Iterative 4D reconstruction of dynamic SPECT images

[Abstract] The 22nd International Congress and Exhibition, Barcelona, Spain, June 25-28, 2008The present work presents a new approach for the 4D reconstruction algorithm for dynamic SPECT in a parallel ray geometry based on B-splines including attenuation map from CT and geometry efficiency correction. In this work we make use of 4 piecewise piecewise quadratic temporal splines and a reconstruction algorithm based on the iterative maximization of Poisson likelihood. Results on a Tecnetium (99mTc-Teboroxime) canine study are shownPublicad

Statistical 4D reconstruction of dynamic CT images: preliminary results

[Poster] 4th European Molecular Imaging Meeting, Barcelona, Spain, May 27 - 30, 2009Preliminary results are presented of a 4d reconstruction algorithm for dynamic contrast enhanced CT, in a micro-CT based on cone beam geometry. The method is based on modelling the spatial and temporal distribution of the contrast inside the field of view. The use of non-uniform time sampling with b-splines yielded smooth time-activity curves that captured the relatively fast rise and fall of contrast in the aorta, as well as the uptake and retention of contrast in the kidneysThis work is supported by Ministerio de Ciencia e innovación (TeC2008-06715-C02-01 and TeC2007-64731/TCM), Ministerio de industria (CdTeaM, Programa CeniT), and the reCaVa-reTiC network.Publicad

Isolated bladder exstrophy associated with a de novo 0.9 Mb microduplication on chromosome 19p13.12.

The exstrophy-epispadias complex (BEEC) is a urogenital birth defect of varying severity. The causes of the BEEC are likely to be heterogeneous, with individual environmental or genetic risk factors still being largely unknown. In this study, we aimed to identify de novo causative copy number variations (CNVs) that contribute to the BEEC. METHODS Array-based molecular karyotyping was performed to screen 110 individuals with BEEC. Promising CNVs were tested for de novo occurrence by investigating parental DNAs. Genes located in regions of rearrangements were prioritized through expression analysis in mice to be sequenced in the complete cohort, to identify high-penetrance mutations involving small sequence changes. RESULTS A de novo 0.9 Mb microduplication involving chromosomal region 19p13.12 was identified in a single patient. This region harbors 20 validated RefSeq genes, and in situ hybridization data showed specific expression of the Wiz gene in regions surrounding the cloaca and the rectum between GD 9.5 and 13.5. Sanger sequencing of the complete cohort did not reveal any pathogenic alterations affecting the coding region of WIZ. CONCLUSIONS The present study suggests chromosomal region 19p13.12 as possibly involved in the development of CBE, but further studies are needed to prove a causal relation. The spatiotemporal expression patterns determined for the genes encompassed suggest a role for Wiz in the development of the phenotype. Our mutation screening, however, could not confirm that WIZ mutations are a frequent cause of CBE, although rare mutations might be detectable in larger patient samples

Bodyweight Perceptions among Texas Women: The Effects of Religion, Race/Ethnicity, and Citizenship Status

Despite previous work exploring linkages between religious participation and health, little research has looked at the role of religion in affecting bodyweight perceptions. Using the theoretical model developed by Levin et al. (Sociol Q 36(1):157–173, 1995) on the multidimensionality of religious participation, we develop several hypotheses and test them by using data from the 2004 Survey of Texas Adults. We estimate multinomial logistic regression models to determine the relative risk of women perceiving themselves as overweight. Results indicate that religious attendance lowers risk of women perceiving themselves as very overweight. Citizenship status was an important factor for Latinas, with noncitizens being less likely to see themselves as overweight. We also test interaction effects between religion and race. Religious attendance and prayer have a moderating effect among Latina non-citizens so that among these women, attendance and prayer intensify perceptions of feeling less overweight when compared to their white counterparts. Among African American women, the effect of increased church attendance leads to perceptions of being overweight. Prayer is also a correlate of overweight perceptions but only among African American women. We close with a discussion that highlights key implications from our findings, note study limitations, and several promising avenues for future research

Longitudinal Evaluation of Fatty Acid Metabolism in Normal and Spontaneously Hypertensive Rat Hearts with Dynamic MicroSPECT Imaging

The goal of this project is to develop radionuclide molecular imaging technologies using a clinical pinhole SPECT/CT scanner to quantify changes in cardiac metabolism using the spontaneously hypertensive rat (SHR) as a model of hypertensive-related pathophysiology. This paper quantitatively compares fatty acid metabolism in hearts of SHR and Wistar-Kyoto normal rats as a function of age and thereby tracks physiological changes associated with the onset and progression of heart failure in the SHR model. The fatty acid analog, 123I-labeled BMIPP, was used in longitudinal metabolic pinhole SPECT imaging studies performed every seven months for 21 months. The uniqueness of this project is the development of techniques for estimating the blood input function from projection data acquired by a slowly rotating camera that is imaging fast circulation and the quantification of the kinetics of 123I-BMIPP by fitting compartmental models to the blood and tissue time-activity curves

Murine expression and mutation analyses of the prostate androgen-regulated mucin-like protein 1 (Parm1) gene, a candidate for human epispadias.

Background Epispadias is the mildest phenotype of the human bladder exstrophy–epispadias complex (BEEC), and presents with varying degrees of severity. This urogenital birth defect results from a disturbance in the septation process, during which separate urogenital and anorectal components are formed through division of the cloaca. This process is reported to be influenced by androgen signaling. The human PARM1 gene encodes the prostate androgen-regulated mucin-like protein 1, which is expressed in heart, kidney, and placenta. Methods We performed whole mount in situ hybridization analysis of Parm1 expression in mouse embryos between gestational days (GD) 9.5 and 12.5, which are equivalent to human gestational weeks 4–6. Since the spatio-temporal localization of Parm1 corresponded to tissues which are affected in human epispadias, we sequenced PARM1 in 24 affected patients. Results We found Parm1 specifically expressed in the region of the developing cloaca, the umbilical cord, bladder anlage, and the urethral component of the genital tubercle. Additionally, Parm1 expression was detected in the muscle progenitor cells of the somites and head mesenchyme. PARM1 gene analysis revealed no alterations in the coding region of any of the investigated patients. Conclusions These findings suggest that PARM1 does not play a major role in the development of human epispadias. However, we cannot rule out the possibility that a larger sample size would enable detection of rare mutations in this gene

Measurements of NaI:Tl Electron Response using SLYNCI: Comparison of Different Samples

This paper measures the sample to sample variation in the light yield non-proportionality of NaI:Tl, and so explores whether this is an invariant characteristic of the material or whether it is dependent on the chemical and physical properties of tested sample. In this work we report on the electron response of nine crystals of NaI(Tl), differing in shape, volume, age, manufacturer and quality. The non-proportionality has been measured at the SLYNCI facility in the energy range between 3.5 to 460 keV. The Scintillation Light Yield Non-proportionality Characterization Instrument (SLYNCI) is a next generation Compton Coincidence device, explicitly designed to study the 'non-proportionality' of the electron response in scintillators and the contribution of this effect to the intrinsic energy resolution. We also discuss the gamma response, x-ray excited emission spectra and decay times for the nine crystals, in order to provide a complete characterization of their physical properties and determine whether the mechanism of scintillation varies between samples