In contrast to conventional diffusion magnetic resonance imaging (MRI), multi-b-value diffusion MRI methods are able to separate the signal from free water, pseudo-diffusion, and non-Gaussian components of water molecule diffusion. These approaches can then be utilised in so-called intravoxel incoherent motion imaging and diffusion kurtosis imaging. Various parameters provided by these methods can describe additional characteristics of the tissue microstructure and potentially help in the diagnosis and classification of various pathological processes. In this review, we present the basic principles and methods of analysing multi-b-value diffusion imaging data and specifically focus on the known possibilities for its use in the diagnosis of brain lesions. We also suggest possible directions for further research.
- MeSH
- difuzní magnetická rezonance * metody MeSH
- lidé MeSH
- magnetická rezonanční tomografie metody MeSH
- mozek diagnostické zobrazování MeSH
- nemoci nervového systému * MeSH
- pohyb těles MeSH
- senzitivita a specificita MeSH
- voda MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
PURPOSE: To demonstrate advantages of spectral dual-layer computed tomography (CT) in diagnosing pulmonary embolism (PE). To compare D-dimer values in patients with PE and concomitant COVID-19 pneumonia to those in patients without PE and COVID-19 pneumonia. To compare D-dimer values in cases of minor versus extensive PE. METHODS: A monocentric retrospective study of 1500 CT pulmonary angiographies (CTPAs). Three groups of 500 consecutive examinations: 1) using conventional multidetector CT (CTC), 2) using spectral dual-layer CT (CTS), and 3) of COVID-19 pneumonia patients using spectral dual-layer CT (COV). Only patients with known D-dimer levels were enrolled in the study. RESULTS: Prevalence of inconclusive PE findings differed significantly between CTS and CTC (0.8 % vs. 5.4 %, p < 0.001). In all groups, D-dimer levels were significantly higher in PE positive patients than in patients without PE (CTC, 8.04 vs. 3.05 mg/L; CTS, 6.92 vs. 2.57 mg/L; COV, 10.26 vs. 2.72 mg/L, p < 0.001). There were also statistically significant differences in D-dimer values between minor and extensive PE in the groups negative for COVID-19 (CTC, 5.16 vs. 8.98 mg/L; CTS 3.52 vs. 9.27 mg/L, p < 0.001). The lowest recorded D-dimer value for proven PE in patients with COVID-19 pneumonia was 1.19 mg/L. CONCLUSION: CTPAs using spectral dual-layer CT reduce the number of inconclusive PE findings. Plasma D-dimer concentration increases with extent of PE. Cut-off value of D-dimer with 100 % sensitivity for patients with COVID-19 pneumonia could be doubled to 1.0 mg/L. This threshold would have saved 110 (22 %) examinations in our cohort.
- Publikační typ
- časopisecké články MeSH
Ligula intestinalis (Linnaeus, 1758) is a tapeworm parasite with a worldwide distribution that uses a wide variety of fish species as its second intermediate host. In the present study, we investigated the prevalence and population genetic structure of plerocercoids of L. intestinalis in five common cyprinoid species, roach Rutilus rutilus (Linnaeus), freshwater bream Abramis brama (Linnaeus), white bream Blicca bjoerkna (Linnaeus), bleak Alburnus alburnus (Linnaeus), and rudd Scardinius erythrophthalmus (Linnaeus), collected in six water bodies of the Czech Republic (Milada, Most, Medard, Jordán, Římov and Lipno). Of the six study sites, the highest frequency of parasitism was recorded in Lake Medard (15%). The overall prevalence rate among the species was as follows: roach > rudd ≥ freshwater bream > bleak > white bream. Two mitochondrial genes (cytb and COI) were used to compare the population genetic structure of parasite populations using selected samples from the five fish species. The results of the phylogenetic analysis indicated that all populations of L. intestinalis were placed in Clade A, previously identified as the most common in Europe. At a finer scale, haplotype network and PCoA analyses indicated the possible emergence of host specificity of several mtDNA haplotypes to the freshwater bream. Moreover, pairwise Fixation indices (FST) revealed a significant genetic structure between the parasite population in freshwater bream and other host species. Parasite populations in roach not only showed the highest rate of prevalence but also depicted a maximum number of shared haplotypes with populations from bleak and rudd. Our results suggest that recent ecological differentiation might have influenced tapeworm populations at a fine evolutionary scale. Thus, the differences in prevalence between fish host species in different lakes might be influenced not only by the parasite's ecology, but also by its genetic diversity.
- MeSH
- Cestoda * genetika MeSH
- cestodózy * epidemiologie parazitologie veterinární MeSH
- Cyprinidae * parazitologie MeSH
- fylogeneze MeSH
- genetické struktury MeSH
- interakce hostitele a parazita MeSH
- jezera MeSH
- mitochondriální DNA MeSH
- nemoci ryb * epidemiologie parazitologie MeSH
- paraziti * MeSH
- populační genetika MeSH
- prevalence MeSH
- voda MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Česká republika MeSH
Main symptoms found in patients with same diseases as for example COVID-19 is febrile. The infrared thermography (IRT) represents a fast measurement in case of screening in public places. One of the limitations of IRT is the resolution of sensor, which has close connection with the distance between camera and ROI. To maximize the effectivity of resolution of the camera is to reduce the distance from the object. The aim of presented study showed the possibility how to protect the camera or medical staff that operates the device against potential infection or contamination from the person with infection. Two protective foils of different thickness (40 μm; 9 μm) were tested as a barrier between the IRT and the ROI (black body model and human face). Even though the results have shown that the transparent foils decrease linearly the measured value of the temperature, it can be used as a protective barrier between IRT and the object if an appropriate recalculation is done during analysis of IRT images. Results are acceptable in the case of 9μm foil especially. The authors see this possibility as a minor concession from IRT standards but as a great help in health protection. The transparent foil can be used as protective barrier of the infrared camera.
- MeSH
- COVID-19 prevence a kontrola MeSH
- horečka diagnóza MeSH
- infračervené záření MeSH
- kůže diagnostické zobrazování MeSH
- lidé MeSH
- tělesná teplota * MeSH
- termografie * metody MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
Autoři předkládají první zkušenosti s CT vyšetřováním hrudníku u pacientů s infekcí COVID-19 od začátku pandemie tohoto onemocnění v České republice. Rozebírají časovou křivku počtu vyšetření v korelaci s výsledky testu PCR i s dalšími metodami. Dále diskutují praktická hlediska provedení CT vyšetření s ohledem na hygienické podmínky a ochranu personálu. V diskusi pak zmiňují nejvýznamnější témata v souvislosti s indikacemi, technickým provedením i hodnocením nálezů jednotlivých zobrazovacích metod.
Authors present their first experiencies with CT imaging of thorax in patients with COVID-19 infection since the beginning of pandemy of this disease in the Czech Republic. Number of examination timeline is discussed in correla-tion with PCR tests and other methods. Practical aspects of CT examination is also mentioned, especially hygiene measures and staff protection. Discussion is focused to the most frequent topic linked with imaging method indications, technical issues and results of the individual imaging methods.
Catfish have spread across Europe and several countries out of this region within the last decades. Basic knowledge of this apex predator has revealed concerns of invasive behaviour and questions regarding its utilization as a biomanipulation species. However, a method enabling its regulation to a required level has not yet been developed. We simulated the impact of angling on the catfish population by method of hook-lines in two post-mining lakes with a monitored population consisting of tagged individuals and in two reservoirs as reference sites. Further, the efficiency of hook-lines as a reducing device was examined and the economic aspects were determined. Catfish population in localities where the species is unwanted or invasive may be efficiently reduced to a harmless level by hook-lines and angling (depending on the approach of anglers). The most efficient time of the year seems to be spring to early summer with catch efficiency of 5.4 individuals per 10 baits in one day. The catch efficiency markedly decreased during the second part of the year and did not exceed 2.8 individuals per 10 baits in one day. Mean size of catfish had negative impact whereas catfish biomass had positive impact on the catch efficiency. Trophic status and number of catfish in the locality had no impact on the catch efficiency. According to model, 11-18 bait-days per 1 ha per season is efficient to decrease catfish population to 10% of the original size. Both angling and hook-lines are very simple, they are financially and time bearable mechanisms of catfish regulation in any condition. However, catfish play an important role as a biomanipulative species in many localities. In this case where catfish is beneficial, angling presents a real threat of population collapse and loss of the biomanipulative effect.
PURPOSE: To compare the accumulation and effect of liposomal doxorubicin in liver tissue treated by radiofrequency ablation (RFA) and irreversible electroporation (IRE) in in vivo porcine models. MATERIALS AND METHODS: Sixteen RFA and 16 IRE procedures were performed in healthy liver of two groups of three pigs. Multi-tined RFA parameters included: 100 W, target temperature 105°C for 7 min. 100 IRE pulses were delivered using two monopolar electrodes at 2250 V, 1 Hz, for 100 µsec. For each group, two pigs received 50 mg liposomal doxorubicin (0.5 mg/kg) as a drip infusion during ablation procedure, with one pig serving as control. Samples were harvested from the central and peripheral zones of the ablation at 24 and 72 h. Immunohistochemical analysis to evaluate the degree of cellular stress, DNA damage, and degree of apoptosis was performed. These and the ablation sizes were compared. Doxorubicin concentrations were also analyzed using fluorescence photometry of homogenized tissue. RESULTS: RFA treatment zones created with concomitant administration of doxorubicin at 24 h were significantly larger than controls (2.5 ± 0.3 cm vs. 2.2 ± 0.2 cm; p = 0.04). By contrast, IRE treatment zones were negatively influenced by chemotherapy (2.2 ± 0.4 cm vs. 2.6 ± 0.4 cm; p = 0.05). At 24 h, doxorubicin concentrations in peripheral and central zones of RFA were significantly increased in comparison with untreated parenchyma (0.431 ± 0.078 µg/g and 0.314 ± 0.055 µg/g vs. 0.18 ± 0.012 µg/g; p < 0.05). Doxorubicin concentrations in IRE zones were not significantly different from untreated liver (0.191 ± 0.049 µg/g and 0.210 ± 0.049 µg/g vs. 0.18 ± 0.012 µg/g). CONCLUSIONS: Whereas there is an increased accumulation of periprocedural doxorubicin and an associated increase in ablation zone following RFA, a contrary effect is noted with IRE. These discrepant findings suggest that different mechanisms and synergies will need to be considered in order to select optimal adjuvants for different classes of ablation devices.
- MeSH
- doxorubicin aplikace a dávkování analogy a deriváty metabolismus MeSH
- elektroporace metody MeSH
- játra chirurgie MeSH
- modely u zvířat MeSH
- polyethylenglykoly metabolismus MeSH
- prasata MeSH
- radiofrekvenční ablace metody MeSH
- zvířata MeSH
- Check Tag
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Purpose: Quantify changes in blood flow velocity in the radial artery after local dynamic exercise and compare these results between a group of women and men. Acquire data of normal resting blood flow in the radial artery. Methods: We examined 42 healthy young volunteers (21 men and 21 women) of the age about 20. A pocket Doppler ultrasound device was used for measurements. Physical exercise was defined as one-minute-long, one-handed weightlifting. Hemodynamic parameters were registered during resting before exercise and immediately after exercise. Results: Resting baseline values: overall maximum blood flow velocity 26.49 cm/s (SD: 9.99 cm/s), mean blood flow velocity 8.46 cm/s (SD: 6.17 cm/s), and pulsatility index (PI) 5.46 (SD: 5.7) for the whole group. Mean percentage increase of maximum blood flow velocity is 36.5%, mean blood flow velocity 243%. PI was reduced by 52.8%. There was a presumed significant difference in the percentage change of PI between the group of women and men (p<0.05). There is also a typical change in velocity waveform after exercise. Conclusion: The most altered parameter is mean blood flow velocity, which corresponds to an observed change of velocity waveform probably caused by local vasodilatation lasting only for several seconds.
The higher proportion of males of the invasive round goby Neogobius melanostomus in samples from two activity selective passive fishing gears compared with one activity non-selective fishing gear in three Dutch lakes is related to higher male locomotory activity and is a sex-dependent trait. This difference in activity reflects the different ecology of male and female N. melanostomus.
- MeSH
- ekologie metody MeSH
- fenotyp MeSH
- jezera MeSH
- lokomoce * MeSH
- Perciformes * MeSH
- zavlečené druhy * MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
For ethical reasons and animal welfare, it is becoming increasingly more important to carry out ecological surveys with a non-invasive approach. Information about fish distribution and abundance in the upper water column is often fundamental. However, this information is extremely hard to obtain using classical hydroacoustic methods. We developed a rigid frame system for pushing upward looking transducers of the scientific echo sounder (38 and 120 kHz) in front of the research vessel. The efficiency of the new approach for monitoring juvenile fish at night was investigated by comparing the results with a quantitative fry trawl in the Římov Reservoir in the Czech Republic. The experimental setup enabled comparisons for the 0-3 m and 3-6 m depth layers, which are utilized by almost all juvenile fish in summer. No statistically significant differences in the estimated abundance of juveniles were found between the two sampling methods. The comparison of abundance estimates gathered by the two frequencies were also not significantly different. The predicted mean lengths from acoustic sampling and the trawl catches differed by less than 10 mm in all comparisons. Results suggest that mobile hydroacoustic upward-looking systems can fill the methodological gap in non-invasive surveying of surface fishes.
- MeSH
- akustika přístrojové vybavení MeSH
- jezera MeSH
- měniče MeSH
- populační dynamika MeSH
- průzkumy a dotazníky MeSH
- roční období MeSH
- rozšíření zvířat fyziologie MeSH
- rybářství statistika a číselné údaje MeSH
- ryby fyziologie MeSH
- zachování přírodních zdrojů * MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
