PubMed · 15617359
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Helen Philips. 2004-10-14. Brainstorming.. https://pubmed.ncbi.nlm.nih.gov/15617359/
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Currently, images acquired via magnetic resonance imaging (MRI) and functional magnetic resonance imaging (fMRI) technology are reconstructed using the discrete inverse Fourier transform. While computationally convenient, this approach is not able to filter out noise. This is a serious limitation because the amount of noise in MRI and fMRI can be substantial. In this paper, we propose an alternative approach to reconstruction, based on penalized likelihood methodology. In particular, we focus on non-linear shrinkage estimators and show that this approach achieves a great reduction in integrated mean squared error (IMSE) of the estimated image with respect to the currently used estimator. This approach is extremely fast and easy to implement computationally. In addition, it can be combined with various alternative approaches to MR image reconstruction and can be easily adapted to other, non-MRI contexts, in which the observed data and the quantities of interest are related via a linear transform.
Reported are three adults who developed frequent episodes of a complex neurologic syndrome years after radiation therapy for a brain tumor. MRI and [(18)F]fluorodeoxyglucose PET performed during the episodes demonstrated dramatic gyral thickening with enhancement and intense hypermetabolism in symptomatic regions that resolved on follow-up studies. EEG during episodes showed only slowing. The differential diagnosis and imaging findings are reviewed.
BACKGROUND: Previous studies comparing children with cardiac disease with children with lung disease or healthy children indicated that natriuretic peptides are promising markers in pediatric patients. The aim of this study was to further clarify the diagnostic usefulness of N-terminal pro-B-type natriuretic peptide (NT-proBNP) measurements in a less preselected population of children younger than 3 years, a population in which clinical symptoms are frequently unspecific. METHODS: NT-proBNP concentrations (Roche Diagnostics) were measured in sera of 142 pediatric patients (age range, 33-1070 days) presenting at the Gynaecologic and Pediatric Hospital (Linz, Austria) between January 2003 and January 2004. ROC curve analysis for the diagnostic performance of NT-proBNP, the Mann-Whitney U-test for group comparison, and linear regression analysis for influencing factors were performed. RESULTS: NT-proBNP concentrations were significantly increased in infants with cardiac diseases [median (25th-75th percentile), 3681 (1045-13557) ng/L; n = 23] compared with infants with other diseases [241 (116-542) ng/L; n = 119], and ROC analysis revealed good performance for NT-proBNP in differentiating between infants with and without cardiac diseases [mean area under the curve (AUC) with 95% confidence interval (CI), 0.87 (0.76-0.94)]. A subgroup analysis of exactly age- and sex-matched infants was performed, which revealed results comparable to those for the whole study population [mean (95% CI) AUC, 0.84 (0.68-0.93)]. CONCLUSION: In a heterogeneous group of pediatric patients < 3 years of age, NT-proBNP showed good diagnostic performance to distinguish between cardiac diseases and various noncardiac diseases.