Automated Cardiac Resting Phase Detection Targeted on the Right Coronary Artery

Static cardiac imaging such as late gadolinium enhancement, mapping, or 3-D coronary angiography require prior information, e.g., the phase during a cardiac cycle with least motion, called resting phase (RP). The purpose of this work is to propose a fully automated framework that allows the detection of the right coronary artery (RCA) RP within CINE series. The proposed prototype system consists of three main steps. First, the localization of the regions of interest (ROI) is performed. Second, the cropped ROI series are taken for tracking motions over all time points. Third, the output motion values are used to classify RPs. In this work, we focused on the detection of the area with the outer edge of the cross-section of the RCA as our target. The proposed framework was evaluated on 102 clinically acquired dataset at 1.5T and 3T. The automatically classified RPs were compared with the reference RPs annotated manually by a expert for testing the robustness and feasibility of the framework. The predicted RCA RPs showed high agreement with the experts annotated RPs with 92.7% accuracy, 90.5% sensitivity and 95.0% specificity for the unseen study dataset. The mean absolute difference of the start and end RP was 13.6 $\pm$ 18.6 ms for the validation study dataset (n=102). In this work, automated RP detection has been introduced by the proposed framework and demonstrated feasibility, robustness, and applicability for static imaging acquisitions.Comment: Accepted for publication at the Journal of Machine Learning for Biomedical Imaging (MELBA) https://melba-journal.org/2023:00

Preliminary assessment of the imaging capability of the YAP-(S)PET small animal scanner in neuroscience

The new and fully engineered version of the YAP–(S)PET small animal scanner has been tested at the University of Mainz for preliminary assessment of its imaging capability for studies related to neuropharmacology and psychiatry. The main feature of the scanner is the capability to combine PET and SPECT techniques. It allows the development of new and interesting protocols for the investigation of many biological phenomena, more effectively than with PET or SPECT modalities alone. The scanner is made up of four detector heads, each one composed of a 4 � 4c m 2 of YAlO3:Ce (or YAP:Ce) matrix, and has a field of view (FOV) of 4 cm axially � 4c m + transaxially. In PET mode, the volume resolution is less than 8 mm 3 and is nearly constant over the whole FOV, while the sensitivity is about 2%. The SPECT performance is not so good, due to the presence of the multi-hole lead collimator in front of each head. Nevertheless, the YAP–PET scanner offers excellent resolution and sensitivity for performing on the availability of D2-like dopamine receptors on mice and rats in both PET and SPECT modalities

Progression of electrocardiogram changes in an untreated fabry disease: a case report

Background Fabry disease (FD) is a rare lysosomal storage disorder with multiorgan manifestation and associated with an increased morbidity and mortality. Fabry cardiomyopathy includes left ventricular `hypertrophy' (LVH), cardiac arrhythmias, and heart failure. We report a case of an untreated FD with characteristic findings in electrocardiogram (ECG) over a follow-up period of 10 years. Case summary A 53-year-old man with FD presented to our outpatient department. He suffered from symptomatic ventricular extrasystoles. Echocardiography detected LVH and reduced global longitudinal strain. Twelve years ago, first examination was conducted due to ventricular arrhythmias. Electrocardiogram showed a short PQ minus P-wave (PendQ) interval and negative T-waves. Over time, the number of leads with negative T-waves increased. Moreover, the echocardiography revealed a thickened left ventricular wall. Without any further examinations at that time, the patient was treated for arterial hypertension with proteinuria. Ten years after first symptoms appeared, FD was diagnosed utilizing cardiac magnetic resonance imaging and genetic tests. Hence, enzyme replacement therapy was initiated. Discussion The ECG is a fast diagnostic method and it may - even without additional organ manifestations - provide preliminary suspicion of FD. In particular, as shown in our case, a short PendQ and QT interval indicate FD. Over time, disease progression can be detected through ECG changes. T-waves correlate with an increasing LVH and a reduction in longitudinal function in echocardiographic examinations. Unexplained LVH must be followed by differential diagnosis. In case of confirmed FD, patients should be treated by multidisciplinary teams in experienced centres

ORC on tour: Integrated design of dynamic ORC processes and working fluids for waste-heat recovery from heavy-duty vehicles

Organic Rankine Cycles (ORC) convert low temperature heat into power. To maximize conversion efficiency, both ORC process and working fluid have to be tailored to the specific application. Common solution approaches for the resulting integrated design of ORC process and working fluid are limited to steady-state applications. However, for applications in dynamic settings, steady-state design approaches can lead to suboptimal solutions due to the neglect of the dynamic behavior. In this work, we present an approach for the integrated design of ORC process and working fluid considering the dynamics. The approach is based on the Continuous-Molecular Targeting–Computer-aided Molecular Design (CoMT-CAMD) framework. Herein, the physically based Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT) is used as thermodynamic model. To capture the ORC behavior under dynamic conditions, dynamic models for the ORC equipment are integrated into the process model. The result is an optimal control problem (OCP) yielding an optimal working fluid and the corresponding optimal process control for a given dynamic input. This so-called dynamic CoMT-CAMD approach is applied to an ORC for waste-heat recovery on a heavy-duty vehicle. Whereas steady-state design approaches fail, the presented approach identifies the optimal working fluid and the corresponding optimal control of the ORC process

Integrated design of ORC process and working fluid using PC-SAFT and Modelica

Organic Rankine Cycles (ORC) use low-temperature heat to generate electrical power. To use the full potential of a heat source, the ORC has to be tailored to the specific application. Tailoring a cycle means an integrated design of both process and working fluid. This integrated design leads to complex mixed-integer nonlinear program (MINLP) optimization problems. To avoid this complexity, working fluid candidates are commonly preselected using heuristic guidelines; subsequently, the process is optimized for the set of preselected working fluids. However, the preselection can fail, leading to suboptimal solutions. An approach for integrated design of ORC process and working fluid is the Continuous-Molecular Targeting–Computer-aided Molecular Design (CoMT-CAMD) approach. CoMT-CAMD employs the physically-based Perturbed-chain Statistical Associating Fluid Theory (PC-SAFT) equation of state as thermodynamic model of the working fluid. In PC-SAFT, each working fluid is described by a set of pure component parameters. In a first step, the so-called CoMT step, the discrete pure component parameters are relaxed resulting in a hypothetical optimal working fluid and the corresponding optimal process. In a second step, real working fluids with similar properties are identified using Computer-aided Molecular Design and a second-order Taylor approximation of the objective function around the hypothetical optimum. So far, the process models in CoMT-CAMD were implemented in a procedural programming language, which hinders the reusability, the use for more complex processes and dynamic simulations. In this work, we integrate CoMT-CAMD into the object-oriented modelling language Modelica. For this purpose, Modelica is directly linked to PC-SAFT. Thereby, already existing model libraries for Modelica can be used to model the ORC process. The resulting design approach is applied to the integrated design of an ORC process and working fluid for a geothermal power station.ISSN:1876-610