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Aims Transcatheter aortic valve implantation (TAVI) has become a minimally invasive alternative to surgical aortic valve replacement. Hypo-attenuated leaflet thickening (HALT)—a marker of subclinical leaflet thrombosis commonly detected by cardiac computed tomography (CT) after TAVI—may influence valve durability and function. The purpose of this study was to compare commissural alignment of the native and prosthetic aortic valves in cardiac CT in subjects with and without HALT and thereby identify commissural misalignment as potential predictor for leaflet thrombosis after TAVI. Methods and results In 170 subjects, 85 with and 85 without HALT in post-TAVI CT, commissural orientation of the prosthesis was determined comparing native and prosthetic aortic valve orientation in cardiac CT by measuring the commissural angle relative to the right coronary ostium in the aortic valve plane. For the prosthetic valve, any deviation ≤ 15° compared to the native valve was classified as “aligned”; 16–30° as “mild”, 31–45° as “moderate” and ≥ 45° as “severe” misalignment. Among subjects with HALT, median angular deviation was higher (36°, IQR 31°) than in the control group (29°, IQR 29°, p = 0.042). “Severe” misalignment was more frequent in subjects who developed HALT (n = 31, 37%) compared to the control group (n = 17, 20%, p = 0.013). In logistic regression analysis, more severe deviation (p = 0.015, OR = 1.02 per 1° deviation) and “severe” misalignment (p = 0.018, OR = 2.2) represented independent predictors for the occurrence of HALT after TAVI. Conclusion Subclinical leaflet thrombosis after TAVI is associated with commissural misalignment. Potential clinical advantages of obtaining commissural alignment remain to be systematically assessed. Graphical abstract Association of HALT with commissural misalignment after TAVI. HALT hypo-attenuated leaflet thickening, IQR interquartile range, TAVI transfemoral aortic valve replacement

Coronary computed tomography (CT) angiography has become a major cornerstone in the diagnostic workup of cardiologic patients, particularly for evaluation of the coronary arteries and preprocedural planning of interventions for structural heart disease. Despite the possible problems that intensive electromagnetic radiation (including X‑rays) might cause when directly impacting on implanted cardiac devices, cardiac CT is a safe diagnostic test and should not be withheld from patients with devices if properly indicated. Sufficient image quality is paramount for the evaluation; hence, special attention should be paid to a low heart rate ( 60 bpm) and sufficient compliance with breathing instructions. Furthermore, pacemaker or implantable cardioverter-defibrillator (ICD) leads may cause metal artifacts, especially around the lead tip. Their dense material causes beam hardening and streak artifacts which may result in reduced image quality and limited diagnostic assessability. The prevalence of such artifacts depends not only on lead material but also on lead positioning relative to the gantry plane. Metal artifacts are more frequent in patients with unipolar leads and shock coils, which can impair the assessment of coronary arteries, mainly of the right coronary artery (RCA). Artifacts caused by left ventricular (LV) leads of cardiac resynchronization therapy (CRT) systems tend to affect assessment of the left circumflex artery (LCX). By using dual energy CT and postprocessing algorithms, the impact of artifacts can be reduced and diagnostic image quality can be achieved in most cases. Unfortunately, the actual occurrence of such artifacts or the degree of impairment of image quality cannot be reliably predicted.Die kardiale Computertomographie (CT) stellt heutzutage eine wichtige Säule in der kardiologischen Diagnostik dar, insbesondere zur Koronardiagnostik und präinterventionellen Planung bei strukturellen Herzerkrankungen. Trotz möglicher Auswirkungen von intensiver elektromagnetischer (Röntgen‑)Strahlung bei direkter Einwirkung auf implantierte kardiale Devices ist sie eine sichere und sinnvolle Untersuchung und sollte bei entsprechender Indikation nicht verwehrt werden. Zur Beurteilung ist die Bildqualität von entscheidender Bedeutung. Hierbei ist insbesondere auf eine niedrige Herzfrequenz ( 60/min) und auf die Einhaltung der Atemkommandos zu achten. Zusätzlich können bei Device-Trägern Artefakte durch einliegende Sonden von Schrittmachern oder implantierbaren Kardioverter-Defibrillatoren (ICD) auftreten, insbesondere an den Sondenspitzen. Das röntgendichte Material kann „beam hardening“ und „streak artifacts“ verursachen, welche die Bildqualität beeinträchtigen und die diagnostische Aussagekraft einschränken können. Das Sondenmaterial und die Sondenlage relativ zum Strahlengang sind relevant für das Auftreten der Metallartefakte. Diese treten besonders häufig bei unipolaren Sonden sowie Shock-Coils auf, und Beeinträchtigungen im Rahmen der Koronardiagnostik betreffen meist die Beurteilbarkeit der rechten Koronararterie (RCA). Artefakte durch linksventrikuläre (LV) Sonden bei Systemen zur kardialen Resynchronisationstherapie (CRT) beeinträchtigen vornehmlich die Beurteilung des Ramus circumflexus („left circumflex“, LCX). Durch den Einsatz von Dual-Energy-Scannern sowie Methoden des Post-Processings kann der Einfluss von Artefakten reduziert und häufig eine ausreichende diagnostische Bildqualität erreicht werden. Eine Vorhersage über das Auftreten von Artefakten oder die diagnostische Wertigkeit kann vorweg jedoch nicht hinreichend getroffen werden.

Objectives We evaluated the influence of image reconstruction kernels on the diagnostic accuracy of CT-derived fractional flow reserve (FFRCT) compared to invasive FFR in patients with coronary artery disease. Methods Sixty-nine patients, in whom coronary CT angiography was performed and who were further referred for invasive coronary angiography with FFR measurement via pressure wire, were retrospectively included. CT data sets were acquired using a third-generation dual-source CT system and rendered with medium smooth (Bv40) and sharp (Bv49) reconstruction kernels. FFRCT was calculated on-site using prototype software. Coronary stenoses with invasive FFR ≤ 0.80 were classified as significant. Agreement between FFRCT and invasive FFR was determined for both reconstruction kernels. Results One hundred analyzed vessels in 69 patients were included. Twenty-five vessels were significantly stenosed according to invasive FFR. Using a sharp reconstruction kernel for FFRCT resulted in a significantly higher correlation with invasive FFR (r = 0.74, p r = 0.58, p p = 0.04) and a higher AUC in ROC curve analysis to correctly identify/exclude significant stenosis (AUC = 0.92 vs. AUC = 0.82 for sharp vs. medium smooth kernel, respectively, p = 0.02). A FFRCT value of ≤ 0.8 using a sharp reconstruction kernel showed a sensitivity of 88% and a specificity of 92% for detecting ischemia-causing lesions, resulting in a diagnostic accuracy of 91%. The medium smooth reconstruction kernel performed worse (sensitivity 60%, specificity 89%, accuracy 82%). Conclusion Compared to invasively measured FFR, FFRCT using a sharp image reconstruction kernel shows higher diagnostic accuracy for detecting lesions causing ischemia, potentially altering decision-making in a clinical setting. Key Points • Image reconstruction parameters influence the diagnostic accuracy of simulated fractional flow reserve derived from coronary computed tomography angiography. • Using a sharp kernel image reconstruction algorithm delivers higher diagnostic accuracy compared to medium smooth kernel image reconstruction (gold standard invasive fractional flow reserve).

The effects of systemic fungicides on the host-pathogen interface between barley and powdery mildew were studied using cytological methods and specific staining procedures. Propiconazole, etaconazole, bitertanol, triforine, imazalil, nuarimol, tridemorph and fenpropimorph, which are all inhibitors of sterol biosynthesis, stopped growth of the fungus 2 days after application and led to deposits of plant origin around haustoria; these contained polysaccharides, especially callose. This encapsulation resembled the reaction often observed in resistant plants. In contrast, pyrazophos and ethirimol, applied at reduced concentrations, inhibited the fungus at the haustorial stage but did not induce encapsulation. These results suggest that encapsulation is not simply a reaction to the previously damaged fungus, but may be an indirect effect of sterol biosynthesis-inhibiting fungicides on the host metabolism which is elicited by the fungus. The results are discussed in the context of previous observations on the modes of action of these fungicides.