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BACKGROUND AND PURPOSE: A previous study demonstrated the need to use delayed acquisition rather than first-pass data for accurate blood-brain barrier permeability surface product (BBBP) calculation from perfusion CT (PCT) according to the Patlak model, but the optimal duration of the delayed acquisition has not been established. Our goal was to determine the optimal duration of the delayed PCT acquisition to obtain accurate BBBP measurements while minimizing potential motion artifacts and radiation dose. MATERIALS AND METHODS: We retrospectively identified 23 consecutive patients with acute ischemic anterior circulation stroke who underwent a PCT study with delayed acquisition. The Patlak model was applied for the full delayed acquisition (90–240 seconds) and also for truncated analysis windows (90–210, 90–180, 90–150, 90–120 seconds). Linear regression of Patlak plots was performed separately for the full and truncated analysis windows, and the slope of these regression lines was used to indicate BBBP. The full and truncated analysis windows were compared in terms of the resulting BBBP values and the quality of the Patlak fitting. RESULTS: BBBP values in the infarct and penumbra were similar for the full 90- to 240-second acquisition (95% confidence intervals for the infarct and penumbra: 1.62–2.47 and 1.75–2.41 mL ×100 g−1 × min−1, respectively) and the 90- to 210-second analysis window (1.82–2.76 and 2.01–2.74 mL × 100 g−1 × min−1, respectively). BBBP values increased significantly with shorter acquisitions. The quality of the Patlak fit was excellent for the full 90- to 240-second and 90- to 210-second acquisitions, but it degraded with shorter acquisitions. CONCLUSIONS: The duration for the delayed PCT acquisition should be at least 210 seconds, because acquisitions shorter than 210 seconds lead to significantly overestimated BBBP values.

Tumoural angioneogenesis and its quantification are important in predicting the tumour grade and in the management with respect to the treatment available and to assess the response to treatment and the prognosis. It also plays major role in the growth ...

SUMMARY: Perfusion imaging of brain tumors has been performed by using various tracer and nontracer modalities and can provide additional physiologic and hemodynamic information, which is not available with routine morphologic imaging. Tumor vascular perfusion parameters obtained by using CT or MR perfusion have been used for tumor grading, prognosis, and treatment response in addition to differentiating treatment/radiation effects and non-neoplastic lesions from neoplasms. This article is an overview of the utility of PCT for assessment of brain tumors and describes the technique, its advantages, and limitations. BBB : blood-brain barrier CBF : cerebral blood flow CBV : cerebral blood volume DSC : dynamic susceptibility contrast FDG-PET : fluorodeoxyglucose–positron-emission tomography K trans : volume transfer coefficient MRI : MR imaging MTT : mean transit time MVCP : microvascular cellular proliferation MVD : microvascular density PCT : perfusion CT PS : permeability surface-area product rCBV : regional cerebral blood flow ROI : region of interest rPSR : relative percentage signal recovery SDF-1 : stromal derived factor-1 TDL : tumefactive demyelinating lesion TVA : total vascular area VEGF : vascular endothelial growth factor WHO : World Health Organization

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This patent search tool allows you not only to search the PCT database of about 2 million International Applications but also the worldwide patent collections. This search facility features: flexible search syntax; automatic word stemming and relevance ranking; as well as graphical results.

Objective: To determine diagnostic performance of serum PCT-Q (BRAHMS procalcitonin commercial kit) for bacterial lower respiratory tract infection among COPD patient with exacerbation. Material and methods: Prospective study was conducted in 40 hospitalized COPD patients with exacerbation between June 2008 and January 2009. Patient clinical profiles including the presence of infiltrate on chest roentgenogram, leukocytosis, positive sputum culture for bacteria and clinical outcome (mortality, length of stay and mechanical ventilation requirement) were determined. Serum procalcitonin concentration was measured by both PCT-Q commercial kits and standard quantitative assay on the first day of admission. Result: The diagnostic yield of PCT-Q for pneumonic exacerbation (the presence of pulmonary infiltrate) exhibits sensitivity and specificity of 100% and 71.9% whereas the test exhibits 50.0% sensitivity and 73.3% specificity for the presence of leukocytosis. However, positive PCT-Q provides 40.9 % sensitivity and 50.0%specificity for determining bacterial causes of exacerbation (defined by bacterial culture positivity in sputum). There is no significant correlation between positive PCT-Q and the mechanical ventilator requirement (p=0.864) as well as an average length of stay (p=0.139). The correlation between the positive PCT-Q and positive standard serum assay is noted. Conclusion: PCT-Q can be used as biomarker for pneumonic exacerbation in COPD patients whereas the PCT-Q level is poorly correlated with the clinical outcome. In addition, correlation of kits and standard assay is noted. However, the benefit of PCT-Q is shorter turnaround time.

Hepatocellular carcinoma (HCC) is the most common primary liver cancer. Imaging is important for establishing a diagnosis of HCC. Several imaging modalities including ultrasonography (US), computed tomography (CT), magnetic resonance imaging (MRI), positron ...

Sepsis is one of the leading causes of mortality and morbidity, even with the current availability of extended spectrum antibiotics and advanced medical care. Biomarkers offer a tool in facilitating early diagnosis, in identifying patient populations ...

Aims: To study the clinical significance and prognostic value of monitoring procalcitonin (PCT) and interleukin 6 (IL-6) levels in acute respiratory distress syndrome (ARDS) patients with multiple organ dysfunction (MODS). Methods: We enrolled 24 ARDS ...

BACKGROUND AND PURPOSE: The Patlak model has been applied to first-pass perfusion CT (PCT) data to extract information on blood-brain barrier permeability (BBBP) to predict hemorrhagic transformation in patients with acute stroke. However, the Patlak model was originally described for the delayed steady-state phase of contrast circulation. The goal of this study was to assess whether the first pass or the delayed phase of a contrast bolus injection better respects the assumptions of the Patlak model for the assessment of BBBP in patients with acute stroke by using PCT. MATERIALS AND METHODS: We retrospectively identified 125 consecutive patients (29 with acute hemispheric stroke and 96 without) who underwent a PCT study by using a prolonged acquisition time up to 3 minutes. The Patlak model was applied to calculate BBBP in ischemic and nonischemic brain tissue. Linear regression of the Patlak plot was performed separately for the first pass and for the delayed phase of the contrast bolus injection. Patlak linear regression models for the first pass and the delayed phase were compared in terms of their respective square root mean squared errors (√MSE) and correlation coefficients ( R ) by using generalized estimating equations with robust variance estimation. RESULTS: BBBP values calculated from the first pass were significantly higher than those from the delayed phase, both in nonischemic brain tissue (2.81 mL × 100 g−1 × min−1 for the first pass versus 1.05 mL × 100 g−1 × min−1 for the delayed phase, P < .001) and in ischemic tissue (7.63 mL × 100 g−1 × min−1 for the first pass versus 1.31 mL × 100 g−1 × min−1 for the delayed phase, P < .001). Compared with regression models from the first pass, Patlak regression models obtained from the delayed data were of better quality, showing significantly lower √MSE and higher R . CONCLUSION: Only the delayed phase of PCT acquisition respects the assumptions of linearity of the Patlak model in patients with and without stroke.

Clinical specimens are each inherently unique, limited and non-renewable. As such, small samples such as tissue biopsies are often completely consumed after a limited number of analyses. Here we present a method that enables fast and reproducible conversion ...

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Ischemic stroke results from occlusion of a cerebral artery, and it is the leading cause of disability and the fifth leading cause of death in the United States.1 Cerebral artery occlusion results in irreversible death of a component of cerebral tissue, which is referred to as the core infarction. There is an additional component of brain tissue that is ischemic, but viable, which is commonly referred to as the penumbra. The penumbra is at risk of irreversible infarction if timely restoration of blood flow is not achieved, and the preservation of the penumbra by restoration of arterial blood flow is the target of reperfusion therapy in the treatment of ischemic stroke.

Ischemic stroke results from occlusion of a cerebral artery, and it is the leading cause of disability and the fifth leading cause of death in the United States.1 Cerebral artery occlusion results in irreversible death of a component of cerebral tissue, which is referred to as the core infarction. There is an additional component of brain tissue that is ischemic, but viable, which is commonly referred to as the penumbra. The penumbra is at risk of irreversible infarction if timely restoration of blood flow is not achieved, and the preservation of the penumbra by restoration of arterial blood flow is the target of reperfusion therapy in the treatment of ischemic stroke.

Nature Communications - Whether accelerated Arctic warming is favorable for more frequent severe winter weather remains controversial. Here the authors present an observational analysis that links...

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Metallurgical and Materials Transactions A - Ballistic impact experiments were conducted on 12.5 mm thick commercial purity titanium and Ti-6 pct Al-4 pct V alloy plates using steel...

This patent search tool allows you not only to search the PCT database of about 2 million International Applications but also the worldwide patent collections. This search facility features: flexible search syntax; automatic word stemming and relevance ranking; as well as graphical results.

Procalcitonin concentrations are considered as a component of the inflammatory response and as an acute-phase marker, after shock or tissue injury (i.e. burn, trauma, surgery) or infections and sepsis. No data are so far available on the dynamics of procalcitonin ...

Background Early sepsis diagnosis is crucial for the correct management of burn patients, and it clearly influences outcomes. The systemic inflammatory response triggered by burns mimics sepsis presentation and complicates early sepsis diagnosis. Biomarkers were advocated to aid the diagnosis of early sepsis. Serum procalcitonin (PCT) exhibits fair accuracy and good correlation with sepsis severity, being used in diverse clinical settings. However, few studies have evaluated perioperative changes in PCT levels in burn patients. The present study evaluated PCT kinetics during the first days after burn injury and subsequent surgical interventions to assess PCT utility in distinguishing septic from non-septic inflammatory responses. Methods This study was a retrospective observational study of all burn patients admitted to the Coimbra Burns Unit (Portugal) between January 2011 and December 2014 who presented with a total burn surface area ≥ 15% and who underwent subsequent surgery. PCT kinetics were investigated a) during the first five days after burn injury and b) preoperatively during the five days after surgery in three subsets of patients, including those with no preoperative and no postoperative sepsis (NN), no preoperative but postoperative sepsis (NS), and preoperative and postoperative sepsis (SS). A total of 145 patients met the selection criteria and were included in the analysis. Results PCT levels in the first five days after burn injury were significantly higher in patients who developed at least one sepsis episode (n = 85) compared with patients who did not develop sepsis (n = 60). PCT values > 1.00 ng/mL were clearly associated with sepsis. Study participants (n = 145) underwent a total of 283 surgical interventions. Their distribution by preoperative/postoperative sepsis status was 142 (50.2%) in NN; 62 (21.9%) in NS; and 79 (27.9%) in SS. PCT values exhibited a parallel course in the three groups that peaked on the second postoperative day and returned to preoperative levels on the third day or later. The lowest PCT values were found in NN, and the highest values were observed in SS; the NS values were intermediate. Conclusions PCT kinetics coupled with a clinical examination may be helpful for sepsis diagnosis during the first days after burn injury and burn surgery.

* Virus drives risk-averse trade in Asia * China GDP misses expectations, but domestic demand impresses * Powell testimony to continue By Tom Westbrook SINGAPORE, July 15 (Reuters) - Spiking coronavirus cases kept the dollar supported in Asia on Thursday and it clawed back a little of a drop which had followed insistence from Federal Reserve chair Jerome Powell that he isn't in a hurry to withdraw policy support. The dollar was up about half a percent on the New Zealand dollar by midday in Tokyo, up about 0.3% on the Australian dollar and British pound and up roughly 0.1% against the euro. Mixed economic data in China - showing a largely expected growth slowdown, but signs of more resilient domestic demand - also did little to improve the mood.

Treasurer Josh Frydenberg says a fall in the unemployment rate below five per cent is a further sign...