti-KS (8%), and anti-OJ (5%). These anti-ARS Abs were mutually exclusive, except for one serum Ab that had both anti-PL-7 and PL-12 reactivity. Myositis was closely associated with anti-Jo-1, anti-EJ, and anti-PL-7, while interstitial lung disease (ILD) was correlated with all 6 anti-ARS Abs. Dermatomyositis (DM)-specific skin manifestations (heliotrope rash and Gottron's sign) were frequently observed in patients with anti-Jo-1, anti-EJ, anti-PL-7, and anti-PL-12. Therefore, most clinical diagnoses were polymyositis or DM for anti-Jo-1, anti-EJ, and anti-PL-7; clinically amyopathic DM or ILD for anti-PL-12; and ILD for anti-KS and anti-OJ. Patients with anti-Jo-1, anti-EJ, and anti-PL-7 developed myositis later if they had ILD alone at the time of disease onset, and most patients with anti-ARS Abs eventually developed ILD if they did not have ILD at disease onset. CONCLUSION: Patients with anti-ARS Abs are relatively homogeneous. However, the distribution and timing of myositis, ILD, and rashes differ among patients with individual anti-ARS Abs. Thus, identification of individual anti-ARS Abs is beneficial to define this rather homogeneous subset and to predict clinical outcomes within the "anti-synthetase syndrome.

Common and Distinct Clinical Features in Adult Patients with Anti-Aminoacyl-tRNA Synthetase Antibodies: Heterogeneity within the Syndrome

Objective: To identify similarities and differences in the clinical features of adult Japanese patients with individual anti-aminoacyl-tRNA synthetase antibodies (anti-ARS Abs). Methods: This was a retrospective analysis of 166 adult Japanese patients with anti-ARS Abs detected by immunoprecipitation assays. These patients had visited Kanazawa University Hospital or collaborating medical centers from 2003 to 2009. Results: Anti-ARS Ab specificity included anti-Jo-1 (36%), anti-EJ (23%), anti-PL-7 (18%), anti-PL-12 (11%), anti-KS (8%), and anti-OJ (5%). These anti-ARS Abs were mutually exclusive, except for one serum Ab that had both anti-PL-7 and PL-12 reactivity. Myositis was closely associated with anti-Jo-1, anti-EJ, and anti-PL-7, while interstitial lung disease (ILD) was correlated with all 6 anti-ARS Abs. Dermatomyositis (DM)-specific skin manifestations (heliotrope rash and Gottron\u27s sign) were frequently observed in patients with anti-Jo-1, anti-EJ, anti-PL-7, and anti-PL-12. Therefore, most clinical diagnoses were polymyositis or DM for anti-Jo-1, anti-EJ, and anti-PL-7; clinically amyopathic DM or ILD for anti-PL-12; and ILD for anti-KS and anti-OJ. Patients with anti-Jo-1, anti-EJ, and anti-PL-7 developed myositis later if they had ILD alone at the time of disease onset, and most patients with anti-ARS Abs eventually developed ILD if they did not have ILD at disease onset. Conclusion: Patients with anti-ARS Abs are relatively homogeneous. However, the distribution and timing of myositis, ILD, and rashes differ among patients with individual anti-ARS Abs. Thus, identification of individual anti-ARS Abs is beneficial to define this rather homogeneous subset and to predict clinical outcomes within the "anti-synthetase syndrome."

Comparison of clinical features in 165 adult Japanese patients with anti-aminoacyl-tRNA synthetase antibodies.^*

*<p>Unless noted otherwise, values are percentages of patients. NS: not significant; CK: creatine kinase; LDH: lactate dehydrogenase. One patient with DM who had antibodies reactive to both PL-7 and PL-12 was excluded from the analysis. Significant differences (overall <i>P</i><0.05) were further analyzed by pairwise comparisons.</p>a<p><i>P</i><0.05 between anti-PL-7 and anti-PL-12; <i>P</i><0.01 between anti-Jo-1 and anti-PL-12, and between anti-KS and anti-Jo-1 or anti-PL-7;</p>b<p><i>P</i><0.05 between anti-Jo-1 and anti-PL-7 or anti-PL-12, and between anti-EJ and anti-PL-7; <i>P</i><0.01 between anti-EJ and anti-PL-12.</p>c<p><i>P</i><0.05 between anti-EJ and anti-PL-12; <i>P</i><0.01 between anti-Jo-1 and anti-PL-12, anti-KS or anti-OJ, between anti-EJ and anti-KS, and between anti-PL-7 and anti-PL-12, anti-KS or anti-OJ.</p>d<p><i>P</i><0.05 between anti-Jo-1 and anti-PL-7, anti-KS or anti-OJ; <i>P</i><0.01 between anti-Jo-1 and anti-EJ or anti-PL-12.</p>e<p><i>P</i><0.05 between anti-Jo-1 and anti-EJ; <i>P</i><0.01 between anti-PL-7 and anti-Jo-1 or anti-KS.</p>f<p><i>P</i><0.05 between anti-KS and anti-EJ or anti-PL-12; <i>P</i><0.01 between anti-PL-7 and anti-KS.</p>g<p><i>P</i><0.05 between anti-Jo-1 and anti-PL-12 or anti-KS; <i>P</i><0.01 between anti-Jo-1 and anti-EJ.</p>h<p><i>P</i><0.05 between anti-EJ and anti-PL-12 or anti-KS; <i>P</i><0.01 between anti-Jo-1 and anti-PL-12 or anti-KS, and between anti-PL-7 and anti-PL-12 or anti-KS.</p>i<p><i>P</i><0.05 between anti-PL-7 and anti-PL-12; <i>P</i><0.01 between anti-Jo-1 and anti-PL-12, and between anti-KS and anti-Jo-1, anti-EJ or anti-PL-7.</p

Enrollment and selection of patients.

<p>DM; dermatomyositis, PM; polymyositis, SSc; systemic sclerosis, ILD; interstitial lung disease, SLE; systemic lupus erythematosus, MCTD; mixed connective tissue disease, Sjogren; Sjogren’s syndrome, RA; rheumatoid arthritis.</p

Cause of death in patients with anti-aminoacyl-tRNA synthetase antibodies.

<p>ILD: interstitial lung disease; DM: dermatomyositis; PM: polymyositis; SSc: systemic sclerosis.</p

Initial manifestations in patients with anti-aminoacyl-tRNA synthetase antibodies.^*

*<p>Values are percentages of patients.</p>**<p>These patients had polyarthritis at presentation. Significant differences (overall <i>P</i><0.05) were further analyzed by pairwise comparisons.</p>a<p><i>P</i><0.05 between anti-PL-12 and anti-Jo-1 or anti-KS; <i>P</i><0.01 between anti-KS and anti-Jo-1, anti-EJ or anti-PL-7.</p

The clinical course of anti-synthetase syndrome patients who developed myositis or interstitial lung disease (ILD) with or without skin manifestations at disease onset.

<p>According to the clinical course, patients were classified into four types: remained with ILD alone, developed myositis during follow-up, developed ILD during follow-up, and remained with myositis alone. The clinical course of those who had ILD with or without skin manifestations, but without muscle involvement at their first assessment (A), and the clinical course of those who had myositis with or without skin manifestations, but without ILD at their first assessment (B).</p