Abstract Motivation This work presents the development of an open source tool for the quantification of dynamic susceptibility-weighted contrast-enhanced (DSC) perfusion studies. The development of ...this tool is motivated by the lack of open source tools implemented on open platforms to allow external developers to implement their own quantification methods easily and without the need of paying for a development license. Materials and methods This quantification tool was developed as a plugin for the ImageJ image analysis platform using the Java programming language. A modular approach was used in the implementation of the components, in such a way that the addition of new methods can be done without breaking any of the existing functionalities. For the validation process, images from seven patients with brain tumors were acquired and quantified with the presented tool and with a widely used clinical software package. The resulting perfusion parameters were then compared. Results Perfusion parameters and the corresponding parametric images were obtained. When no gamma-fitting is used, an excellent agreement with the tool used as a gold-standard was obtained ( R2 >0.8 and values are within 95% CI limits in Bland–Altman plots). Conclusion An open source tool that performs quantification of perfusion studies using magnetic resonance imaging has been developed and validated using a clinical software package. It works as an ImageJ plugin and the source code has been published with an open source license.
Altınel and Öncan (2005) (A new enhancement of the Clarke and Wright
savings heuristic for the capacitated vehicle routing problem) proposed a
parametric Clarke and Wright heuristic to solve the ...capacitated vehicle routing
problem (CVRP). The performance of this parametric heuristic is sensitive to
fine-tuning. Antinel and Öncan used an enumerative parameter-setting
approach and improved on the results obtained with the original Clarke and
Wright heuristic, but their approach requires much more computation time to
solve an instance. Battarra et al (2008) (Tuning a parametric
Clarke-Wright heuristic through a genetic algorithm) proposed a genetic
algorithm to set the parameter values. They succeeded in reducing the time
needed to solve an instance, but the quality of the solution was slightly worse.
In this paper, we propose to use the EAGH (empirically adjusted greedy
heuristics) procedure to set the parameter values. A computational experiment
shows the efficiency of EAGH; in an even shorter time, we improve on the best
results obtained with any parametric Clarke and Wright heuristic method proposed
in the literature.
The problem of setting the parameter values of a metaheuristic algorithm that optimise its performance is complex and time-consuming. Although the performance of a metaheuristic can be very sensitive ...to the parameter values, it is usual in the literature that the selection of the value parameters is not enough justified. There are in the literature two procedures that facilitate the task of fine-tuning: CALIBRA and the Nelder & Mead (N&M) algorithm. We propose a hands-off systematic procedure for fine-tuning metaheuristics that takes the advantages of CALIBRA and the N&M algorithm.
Background:
Despite medical therapy, 30% of patients with ulcerative colitis (UC) need to undergo surgery. Around 50% of patients with proctocolectomy with ileal pouch–anal anastomosis (IPAA) develop ...complications of the pouch. Clinical evidence for the use of infliximab (IFX) in refractory pouchitis is limited. The aim of this study was to report efficacy of IFX in these patients.
Methods:
A retrospective, multicenter study was designed. Patients older than 18 years with chronic refractory pouchitis treated with IFX (5 mg/kg) were included. Short‐term IFX efficacy was evaluated at week 8 and mid‐term efficacy at weeks 26 and 52. Complete response was defined as cessation of diarrhea and urgency and partial response as marked clinical improvement but persisting symptoms. The modified Pouchitis Disease Activity Index (mPDAI) without endoscopy was calculated when available.
Results:
Thirty‐three consecutive UC patients with chronic refractory pouchitis were included (18 male, mean age 45 years, range 21–67). At week 8, 21% patients achieved complete response and 63% showed partial clinical response. At weeks 26 and 52, 33% and 27% achieved complete response and 33% and 18% showed partial clinical response, respectively. Thirteen patients (39%) withdrew treatment (four for lack of efficacy, four for loss of response and five for adverse events). None of the potential factors analyzed had an influence on response to IFX.
Conclusions:
IFX was effective in the short‐ and mid‐term in patients with chronic refractory pouchitis. However, medication had to be discontinued in a high number of patients. (Inflamm Bowel Dis 2011;)
A microscopic laser-induced breakdown spectrometer was used to evaluate the analytical matrix effect commonly observed in the analysis of geological materials. Samples were analyzed in either the ...powder or pressed pellet forms. Calibration curves of a number of iron and aluminum compounds showed a linear relationship between the elemental concentration and peak intensity. A direct determination of elemental content can thus be made from extrapolation on these calibration curves. To investigate matrix effects, synthetic model samples were prepared from various iron and aluminum compounds spiked with SiO
2 and CaCO
3. The addition of these matrices had a pronounced analytical effect on those compounds prepared as pressed pellets. However, results indicated the absence of matrix effects when the samples were presented to the laser as loose powders on tape and results were compared to certified values, indicating the reliability of this approach for accurate analysis, provided the sample particle diameters are greater than ≈100
μm. Finally, the simultaneous analysis of two different elements was demonstrated using powders on tape.
Background Intestinal manometry is the current gold standard for diagnosing small bowel dysmotility; however, the functional significance of abnormal manometry is unknown. Our aim was to determine ...whether, and to what extent, intestinal gas propulsion is impaired in patients with manometrically proven dysmotility compared with healthy controls and patients with IBS.
Methods Clearance and tolerance of a jejunal gas load (12 mL min−1 for 2 h) were measured in 15 patients with severe abdominal symptoms and intestinal dysmotility evidenced by manometry, 15 patients with IBS and 15 healthy subjects. Thereafter, the effect of neostigmine (0.5 mg i.v. bolus) vs placebo (i.v. saline) was tested in six dysmotility patients.
Key Results After 2‐h gas infusion, patients with dysmotility developed significantly more gas retention (717 ± 91 mL) than IBS patients (372 ± 82 mL; P = 0.0037) and healthy subjects (17 ± 67 mL; P < 0.0001 vs dysmotility; P = 0.0060 vs IBS). Despite the greater retention in dysmotility patients, abdominal perception (2.5 ± 0.6 score) and distension (7 ± 2 mm girth increment) were similar to IBS (3.9 ± 0.6 score and 7 ± 2 mm, respectively). In dysmotility patients, neostigmine produced immediate clearance of gas, and by 30 min had reduced gas retention (by −552 ± 182 vs 72 ± 58 mL after saline; P = 0.008), abdominal symptoms (by −0.8 ± 0.3 score vs 0.3 ± 0.2 after saline; P = 0.019) and distension (girth change −5 ± 1 mm; P = 0.003 vs−2 ± 2 mm after saline).
Conclusion & Inferences Patients with manometric dysmotility have markedly impaired intestinal gas propulsion. In IBS patients, impaired gas propulsion is less pronounced but associated with concomitant sensory dysfunction and poor tolerance of gas retention.
Background We previously showed that changes in intra‐abdominal content induce a volume‐dependent muscular response of the anterior abdominal wall and the diaphragm. We aimed to determine the ...contribution of the thorax to abdominal accommodation and the influence of the intra‐abdominal expansion rate.
Methods Gas (1440 mL total load) was infused into the colon of nine healthy subjects, while abdomino‐thoracic perimeters (by tape measure), electromyography (EMG) activity of the diaphragm (via six ring electrodes over an esophageal tube in the hiatus), intercostals and anterior abdominal wall (via five pairs of surface electrodes) and the position of the diaphragm by ultrasonography were measured. Infusion rates of 24, 48, and 96 mL min−1 were tested on separate days.
Key Results Gas infusion induced anterior abdominal wall contraction (18 ± 1% EMG increment; P < 0.001) with relatively modest girth increment (4.9 ± 0.9 mm; P = 0.001), diaphragmatic relaxation (by 15 ± 1%; P < 0.001) with cephalad displacement (by 23 ± 6 mm; P = 0.005), and intercostal contraction (by 19 ± 2%; P < 0.001) with increased thoracic perimeter (by 2.0 ± 0.5 mm; P = 0.009). Responses were similar with the three infusion rates.
Conclusions & Inferences Accommodation of intra‐abdominal loads involves a volume‐related integrated abdomino‐thoracic response regardless of the expansion rate.
Background Using an experimental model of colonic gas infusion, we previously showed that the abdominal walls adapt to its content by an active phenomenon of abdominal accommodation. We now ...hypothesized that abdominal accommodation is a physiological phenomenon, and aimed to confirm that it can be induced by ingestion of a meal; a secondary aim was to determine whether the response to gut filling is region‐specific.
Methods In healthy subjects (n = 24) a nutrient test meal was administered until tolerated at a rate of 50 mL min−1. Electromyographic (EMG) activity of the anterior wall (upper and lower rectus, external and internal oblique) was measured via four pairs of surface electrodes, and EMG activity of the diaphragm via intraluminal electrodes on an esophageal tube. To address the secondary aim, the response to gastric filling was compared with that induced by colonic filling (1440 mL 30 min−1 anal gas infusion; n = 8).
Key Results Participants tolerated 927 ± 66 mL of meal (450–1500 mL). Meal ingestion induced progressive diaphragmatic relaxation (EMG reduction by 16 ± 2%; P < 0.01) and selective contraction of the upper abdominal wall (24 ± 2% increase in activity of the upper rectus and external oblique; P < 0.01 for both), with no significant changes in the lower rectus (4 ± 2%) or internal oblique (5 ± 3%). Colonic gas infusion induced a similar response, but with an overall contraction of the anterior wall.
Conclusions & Inferences Meal ingestion induces a metered and region‐specific response of the abdominal walls to accommodate the volume load. Abnormal abdominal accommodation could be involved in postprandial bloating.
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