2D perfusion angiography as quantitative method to evaluate iloprost effect on foot circulation

Summary: Background: Two-dimensional (2D) perfusion angiography is useful for the evaluation of foot perfusion in patients with critical limb-threatening ischemia (CLTI). Iloprost is a synthetic prostacyclin analogue presenting vasodilating properties. Aim of this study was to demonstrate the utility of 2D perfusion angiography as quantitative method to evaluate iloprost effect on foot circulation. Patients and methods: Between January 2020 and June 2020 25 patients with CLTI underwent below-the-knee (BTK) endovascular revascularization, intra-arterial administration of iloprost, and assessment of foot perfusion by 2D perfusion angiography. Iloprost was administered as an intra-arterial bolus of 3 μg over 1–3 minutes immediately after BTK revascularization. The 2D perfusion angiography was performed in a standardized manner with a 5-F catheter placed into the popliteal artery. A wide region of interest (ROI) was identified to assess the foot perfusion. Time–density curves were calculated by the perfusion software. Changes of the overall time-density curves before and after the administration of iloprost were evaluated. Results: Endovascular revascularization was successful in all cases. The mean reduction of systolic pressure value after iloprost administration was 23.1 mmHg. Eight patients (32%) experienced a minor complication (6 cutaneous rush, 2 symptomatic hypotension >40 mmHg). In 20 patients the time-density curves under ROI increased after the intra-arterial administration of iloprost (+31.6%, range from +4.9% to +78.7%). Five patients had no modification or a slight decrease of foot perfusion after iloprost administration (non-responders patients). Conclusions: Patients undergoing intra-arterial administration of iloprost accounted for a not negligible rate of minor complications. 2D perfusion angiography was valuable as quantitative method to evaluate the iloprost effect on foot circulation. This technique could be useful to classify the patients in responders or non-responders to iloprost therapy.

Application of Multislice Spiral CT Imaging Technology in the Diagnosis of Patients with Chest Sarcoidosis

Objective. To study the qualitative value of multislice spiral CT (MSCT) dynamic enhancement scanning for solitary nodules (SPN) of the chest. Methods. In this paper, 40 cases of chest nodules (including 25 cases of malignant nodules, 8 cases of inflammatory nodules, and 7 cases of benign nodules) were first scanned to determine the scope of nodules. At the two rates of 5 ml/s and 3 ml/s, CT dynamic enhancement scans were performed at the center of the nodule, and the CT values, peak enhancement (PH) and peak time (PT) before and after SPN enhancement, were recorded. It is mainly strengthened, with 80% (20/25) of net added value between 20 and 60 Hu, and 20% (5/25) >60 Hu or <20 Hu. The enhancement peak and peak time are (31.31 ± 10.62) Hu and 45 s, respectively. The time-density curve (T-DC) showed a slowly rising type; the inflammatory nodules were mainly severely strengthened, with a net increase of >40 Hu. The enhancement peak value is (49.25 ± 12.44) Hu, and the peak time is 80 s and 140 s. There is a characteristic of rising and falling and then rising in the curve. Conclusion. Multislice spiral CT dynamic enhancement scan reflects the dynamic characteristics of chest nodular blood flow, which can be used to noninvasively evaluate and diagnose SPN.

Statistical Relationship Between the Decrease of Major Seismicity and Drought in Southern California Since 1900

The seismicity in Southern California significantly decreased over the last decades. The decrease went in parallel with the reduction of meteoric groundwater recharge, which is a well-known factor capable of affecting seismicity. In this work the existence of a systematic statistical relationship was investigated by comparing the time density of Mw ≥ 5.7 earthquakes since 1900 with the time series of the Palmer Drought Severity Index (PDSI), an indicator of soil moisture roughly correlated with groundwater recharge. Given the non-stationarity of the two signals, the formal comparison was performed using both binomial logistic regression and cointegration testing. The analysis showed a significant statistical relationship, with peaks of seismicity 8 years behind those of PDSI. This finding suggests the hypothesis that groundwater recharge might affect earthquakes at a multi-year time scale. Proving this theory requires accurate measures and hydrogeological modeling, which is behind the scope of this work. Nonetheless, according to previous studies, the observed time lag might be explained by the slow propagation of pore pressure from the surface to the seismogenic volume. The ongoing trend towards an arid climate, made more evident by the recent severe droughts, might have contributed to the earthquake reduction of the last decades. The connection is particularly evident in the Salton Trough, with possible implications for the interpretation of its paleoseismicity.

COMPARISON OF OFFSET PRINTING INK QUALITY ON THE MARKET

Ink quality study have been observed on ink products in the market as a right confirmation of ink users for printint production. The study is also conducted to ensure the suitability of the ink with the printing materials and machines used by consumers. The observation was conducted on two brands of ink from the same manufacturer. The quality data studied were viscosity, spreadability, drying time, density and L*a*b. The results show that, although both inks are produced by the same manufacturer and are intended for the same market, there are differences in quality, namely one has a higher viscosity and a faster drying time than the other.Keywords—quality of printing ink, viscosity, spreadability, drying time, density and L*a*b

Carotid webs produce greater hemodynamic disturbances than atherosclerotic disease: a DSA time–density curve study

BackgroundCarotid webs (CaWs) are associated with ischemic strokes in younger patients without degrees of stenosis that are traditionally considered clinically significant.ObjectiveTo compare the hemodynamic parameters in the internal carotid artery (ICA) bulbar segment in patients with CaW with those in patients with atherosclerotic lesions using time–density curve (TDC) analysis of digital subtraction angiography (DSA) images.MethodsWe retrospectively assessed DSA images of 47 carotid arteries in 41 adult patients who underwent ICA catheter angiography for evaluation after ischemic stroke. Hemodynamic parameters, including full width at half maximum (FWHM) and area under the time–density curve (AUC) as proxies for increased flow stasis, were calculated using TDC analyses of a region of interest (ROI) in the ICA bulb immediately rostral to the web/atherosclerotic plaque, relative to a standardized ROI in the ipsilateral distal common carotid artery (eg, relative FWHM (rFWHM)). Hemodynamic parameters were compared using non-parametric Kruskal-Wallis tests. Logistic regression was used to predict CaW versus mild/moderate atherosclerosis for each hemodynamic parameter, adjusting for degree of stenosis.ResultsMean age of patients was 56.0±13 years, with 22 (53.7%) women. 17 CaWs, 22 atherosclerotic plaques (15 mild/moderate and 7 severe), and eight normal carotid arteries were assessed. Significant between-group differences were present in the relative total AUC (p<0.001), relative AUC at wash out (p=0.031), and relative FWHM (p=0.001). Logistic regression to predict CaW versus mild/moderate atherosclerosis showed that rAUC total had the highest predictive value (pAUC=0.96, 95% CI 0.90 to 1.00), followed by rFWHM (0.87, 95% CI 0.74 to 1.00), and rAUC WO (0.74, 95% CI (0.57 to 0.91).ConclusionCaW results in larger local hemodynamic disruption, characterized by flow stasis, than mild/moderate carotid atherosclerotic lesions, suggesting that CaWs may produce larger regions of thrombogenic flow stasis.

Response Time Distribution in a Tandem Pair of Queues with Batch Processing

Response time density is obtained in a tandem pair of Markovian queues with both batch arrivals and batch departures. The method uses conditional forward and reversed node sojourn times and derives the Laplace transform of the response time probability density function in the case that batch sizes are finite. The result is derived by a generating function method that takes into account that the path is not overtake-free in the sense that the tagged task being tracked is affected by later arrivals at the second queue. A novel aspect of the method is that a vector of generating functions is solved for, rather than a single scalar-valued function, which requires investigation of the singularities of a certain matrix. A recurrence formula is derived to obtain arbitrary moments of response time by differentiation of the Laplace transform at the origin, and these can be computed rapidly by iteration. Numerical results for the first four moments of response time are displayed for some sample networks that have product-form solutions for their equilibrium queue length probabilities, along with the densities themselves by numerical inversion of the Laplace transform. Corresponding approximations are also obtained for (non-product-form) pairs of “raw” batch-queues—with no special arrivals—and validated against regenerative simulation, which indicates good accuracy. The methods are appropriate for modeling bursty internet and cloud traffic and a possible role in energy-saving is considered.

Rippling 3-Riemannian structure describing gravity with dark matter effects

In an attempt to solve the missing mass problem, the paper introduces a probabilistic three-dimensional structure which is locally described by energy density, time density and a Riemannian metric. This proposition has its roots in the results of general relativity and quantum theory. On large scale, source mass binds energy density which causes curvature in the Riemannian manifold of space measure leading to variations in length and time scales. Additional gravitational effects are predicted for a source mass which are caused by the flow of bounded energy density and is proposed as a candidate for `dark matter' model. The paper makes testable predictions some of which may have already been observed as `dark matter' or `dark energy'.

Time-Inhomogeneous Feller-type Diffusion Process with Absorbing Boundary Condition

A time-inhomogeneous Feller-type diffusion process with linear infinitesimal drift $$\alpha (t)x+\beta (t)$$ α ( t ) x + β ( t ) and linear infinitesimal variance 2r(t)x is considered. For this process, the transition density in the presence of an absorbing boundary in the zero-state and the first-passage time density through the zero-state are obtained. Special attention is dedicated to the proportional case, in which the immigration intensity function $$\beta (t)$$ β ( t ) and the noise intensity function r(t) are connected via the relation $$\beta (t)=\xi \,r(t)$$ β ( t ) = ξ r ( t ) , with $$0\le \xi <1$$ 0 ≤ ξ < 1 . Various numerical computations are performed to illustrate the effect of the parameters on the first-passage time density, by assuming that $$\alpha (t)$$ α ( t ) , $$\beta (t)$$ β ( t ) or both of these functions exhibit some kind of periodicity.

Association of 2D Perfusion Angiography and Wound Healing Rate in Combined Femoro-popliteal and Below-the-Knee Lesions in Ischemic Patients Undergoing Isolated Femoro-popliteal Endovascular Revascularization

The aim of this study was to demonstrate the association between 2-dimensional (2D) perfusion angiography and wound healing rate in patients with combined femoro-popliteal and below-the-knee lesions in critical limb-threatening ischemia (CLTI) and foot wounds undergoing isolated femoro-popliteal endovascular revascularization. Between January and June 2019, 24 patients with multilevel CLTI and foot wounds underwent isolated femoro-popliteal endovascular revascularization. In all of them, an assessment of foot perfusion by 2D perfusion angiography was performed. To evaluate the foot perfusion, a region of interest was identified, and time–density curves were calculated. Changes of the overall time–density curves were evaluated together with transcutaneous oximetry (TcPO2) using bivariate correlation (Pearson correlation coefficient) and associated with 6-month wound healing. The mean increase of time–density curves was 212.2% (range from +9.8% to +1984.9%) and the mean increase of TcPO2 was 116.4% (range from −4.7% to 485.7%). No significant association between time–density curves and TcPO2 values (Pearson correlation coefficient: −0.24) was observed ( P = .3). At 6 months, wound healing occurred in 15 of 24 (62.5%) patients. In conclusion, this preliminary experience confirmed that 2D perfusion angiography associates with wound healing rate in CLTI patients with ischemic foot wounds and combined femoro-popliteal and below-the-knee lesions who are undergoing isolated femoro-popliteal endovascular revascularization. No association between time–density curves and TcPO2 values was observed.