Interobserver variability in target definition for stereotactic arrhythmia radioablation

Background: Stereotactic arrhythmia radioablation (STAR) is a potential new therapy for patients with refractory ventricular tachycardia (VT). The arrhythmogenic substrate (target) is synthesized from clinical and electro-anatomical information. This study was designed to evaluate the baseline interobserver variability in target delineation for STAR. Methods: Delineation software designed for research purposes was used. The study was split into three phases. Firstly, electrophysiologists delineated a well-defined structure in three patients (spinal canal). Secondly, observers delineated the VT-target in three patients based on case descriptions. To evaluate baseline performance, a basic workflow approach was used, no advanced techniques were allowed. Thirdly, observers delineated three predefined segments from the 17-segment model. Interobserver variability was evaluated by assessing volumes, variation in distance to the median volume expressed by the root-mean-square of the standard deviation (RMS-SD) over the target volume, and the Dice-coefficient. Results: Ten electrophysiologists completed the study. For the first phase interobserver variability was low as indicated by low variation in distance to the median volume (RMS-SD range: 0.02–0.02 cm) and high Dice-coefficients (mean: 0.97 ± 0.01). In the second phase distance to the median volume was large (RMS-SD range: 0.52–1.02 cm) and the Dice-coefficients low (mean: 0.40 ± 0.15). In the third phase, similar results were observed (RMS-SD range: 0.51–1.55 cm, Dice-coefficient mean: 0.31 ± 0.21). Conclusions: Interobserver variability is high for manual delineation of the VT-target and ventricular segments. This evaluation of the baseline observer variation shows that there is a need for methods and tools to improve variability and allows for future comparison of interventions aiming to reduce observer variation, for STAR but possibly also for catheter ablation

Dearomatization Approach Toward Superbenzoquinone Based Diradicaloid, Tetraradicaloid, and Hexaradicaloid

10.1002/anie.201907030Angewandte Chemie International Edition584014319-1432

Verificatieonderzoek ecologie Krimpenerwaard fase 2 en fase 3; onderzoek aan deklagen op slootdempingen; opschaling naar de Krimpenerwaard; bijlage 4 bij eindrapport Verificatieonderzoek ecologie Krimpenerwaard (Alterra-rapport 1016)

De vele met afval gedempte sloten in de Krimpenerwaard vormen een geval van ernstige bodemverontreiniging. In het gebiedsgericht bodembeheerplan wordt voorgesteld de milieurisico¿s te ondervangen door afdekken met 30cm schone grond. De noodzaak en toereikendheid van deze voorgenomen standaardmaatregel worden geverifieerd met betrekking tot landbouwkundige risico¿s, verspreidingsrisico¿s en ecologische risico¿s. Ecologische risico¿s werden bepaald op basis van aanwezigheid en beschikbaarheid van contaminanten in het dempingsmateriaal, herverontreiniging van de deklaag door bioturbatie en opname door planten, en effecten op bodemleven en weidevogels. Beoordeling van effecten vond plaats ten opzichte van een gebiedseigen referentie aan de hand van tevoren vastgestelde criteria. Dit rapport beschrijft het onderzoek aan locaties met een in het verleden reeds aangebrachte deklaag, en een opschaling van nadelige effecten naar gebiedsniveau

A pilot study to examine the association between human gut microbiota and the host's central obesity

10.1002/jgh3.12184JGH Open36480-48