Optimally Stabilized PET Image Denoising Using Trilateral Filtering

Low-resolution and signal-dependent noise distribution in positron emission tomography (PET) images makes denoising process an inevitable step prior to qualitative and quantitative image analysis tasks. Conventional PET denoising methods either over-smooth small-sized structures due to resolution limitation or make incorrect assumptions about the noise characteristics. Therefore, clinically important quantitative information may be corrupted. To address these challenges, we introduced a novel approach to remove signal-dependent noise in the PET images where the noise distribution was considered as Poisson-Gaussian mixed. Meanwhile, the generalized Anscombe's transformation (GAT) was used to stabilize varying nature of the PET noise. Other than noise stabilization, it is also desirable for the noise removal filter to preserve the boundaries of the structures while smoothing the noisy regions. Indeed, it is important to avoid significant loss of quantitative information such as standard uptake value (SUV)-based metrics as well as metabolic lesion volume. To satisfy all these properties, we extended bilateral filtering method into trilateral filtering through multiscaling and optimal Gaussianization process. The proposed method was tested on more than 50 PET-CT images from various patients having different cancers and achieved the superior performance compared to the widely used denoising techniques in the literature.Comment: 8 pages, 3 figures; to appear in the Lecture Notes in Computer Science (MICCAI 2014

An Exploratory Analysis of Father Involvement in Low-Income Families

Using data from the Fragile Families study, this paper explores factors that influence paternal involvement in low-income families. 4873 fathers from the Fragile Families study were classified using CART (Classification and Regression Tree Analysis). CART is a nonparametric technique that allows many different factors to be combined in order to classify homogeneous subgroups within a sample. The CART analysis distinguished between residential and non-residential fathers. In addition, among residential fathers, race emerged as the distinguishing factor. For White men, residential status was the only factor to affect involvement. For African American and Hispanic men however, interactions among several sociodemographic characteristics revealed that both contextual and individual factors affect paternal involvement. Results suggest that an ecological approach is necessary in the investigation of paternal involvement.

Test-retest analysis of a non-invasive method of quantifying [C-11]-PBR28 binding in Alzheimer's disease

Purpose: In order to maximise the utility of [11C]-PBR28 for use in longitudinal studies and clinical trials in Alzheimer’s disease (AD), there is a need to develop non-invasive metrics of tracer binding that do not require arterial cannulation. Recent work has suggested that standardised uptake value (SUV)-based methods may be sensitive to changes in translocator protein (TSPO) levels associated with neurodegeneration. However, the test-retest reliability of these approaches in AD over a time period relevant for clinical trials is unknown. In this study, the test-retest reliability of three SUV-based metrics was assessed in AD patients over 12 weeks. Methods: Five patients with mild AD and the high-affinity binding TSPO genotype underwent two [11C]-PBR28 PET scans approximately 12 weeks apart. The test-retest reliability (TRR) of the unadjusted SUV, SUV relative to cerebellar grey matter (SUVRC) and SUV normalised to whole brain activity (SUVRWB) in nine cortical and limbic regions of interest was assessed using the absolute variability and the intraclass correlation coefficient. Results: Of the three measures, SUVRWB performed best overall, showing low absolute variability (mean −0.13 %, SD 2.47 %) and high reliability (mean ICC = 0.83). Unadjusted SUV also performed well, with high reliability (ICC = 0.94) but also high variability (mean −1.24 %, SD 7.28 %). By comparison, the SUVRC showed higher variability (mean −3.98 %, SD 7.07 %) and low reliability (ICC = 0.65). Conclusions: In this AD sample, we found that SUV-derived metrics of [11C]-PBR28 binding showed high stability over 12 weeks. These results compare favourably with studies reporting TRR of absolute quantification of [11C]-PBR28. Pending further validation of SUV-based measures of [11C]-PBR28, semi-quantitative methods of [11C]-PBR28 analysis may prove useful in longitudinal studies of AD

Offspring ADHD as a risk factor for parental marital problems: Controls for genetic and environmental confounds

Background: Previous studies have found that child attention-deficit/hyperactivity disorder (ADHD) is associated with more parental marital problems. However, the reasons for this association are unclear. The association might be due to genetic or environmental confounds that contribute to both marital problems and ADHD. Method: Data were drawn from the Australian Twin Registry, including 1,296 individual twins, their spouses, and offspring. We studied adult twins who were discordant for offspring ADHD. Using a discordant twin pairs design, we examined the extent to which genetic and environmental confounds, as well as measured parental and offspring characteristics, explain the ADHD-marital problems association. Results: Offspring ADHD predicted parental divorce and marital conflict. The associations were also robust when comparing differentially exposed identical twins to control for unmeasured genetic and environmental factors, when controlling for measured maternal and paternal psychopathology, when restricting the sample based on timing of parental divorce and ADHD onset, and when controlling for other forms of offspring psychopathology. Each of these controls rules out alternative explanations for the association. Conclusion: The results of the current study converge with those of prior research in suggesting that factors directly associated with offspring ADHD increase parental marital problems

Functional brain networks before the onset of psychosis: A prospective fMRI study with graph theoretical analysis☆☆☆

Individuals with an at-risk mental state (ARMS) have a risk of developing a psychotic disorder significantly greater than the general population. However, it is not currently possible to predict which ARMS individuals will develop psychosis from clinical assessment alone. Comparison of ARMS subjects who do, and do not, develop psychosis can reveal which factors are critical for the onset of illness. In the present study, 37 patients with an ARMS were followed clinically at least 24 months subsequent to initial referral. Functional MRI data were collected at the beginning of the follow-up period during performance of an executive task known to recruit frontal lobe networks and to be impaired in psychosis. Graph theoretical analysis was used to compare the organization of a functional brain network in ARMS patients who developed a psychotic disorder following the scan (ARMS-T) to those who did not become ill during the same follow-up period (ARMS-NT) and aged-matched controls. The global properties of each group's representative network were studied (density, efficiency, global average path length) as well as regionally-specific contributions of network nodes to the organization of the system (degree, farness-centrality, betweenness-centrality). We focused our analysis on the dorsal anterior cingulate cortex (ACC), a region known to support executive function that is structurally and functionally impaired in ARMS patients. In the absence of between-group differences in global network organization, we report a significant reduction in the topological centrality of the ACC in the ARMS-T group relative to both ARMS-NT and controls. These results provide evidence that abnormalities in the functional organization of the brain predate the onset of psychosis, and suggest that loss of ACC topological centrality is a potential biomarker for transition to psychosis

The Gloomy Prospect Wins: Statistical Significance and Population Stratification in Genome Wide Association Studies

This one-hour lecture by Dr. Eric Turkheimer of the University of Virginia's Department of Psychology explored the following:

The contemporary era has seen a convergence of genomic technology and traditional social scientific concerns with complex human individual differences. Rather than finally turning social science into a replicable hard-scientific enterprise, genomics has gotten bogged down in the long-standing frustrations of social science. A recent report of an extensive genome wide association study of human height demonstrates the profound difficulties of explaining uncontrolled human variation at a genomic level. The statistical technologies that have been brought to bear on the problem of genomic association are simply modifications of similar methods that have been used by social scientists for decades, with little success. The motivation for the statistical methods in genomics is the same as it is in traditional social science: An attempt to discern linear causation in complex systems when experimental control is not possible.

For an audio recording of Dr. Turkheimer's lecture, please visit "http://cirge.stanford.edu/activities/events.html.":http://cirge.stanford.edu/activities/events.htm

Crying and feeding problems in infancy and cognitive outcome in preschool children born at risk : a prospective population study

Objective: To investigate whether regulatory problems, i.e., crying and feeding problems in infants > 3 months of age, predict cognitive outcome in preschool children born at risk even when controlled for confounding factors. Methods: A prospective longitudinal study of children born in a geographically defined area in Germany. N = 4427 children of 6705 eligible survivors (66%) participated at all four assessment points (neonatal, 5, 20, and 56 months of age). Excessive crying and feeding problems were measured at 5 months. Mental development was assessed with the Griffiths Scale at 20 months, and cognitive assessments were conducted at 56 months. Neonatal complications, neurological, and psychosocial factors were controlled as confounders in structural equation modeling and analyses of variance. Results: One in five infants suffered from single crying or feeding problems, and 2% had multiple regulatory problems, i.e., combined crying and feeding problems at 5 months. In girls, regulatory problems were directly predictive of lower cognition at 56 months, even when controlled for confounders, whereas in boys, the influence on cognition at 56 months was mediated by low mental development at 20 months. Both in boys and girls, shortened gestational age, neonatal neurological complications, and poor parent-infant relationship were predictive of regulatory problems at 5 months and lower cognition at 56 months. Conclusion: Regulatory problems in infancy have a small but significant adverse effect on cognitive development

Parental depression and offspring psychopathology: A Children of Twins study

Background Associations between parental depression and offspring affective and disruptive disorders are well documented. Few genetically informed studies have explored the processes underlying intergenerational associations. Method A semi-structured interview assessing DSM-III-R psychiatric disorders was administered to twins (n=1296) from the Australian Twin Register (ATR), their spouses (n=1046) and offspring (n=2555). We used the Children of Twins (CoT) design to delineate the extent to which intergenerational associations were consistent with a causal influence or due to genetic confounds. Results In between-family analyses, parental depression was associated significantly with offspring depression [hazard ratio (HR) 1.52, 95% confidence interval (CI) 1.20–1.93] and conduct disorder (CD; HR 2.27, CI 1.31–3.93). Survival analysis indicated that the intergenerational transmission of depression is consistent with a causal (environmental) inference, with a significant intergenerational association in offspring of discordant monozygotic (MZ) twin pairs (HR 1.39, CI 1.00–1.94). Logistic regression analysis suggested that the parental depression–offspring CD association was due to shared genetic liability in the parents and offspring. No intergenerational association was found when comparing the offspring of discordant MZ twins [odds ratio (OR) 1.41, CI 0.63–3.14], but offspring of discordant dizygotic (DZ) twins differed in their rates of CD (OR 2.53, CI 0.95–6.76). All findings remained after controlling for several measured covariates, including history of depression and CD in the twins' spouses. Conclusions The mechanisms underlying associations between parental depression and offspring psychopathology seem to differ depending on the outcome. The results are consistent with a causal environmental role of parental depression in offspring depression whereas common genetic factors account for the association of parental depression and offspring CD