Assessment of Intracranial Arterial Stenosis with Multidetector Row CT Angiography: A Postprocessing Techniques Comparison

BACKGROUND AND PURPOSE: It was demonstrated the some patients with stroke have intracranial stenosis of 50% or greater and the identification of intracranial arterial stenosis is extremely important in order to plan a correct therapeutical approach. The aim of this study was to assess the image quality and intertechnique agreement of various postprocessing methods in the detection of intracranial arterial stenosis. MATERIAL AND METHODS: Eighty-five patients who were studied by using a multidetector row CT scanner were retrospectively analyzed. A total of 2040 segments were examined in the 85 subjects. Intracranial vasculature was assessed by using MPR, CPR, MIP, and VR techniques. Two radiologists reviewed the CT images independently. Cohen weighted κ statistic was applied to calculate interobserver agreement and for image accuracy for each reconstruction method. Sensitivity, specificity, PPV, and NPV were also calculated by using the consensus read as the reference. RESULTS: Two hundred fifteen (10.5%) stenosed artery segments were identified by the observers in consensus. The best intermethod κ values between observers 1 and 2 were obtained by VR and MIP (κ values of 0.878 and 0.861, respectively), whereas MPR provided the lowest value (κ value of 0.282). VR showed a sensitivity for detecting stenosed segments of 88.8% and 91.6% for observers 1 and 2, respectively. The highest positive predictive value was also obtained by VR at 95% and 99% for observers 1 and 2, respectively. Image accuracy obtained by using VR was the highest among all reconstruction methods in both observers (185/255 and 177/255 for observers 1 and 2, respectively). CONCLUSIONS: The results of our study suggest that VR and MIP techniques provide the best interobserver and intertechnique concordance in the analysis of intravascular cranial stenosis

Role of coronary microvascular dysfunction in heart failure with preserved ejection fraction

Heart failure with preserved ejection fraction (HFpEF) is one of the greatest unmet needs in modern medicine. The lack of an appropriate therapy may reflect the lack of an accurate comprehension of its pathophysiology. Coronary microvascular rarefaction in HFpEF was first hypothesized in an autopsy study that showed how HFpEF patients had lower microvascular density and more myocardial fibrosis than control subjects. This was later confirmed in vivo when it was noted that HFpEF is associated with reduced myocardial flow reserve (MFR) at single photon emission computed tomography (SPECT) and that coronary microvascular dysfunction may play a role in HFpEF disease processes. HFpEF patients were found to have lower coronary flow reserve (CFR) and a higher index of microvascular resistance (IMR). What is the cause of microvascular dysfunction? In 2013, a new paradigm for the pathogenesis of HFpEF has been proposed. It has been postulated that the presence of a proinflammatory state leads to coronary microvascular endothelial inflammation and reduced nitric oxide bioavailability, which ultimately results in heart failure. Recently, it has also been noted that inflammation is the main driver of HFpEF, but via an increase in inducible nitric oxide synthase (iNOS) resulting in a decrease in unfolded protein response. This review summarizes the current evidence on the etiology of coronary microvascular dysfunction in HFpEF, focusing on the role of inflammation and its possible prevention and therapy

Electromagnetic analysis and performance comparison of fully 3D-printed antennas

In this work, the possibility of directly prototyping antennas by exploiting additive manufacturing 3D-printing technology is investigated. In particular, the availability of printable filaments with interesting conductive properties allows for printing of even the antenna conductive elements. Three samples of a 2.45 GHz microstrip patch antenna have been 3D-printed by using different approaches and materials, and their performance evaluated and compared. In particular, the same dielectric substrate printed in polylactic acid (PLA) has been adopted in all cases, whilst copper tape and two different conductive filaments have been used to realize the conductive parts of the three antenna samples, respectively. Even if an expected radiation efficiency reduction has been observed for the conductive filament case, the comparative analysis clearly demonstrates that 3D-printing technology can be exploited to design working fully-printed antennas, including the conductive parts

COVID-19: The wrong target for healthcare liability claims

Regrettably, after a first moment of appreciation and praise of the citizens for healthcare personnel facing COVID 19 pandemia, numerous episodes of actions taken against them on the issue of their legal liability followed. Impelling is to start an argumentation on this problem that aims to establish a shared conduct in dealing with them. The authors propose a basis for discussion on which to begin a constructive debate

CT attenuation analysis of carotid intraplaque hemorrhage

Background and Purpose: Intraplaque hemorrhage is considered a leading parameter of carotid plaque vulnerability. Our purpose was to assess the CT characteristics of intraplaque hemorrhage with histopathologic correlation to identify features that allow for confirming or ruling out the intraplaque hemorrhage. MATERIALS AND METHODS: This retrospective study included 91 patients (67 men; median age, 657 years; age range, 41-83 years) who underwent CT angiography and carotid endarterectomy from March 2010 to May 2013. Histopathologic analysis was performed for the tissue characterization and identification of intraplaque hemorrhage. Two observers assessed the plaque's attenuation values by using an ROI (≤1 and ≥2 mm2). Receiver operating characteristic curve, Mann-Whitney, and Wilcoxon analyses were performed. RESULTS: A total of 169 slices were assessed (59 intraplaque hemorrhage, 63 lipid-rich necrotic core, and 47 fibrous); the average values of the intraplaque hemorrhage, lipid-rich necrotic core, and fibrous tissue were 17.475 Hounsfield units (HU) and 18.407 HU, 39.476 HU and 48.048 HU, and 91.66 HU and 93.128 HU, respectively, before and after the administration of contrast medium. The Mann-Whitney test showed a statistically significant difference of HU values both in basal and after the administration of contrast material phase. Receiver operating characteristic analysis showed a statistical association between intraplaque hemorrhage and low HU values, and a threshold of 25 HU demonstrated the presence of intraplaque hemorrhage with a sensitivity and specificity of 93.22% and 92.73%, respectively. The Wilcoxon test showed that the attenuation of the plaque before and after administration of contrast material is different (intraplaque hemorrhage, lipid-rich necrotic core, and fibrous tissue had P values of .006, .0001, and .018, respectively). CONCLUSIONS: The results of this preliminary study suggest that CT can be used to identify the presence of intraplaque hemorrhage according to the attenuation. A threshold of 25 HU in the volume acquired after the administration of contrast medium is associated with an optimal sensitivity and specificity. Special care should be given to the correct identification of the ROI

Why is it Important to Assess and Treat Alexithymia in the Cardiologic Field? An Overview of the Literature

Background: Alexithymia has been found to be associated with several somatic illnesses, such as cardiovascular, indicating that it might be a risk factor for early death in the long-term course of post-myocardial infarction. From the cardiology perspective, the aim was to collect current evidence about the relationship between alexithymia and somatic illness. Methods: The literature was synthesized and summarized in a narrative format. The literature search was carried out in PubMed. Pertinent studies published in the last 50 years written in English were included and organized by three main topics (“The relation between alexithymia and somatic illness from the cardiology perspective”; “How do assess alexithymia?”; “Treating alexithymia”) to be discussed. Results: High alexithymia is a dimensional trait that affects around 10% of the general population and up to 55% of people with essential hypertension. Also, the link between alexithymia and cardiovascular activity has been pointed out. There are several validated tools to assess alexithymia, as well as treatment options. Conclusion: Knowledge about the main features of alexithymia, as well as its assessment and treatment, can promote a multifactorial approach to the primary, secondary, and tertiary prevention of cardiac diseases

correlation between fissured fibrous cap and contrast enhancement preliminary results with the use of cta and histologic validation

BACKGROUND AND PURPOSE: Previous studies demonstrated that carotid plaques analyzed by CTA can show contrast plaque enhancement. The purpose of this preliminary work was to evaluate the possible association between the fissured fibrous cap and contrast plaque enhancement. MATERIALS AND METHODS: Forty-seven consecutive (men = 25; average age = 66.8 ± 9 years) symptomatic patients studied by use of a multidetector row CT scanner were prospectively analyzed. CTA was performed before and after contrast and radiation doses were recorded; analysis of contrast plaque enhancement was performed. Patients underwent carotid endarterectomy en bloc; histologic sections were prepared and evaluated for fissured fibrous cap and microvessel attenuation. The Mann-Whitney test was performed to evaluate the differences between the 2 groups. A multiple logistic regression analysis was performed to assess the effect of fissured fibrous cap and microvessel attenuation on contrast plaque enhancement. Receiver operating characteristic curve and area under the curve were also calculated. RESULTS: Twelve patients had fissured fibrous cap. In 92% (11/12) of fissured fibrous cap–positive plaques, we found contrast plaque enhancement, whereas in 69% (24/35) of the plaques without fissured fibrous cap contrast plaque enhancement was found. The Mann-Whitney test showed a statistically significant difference between the contrast enhancement in plaques with fissured fibrous cap (Hounsfield units = 22.6) and without fissured fibrous cap (Hounsfield units = 12.9) ( P = .011). On the regression analysis, both fissured fibrous cap and neovascularization were associated with contrast plaque enhancement ( P = .0366 and P = .0001). The receiver operating characteristic curve confirmed an association between fissured fibrous cap and contrast plaque enhancement with an area under the curve of 0.749 ( P = .005). CONCLUSIONS: The presence of fissured fibrous cap is associated with contrast plaque enhancement. Histologic analysis showed that the presence of fissured fibrous cap is associated with a larger contrast plaque enhancement compared with the contrast plaque enhancement of plaques without fissured fibrous cap

Electromagnetic characterisation of conductive 3D-Printable filaments for designing fully 3D-Printed antennas

Additive manufacturing (AM) 3D-printing technology is increasingly bringing benefits even in electromagnetics, with interesting prospects of application. Apart from the use of additive manufacturing for realising dielectric components of suitably shaped antennas, the ambitious target is, undoubtedly, the fully 3D realisation of radiofrequency and microwave circuits as well as radiating structures, including, therefore, conductive parts. In this regard, 3D-printable filaments with interesting conductive properties are being produced. However, their rigorous conductivity characterisation is still missing, making it difficult to estimate the real behaviour of the final 3D printed electromagnetic device. To fill this gap, the conductivity of one of the most interesting conductive filaments, named Electrifi, is first experimentally evaluated in a frequency range as large as 0.72-6 GHz, accounting also for its roughness. Then it has been validated by designing, realising, and testing three fully 3D-printed antennas. Specifically, two bow-tie antennas, operating at 2.8 and 4 GHz, respectively, and an ultrawideband antenna, borrowed from the existing literature, operating between 1 and 7 GHz. The good agreement between simulated and measured results demonstrates the reliability of the performed electrical conductivity characterisation, even in the design of efficient radiating structures entirely realised with thermoplastic materials with copper nanoparticle additives

Evaluating the Effectiveness of Planar and Waveguide 3D-Printed Antennas Manufactured Using Dielectric and Conductive Filaments

3D printing is a technology suitable for creating electronics and electromagnetic devices. However, the manufacturing of both dielectric and conductive parts in the same process still remain a challenging task. This study explores the combination of 3D printing with traditional manufacturing techniques for antenna design and fabrication, giving the designer the advantage of using the additive manufacturing technology only to implement the most critical parts of a certain structure, ensuring a satisfying electromagnetic performance, but limiting the production cost and complexity. In the former part of the study, the focus is on three proximity-coupled patch antennas. It demonstrates how hybrid devices made of metal, dielectric, and 3D-printed (using Fused Filament Fabrication) conductive polymers can be successfully simulated and created for different operating frequency bands. In the latter part, the study compares three prototypes of a 5G-NR, high gain, and wideband waveguide antenna: respectively a fully 3D printed one made of electrifi (which is the most conductive commercial 3D-printable filament), an all-metal one, and a hybrid (3D-printed electrifi & metal) one. The results show a 15% reduction in efficiency when using the all-Electrifi configuration compared to all-metal one, and a 4-5% reduction when using the hybrid version

Relationship between white matter hyperintensities volume and the circle of Willis configurations in patients with carotid artery pathology

Purpose We aimed to assess if there is a difference of distribution and volume of white matter hyperintensities (WMH) in the brain according to the Circle of Willis (CoW) configuration in patients with carotid artery pathology. Material and methods One-hundred consecutive patients (79 males, 21 females; mean age 70 years; age range 46–84 years) that underwent brain MRI before carotid endarterectomy (CEA) were included. FLAIR-WMH lesion volume was performed using a semi-automated segmentation technique and the status of the circle of Willis was assessed by two neuroradiologists in consensus. Results We found a prevalence of 55% of variants in the CoW configuration; 22 cases had one variants (40%); 25 cases had two variants (45.45%) and 8 cases showed 3 variants (14.55%). The configuration that was associated with the biggest WMH volume and number of lesions was the A1 + PcoA + PcoA. The PcoA variants were the most prevalent and there was no statistically significant difference in number of lesions and WMH for each vascular territory assessed and the same results were found for AcoA and A1 variants. Conclusion Results of our study suggest that the more common CoW variants are not associated with the presence of an increased WMH or number of lesions whereas uncommon configurations, in particular when 2 or more segment are missing increase the WMH volume and number of lesions. The WHM volume of the MCA territory seems to be more affected by the CoW configuration