A comparison of pseudo-continuous arterial spin labelling and dynamic susceptibility contrast MrI with and without contrast agent leakage correction in paediatric brain tumours

OBJECTIVE: To investigate correlations between MRI perfusion metrics measured by dynamic susceptibility contrast and arterial spin labelling in paediatric brain tumours. METHODS: 15 paediatric patients with brain tumours were scanned prospectively using pseudo-continuous arterial spin labelling (ASL) and dynamic susceptibility contrast (DSC-) MRI with a pre-bolus to minimise contrast agent leakage. Cerebral blood flow (CBF) maps were produced using ASL. Cerebral blood volume (CBV) maps with and without contrast agent leakage correction using the Boxerman technique and the leakage parameter, K2, were produced from the DSC data. Correlations between the metrics produced were investigated. RESULTS: Histology resulted in the following diagnoses: pilocytic astrocytoma (n = 7), glioblastoma (n = 1), medulloblastoma (n = 1), rosette-forming glioneuronal tumour of fourth ventricle (n = 1), atypical choroid plexus papilloma (n = 1) and pilomyxoid astrocytoma (n = 1). Three patients had a non-invasive diagnosis of low-grade glioma. DSC CBV maps of T1-enhancing tumours were difficult to interpret without the leakage correction. CBV values obtained with and without leakage correction were significantly different (p < 0.01). A significant positive correlation was observed between ASL CBF and DSC CBV (r = 0.516, p = 0.049) which became stronger when leakage correction was applied (r = 0.728, p = 0.002). K2 values were variable across the group (mean = 0.35, range = −0.49 to 0.64). CONCLUSION: CBV values from DSC obtained with and without leakage correction were significantly different. Large increases in CBV were observed following leakage correction in highly T1-enhancing tumours. DSC and ASL perfusion metrics were found to correlate significantly in a range of paediatric brain tumours. A stronger relationship between DSC and ASL was seen when leakage correction was applied to the DSC data. Leakage correction should be applied when analysing DSC data in enhancing paediatric brain tumours. ADVANCES IN KNOWLEDGE: We have shown that leakage correction should be applied when investigating enhancing paediatric brain tumours using DSC-MRI. A stronger correlation was found between CBF derived from ASL and CBV derived from DSC when a leakage correction was employed

Evaluation of intravoxel incoherent motion fitting methods in low-perfused tissue

Purpose To investigate the robustness of constrained and simultaneous intravoxel incoherent motion (IVIM) fitting methods and the estimated IVIM parameters (D, D* and f) for applications in brain and low‐perfused tissues. Materials and Methods Model data simulations relevant to brain and low‐perfused tumor tissues were computed to assess the accuracy, relative bias, and reproducibility (CV%) of the fitting methods in estimating the IVIM parameters. The simulations were performed at a series of signal‐to‐noise ratio (SNR) levels to assess the influence of noise on the fitting. Results The estimated IVIM parameters from model simulations were found significantly different (P < 0.05) using simultaneous and constrained fitting methods at low SNR. Higher accuracy and reproducibility were achieved with the constrained fitting method. Using this method, the mean error (%) for the estimated IVIM parameters at a clinically relevant SNR = 40 were D 0.35, D* 41.0 and f 4.55 for the tumor model and D 1.87, D* 2.48, and f 7.49 for the gray matter model. The most robust parameters were the IVIM‐D and IVIM‐f. The IVIM‐D* was increasingly overestimated at low perfusion. Conclusion A constrained IVIM fitting method provides more accurate and reproducible IVIM parameters in low‐perfused tissue compared with simultaneous fitting. Level of Evidence:

Individually assessed creep food consumption by suckled piglets: influence on post-weaning food intake characteristics and indicators of gut structure and hind-gut fermentation

Individual food intake characteristics and indicators of gut physiology of group-housed weanling pigs were measured in relation to pre-weaning consumption of creep food. Additionally, the effects of creep food consumption on pre-weaning body weight and gain were assessed. A total of 48 litters was used in two trials. From 11 days of age until weaning (day 28), all 48 litters were given a creep food (12.7 MJ net energy (NE) per kg, 15.2 g lysine per kg) supplemented with 10 g chromium III oxide per kg. Piglets showing green-coloured faeces on three sampling days were designated as good eaters, whereas piglets that never showed green faeces were labelled as non-eaters. Piglets having green faeces once or twice were designated as moderate eaters. Based on availability, body weight, litter origin, genotype and gender 29 good eaters, 32 moderate eaters and 29 non-eaters were selected in the first trial. In the second trial there were 30 good eaters, 33 moderate eaters, and 27 non-eaters. In each trial eight piglets of each creep-food eating type were immediately killed to serve as a reference group. The remaining piglets of each eating type were weaned and placed in pens equipped with computerized feeding stations so that distributions of body weight, litter origin, and gender were similar within pens. In each trial, eight pigs of each eating type were killed 5 days after weaning in order to determine villous heights and crypt depths in the proximal small intestine and volatile fatty acid (VFA) concentrations in the colon. While being suckled, body weight was not related to the pre-weaning consumption of creep food (P > 0.1) whereas average daily gain of the good eaters during the creep feeding period was higher (P 0.1) by the pre-weaning food consumption. After weaning, food intake and gain of the total group of good eaters were higher (P 0.1). Neither total VFA concentration nor the proportion of branched-chain VFA were affected by creep food consumption while being suckled. Total VFA concentration in the colon was positively associated with body-weight gain (P <0.001). This study confirms earlier findings that consumption of creep food while being suckled stimulates food intake and growth after weaning. However, the beneficial effects were not associated with a prevention of damage to morphology of the small intestine

Postponed or immediate drainage of infected necrotizing pancreatitis (POINTER trial): study protocol for a randomized controlled trial

Background Infected necrosis complicates 10% of all acute pancreatitis episodes and is associated with 15–20% mortality. The current standard treatment for infected necrotizing pancreatitis is the step-up approach (catheter drainage, followed, if necessary, by minimally invasive necrosectomy). Catheter drainage is preferably postponed until the stage of walled-off necrosis, which usually takes 4 weeks. This delay stems from the time when open necrosectomy was the standard. It is unclear whether such delay is needed for catheter drainage or whether earlier intervention could actually be beneficial in the current step-up approach. The POINTER trial investigates if immediate catheter drainage in patients with infected necrotizing pancreatitis is superior to the current practice of postponed intervention. Methods POINTER is a randomized controlled multicenter superiority trial. All patients with necrotizing pancreatitis are screened for eligibility. In total, 104 adult patients with (suspected) infected necrotizing pancreatitis will be randomized to immediate (within 24 h) catheter drainage or current standard care involving postponed catheter drainage. Necrosectomy, if necessary, is preferably postponed until the stage of walled-off necrosis, in both treatment arms. The primary outcome is the Comprehensive Complication Index (CCI), which covers all complications between randomization and 6-month follow up. Secondary outcomes include mortality, complications, number of (repeat) interventions, hospital and intensive care unit (ICU) lengths of stay, quality-adjusted life years (QALYs) and direct and indirect costs. Standard follow-up is at 3 and 6 months after randomization. Discussion The POINTER trial investigates if immediate catheter drainage in infected necrotizing pancreatitis reduces the composite endpoint of complications, as compared with the current standard treatment strategy involving delay of intervention until the stage of walled-off necrosis

Recognizing Resillience: Development and Validation of an Instrument to Recognize Resilience in Dutch Middle-Adolescents.

This paper presents the development and construct validation of an instrument for identification of resilient and less-resilient middle adolescents in high school. Purpose of this identification is a qualitative in-depth interview study of perceptions of resilient and less resilient middle-adolescents on their school environment. The qualitative study will function as examination of contentvalidity of the presented instrument. A 33-item Resilient Behavior Questionnaire (VVL) and a 105-item personality questionnaire NPV-J (Dutch Personality Questionnaire- Youngsters) were administered to a sample of 400 middle adolescent high school students (age range 14-16). It was hypothesized that scores on specific components in the VVL would correlate highly with relevant factors of personality in the NPV-J. Principal Component Analysis and Correlation Analysis served as methods of investigation. Results of the quantitative study reveal three components in the VVL and a high correlation between the scores on these components and the resilient personality factor perseverance and non-resilient factor inadequacy in the NPV-J. Discussion focuses on explanation of the results and implications for further development of the VVL

The IVOG feeding station: a tool for monitoring the individual feed intake of group-housed weanling pigs

Three batches of weanling pigs (total n=310 pigs) were used in a 34-day experiment to validate the use of an IVOG? feeding station as a tool for monitoring individual feed intake of group-housed weanling pigs. An IVOG? feeding station for weanling pigs consists of a single-space dry feeder placed on a load cell in combination with electronic identification. Data of 192 weanling pigs (18 pens) fed by IVOG? feeding stations were used to develop a protocol for the screening of IVOG? data. To assess the quality of the IVOG? data, the feed intake per pen computed from the screened IVOG? data was compared with the feed intake calculated from feed weighing. To assess the suitability of the use of IVOG? feeding stations under practical pig husbandry conditions, performance of 96 weanling pigs fed by the IVOG? feeding stations was compared with that of 118 weanling pigs that were fed using commercial single-space dry feeders (11 pens). Feed intake per pen computed from the IVOG? data was similar to the feed intake calculated from feed weighing (average recovery 101.1€for all test periods (p > 0.1). Furthermore, feed recovery did not differ among feeding stations (p > 0.1). During the first 13 days after weaning, the average daily feed intake (ADFI) of weanling pigs fed by the single-space dry feeders was higher (p 0.1) between both feeding systems. During the remaining 21 days and averaged over the entire experimental period, performance did not differ between the feeding systems (p > 0.1). It can be concluded that IVOG? feeding stations for weanling pigs are a suitable tool to monitor individual feed intake of group-housed weanling pigs

The IVOG feeding station: a tool for monitoring the individual feed intake of group-housed weanling pigs

Three batches of weanling pigs (total n=310 pigs) were used in a 34-day experiment to validate the use of an IVOG? feeding station as a tool for monitoring individual feed intake of group-housed weanling pigs. An IVOG? feeding station for weanling pigs consists of a single-space dry feeder placed on a load cell in combination with electronic identification. Data of 192 weanling pigs (18 pens) fed by IVOG? feeding stations were used to develop a protocol for the screening of IVOG? data. To assess the quality of the IVOG? data, the feed intake per pen computed from the screened IVOG? data was compared with the feed intake calculated from feed weighing. To assess the suitability of the use of IVOG? feeding stations under practical pig husbandry conditions, performance of 96 weanling pigs fed by the IVOG? feeding stations was compared with that of 118 weanling pigs that were fed using commercial single-space dry feeders (11 pens). Feed intake per pen computed from the IVOG? data was similar to the feed intake calculated from feed weighing (average recovery 101.1€for all test periods (p > 0.1). Furthermore, feed recovery did not differ among feeding stations (p > 0.1). During the first 13 days after weaning, the average daily feed intake (ADFI) of weanling pigs fed by the single-space dry feeders was higher (p 0.1) between both feeding systems. During the remaining 21 days and averaged over the entire experimental period, performance did not differ between the feeding systems (p > 0.1). It can be concluded that IVOG? feeding stations for weanling pigs are a suitable tool to monitor individual feed intake of group-housed weanling pigs

Individually measured feed intake characteristics and growth performance of group-housed weanling pigs: effects of sex, initial body weight, and body weight distribution within groups

Feed intake characteristics of 192, 27-d-old weanling pigs housed in groups and given ad libitum access to feed and water were measured individually with the use of computerized feeding stations. The groups were either homogeneous or heterogeneous as to BW distribution; pigs of three defined initial BW classes were used (mean BW of 6.7, 7.9, or 9.3 kg). The effects of BW distribution, BW class, and sex were studied with regard to average performance traits, latency time (interval between weaning and first feed intake), initial feed intake (intake during the first 24 h following first feed intake), and daily increase in feed intake during the interval between first feed intake and the day on which energy intake met or exceeded 1.5 times the maintenance requirement. Homogeneous and heterogeneous groups had similar latency times, initial feed intakes, and daily increases in feed intake. For the period 0 to 34 d after weaning, ADFI and ADG were also similar for homogeneous and heterogeneous groups, but gain:feed ratio was greater (P < 0.05) in the homogeneous groups. Gilts had higher (P < 0.05) initial feed intakes than barrows and also had greater (P < 0.05) ADFI and ADG during the period 0 to 13 d after weaning. Pigs with average BW of 6.7 kg had higher (P < 0.05) initial feed intakes than their counterparts with average BW of 7.9 kg and 9.3 kg, but the daily increase in feed intake was similar for the three groups. The lighter pigs had more daily visits and a lower feed intake per visit and tended to have a shorter postweaning latency to the onset of feeding than the heavier pigs. This study indicates that the high variability in early feeding behavior among group-housed weanling pigs may be related to BW and sex