| 1. |
- Jones, Robert P., et al.
(author)
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Patterns of Recurrence After Resection of Pancreatic Ductal Adenocarcinoma : A Secondary Analysis of the ESPAC-4 Randomized Adjuvant Chemotherapy Trial
- 2019
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In: JAMA Surgery. - : AMER MEDICAL ASSOC. - 2168-6254 .- 2168-6262. ; 154:11, s. 1038-1048
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Journal article (peer-reviewed)abstract
- Importance: The patterns of disease recurrence after resection of pancreatic ductal adenocarcinoma with adjuvant chemotherapy remain unclear.Objective: To define patterns of recurrence after adjuvant chemotherapy and the association with survival.Design, Setting, and Participants: Prospectively collected data from the phase 3 European Study Group for Pancreatic Cancer 4 adjuvant clinical trial, an international multicenter study. The study included 730 patients who had resection and adjuvant chemotherapy for pancreatic cancer. Data were analyzed between July 2017 and May 2019.Interventions: Randomization to adjuvant gemcitabine or gemcitabine plus capecitabine.Main Outcomes and Measures: Overall survival, recurrence, and sites of recurrence.Results: Of the 730 patients, median age was 65 years (range 37-81 years), 414 were men (57%), and 316 were women (43%). The median follow-up time from randomization was 43.2 months (95% CI, 39.7-45.5 months), with overall survival from time of surgery of 27.9 months (95% CI, 24.8-29.9 months) with gemcitabine and 30.2 months (95% CI, 25.8-33.5 months) with the combination (HR, 0.81; 95% CI, 0.68-0.98; P=.03). The 5-year survival estimates were 17.1% (95% CI, 11.6%-23.5%) and 28.0% (22.0%-34.3%), respectively. Recurrence occurred in 479 patients (65.6%); another 78 patients (10.7%) died without recurrence. Local recurrence occurred at a median of 11.63 months (95% CI, 10.05-12.19 months), significantly different from those with distant recurrence with a median of 9.49 months (95% CI, 8.44-10.71 months) (HR, 1.21; 95% CI, 1.01-1.45; P=.04). Following recurrence, the median survival was 9.36 months (95% CI, 8.08-10.48 months) for local recurrence and 8.94 months (95% CI, 7.82-11.17 months) with distant recurrence (HR, 0.89; 95% CI, 0.73-1.09; P=.27). The median overall survival of patients with distant-only recurrence (23.03 months; 95% CI, 19.55-25.85 months) or local with distant recurrence (23.82 months; 95% CI, 17.48-28.32 months) was not significantly different from those with only local recurrence (24.83 months; 95% CI, 22.96-27.63 months) (P=.85 and P=.35, respectively). Gemcitabine plus capecitabine had a 21% reduction of death following recurrence compared with monotherapy (HR, 0.79; 95% CI, 0.64-0.98; P=.03).Conclusions and Relevance: There were no significant differences between the time to recurrence and subsequent and overall survival between local and distant recurrence. Pancreatic cancer behaves as a systemic disease requiring effective systemic therapy after resection.Trial Registration: ClinicalTrials.gov identifier: NCT00058201, EudraCT 2007-004299-38, and ISRCTN 96397434. This secondary analysis of a randomized clinical trial investigates patterns of recurrence after adjuvant chemotherapy in pancreatic cancer and the association with survival.
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| 2. |
- Delgado, Anna Falk, et al.
(author)
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Glioma Grade Discrimination with MR Diffusion Kurtosis Imaging : A Meta-Analysis of Diagnostic Accuracy
- 2018
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In: Radiology. - : RADIOLOGICAL SOC NORTH AMERICA. - 0033-8419 .- 1527-1315. ; 287:1, s. 119-127
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Journal article (peer-reviewed)abstract
- Purpose: To assess the diagnostic test accuracy and sources of heterogeneity for the discriminative potential of diffusion kurtosis imaging (DKI) to differentiate low-grade glioma (LGG) (World Health Organization [WHO] grade II) from high-grade glioma (HGG) (WHO grade III or IV).Materials and Methods: The Cochrane Library, Embase, Medline, and the Web of Science Core Collection were systematically searched by two librarians. Retrieved hits were screened for inclusion and were evaluated with the revised tool for quality assessment for diagnostic accuracy studies (commonly known as QUADAS-2) by two researchers. Statistical analysis comprised a random-effects model with associated heterogeneity analysis for mean differences in mean kurtosis (MK) in patients with LGG or HGG. A bivariate restricted maximum likelihood estimation method was used to describe the summary receiver operating characteristics curve and bivariate meta-regression.Results: Ten studies involving 430 patients were included. The mean difference in MK between LGG and HGG was 0.17 (95% confidence interval [CI]: 0.11, 0.22) with a z score equal to 5.86 (P<.001). The statistical heterogeneity was explained by glioma subtype, echo time, and the proportion of recurrent glioma versus primary glioma. The pooled area under the curve was 0.94 for discrimination of HGG from LGG, with 0.85 (95% CI: 0.74, 0.92) sensitivity and 0.92 (95% CI: 0.81, 0.96) specificity. Heterogeneity was driven by neuropathologic subtype and DKI technique.Conclusion: MK shows high diagnostic accuracy in the discrimination of LGG from HGG.
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| 3. |
- Falk Delgado, Anna, et al.
(author)
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Diagnostic value of alternative techniques to gadolinium-based contrast agents in MR neuroimaging : a comprehensive overview
- 2019
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In: Insights into Imaging. - : Springer Science and Business Media LLC. - 1869-4101. ; 10:1
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Research review (peer-reviewed)abstract
- Gadolinium-based contrast agents (GBCAs) increase lesion detection and improve disease characterization for many cerebral pathologies investigated with MRI. These agents, introduced in the late 1980s, are in wide use today. However, some non-ionic linear GBCAs have been associated with the development of nephrogenic systemic fibrosis in patients with kidney failure. Gadolinium deposition has also been found in deep brain structures, although it is of unclear clinical relevance. Hence, new guidelines from the International Society for Magnetic Resonance in Medicine advocate cautious use of GBCA in clinical and research practice. Some linear GBCAs were restricted from use by the European Medicines Agency (EMA) in 2017.This review focuses on non-contrast-enhanced MRI techniques that can serve as alternatives for the use of GBCAs. Clinical studies on the diagnostic performance of non-contrast-enhanced as well as contrast-enhanced MRI methods, both well established and newly proposed, were included. Advantages and disadvantages together with the diagnostic performance of each method are detailed. Non-contrast-enhanced MRIs discussed in this review are arterial spin labeling (ASL), time of flight (TOF), phase contrast (PC), diffusion-weighted imaging (DWI), magnetic resonance spectroscopy (MRS), susceptibility weighted imaging (SWI), and amide proton transfer (APT) imaging.Ten common diseases were identified for which studies reported comparisons of non-contrast-enhanced and contrast-enhanced MRI. These specific diseases include primary brain tumors, metastases, abscess, multiple sclerosis, and vascular conditions such as aneurysm, arteriovenous malformation, arteriovenous fistula, intracranial carotid artery occlusive disease, hemorrhagic, and ischemic stroke.In general, non-contrast-enhanced techniques showed comparable diagnostic performance to contrast-enhanced MRI for specific diagnostic questions. However, some diagnoses still require contrast-enhanced imaging for a complete examination.
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| 4. |
- Falk Delgado, Anna, et al.
(author)
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Diffusion kurtosis imaging of gliomas grades II and III : a study of perilesional tumor infiltration, tumor grades and subtypes at clinical presentation
- 2017
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In: Radiology and Oncology. - : Walter de Gruyter GmbH. - 1318-2099 .- 1581-3207. ; 51:2, s. 121-129
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Journal article (peer-reviewed)abstract
- Background. Diffusion kurtosis imaging (DKI) allows for assessment of diffusion influenced by microcellular structures. We analyzed DKI in suspected low-grade gliomas prior to histopathological diagnosis. The aim was to investigate if diffusion parameters in the perilesional normal-appearing white matter (NAWM) differed from contralesional white matter, and to investigate differences between glioma malignancy grades II and III and glioma subtypes (astrocytomas and oligodendrogliomas).Patients and methods. Forty-eight patients with suspected low-grade glioma were prospectively recruited to this institutional review board-approved study and investigated with preoperative DKI at 3T after written informed consent. Patients with histologically proven glioma grades II or III were further analyzed (n=35). Regions of interest (ROIs) were delineated on T2FLAIR images and co-registered to diffusion MRI parameter maps. Mean DKI data were compared between perilesional and contralesional NAWM (student's t-test for dependent samples, Wilcoxon matched pairs test). Histogram DKI data were compared between glioma types and glioma grades (multiple comparisons of mean ranks for all groups). The discriminating potential for DKI in assessing glioma type and grade was assessed with receiver operating characteristics (ROC) curves.Results. There were significant differences in all mean DKI variables between perilesional and contralesional NAWM (p=< 0.000), except for axial kurtosis (p=0.099). Forty-four histogram variables differed significantly between glioma grades II (n=23) and III (n=12) (p=0.003-0.048) and 10 variables differed significantly between ACs (n=18) and ODs (n=17) (p=0.011-0.050). ROC curves of the best discriminating variables had an area under the curve (AUC) of 0.657-0.815.Conclusions. Mean DKI variables in perilesional NAWM differ significantly from contralesional NAWM, suggesting altered microstructure by tumor infiltration not depicted on morphological MRI. Histogram analysis of DKI data identifies differences between glioma grades and subtypes.
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| 5. |
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| 6. |
- Anton, Arthur Markus, et al.
(author)
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Hydrogen bonding and charge transport in a protic polymerized ionic liquid
- 2020
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In: Soft Matter. - : Royal Society of Chemistry (RSC). - 1744-683X .- 1744-6848. ; 16:26, s. 6091-6101
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Journal article (peer-reviewed)abstract
- Hydrogen bonding and charge transport in the protic polymerized ionic liquid poly[tris(2-(2-methoxyethoxy)ethyl)ammoniumacryloxypropyl sulfonate] (PAAPS) are studied by combining Fourier transform infrared (FTIR) and broadband dielectric spectroscopy (BDS) in a wide temperature range from 170 to 300 K. While the former enables to determine precisely the formation of hydrogen bonds and other moiety-specific quantized vibrational states, the latter allows for recording the complex conductivity in a spectral range from 10(-2)to 10(+9) Hz. A pronounced thermal hysteresis is observed for the H-bond network formation in distinct contrast to the reversibility of the effective conductivity measured by BDS. On the basis of this finding and the fact that the conductivity changes with temperature by orders of magnitude, whereas the integrated absorbance of the N-H stretching vibration (being proportional to the number density of protons in the hydrogen bond network) changes only by a factor of 4, it is concluded that charge transport takes place predominantly due to hopping conduction assisted by glassy dynamics (dynamic glass transition assisted hopping) and is not significantly affected by the establishment of H-bonds.
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| 7. |
- Drevhammar, Thomas, et al.
(author)
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Neonatal Resuscitation With T-Piece Systems : Risk of Inadvertent PEEP Related to Mechanical Properties
- 2021
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In: Frontiers in Pediatrics. - : Frontiers Media S.A.. - 2296-2360. ; 9
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Journal article (peer-reviewed)abstract
- Background: Resuscitation of infants using T-piece resuscitators (TPR) allow positive pressure ventilation with positive end-expiratory pressure (PEEP). The adjustable PEEP valve adds resistance to expiration and could contribute to inadvertent PEEP. The study indirectly investigated risk of inadvertent peep by determining expiratory time constants. The aim was to measure system expiratory time constants for a TPR device in a passive mechanical model with infant lung properties.Methods: We used adiabatic bottles to generate four levels of compliance (0.5–3.4 mL/cm H2O). Expiratory time constants were recorded for combinations of fresh gas flow (8, 10, 15 L/min), PEEP (5, 8, 10 cm H2O), airway resistance (50, 200 cm H2O/L/sec and none), endotracheal tube (none, size 2.5, 3.0, 3.5) with a peak inflation pressure of 15 cm H2O above PEEP.Results: Low compliances resulted in time constants below 0.17 s contrasting to higher compliances where the expiratory time constants were 0.25–0.81 s. Time constants increased with increased resistance, lower fresh gas flows, higher set PEEP levels and with an added airway resistance or endotracheal tube.Conclusions: The risk of inadvertent PEEP increases with a shorter time for expiration in combination with a higher compliance or resistance. The TPR resistance can be reduced by increasing the fresh gas flow or reducing PEEP. The expiratory time constants indicate that this may be clinically important. The risk of inadvertent PEEP would be highest in intubated term infants with highly compliant lungs. These results are useful for interpreting clinical events and recordings.
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| 8. |
- Falk, Anna, et al.
(author)
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Discrimination between glioma grades II and III in suspected low-grade gliomas using dynamic contrast-enhanced and dynamic susceptibility contrast perfusion MR imaging : a histogram analysis approach
- 2014
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In: Neuroradiology. - : Springer Science and Business Media LLC. - 0028-3940 .- 1432-1920. ; 56:12, s. 1031-1038
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Journal article (peer-reviewed)abstract
- IntroductionPerfusion magnetic resonance imaging (MRI) can be used in the pre-operative assessment of brain tumours. The aim of this prospective study was to identify the perfusion parameters from dynamic contrast-enhanced (DCE) and dynamic susceptibility contrast (DSC) perfusion imaging that could best discriminate between grade II and III gliomas.MethodsMRI (3 T) including morphological ((T2 fluid attenuated inversion recovery (FLAIR) and T1-weighted (T1W)+Gd)) and perfusion (DCE and DSC) sequences was performed in 39 patients with newly diagnosed suspected low-grade glioma after written informed consent in this review board-approved study. Regions of interests (ROIs) in tumour area were delineated on FLAIR images co-registered to DCE and DSC, respectively, in 25 patients with histopathological grade II (n = 18) and III (n = 7) gliomas. Statistical analysis of differences between grade II and grade III gliomas in histogram perfusion parameters was performed, and the areas under the curves (AUC) from the ROC analyses were evaluated.ResultsIn DCE, the skewness of transfer constant (k trans) was found superior for differentiating grade II from grade III in all gliomas (AUC 0.76). In DSC, the standard deviation of relative cerebral blood flow (rCBF) was found superior for differentiating grade II from grade III gliomas (AUC 0.80).ConclusionsHistogram parameters from k trans (DCE) and rCBF (DSC) could most efficiently discriminate between grade II and grade III gliomas.
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| 9. |
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| 10. |
- Falk Delgado, Anna, et al.
(author)
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Preoperative Quantitative MR Tractography Compared with Visual Tract Evaluation in Patients with Neuropathologically Confirmed Gliomas Grades II and III : A Prospective Cohort Study
- 2016
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In: Radiology research and practice. - : Hindawi Limited. - 2090-1941 .- 2090-195X. ; 2016:1, s. 1-15
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Journal article (peer-reviewed)abstract
- Background and Purpose. Low-grade gliomas show infiltrative growth in white matter tracts. Diffusion tensor tractography can noninvasively assess white matter tracts. The aim was to preoperatively assess tumor growth in white matter tracts using quantitative MR tractography (3T). The hypothesis was that suspected infiltrated tracts would have altered diffusional properties in infiltrated tract segments compared to noninfiltrated tracts. Materials and Methods. Forty-eight patients with suspected low-grade glioma were included after written informed consent and underwent preoperative diffusion tensor imaging in this prospective review-board approved study. Major white matter tracts in both hemispheres were tracked, segmented, and visually assessed for tumor involvement in thirty-four patients with gliomas grade II or III (astrocytomas or oligodendrogliomas) on postoperative neuropathological evaluation. Relative fractional anisotropy (rFA) and mean diffusivity (rMD) in tract segments were calculated and compared with visual evaluation and neuropathological diagnosis. Results. Tract segment infiltration on visual evaluation was associated with a lower rFA and high rMD in a majority of evaluated tract segments (89% and 78%, resp.). Grade II and grade III gliomas had similar infiltrating behavior. Conclusion. Quantitative MR tractography corresponds to visual evaluation of suspected tract infiltration. It may be useful for an objective preoperative evaluation of tract segment involvement.
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