Disturbed Interplay Between Mid- and High-Level Vision in ASD? Evidence from a Contour Identification Task with Everyday Objects

Atypical visual processing in children with autism spectrum disorder (ASD) does not seem to reside in an isolated processing component, such as global or local processing. We therefore developed a paradigm that requires the interaction between different processes—an identification task with Gaborized object outlines—and applied this to two age groups of 6-to-10 and 10-to-14 year old children with and without ASD. Event history analyses demonstrated an identification disadvantage in the ASD group, which remained quite stable during the temporal unfolding of the outline. The typically developing group particularly outperformed the ASD group when more complex contours were shown. Together, our results suggest that the interplay between local and global processes and between bottom-up and top-down processes is disturbed in ASD.     

Mid-term clinical and haemodynamic results after aortic valve replacement with the Trifecta bioprosthesis

 Open in a separate windowOBJECTIVESThe aim of this study was to evaluate the clinical and haemodynamic results after implantation of the Trifecta bioprosthesis.METHODSThis study is a retrospective analysis of all patients undergoing Trifecta aortic valve replacement between 01 January 2012 and 31 December 2017 at the Ghent University Hospital. Univariable and multivariable analyses were performed to identify predictors of valve- and procedure-related complications and mortality. The haemodynamic performance was analysed by longitudinal Doppler echocardiography.RESULTSThe mean age of the 182 patients was 77 [standard deviation (SD): 5.5] years; 54.9% were women. The mean follow-up was 39.8 (SD: 24.3) months. Overall survival at 1 and 5 years was 86% (SD: 3%) and 68% (SD: 4%), respectively, and overall freedom from structural valve deterioration was 100% and 98% at 1 and 5 years, respectively. There was no valve thrombosis nor early endocarditis. Urgent surgery was the only risk factor for early mortality in the multivariable analysis [P = 0.009, odds ratio 0.06, 95% confidence interval (CI) 0.01–0.5]. Preoperative atrial fibrillation was the most important predictor of late mortality (P = 0.001, hazard ratio 3.68, 95% CI 1.65–8.21). The average peak gradients were stable from discharge up to 1 and 5 years postoperatively [15 (SD: 6) and 17 (SD: 8) mmHg].CONCLUSIONSThese results confirm the excellent clinical performance of the Trifecta valve, particularly in an elderly age group. Through the 7-year follow-up period, low transvalvular gradients persisted, and only a few patients needed reoperation. Although structural valve degeneration occurred rarely, it was unrelated to valve size or age at implantation; therefore, further long-term follow-up remains mandatory.     

Sunscreen use and skin protection behavior on the Belgian beach

BACKGROUND: Public health campaigns encourage the public to protect themselves against skin cancer by using sunscreens and taking other protective measures. However, it is difficult to estimate the level of awareness among the general public. METHODS: This study explores the prevalence and predictors of solar protection behavior in a community sample of beachgoers. During the months of May, June, July and August 2001 a total of 360 participants (145 men and 215 women) were randomly selected from several Belgian beaches in and around the city of Ostend, Belgium. The solar protection behavior of each participant was assessed by direct observation and interview. RESULTS: The risk awareness percentages were 70.6% for skin cancer, 60.8% for sunburn and 25.0% for skin aging. These percentages were considerably higher in the female participant group than in the male group. Sunscreen cream was the most popular preventive behavior, especially in the female population, whereas the alternative protective measures (limited exposure during peak sun hours, the use of shade and the use of protective clothing and hats) were more popular in the male group. CONCLUSIONS: While solar protection has become part of routine beach behavior, there is room for improvement by more frequent application of sunscreen cream, the use of a higher sun protection factor (SPF) (15+), timed sunbathing, more use of clothing and hats and more seeking of shade. The results of this study can assist in evaluating the effectiveness of current sun-protection campaigns and health education programs.     

Riedel's thyroiditis and retroperitoneal fibrosis in multifocal fibrosclerosis: positron emission tomographic findings

PURPOSE: The authors describe F-18 fluorodeoxyglucose positron emission tomographic (FDG PET) imaging features of Riedel's thyroiditis and retroperitoneal fibrosis in a patient with multifocal fibrosclerosis. MATERIALS AND METHODS: A 41-year-old woman in whom Riedel's thyroiditis had been diagnosed 7 months earlier was examined for fatigue, anorexia, and lower back pain, irradiating to the abdomen. Abdominal sonography and computed tomography showed a retroperitoneal mass. A biopsy of this mass showed histopathologic findings of retroperitoneal fibrosis. FDG PET was performed to evaluate the activity of the retroperitoneal fibrosis and to screen for other areas of fibrosclerosis. RESULTS: The FDG-PET images showed an intense hypermetabolic abdominal mass surrounding the aorta and increased glucose metabolism in the thyroid. No other sites of abnormal FDG metabolism were noted. These abnormalities disappeared after 4 months of steroid therapy. CONCLUSIONS: Sites of multifocal fibrosclerosis can be demonstrated by FDG PET, probably as a result of active inflammation involving lymphocytes, plasma cells, and fibroblast proliferation. FDG PET can help to establish the diagnosis of multifocal fibrosclerosis and evaluate the activity and patient response to corticosteroid therapy.     

Cardiac phantom measurement validating the methodology for a cardiac multi-centre trial with positron emission tomography

In an ongoing international multi-centre trial, positron emission tomography (PET) is being used to evaluate the effect of a new P-selectin antagonist on the infarct size in patients with acute myocardial infarction, treated with thrombolysis. Although it is possible to correct for site-dependent factors, it is desirable to reduce these factors to a minimum. Therefore, acquisition and reconstruction protocols have been defined that can be closely followed by all participating centres. The resulting reconstructed images are transferred to the core centre for central processing with semi-automatic software. This paper reports on the multi-centre phantom experiment that was carried out to assess the inter-centre reproducibility of defect size determination with this protocol. Also, the spatial resolution of the short axis slices was examined. In addition, the analysis procedure was applied to normal PET studies to evaluate the specificity of perfusion defect detection. The transmural cold defect in the phantom occupied 14.8% of the left ventricular area. The automated analysis was applied to the phantom measurements from the 14 participating PET cameras. It yielded an accurate estimate of 15.1% with a standard deviation of 0.6%, indicating excellent reproducibility. The spatial resolution in the short axis slices was similar for all PET systems: 9.6+/-0.8 mm. The same procedure produced a defect size of zero in the studies of normal volunteers. This study indicates that cardiac studies from multiple PET systems can be pooled for statistical analysis.     

Positron emission tomography for assessment of the response to induction radiochemotherapy in locally advanced oesophageal cancer.

AIMS: This prospective study was designed to determine the utility of 18F-labelled deoxyglucose (FDG) in positron emission tomography (PET) (FDG-PET) for assessing the response to neoadjuvant chemoradiation therapy (CRT) in locally advanced oesophageal tumours. PATIENTS AND METHODS: Thirty-six patients with locally advanced oesophageal cancer (clinical T4 stage) without organ metastases, underwent FDG-PET before and 1 month after CRT. Patients were classified as major responders by serial FDG-PET when the post-CRT PET demonstrated a strong reduction of FDG uptake at the primary tumour site (>80% reduction of tumour-to-liver uptake ratio) without any abnormal FDG uptake elsewhere in the body. PET response was compared with histology obtained during post-induction transthoracic oesophagectomy. RESULTS: A strong correlation was found between the extent of lymph node (LN) involvement as shown by the pre-CRT PET and the major response rate (P = 0.001): such response occurred in nine of 11 N0M0 patients (82%), in three of nine N(1-2)M0 patients (33%) and in two of 16 patients (13%) with distant lymphatic spread. Such a correlation was not found for computed tomography or endoscopic ultrasonography. The sensitivity of serial FDG-PET for a major CRT response was 10 of 14 (71%), its specificity 18 of 22 (82%). The concordance between the response assessment by PET and histopathology was 78%. The median survival time after CRT of PET major responders compared with PET non-major responders was 16.3 months and 6.4 months, respectively. The metabolic response as measured by serial FDG-PET is a stronger prognostic factor for overall survival (P = 0.002) than the extent of LN involvement seen on the pretreatment FDG-PET (P = 0.087). CONCLUSIONS: These data indicate that CRT response as assessed by serial FDG-PET is strongly correlated with pathological response and survival.     

PET reversed mismatch in an experimental model of subacute myocardial infarction

The aim of this study was to evaluate the relationship between flow/metabolism, histology and functional follow-up in a sheep model of subacute myocardial infarction. In eight juvenile sheep, a myocardial infarction was induced by intracoronary injection of macrobeads. Left ventricular function was evaluated using echocardiography. 2-[18F]fluoro-2-deoxy-D-glucose (18F-FDG)/nitrogen-13-labelled ammonia (13NH3) positron emission tomography (PET) was performed at 6 weeks and 16 weeks after embolization. In five sheep, a dynamic carbon-11 acetate study was performed. In each animal, two regions of interest were defined on the polar map, corresponding to the embolized and the non-embolized region. After the final measurements, the hearts were processed for histological evaluation. PET revealed a moderately decreased flow and oxidative metabolism in the embolized region at 6 weeks, without significant changes at follow-up. At 6 weeks, 18F-FDG uptake in the embolized area was more severely decreased as compared to the flow index in the embolized area (P < 0.05). At 16 weeks, 18F-FDG metabolism had significantly recovered (P < 0.05). Serial echocardiography showed a persistent decrease in global and regional left ventricular function. Histology revealed a mix of micro-infarcted and viable tissue in the embolized region. In this model of subacute myocardial infarction, a PET "reversed mismatch" pattern was observed, with partial recovery of 18F-FDG uptake at follow-up. The histological counterpart of this PET pattern appears to be patchy necrosis.