Abstract
Background
Positron Emission Tomography (PET) is increasingly utilized in radiomics studies for treatment evaluation purposes. Nevertheless, lesion volume identification in PET images is a ...critical and still challenging step in the process of radiomics, due to the low spatial resolution and high noise level of PET images. Currently, the biological target volume (BTV) is manually contoured by nuclear physicians, with a time expensive and operator-dependent procedure.
This study aims to obtain BTVs from cerebral metastases in patients who underwent L-
11
Cmethionine (11C-MET) PET, using a fully automatic procedure and to use these BTVs to extract radiomics features to stratify between patients who respond to treatment or not. For these purposes, 31 brain metastases, for predictive evaluation, and 25 ones, for follow-up evaluation after treatment, were delineated using the proposed method. Successively, 11C-MET PET studies and related volumetric segmentations were used to extract 108 features to investigate the potential application of radiomics analysis in patients with brain metastases. A novel statistical system has been implemented for feature reduction and selection, while discriminant analysis was used as a method for feature classification.
Results
For predictive evaluation, 3 features (asphericity, low-intensity run emphasis, and complexity) were able to discriminate between responder and non-responder patients, after feature reduction and selection. Best performance in patient discrimination was obtained using the combination of the three selected features (sensitivity 81.23%, specificity 73.97%, and accuracy 78.27%) compared to the use of all features. Secondly, for follow-up evaluation, 8 features (SUV
mean
, SUL
peak
, SUV
min
, SUL
peak
prod-surface-area, SUV
mean
prod-sphericity, surface mean SUV 3, SUL
peak
prod-sphericity, and second angular moment) were selected with optimal performance in discriminant analysis classification (sensitivity 86.28%, specificity 87.75%, and accuracy 86.57%) outperforming the use of all features.
Conclusions
The proposed system is able i) to extract 108 features for each automatically segmented lesion and ii) to select a sub-panel of 11C-MET PET features (3 and 8 in the case of predictive and follow-up evaluation), with valuable association with patient outcome. We believe that our model can be useful to improve treatment response and prognosis evaluation, potentially allowing the personalization of cancer treatment plans.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Background. Mitral valve (MV) procedure for dilated cardiomyopathy is becoming popular. We analyzed the indications to MV repair or replacement according to our 10-year experience.
Methods. From ...January 1990 to May 2000, 49 patients with dilated cardiomyopathy (12 idiopathic and 37 ischemic) underwent MV operation, 29 repair and 20 replacement. Preoperative evaluation included measurement of MV coaptation depth (CD) as a mirror of the abnormalities of MV apparatus leading to functional mitral regurgitation.
Results. Thirty-day mortality was 4.2% (2 patients). One-, 3-, 5-, and 10-year actuarial survival was, respectively, 90%, 87%, 78%, and 73%. The possibility of survival with at least one New York Heart Association functional class improvement was 88%, 76%, 71%, and 65%. Return of functional mitral regurgitation after MV repair was nearly inevitable; however, using a scale from 0 to 4, mean postoperative functional mitral regurgitation was 1.2 ± 0.8 when preoperative MVCD was 10 mm or less and 2.5 ± 0.7 when preoperative MVCD was 11 mm or higher (
p < 0.05). Globally, functional results were not influenced by the strategy of treatment (MV repair or replacement).
Conclusions. Mitral valve operation can give satisfying survival and good palliation of dilated cardiomyopathy. The MVCD can be helpful in the choice of the surgical strategy on the MV.
Left ventricular free-wall rupture (LVFWR) is an uncommon but serious mechanical complication of acute myocardial infarction. Surgical repair, though challenging, is the only definitive treatment. ...Given the rarity of this condition, however, results after surgery are still not well established. The aim of this study was to review a multicenter experience with the surgical management of post-infarction LVFWR and analyze the associated early outcomes.
Using the CAUTION (Mechanical Complications of Acute Myocardial Infarction: an International Multicenter Cohort Study) database, we identified 140 patients who were surgically treated for post–acute myocardial infarction LVFWR in 15 different centers from 2001 to 2018. The main outcome measured was operative mortality. Multivariate analysis was carried out by constructing a logistic regression model to identify predictors of postoperative mortality.
The mean age of patients was 69.4 years. The oozing type of LVFWR was observed in 79 patients (56.4%), and the blowout type in 61 (43.6%). Sutured repair was used in the 61.4% of cases. The operative mortality rate was 36.4%. Low cardiac output syndrome was the main cause of perioperative death. Myocardial rerupture after surgery occurred in 10 patients (7.1%). Multivariable analysis revealed that preoperative left ventricular ejection fraction (P < .001), cardiac arrest at presentation (P = .011), female sex (P = .044), and the need for preoperative extracorporeal life support (P = .003) were independent predictors for operative mortality.
Surgical repair of post-infarction LVFWR carries a high operative mortality. Female sex, preoperative left ventricular ejection fraction, cardiac arrest, and extracorporeal life support are predictors of early mortality.
Plants evolved in the presence of the Earth's magnetic field (or geomagnetic field, GMF). Variations in MF intensity and inclination are perceived by plants as an abiotic stress condition with ...responses at the genomic and metabolic level, with changes in growth and developmental processes. The reduction of GMF to near null magnetic field (NNMF) values by the use of a triaxial Helmholtz coils system was used to evaluate the requirement of the GMF for Lima bean (
L.) photosynthesis and reactive oxygen species (ROS) production. The leaf area, stomatal density, chloroplast ultrastructure and some biochemical parameters including leaf carbohydrate, total carbon, protein content and δ
C were affected by NNMF conditions, as were the chlorophyll and carotenoid levels. RubisCO activity and content were also reduced in NNMF. The GMF was required for the reaction center's efficiency and for the reduction of quinones. NNMF conditions downregulated the expression of the
homologs
and
, implying a connection between magnetoreception and photosynthetic efficiency. Finally, we showed that the GMF induced a higher expression of genes involved in ROS production, with increased contents of both H
O
and other peroxides. Our results show that, in Lima bean, the GMF is required for photosynthesis and that
and
may play a role in the modulation of MF-dependent responses of photosynthesis and plant oxidative stress.
Plants often encounter light intensities exceeding the capacity of photosynthesis (excessive light) mainly due to biotic and abiotic factors, which lower CO2 fixation and reduce light energy sinks. ...Under excessive light, the photosynthetic electron transport chain generates damaging molecules, hence leading to photooxidative stress and eventually to cell death. In this review, we summarize the mechanisms linking the excessive absorption of light energy in chloroplasts to programmed cell death in plant leaves. We highlight the importance of reactive carbonyl species generated by lipid photooxidation, their detoxification, and the integrating role of the endoplasmic reticulum in the adoption of phototolerance or cell-death pathways. Finally, we invite the scientific community to standardize the conditions of excessive light treatments.
Capturing light intensities exceeding the capacity of photosynthesis can lead to cell death in plant leaves. In this review, the authors summarize recent findings on the mechanisms mediating light-induced cell death, highlighting the roles of reactive carbonyl species, the endoplasmic reticulum, and phytohormones in the adoption of phototolerance versus cell-death pathways.
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