94 research outputs found
Images beyond clinical presentation? Promising, but not confirmed in ESRD transplant candidates
Traditional, forgotten and new left ventricular systolic function parameters on a 64-row multidetector cardiac computed tomography: A reproducibility study
Background: Multidetector computed tomography angiography (MDCT) can provide data regardingcardiac function if a retrospective scanning is applied. We aimed at examination of thereproducibility of traditional and more sensitive parameters of the left ventricular (LV) contractilityby means of a 64-row CT in order to establish errors of measurement and to determine limits thatallow for a reliable detection of their changes.Methods and Results: A random sample of 25 individuals, including 15 females (aged 64 ± 13years) and 10 males (54 ± 13 years), who had MDCT examination were retrospectively includedin this study. Data reconstructions were performed on a dedicated workstation. In each case, axialimage series were created with a 10% step from 0% to 90% of the RR interval using a 2 mm slicethickness. LV volume was determined in each phase. Detailed LV volume changes within phaseswere analyzed to determine the largest difference between the neighbor phases (peak ejection volume,PEV, mL) during systole and to calculate the peak ejection rate (PER i.e. PEV/phase duration[1/10th of RR interval], mL/s). The derived parameters were calculated as the PER normalized forLVEDV (PER-V, 1/s), the PER normalized for LVM (PER-M, mL/g × s) and the PER normalizedfor LVEDV times the PER normalized for LVM product (PER-VM, ml/g × s2). Considering the errorspercentages, the respective values for intra- and inter-observer errors were around 5% and 8%for standard LV systolic measures. The percentage intra-observer errors’ ranged between –7.8% and–10.8%, and the inter-observer errors’ ranged between –11.8% and –15.7% for both PEV and PER.For the same reader, the percentage errors ranged between –8.7% and +11.9% for PER-V, –10% and+12.7% for PER-M and –18.2% and +24% for PER-VM. For the independent reader the correspondingvalues were –15.2% and +15.5%, –12.3% and +16.3%, and –26.6% and +30.9%. The intra--class coeffi cients for repeated measurements for both the same reader (intra-observer) or independentreader (inter-observer) did reach values above 0.9 and around 0.8, respectively.Conclusions: We concluded that traditional LV systolic parameters, as well as more sensitive measuresof cardiac contractility could be determined reliably by means of a 64-row MDCT. The errorsfor global LV systolic function measures amount to about 5%, for PEV and PER about 15% and forthe PER-derived parameters about 25%. The measurement errors established might help to assessthe signifi cance of changes in repeated MDCT examinations
On implementation of efficient inline DDoS detector based on AATAC algorithm
Distributed Denial of Service (DDoS) attacks constitute a major threat in the current Internet. These cyber‑attacks aim to flood the target system with tailored malicious network traffic overwhelming its service capacity and consequently severely limiting legitimate users from using the service. This paper builds on the state-of-the-art AATAC algorithm (Autonomous Algorithm for Traffic Anomaly Detection) and provides a concept of a dedicated inline DDoS detector capable of real-time monitoring of network traffic and near-real-time anomaly detection.The inline DDoS detector consists of two main elements: 1) inline probe(s) responsible for link-rate real-time processing and monitoring of network traffic with custom-built packet feature counters, and 2) an analyser that performs the near-real-time statistical analysis of these counters for anomaly detection. These elements communicate asynchronously via the Redis database, facilitating a wide range of deployment scenarios. The inline probes are based on COTS servers and utilise the DPDK framework (Data Plane Development Kit) and parallel packet processing on multiple CPU cores to achieve link rate traffic analysis, including tailored DPI analysis
Anatomical variants of left circumflex artery, coronary sinus and mitral valve can determine safety of percutaneous mitral annuloplasty
Background: The anatomical variants of the relations of the left circumflex artery (LCx) andthe coronary sinus (CS) determine the safety of percutaneous mitral annuloplasty (PMA) asan occlusion of the LCx and its consequences might occur in some cases. Thus, knowledge ofthe anatomy of cardiac anatomy and any variations are important for surgeons.Methods: In 320 (126 women, age 59 ± 11) patients, a 64-slice computed tomography (MSCT) (Aquilion 64) was performed due to a suspicion of coronary artery disease. A scanwith ECG-gating was performed using a slice thickness of 0.5 mm during a breath-hold. The helical pitch was 12.8, rotation time: 0.4 s and average tube voltage: 135 kV at 380 mA.100 mL of non-ionic contrast agent was given in three phases at an average rate of 4.5 mL/s.In each case, ten 3D volume rendering and 2D multiplanar reconstructions of the vessels werecreated (Vitrea 2).Results: The CS was visualized in all cases and the LCx in 315 (98.4%). In 302 (95.8%)cases, the CS was the dominant vessel; in 10 (3.17%) cases both vessels were equal and the LCxwas dominant in only 3 (0.9%) cases. 52 anatomical variants were identified; 3 of them werethe most common (in 164/315 cases; 50.8%). The CS usually lies above the atrioventricular(AV) sulcus (239–75.9%) and the LCx within the AV sulcus (173–54.9%). In 235 (74.6%)cases, the LCx was closer (than the CS) to the mitral valve. It was found that in 78 (24.7%) cases, the LCx was beneath the CS in selected phases (a risk of LCx occlusion by a PMA device).The LCx closer to the mitral valve, which is considered as a safe feature for PMA, wasobserved in only 75 (23.8%) of the cases. The most dangerous pattern was found in 19 cases(6.1%) — 2 or 3 CS/LCx crosses.Conclusions: The huge anatomical variability of the anatomy of the CS/LCx strengthens the role of MSCT before PMA implantation
A lexicographical approach to the contrastive analysis of Bulgarian and Polish phraseology
A lexicographical approach to the contrastive analysis of Bulgarian and Polish phraseologyThis article discusses the concept behind The Lexicon of Active Bulgarian and Polish Phraseology [Leksykon aktywnej frazeologii bułgarskiej i polskiej] and provides an overview of the key aspects of the methodology used for selecting and composing the dictionary’s entries. The authors outline the theoretical underpinnings of this project, touching on the issue of interlingual equivalence, and explain both the process of selecting and verifying phraseological material and the methodology of presenting lexicographical information in the Lexicon. The article includes various examples of active phraseological units from both languages. Konfrontacja językowa bułgarskiej i polskiej frazeologii – podejście leksykograficzneW artykule przedstawiono podstawowe założenia koncepcji i metodologii układania Leksykonu aktywnej frazeologii bułgarskiej i polskiej. Autorzy prezentują teoretyczne podstawy badania, poruszają problem ekwiwalencji międzyjęzykowej, zasad wyboru i weryfikacji prezentowanego materiału frazeologicznego, metodologii przedstawienia informacji leksykograficznej w Leksykonie. Materiał jest zilustrowany różnorodnymi przykładami aktywnych jednostek frazeologicznych w języku bułgarskim i polskim
Optimal visualization of heart vessels before percutaneous mitral annuloplasty
Background: Multi-slice computed tomography (MSCT) can be useful before percutaneous
mitral annuloplasty (PMA) procedures to visualize the relations between the mitral valve
(MV), left circumflex artery (LCx) and coronary sinus (CS).
Methods and results: We performed a 64-slice MSCT in 196 patients (109 male; age 56.6 ± 11.4) with suspected coronary artery disease. A retrospective scan with ECG-gating was
performed in each. In each case 3D VR and 2D MPR reconstructions were created. We used
a subjective assessment of the quality of visualization to find the optimal phases of visualization
for LCx, CS and both vessels together (relations). The quality of visualization were graded by
2 experts on 6-points scale. LCx was usually optimally visualized in the diastolic phases (70-80-90%) - 126/196 (64.3%). CS was usually optimally visualized in the systolic phases
(30-40-50%) - 177/196 (90.3%). The optimal phase for parallel visualization of LCx/CS
(to observe anatomical relations) was 70-80% - 140/196 (71.4%). Good quality visualization
was obtained for both vessels: LCx: 3.6 ± 1.4/CS: 4.1 ± 1.1.
Conclusions: Reconstructions of parallel visualization of LCx/CS for PMA procedures to
observe the relations between those vessels should be considered during diastole. In addition,
independent reconstructions should also be performed optimized for the LCx and the CS.
(Cardiol J 2012; 19, 5: 459-465
Traditional risk factors and coronary artery calcium in young adults
Background and methods: 362 symptomatic subjects of 45 years of age or younger were selected from a large database of around 4100 persons who underwent coronary artery calcium (CAC) scoring by means of a 64-multidetector computed tomography (MDCT). Amongst them, a group with the CAC > 0 Agatston units (n = 65) and a group with no detectable calcium (CAC = 0, n = 297) were compared in terms of risk factors presence. Risk factors considered were gender, body mass index, smoking habits, blood pressure level, blood lipids, presence of diabetes mellitus, family history of cardiovascular disease, and physical activity.
Results: The vast majority of subjects with a positive CAC were males (54, 83.1%) compared to those with a negative CAC (147, 49.5%, p 0 were observed in obese subjects (38.5% vs. 24.2%, p 0 (76.9% vs. 60.6%, p < 0.05). Also, the frequency of a positive CAC was significantly higher in patients with diabetes mellitus (10.8%), compared to those without diabetes mellitus (4.0%, p < 0.05). Effects of high lipids, family history, and physical activity were not observed. Accumulation of at least 4 risk factors was associated with more frequent positive CAC (26.0 vs. 15.9%, p < 0.05). Multivariate regression analysis showed that only male gender and presence of diabetes mellitus were independent predictors of a positive CAC in younger subjects (F = 5.06, p < 0.001, multiple R = 0.321).
Conclusions: Traditional risk factors, apart from gender and diabetes mellitus, do not seem to allow for distinguishing young persons with a premature coronary atherosclerosis. Therefore, CAC scoring might be considered justified in symptomatic young men with diabetes mellitus
Quality of visualization of coronary venous system in 64-slice computed tomography
Background: Multi-slice computed tomography (MSCT) can be used to visualize the anatomy
of the coronary venous system (CVS). A pre-procedural evaluation of target veins is a very important
element of cardiac resynchronization. Thus, the quality of visualization of the CVS is of great
importance. The aim of this study was to analyze the quality of visualization of CVS in MSCT.
Methods: In 220 subjects (129 male, average age 57.2 ± 11.8 years), a 64-slice CT (Aquilion 64,
Toshiba, Japan) was performed. A scan with ECG-gating was performed using a slice thickness of
0.5 mm during a breath-hold. In each case, 3D volume rendering and 2D MPR reconstructions
were created (Vitrea 2). The quality of visualization was graded independently by two cardiologists
and a radiologist trained in MSCT on a 0-5 points scale for the coronary sinus and main veins
[0 = not visible (lack of vein); 5 = visible as a smoothly bordered vascular structure].
Results: The best visualization of the CVS was obtained for coronary sinus (4.10 ± 1.08), the
worst for antero-lateral vein (2.11 ± 1.10). The average number of visible veins was 3.2 per
case. Statistically, more veins were visible in older subjects - in the group aged 60+ the
average number of visible veins was 3.6 ± 1.1 per case, whereas in those aged under 60 it was
2.9 ± 1.2 (p = 0.0001). There were no statistical gender differences in the quality of CVS
visualization.
Conclusions: The target veins for cardiac resynchronization therapy should be the lateral and
postero-lateral, which are usually well visible. Such a strategy could increase the usefulness of
MSCT. (Cardiol J 2011; 18, 2: 146-150
Can multi-slice computed tomography of the heart be useful in patients with epicardial leads?
New visualization methods are helpful in the noninvasive diagnosis of heart diseases. However,
sometimes epicardial and endocardial leads can cause problems due to a large number of
artifacts. Based on the presented case, we conclude that it is possible to perform multi-slice
computed tomography of coronary arteries despite the coexistence of transvenous and epicardial
leads
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