Exploratory radiomic features from integrated 18F-fluorodeoxyglucose positron emission tomography/magnetic resonance imaging are associated with contemporaneous metastases in oesophageal/gastroesophageal cancer.

PURPOSE: The purpose of this study was to determine if 18F-fluorodeoxyglucose positron emission tomography/magnetic resonance imaging (18F-FDG PET/MRI) features are associated with contemporaneous metastases in patients with oesophageal/gastroesophageal cancer. METHODS: Following IRB approval and informed consent, patients underwent a staging PET/MRI following 18F-FDG injection (326 ± 28 MBq) and 156 ± 23 min uptake time. First-order histogram and second-order grey level co-occurrence matrix features were computed for PET standardized uptake value (SUV) and MRI T1-W, T2-W, diffusion weighted (DWI) and apparent diffusion coefficient (ADC) images for the whole tumour volume. K-means clustering assessed the correlation of feature-pairs with metastases. Multivariate analysis of variance (MANOVA) was performed to assess the statistical separability of the groups identified by feature-pairs. Sensitivity (SN), specificity (SP), positive predictive value (PPV), negative predictive value (NPV), and accuracy (ACC) were calculated for these features and compared with SUVmax, ADCmean and maximum diameter alone for predicting contemporaneous metastases. RESULTS: Twenty patients (18 males, 2 female; median 67 years, range 52-86) comprised the final study cohort; ten patients had metastases. Lower second-order SUV entropy combined with higher second-order ADC entropy were the best feature-pair for discriminating metastatic patients, MANOVA p value <0.001 (SN = 80%, SP = 80%, PPV = 80%, NPV = 80%, ACC = 80%). SUVmax (SN = 30%, SP = 80%, PPV = 60%, NPV = 53%, ACC = 55%), ADCmean (SN = 20%, SP = 70%, PPV = 40%, NPV = 47%, ACC = 45%) and tumour maximum diameter (SN = 10%, SP = 90%, PPV = 50%, NPV = 50%, ACC = 50%) had poorer sensitivity and accuracy. CONCLUSION: High ADC entropy combined with low SUV entropy is associated with a higher prevalence of metastases and a promising initial signature for future study.

Occurrence of Pseudomonas aeruginosa in waters: implications for patients with cystic fibrosis (CF).

Chronic Pseudomonas aeruginosa infection is associated with increased morbidity and mortality in patients with cystic fibrosis (CF). Current understanding of risk factors for acquisition is limited and so the aim of this study was to examine a large sample of environmental waters from diverse sources. Environmental water samples (n = 7904) from jacuzzis, hydrants, swimming pools, hot tubs, plunge pools, bottled natural mineral water, taps, springs, ice machines, water coolers, bores and showers were examined for the presence of P. aeruginosa. Pseudomonas aeruginosa was detected in 524/7904 (6·6%) waters examined. Hot tubs (51/243; 20·9%), tap water (3/40; 8%) and jacuzzis (432/5811; 7·4%) were the most likely environments where P. aeruginosa was isolated. Pseudomonas aeruginosa was isolated from bottled water (2/67; 3%). Our study highlights the ubiquitous nature of P. aeruginosa in the environment. Given CF patients are frequently counselled to make lifestyle changes to minimize P. aeruginosa exposure, these results have important implications. In particular, the occurrence of P. aeruginosa in tap water highlights the need to disinfect the CF patients' nebulizer after each use. SIGNIFICANCE AND IMPACT OF THE STUDY: This study examined a large number of water sources (n = 7904) over a 9-year period for the presence of Pseudomonas aeruginosa. The study highlighted that jacuzzis (n = 5811; 7% positive) and hot tubs had the highest occurrence of this organism (n = 243, 21% positive). Patients with cystic fibrosis (CF) are interested in knowing what water environments are likely to be contaminated with this organism, as this bacterium is an important cause of increased morbidity and mortality in such patients. With such information, CF patients and parents may make informed decisions about lifestyle choice and water environment avoidance.

Muddy puddles - the microbiology of puddles located outside tertiary university teaching hospitals.

In the British Isles, the frequency of rain results in the formation of puddles on footpaths and roads in/around hospitals. No data are available demonstrating the microbiological composition of such puddles and therefore a study was undertaken to examine the microbiology of puddles in the grounds of two tertiary university-teaching hospitals (18 sites) and compared with control puddles from non-hospital rural environments (eight sites), estimating (i) total viable count; (ii) identification of organisms in puddles; (iii) enumeration of Escherichia coli: (iv) detection of Extended Spectrum ß-Lactamase producing organisms and (v) direct antimicrobial susceptibility testing. A mean count of 2·3 × 103  CFU per ml and 1·0 × 109  CFU per ml was obtained for hospital and non-hospital puddles respectively. Isolates (n = 77; 54 hospital and 23 non-hospital) were isolated comprising of 23 species among 17 genera (hospital sites), where the majority (10/16; 62·5%) of genera identified were Gram-negative approximately, a fifth (20·6%) were shared by hospital and non-hospital rural samples. Escherichia coli was detected in half of the hospital puddles and under-half (37·5%) of the rural puddles extended spectrum ß-lactamase organisms were not detected in any samples examined. Rainwater puddles from the hospital and non-hospital environments contain a diverse range of bacteria, which are capable of causing infections. SIGNIFICANCE AND IMPACT OF THE STUDY: This study demonstrated the presence of a wide diversity of bacterial taxa associated with rainwater puddles around hospitals, many of which are capable of causing human disease. Of clinical significance is the presence of Pseudomonas aeruginosa isolated from a hospital puddle, particularly for patients with cystic fibrosis. The presence of potentially disease-causing bacteria in puddles in and around hospitals identifies a new potential environmental reservoir of bacteria. Furthermore work is now needed to define their potential of entering or exiting hospital wards by contaminated footwear.

Primary Rectal Cancer: Repeatability of Global and Local-Regional MR Imaging Texture Features.

Purpose To assess the day-to-day repeatability of global and local-regional magnetic resonance (MR) imaging texture features derived from primary rectal cancer. Materials and Methods After ethical approval and patient informed consent were obtained, two pretreatment T2-weighted axial MR imaging studies performed prospectively with the same imaging unit on 2 consecutive days in 14 patients with rectal cancer (11 men [mean age, 61.7 years], three women [mean age, 70.0 years]) were analyzed to extract (a) global first-order statistical histogram and model-based fractal features reflecting the whole-tumor voxel intensity histogram distribution and repeating patterns, respectively, without spatial information and (b) local-regional second-order and high-order statistical texture features reflecting the intensity and spatial interrelationships between adjacent in-plane or multiplanar voxels or regions, respectively. Repeatability was assessed for 46 texture features, and mean difference, 95% limits of agreement, within-subject coefficient of variation (wCV), and repeatability coefficient (r) were recorded. Results Repeatability was better for global parameters than for most local-regional parameters. In particular, histogram mean, median, and entropy, fractal dimension mean and standard deviation, and second-order entropy, homogeneity, difference entropy, and inverse difference moment demonstrated good repeatability, with narrow limits of agreement and wCVs of 10% or lower. Repeatability was poorest for the following high-order gray-level run-length (GLRL) gray-level zone size matrix (GLZSM) and neighborhood gray-tone difference matrix (NGTDM) parameters: GLRL intensity variability, GLZSM short-zone emphasis, GLZSM intensity nonuniformity, GLZSM intensity variability, GLZSM size zone variability, and NGTDM complexity, demonstrating wider agreement limits and wCVs of 50% or greater. Conclusion MR imaging repeatability is better for global texture parameters than for local-regional texture parameters, indicating that global texture parameters should be sufficiently robust for clinical practice. Online supplemental material is available for this article.

Reproducibility of 2D and 3D fractal analysis techniques for the assessment of spatial heterogeneity of regional blood flow in rectal cancer.

PURPOSE: To characterize the two-dimensional (2D) and three-dimensional (3D) fractal properties of rectal cancer regional blood flow assessed by using volumetric helical perfusion computed tomography (CT) and to determine its reproducibility. MATERIALS AND METHODS: Institutional review board approval and informed consent were obtained. Ten prospective patients (eight men, two women; mean age, 72.3 years) with rectal adenocarcinoma underwent two repeated volumetric helical perfusion CT studies (four-dimensional adaptive spiral mode, 11.4-cm z-axis coverage) without intervening treatment within 24 hours, with regional blood flow derived by using deconvolution analysis. Two-dimensional and 3D fractal analyses of the rectal tumor were performed, after segmentation from surrounding structures by using thresholding, to derive fractal dimension and fractal abundance. Reproducibility was quantitatively assessed by using Bland-Altman statistics. Two-dimensional and 3D lacunarity plots were also generated, allowing qualitative assessment of reproducibility. Statistical significance was at 5%. RESULTS: Mean blood flow was 63.50 mL/min/100 mL ± 8.95 (standard deviation). Good agreement was noted between the repeated studies for fractal dimension; mean difference was -0.024 (95% limits of agreement: -0.212, 0.372) for 2D fractal analysis and -0.024 (95% limits of agreement: -0.307, 0.355) for 3D fractal analysis. Mean difference for fractal abundance was -0.355 (95% limits of agreement: -0.869, 1.579) for 2D fractal analysis and -0.043 (95% limits of agreement: -1.154, 1.239) for 3D fractal analysis. The 95% limits of agreement were narrower for 3D than 2D analysis. Lacunarity plots also visually confirmed close agreement between repeat studies. CONCLUSION: Regional blood flow in rectal cancer exhibits fractal properties. Good reproducibility was achieved between repeated studies with 2D and 3D fractal analysis.

Diffusion tensor imaging of the anal canal at 3 tesla: feasibility and reproducibility of anisotropy measures.

PURPOSE: To assess the feasibility and reproducibility of 3-tesla diffusion tensor imaging (DTI) of the anal canal. MATERIALS AND METHODS: DTI was performed in 25 men with no clinical history of anal canal disease undergoing MRI for prostate cancer. Analysis of fractional anisotropy (FA), relative anisotropy (RA), and apparent diffusion coefficient (ADC) were determined for the epithelial/subepithelial layer, internal sphincter, external sphincter, and puborectalis. The directionality of diffusion was recorded from color-coded tractography maps. Obturator internus and gluteus maximus served as reference muscles. Mean (SD) of values for FA, RA, and ADC were compared using analysis of variance. Intra and inter-rater agreement and test reproducibility (n = 5) was assessed by Bland-Altman statistics. RESULTS: Mean (SD) for the epithelial/subepithelial layer, internal, external sphincter, and puborectalis were as follows: FA: 0.283 (0.099); 0.337 (0.049); 0.415 (0.072); and 0.407 (0.062), respectively. RA: 0.241 (0.094); 0.292 (0.050); 0.371 (0.083); 0.361 (0.067), respectively; and ADC: 1.49 (0.23); 1.59 (0.19); 1.51 (0.28); and 1.54 (0.29) × 10(-3) mm(2) /s, respectively. Good overall intra and inter-rater agreement and test-retest reproducibility was noted (coefficient of variation of 4.8-19.4% and 5.9-12.9%, respectively). CONCLUSION: Anisotropy is evident in the anal canal with good inter-rater agreement and test reproducibility.

Predicting response to neoadjuvant chemotherapy in primary breast cancer using volumetric helical perfusion computed tomography: a preliminary study.

OBJECTIVES: To investigate whether CT-derived vascular parameters in primary breast cancer predict complete pathological response (pCR) to neoadjuvant chemotherapy (NAC). METHODS: Twenty prospective patients with primary breast cancer due for NAC underwent volumetric helical perfusion CT to derive whole tumour regional blood flow (BF), blood volume (BV) and flow extraction product (FE) by deconvolution analysis. A pCR was achieved if no residual invasive cancer was detectable on pathological examination. Relationships between baseline BF, BV, FE, tumour size and volume, and pCR were examined using the Mann-Whitney U test. Receiver operating characteristic (ROC) curve analysis was performed to assess the parameter best able to predict response. Intra- and inter-observer variability was assessed using Bland-Altman statistics. RESULTS: Seventeen out of 20 patients completed NAC with four achieving a pCR. Baseline BF and FE were higher in patients who achieved a pCR compared with those who did not (P = 0.032); tumour size and volume were not significantly different (P > 0.05). ROC analysis revealed that BF and FE were able to identify responders effectively (AUC = 0.87; P = 0.03). There was good intra- and inter-observer agreement. CONCLUSIONS: Primary breast cancers which exhibited higher levels of perfusion before treatment were more likely to achieve a pCR to NAC.

Use of dynamic contrast-enhanced MR imaging to predict survival in patients with primary breast cancer undergoing neoadjuvant chemotherapy.

PURPOSE: To investigate whether early changes in vascular parameters determined with dynamic contrast material-enhanced magnetic resonance (MR) imaging after two cycles of neoadjuvant chemotherapy (NAC) are predictive of disease-free and overall survival in primary breast cancer. MATERIALS AND METHODS: Institutional ethics approval and informed consent were obtained. Patients with primary breast cancer (median age, 45 years; age range, 22-70 years) recruited from January 2001 to September 2008 underwent dynamic contrast-enhanced MR imaging before and after two cycles of NAC. Quantitative and semiquantitative kinetic parameters were calculated, including the volume transfer constant (K(trans)) and the initial area under the gadolinium concentration-time curve over 60 seconds (IAUGC(60)). Cut points optimized to the receiver operating characteristic curve were used to dichotomize MR imaging data for Kaplan-Meier survival analysis. MR imaging parameters and known prognostic indicators in primary breast cancer were correlated with disease-free and overall survival by using the Cox proportional hazards model for univariate and multivariate analyses. RESULTS: MR imaging was performed before (n = 62) and after (n = 58) two cycles of NAC. The median follow-up time was 43.9 months for disease-free survival and 60.3 months for overall survival. There were 28 recurrences; 26 patients had distant metastases (two had additional local recurrence) and two had local recurrence only. There were 20 deaths, all of which were related to breast cancer. At univariate analysis, progesterone receptor status, the type of surgery performed, higher posttreatment K(trans) (P = .048), and larger posttreatment IAUGC(60) (P = .035) were significant predictors of worse disease-free survival. At multivariate analysis, progesterone receptor status (P = .002) and mean transit time (P = .025) were significant predictors of disease-free survival. Univariate analysis showed that clinical tumor stage (P = .005), progesterone receptor status (P = .025), and type of surgery performed (P = .017) were significant predictors of overall survival. Higher posttreatment K(trans) (P = .043), larger IAUGC(60) (P = .029), and larger tumor size at posttreatment MR imaging were predictive of worse overall survival (P = .018). Of these variables, K(trans) remained an independent indicator of overall survival (P = .038). CONCLUSION: Higher posttreatment tumor vascularization as depicted with dynamic contrast-enhanced MR imaging may be associated with higher recurrence and lower survival rates. Dynamic contrast-enhanced MR imaging parameters, in conjunction with traditional prognostic factors, have the potential to be prognostic biomarkers for disease-free and overall survival in primary breast cancer.

Vascular characterisation of triple negative breast carcinomas using dynamic MRI.

OBJECTIVES: Triple-negative (ER-/PR-/HER2-) breast carcinomas (TNBC) are aggressive tumours with underexplored imaging features. This study investigates whether their vascular characteristics as assessed by dynamic contrast-enhanced (DCE) and dynamic susceptibility contrast-enhanced (DSC) MRI are distinct from the prognostically more favourable ER+/PR+/HER2- cancers. METHODS: Patients with primary breast cancer underwent MRI before neoadjuvant chemotherapy and were identified as ER-/PR-/HER2- or ER+/PR+/HER2- from core biopsy specimens. MRI parameters reflecting tissue perfusion, permeability, and extracellular leakage space were measured. Values for inflow transfer constant (K(trans)), outflow rate constant (k(ep)), leakage space (v(e)), area under the gadolinium curve (IAUGC(60) ), relative blood volume (rBV) and flow (rBF), and Mean Transit Time (MTT) were compared across receptor status and with known prognostic variables. RESULTS: Thirty seven patients were assessable in total (16 ER-/PR-/HER2-, 21 ER+/PR+/HER2-). Lower v(e) (p = 0.001), shorter MTT (p = 0.007) and higher k(ep) values (p = 0.044) were observed in TNBC. v(e) was lower across all T stages, node-negative (p = 0.004) and low-grade TNBC (p = 0.037). v(e) was the best predictor of triple negativity (ROC AUC 0.80). CONCLUSIONS: TNBC possess characteristic features on imaging, with lower extracellular space (higher cell density) and higher contrast agent wash-out rate (higher vascular permeability) suggesting a distinctive phenotype detectable by MRI.

The influence of professional factors in determining primary school teachers' commitment to health promotion.

The objectives of the study were to identify the professional issues that teachers perceived as important in their commitment to a health promotion (HP) programme launched in their schools and to understand their perceptions of the impact of the programme on themselves as professionals, individuals, on students, on school staff and on the relationship with students' families. A mixed methods design was used. An anonymous questionnaire was distributed to 54 participating teachers exploring their practices and perceptions of the programme and 26 semi-structured interviews were conducted which examined their professional commitment to the programme. The main factors that teachers identified as shaping their commitment were (1) their perceptions of the programme, specifically, its congruence with their own role and practice and also their perceived impact of the programme upon whole staff relations and (2) the specific school environment including school organization, quality of the relationships with parents and student behaviour. If HP programmes are to be successfully developed in schools, it is necessary to anchor them within the schools' mission. HP programmes need to make sense to teachers' educational perspectives. They need to be responsive to school needs. They also need to be cognisant of the internal tensions that programme implementation can engender among the whole staff, some of whom may be committed to HP in their school, while others, may not value HP in the same way. Therefore, implementation processes that are respectful of the challenges schools encounter and of the differing ontological perspectives that teachers may hold with regard to HP is important.

Primary human breast adenocarcinoma: imaging and histologic correlates of intrinsic susceptibility-weighted MR imaging before and during chemotherapy.

PURPOSE: To investigate the histopathologic and dynamic magnetic resonance (MR) imaging correlates of intrinsic susceptibility-weighted (ISW) MR imaging in patients with primary human breast adenocarcinoma and to assess the relationship between baseline transverse relaxation rate (R2*) and T2* relaxivity change (ΔR2*) and the response to neoadjuvant chemotherapy (NAC). MATERIALS AND METHODS: Institutional ethics approval and informed consent were obtained. Between September 2001 and January 2008, 83 women (median age, 46 years; age range, 26-72 years) with breast cancer were recruited to undergo dynamic contrast medium-enhanced (DCE), dynamic susceptibility contrast-enhanced (DSC), and ISW MR imaging before and after two cycles of NAC. After excluding necrotic, infiltrating, and invasive lobular carcinomas, 31 patients were available for baseline assessment and 27 were available for response assessment. Transfer constant, leakage space, rate constant, initial area under the gadolinium concentration-time curve at 60 seconds, relative blood volume (rBV), relative blood flow (rBF), and R2* were calculated. Relationships between baseline R2* and histopathologic variables (tumor grade, estrogen receptor status, progesterone receptor status, human epidermal growth factor 2 status), tumor size, and dynamic MR imaging parameters were sought. Baseline adenocarcinoma R2* (n = 31) and ΔR2* (n = 27) were correlated with final pathologic response. RESULTS: Inverse correlations between baseline R2* and rBV (ρ = -0.48, P = .013) and rBF (ρ = -0.44, P = .024) were found, but not after NAC. No relationships were observed between baseline R2* and other kinetic imaging parameters, histopathologic characteristics, or tumor size (P > .05). Baseline R2* values were lower in tumors than in normal breast tissue (31.8 sec(-1) vs 36.2 sec(-1), P = .017) but not after NAC. Increases in R2* were observed after treatment (31.1 sec(-1) vs 34.8 sec(-1), P = .006), with larger increases correlating with pathologic response. ΔR2* was not as effective as DCE or DSC MR imaging parameters in the prediction of response. CONCLUSION: R2* is influenced by blood volume in untreated breast adenocarcinomas. Increases in R2* after two cycles of NAC correlate with pathologic response. Therapy-induced uncoupling of the relationship between R2* and rBV and rBF is consistent with responding tumors becoming hypoxic early during treatment. SUPPLEMENTAL MATERIAL: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.10100421/-/DC1.

Reproducibility and correlation between quantitative and semiquantitative dynamic and intrinsic susceptibility-weighted MRI parameters in the benign and malignant human prostate.

PURPOSE: To assess the reproducibility of relaxivity- and susceptibility-based dynamic contrast-enhanced magnetic resonance imaging (MRI) in the benign and malignant prostate gland and to correlate the kinetic parameters obtained. MATERIALS AND METHODS: Twenty patients with prostate cancer underwent paired scans before and after androgen deprivation therapy. Quantitative parametric maps for T(1)- and T(2)*-weighted parameters were calculated (K(trans), k(ep),v(e), IAUC(60), rBV, rBF, and R(2)*). The reproducibility of and correlation between each parameter were determined using standard methods at both timepoints. RESULTS: T(1)-derived parameters are more reproducible than T(2)*-weighted measures, both becoming more variable following androgen deprivation (variance coefficients for prostate K(trans) and rBF increased from 13.9%-15.8% and 42.5%-90.8%, respectively). Tumor R(2)* reproducibility improved after androgen ablation (23.3%-11.8%). IAUC(60) correlated strongly with K(trans), v(e), and k(ep) (all P < 0.001). R(2)* did not correlate with other parameters. CONCLUSION: This study is the first to document the variability and repeatability of T(1)- and T(2)*-weighted dynamic MRI and intrinsic susceptibility-weighted MRI for the various regions of the human prostate gland before and after androgen deprivation. These data provide a valuable source of reference for groups that plan to use dynamic contrast-enhanced MRI or intrinsic susceptibility-weighted MRI for the assessment of treatment response in the benign or malignant prostate.

Measles outbreak linked to a minority group in Austria, 2008.

We report on a measles outbreak originating in an anthroposophic community in Austria, 2008. A total of 394 (94.9%) cases fulfilled the outbreak case definition including 168 cases affiliated to the anthroposophic community. The source case was a school pupil from Switzerland. The Austrian outbreak strain was genotype D5, indistinguishable from the Swiss outbreak strain. A school-based retrospective cohort study in the anthroposophic school demonstrated a vaccine effectiveness of 97.3% in pupils who had received a single dose of measles-containing vaccine and 100% in those who had received two doses. The vaccination coverage of the cases in the anthroposophic community was 0.6%. Of the 226 outbreak cases not belonging to the anthroposophic community, the 10-24 years age group was the most affected. Our findings underline the epidemiological significance of suboptimal vaccination coverage in anthroposophic communities and in older age groups of the general population in facilitating measles virus circulation. The findings of this outbreak investigation suggest that the WHO European Region is unlikely to achieve its 2010 target for measles and rubella elimination.

Dual diagnosis competency among addiction treatment staff: Training levels, training needs and the link to retention.

BACKGROUND: Dually diagnosed clients are described as one of the most challenging treatment populations, often leading to staff frustration, helplessness and negative attitudes. As yet it is unclear whether dual diagnosis (DD)-specific competency and therapeutic optimism among staff are related to client outcomes. METHODS: The study used a 3-month follow-up design involving 124 DD clients starting treatment at 6 UK addiction services. Practitioners (n = 46) treating these clients were assessed regarding their DD specialisation levels. Cox regression analyses were performed to examine predictors of clients' 3-month retention rates. RESULTS: Staff reported a median of 7 years work experience with DD clients, and 80% had received co-morbidity-specific training. Practitioners provided high average ratings on both the DD competency and the therapeutic optimism scale. Nevertheless, 78% of the sample indicated additional support needs in dealing with this client group. Higher levels of DD competencies among staff predicted better client retention. CONCLUSION: The increased provision of support packages for practitioners is vital for improving competency levels in dealing with DD clients, which in turn may lead to improved client outcomes.

A cluster of Legionnaires' disease caused by Legionella longbeachae linked to potting compost in Scotland, 2008-2009.

Three cases of Legionnaires disease caused by Legionella longbeachae Sg 1 associated with potting compost have been reported in Scotland between 2008 and 2009. The exact method of transmission is still not fully understood as Legionnaires disease is thought to be acquired by droplet inhalation. The linked cases associated with compost exposure call for an introduction of compost labelling, as is already in place in other countries where L. longbeachae outbreaks have been reported.

Practical issues and limitations of brain attenuation correction on a simultaneous PET-MR scanner.

BACKGROUND: Despite the advent of clinical PET-MR imaging for routine use in 2011 and the development of several methods to address the problem of attenuation correction, some challenges remain. We have identified and investigated several issues that might affect the reliability and accuracy of current attenuation correction methods when these are implemented for clinical and research studies of the brain. These are (1) the accuracy of converting CT Hounsfield units, obtained from an independently acquired CT scan, to 511 keV linear attenuation coefficients; (2) the effect of padding used in the MR head coil; (3) the presence of close-packed hair; (4) the effect of headphones. For each of these, we have examined the effect on reconstructed PET images and evaluated practical mitigating measures. RESULTS: Our major findings were (1) for both Siemens and GE PET-MR systems, CT data from either a Siemens or a GE PET-CT scanner may be used, provided the conversion to 511 keV µ-map is performed by the PET-MR vendor's own method, as implemented on their PET-CT scanner; (2) the effect of the head coil pads is minimal; (3) the effect of dense hair in the field of view is marked (> 10% error in reconstructed PET images); and (4) using headphones and not including them in the attenuation map causes significant errors in reconstructed PET images, but the risk of scanning without them may be acceptable following sound level measurements. CONCLUSIONS: It is important that the limitations of attenuation correction in PET-MR are considered when designing research and clinical PET-MR protocols in order to enable accurate quantification of brain PET scans. Whilst the effect of pads is not significant, dense hair, the use of headphones and the use of an independently acquired CT-scan can all lead to non-negligible effects on PET quantification. Although seemingly trivial, these effects add complications to setting up protocols for clinical and research PET-MR studies that do not occur with PET-CT. In the absence of more sophisticated PET-MR brain attenuation correction, the effect of all of the issues above can be minimised if the pragmatic approaches presented in this work are followed.

Correction to: Practical issues and limitations of brain attenuation correction on a simultaneous PET-MR scanner.

An amendment to this paper has been published and can be accessed via the original article.

Carbogen breathing increases prostate cancer oxygenation: a translational MRI study in murine xenografts and humans.

Hypoxia has been associated with poor local tumour control and relapse in many cancer sites, including carcinoma of the prostate. This translational study tests whether breathing carbogen gas improves the oxygenation of human prostate carcinoma xenografts in mice and in human patients with prostate cancer. A total of 23 DU145 tumour-bearing mice, 17 PC3 tumour-bearing mice and 17 human patients with prostate cancer were investigated. Intrinsic susceptibility-weighted MRI was performed before and during a period of carbogen gas breathing. Quantitative R(2)* pixel maps were produced for each tumour and at each time point and changes in R(2)* induced by carbogen were determined. There was a mean reduction in R(2)* of 6.4% (P=0.003) for DU145 xenografts and 5.8% (P=0.007) for PC3 xenografts. In all, 14 human subjects were evaluable; 64% had reductions in tumour R(2)* during carbogen inhalation with a mean reduction of 21.6% (P=0.0005). Decreases in prostate tumour R(2)* in both animal models and human patients as a result of carbogen inhalation suggests the presence of significant hypoxia. The finding that carbogen gas breathing improves prostate tumour oxygenation provides a rationale for testing the radiosensitising effects of combining carbogen gas breathing with radiotherapy in prostate cancer patients.

Predictors of 10-year outcome of first-episode psychosis.

BACKGROUND: Predictors of outcome for psychosis are poorly understood. Duration of untreated psychosis (DUP) appears to predict short-term outcome although its medium- to long-term role remains unclear. Neurodevelopmental indices such as pre-morbid function and/or neurological soft signs may predict longer-term outcome. We aimed to assess the impact of a range of clinical and demographic variables on long-term outcome of a geographically defined, epidemiological first-episode psychosis cohort. METHOD: A 10-year follow-up was undertaken of a consecutively presenting sample of 109 cases of first-episode psychosis aged 16-50 years. Baseline assessments included positive, negative and depression symptoms, DUP, neurological soft signs and pre-morbid functioning. Multi-dimensional outcomes were assessed blind to baseline data. RESULTS: All participants were traced at a mean of 10.5 years post-index admission: 11 had died, 10 from non-natural causes. Of the surviving cases, 70% were comprehensively re-assessed by interview. Summary data on the remainder were collected from their family practitioner and chart review. Poor 10-year outcomes were predicted independently by poor pre-morbid functioning, baseline negative symptoms and longer DUP. The same measures, plus neurological soft signs, appeared to predict outcomes in a DSM-IV schizophrenia/schizo-affective subgroup. CONCLUSIONS: Poor pre-morbid functioning, baseline symptoms, DUP and neurological soft signs at onset independently predict poor long-term outcome in first-episode psychosis.

Reproducibility and changes in the apparent diffusion coefficients of solid tumours treated with combretastatin A4 phosphate and bevacizumab in a two-centre phase I clinical trial.

The purpose was to determine the reproducibility of apparent diffusion coefficient (ADC) measurements in a two-centre phase I clinical trial; and to track ADC changes in response to the sequential administration of the vascular disrupting agent, combretastatin A4 phosphate (CA4P), and the anti-angiogenic drug, bevacizumab. Sixteen patients with solid tumours received CA4P and bevacizumab treatment. Echo-planar diffusion-weighted MRI was performed using six b values (b = 0-750 s/mm(2)) before (x2), and at 3 and 72 h after a first dose of CA4P. Bevacizumab was given 4 h after a second dose of CA4P, and imaging performed 3 h post CA4P and 72 h after bevacizumab treatment. The coefficient of repeatability (r) of ADC total (all b values), ADC high (b = 100-750) and ADC low (b = 0-100) was calculated by Bland-Altman analysis. The ADC total and ADC high showed good measurement reproducibility (r% = 13.3, 14.1). There was poor reproducibility of the perfusion-sensitive ADC low (r% = 62.5). Significant increases in the median ADC total and ADC high occurred at 3 h after the second dose of CA4P (p < 0.05). ADC measurements were highly reproducible in a two-centre clinical trial setting and appear promising for evaluating the effects of drugs that target tumour vasculature.