Impact of model-based iterative reconstruction on low-contrast lesion detection and image quality in abdominal CT: a 12-reader-based comparative phantom study with filtered back projection at different tube voltages.

OBJECTIVES: To evaluate the impact of model-based iterative reconstruction (MBIR) on image quality and low-contrast lesion detection compared with filtered back projection (FBP) in abdominal computed tomography (CT) of simulated medium and large patients at different tube voltages. METHODS: A phantom with 45 hypoattenuating lesions was placed in two water containers and scanned at 70, 80, 100, and 120 kVp. The 120-kVp protocol served as reference, and the volume CT dose index (CTDIvol) was kept constant for all protocols. The datasets were reconstructed with MBIR and FBP. Image noise and contrast-to-noise-ratio (CNR) were assessed. Low-contrast lesion detectability was evaluated by 12 radiologists. RESULTS: MBIR decreased the image noise by 24% and 27%, and increased the CNR by 30% and 29% for the medium and large phantoms, respectively. Lower tube voltages increased the CNR by 58%, 46%, and 16% at 70, 80, and 100 kVp, respectively, compared with 120 kVp in the medium phantom and by 9%, 18% and 12% in the large phantom. No significant difference in lesion detection rate was observed (medium: 79-82%; large: 57-65%; P > 0.37). CONCLUSIONS: Although MBIR improved quantitative image quality compared with FBP, it did not result in increased low-contrast lesion detection in abdominal CT at different tube voltages in simulated medium and large patients. KEY POINTS: • MBIR improved quantitative image quality but not lesion detection compared with FBP. • Increased CNR by low tube voltages did not improve lesion detection. • Changes in image noise and CNR do not directly influence diagnostic accuracy.

Lessons Learnt About Conducting a Multilingual Nutrition Survey in Switzerland: Results from menuCH Pilot Survey.

This paper informs about the implementation of the first trilingual Swiss nutrition pilot survey and lessons learnt in terms of recruitment, participation, data collection feasibility, and data management. The population-based cross-sectional nutrition pilot survey took place between June and November 2013. Six trained dietitians interviewed 276 adults aged 18-75 years residing in the cantons of Bern (German), Vaud (French) or Ticino (Italian). Food consumption was assessed with two non-consecutive computer-assisted 24-Hour Dietary Recalls (24HDR), applying a trilingual version of GloboDiet® adapted to specific requirements of Switzerland. The first interview was face-to-face and included anthropometric measurements while the second was by phone. Quality controls consisted mainly in the descriptive analysis of data at food level, and the observation and rating of 21 interviews (4%) by coordinators. Net participation rate was 29%. Participants and non-participants were similar: mean [±SD] age was 49±16 and 47±16 years, and women proportion 49.6% and 49.8%, respectively. Training and data collection proved feasible and deliverable in the six months using the newly developed survey instruments. Dietitians followed the standard operating procedures. Quality controls on food consumption data showed comparable results between face-to-face and phone 24HDR, and across dietitians (median number of reported food items per 24HDR: 27). Procedures to transfer and clean food consumption data were developed. The implementation concept proved applicable in the trilingual Swiss context. Additional resources were planned for increasing participation rate and facilitating data cleaning.

Analysis of relation between hypoxia PET imaging and tissue-based biomarkers during head and neck radiochemotherapy.

BACKGROUND: Tumor hypoxia is associated with poor prognosis and outcome and can be visualized using 18F-MISO-positron emission tomography (PET) imaging. The goal of this study was to evaluate the correlation between biological markers and biological imaging in a group of patients in whom a correlation between biological imaging and outcome has previously been demonstrated. MATERIAL AND METHODS: In a prospective pilot project, 16 patients with locally advanced cancer of the head and neck underwent 18F-MISO-PET scans before and during primary radiochemotherapy in addition to 18F-FDG-PET and computed tomography (CT). Tumor biopsies were stained for three tissue-based markers (Ku80, CAIX, CD44); in addition, human papillomavirus (HPV) status was assessed. H-scores of marker expression were generated and the results were correlated with the biological imaging and clinical outcome. RESULTS: No statistically significant correlation was established between the H-scores for Ku80, CD44 and CAIX or between any of the H-scores and the imaging variables (tumor volume on 18F-FDG-PET in ml, hypoxic subvolume as assessed by 18F-MISO-PET in ml, and SUVmax tumor/SUVmean muscle during the 18F-MISO-PET). A statistically significant negative correlation was found between CD44 H-score and HPV status (p = .004). Cox regression analysis for overall survival and recurrence-free survival showed one significant result for CAIX being associated with improved overall survival [hazard ratio 0.96 (0.93-1.00), p = .047]. CONCLUSION: Expression of Ku80, CAIX and CD44 as assessed by immunohistochemistry of tumor biopsies were not correlated to one another or the biological imaging data. However, there was a significant influence of CAIX on overall survival and between CD44 and HPV.

Health literacy among young adults: a short survey tool for public health and health promotion research.

Health literacy (HL) is context-specific. In public health and health promotion, HL in the private realm refers to individuals' knowledge and skills to prevent disease and to promote health in everyday life. However, there is a scarcity of measurement tools explicitly geared to private realm contexts. Our aim was to develop and test a short survey tool that captures different dimensions of HL in the context of family and friends. We used cross-sectional data from the Swiss Federal Surveys of Adolescents from 2010 to 2011, comprising 7983 males and 366 females between 18 and 25 years. HL was assessed through a set of eight items (self-reports). We used principal component analysis to explore the underlying factor structure among these items in the male sample and confirmatory factor analysis to verify the factor structure in the female sample. The results showed that the tested item set represented dimensions of functional, interactive and critical HL. Two sub-dimensions, understanding versus finding health-relevant information, denoted functional HL. Interactive and critical HL were each represented with two items. A sum score based on all eight items (Cronbach's α: 0.64) showed expected positive associations with own and parental education among males and females (p < 0.05). The short item set appears to be a feasible measurement tool to assess HL in the private realm. Its broader application in survey studies may help to improve our understanding of how this form of HL is distributed in the general population.

Impact of thrombolysis on stroke outcome at 12 months in a population: the Bern stroke project.

BACKGROUND AND PURPOSE: Thrombolysis improves outcome of patients with acute ischemic stroke, but it is unknown whether thrombolysis has a measurable effect on long-term outcome in a defined population. METHODS: We prospectively assessed demographic data, management, and outcome of acute ischemic stroke patients admitted within 48 hours to 18 primary care hospitals of the canton of Bern (969 299 inhabitants) during 12 months. Blinded follow-up was obtained at 3 and 12 months. Predictors of mortality and favorable outcome (modified Rankin Scale score ≤2) at 3 and 12 months using logistic regression were analyzed. RESULTS: From December 2007 to December 2008, 807 patients (mean age, 72 years) were included. Median National Institutes of Health Stroke Scale score on admission was 5; 107 patients (13%) received intravenous, intra-arterial, or mechanical thrombolysis. Estimated cumulative mortality at 3 months was 20.6% and at 12 months 27.4%. Age 75 years or older, higher National Institutes of Health Stroke Scale scores, and higher Charlson comorbidity index were independent predictors of mortality at 3 and 12 months. Estimated favorable outcome at 3 months was 48.2% and at 12 months was 44.6%. Thrombolysis was the only modifiable independent predictor of favorable outcome at 3 (relative risk, 1.49; 95% CI, 1.18-1.89) and 12 months (relative risk, 1.59; 95% CI, 1.24-2.04), whereas age younger than 75 years, male gender, National Institutes of Health Stroke Scale score <4, and lower Charlson comorbidity index were nonmodifiable predictors. CONCLUSIONS: Thirteen percent of acute ischemic stroke patients admitted within 48 hours to Bernese hospitals underwent thrombolysis, which exerted a measurable effect on 3-month outcome in this population. This effect was sustained at 12 months. Age, stroke severity, Charlson comorbidity index, and male gender were independent nonmodifiable predictors of outcome.

Transfection of normal primary human skeletal myoblasts with p21 and p57 antisense oligonucleotides to improve their proliferation: a first step towards an alternative molecular therapy approach of Duchenne muscular dystrophy.

Duchenne muscular dystrophy (DMD), caused by the absence of dystrophin, is associated with decreased muscle cell proliferation. An increased p21 mRNA level in DMD patients may be involved in the process. In this context we are interested to improve the proliferation of primary human skeletal muscle cells (SkMC) by a reduction in the cell cycle proteins p21 and p57 using the appropriate antisense oligonucleotides (ASO). Therefore a transfection procedure needs to be optimized in which the oligonucleotide enters the SkMC with a minimal loss of cell vitality and high efficiency. Three different formulations, Effectene, DAC40, and SuperFect, were compared. Proliferation was analyzed comparing cells transfected with p21 and/or p57 ASO vs. cells transfected with scrambled ASO using a bromodeoxyuridine assay. Under optimal conditions (a mixture of 0.25 microg ASO, 5 microl Effectene, 0.8 microl enhancer) SkMC transfected with p21 ASO reveal an average increase in cell proliferation of 32.5+/-11% after 24 h. p57 ASO shows the same effect, but concomitant transfection of p21 and p57 does not enhance it. A cell vitality of 78+/-14% after 24 h was determined by the MTT test. SkMC transfected with DAC40 reveal a maximal increase in proliferation of 38+/-7% after 48 h and show a vitality of 65+/-8%. In contrast to both these formulations, SuperFect was found to be highly toxic for SkMC, with more than 70% dead cells after 24 h. The increase in proliferation, the functional biological effect of p21 ASO, is well correlated with a decrease in p21 detected by western blot analysis of 31.6% for Effectene. Transfection efficiency was measured directly by FACS analysis using FITC-labeled ASO and data showing ASO internalization in 75.8+/-11.2% of the cell population for Effectene and 74.4+/-6.6% cells for DAC40. Taken together transient transfection of p21 or p57 ASO into primary human SkMC using Effectene significantly improves their proliferation compared to transfection with scrambled ASO without a major loss of cell vitality. This represents a basis for the transfer of this technique to dystrophin-deficient SkMC cultures and the introduction of the short interference-RNA technique which might enhance the effect on cell proliferation.

Serial [18F]-fluoromisonidazole PET during radiochemotherapy for locally advanced head and neck cancer and its correlation with outcome.

PURPOSE: The aim was to assess changes of tumour hypoxia during primary radiochemotherapy (RCT) for head and neck cancer (HNC) and to evaluate their relationship with treatment outcome. MATERIAL AND METHODS: Hypoxia was assessed by FMISO-PET in weeks 0, 2 and 5 of RCT. The tumour volume (TV) was determined using FDG-PET/MRI/CT co-registered images. The level of hypoxia was quantified on FMISO-PET as TBRmax (SUVmaxTV/SUVmean background). The hypoxic subvolume (HSV) was defined as TV that showed FMISO uptake ⩾1.4 times blood pool activity. RESULTS: Sixteen consecutive patients (T3-4, N+, M0) were included (mean follow-up 31, median 44months). Mean TBRmax decreased significantly (p<0.05) from 1.94 to 1.57 (week 2) and 1.27 (week 5). Mean HSV in week 2 and week 5 (HSV2=5.8ml, HSV3=0.3ml) were significantly (p<0.05) smaller than at baseline (HSV1=15.8ml). Kaplan-Meier plots of local recurrence free survival stratified at the median TBRmax showed superior local control for less hypoxic tumours, the difference being significant at baseline and after 2weeks (p=0.031, p=0.016). CONCLUSIONS: FMISO-PET documented that in most HNC reoxygenation starts early during RCT and is correlated with better outcome.

Exploratory geographical analysis of hypoxic subvolumes using 18F-MISO-PET imaging in patients with head and neck cancer in the course of primary chemoradiotherapy.

BACKGROUND AND PURPOSE: Hypoxia in head and neck tumours is associated with poor prognosis and outcome, and can be visualized using (18)F-MISO-PET imaging; however, it is not clear whether the size and location of hypoxic subvolumes remain stable during therapy. In a pilot project, we conducted an exploratory analysis of persistent tumour hypoxia during treatment. MATERIALS AND METHODS: Sixteen patients with locally advanced head and neck tumours underwent consecutive (18)F-MISO-PET scans before and during primary chemoradiotherapy. The size, location and overlap of the hypoxic subvolumes were analysed using a semi-automatic algorithm based on a tumour to normal tissue ratio of 1.5. RESULTS: Quantitative evaluation showed tumour hypoxia in week 0 in 16 out of 16 and in week 2 in 5 out of 14 patients. For the five patients with persistent hypoxia, both increased and decreased hypoxic subvolumes could be observed. Mean hypoxic subvolume overlap was 55% of the hypoxic volume of the first scan and 72% of the hypoxic volume of the second scan. A stationary (in four out of five patients) and dynamic component (in three out of five patients) could be differentiated. CONCLUSION: In patients with persistent hypoxia after 2 weeks of treatment, the hypoxic subvolumes showed mostly a geographically relatively stable conformation.