Precise localization of coronary arteries in Computed Tomography (CT) scans is critical from the perspective of medical assessment of coronary artery disease. Although various methods exist that offer high-quality segmentation of coronary arteries in cardiac contrast-enhanced CT scans, the potential of less invasive, non-contrast CT in this area is still not fully exploited. Since such fine anatomical structures are hardly visible in this type of medical images, the existing methods are characterized by high recall and low precision, and are used mainly for filtering of atherosclerotic plaques in the context of calcium scoring. In this paper, we address this research gap and introduce a deep learning algorithm for segmenting coronary arteries in multi-vendor ECG-gated non-contrast cardiac CT images which benefits from a novel framework for semi-automatic generation of Ground Truth (GT) via image registration. We hypothesize that the proposed GT generation process is much more efficient in this case than manual segmentation, since it allows for a fast generation of large volumes of diverse data, which leads to well-generalizing models. To investigate and thoroughly evaluate the segmentation quality based on such an approach, we propose a novel method for manual mesh-to-image registration, which is used to create our test-GT. The experimental study shows that the trained model has significantly higher accuracy than the GT used for training, and leads to the Dice and clDice metrics close to the interrater variability.
Abstract Background Cardiac Rhabdomyomas (CRs) are the most common cardiac tumors in children and often regress spontaneously, however, large lesions in neonates may cause hemodynamic compromise. Surgical resection is standard for symptomatic tumors, but complete excision may be challenging in cases of diffuse myocardial infiltration or multifocal lesions. Everolimus has emerged as a potential therapeutic option when surgery is not feasible. Case presentation A preterm infant with a giant left ventricular rhabdomyoma causing significant mitral regurgitation and clinical deterioration was unable to undergo complete surgical resection due to diffuse myocardial infiltration. Low-dose everolimus (0.25 mg twice weekly) was initiated, resulting in rapid clinical improvement and remarkable tumor regression from 3.79 × 2.0 cm to 2.7 × 0.7 cm over six weeks. Subsequent echocardiography tests confirmed improved left ventricular function and reduced mitral valve insufficiency Conclusions This case demonstrates that low-dose everolimus may be an effective therapeutic option for symptomatic neonatal CRs when total surgical resection is not feasible, offering a promising alternative for high-risk or unresectable cardiac tumors.
Heart failure with reduced ejection fraction (HFrEF) complicated by malignant ventricular arrhythmias remains a major therapeutic challenge, particularly in patients following complex mitral valve surgery. Conventional right ventricular pacing may aggravate ventricular dyssynchrony and further impair systolic function. Conduction system pacing (CSP) has emerged as a physiologic pacing strategy that directly activates the native His-Purkinje system, most commonly through His bundle pacing or left bundle branch area pacing (LBBAP), allowing near-normal ventricular activation. We report the case of a 70-year-old patient who developed severe heart failure, postoperative bradyarrhythmia, and an extremely high burden of ventricular arrhythmias following urgent mitral valve replacement. Despite pharmacological therapy and unsuccessful catheter ablation, electrical instability persisted. An implantable cardioverter-defibrillator (ICD) incorporating CSP using LBBAP was successfully implanted. Baseline QRS duration prior to pacing was 183 ms, whereas paced QRS duration after LBBAP implantation was 165 ms, consistent with near-physiologic ventricular activation. ECG documentation before and after device implantation demonstrated marked QRS narrowing and substantial suppression of ventricular ectopy after CSP-ICD implantation. Early post-implant monitoring demonstrated a marked reduction in ventricular ectopy and effective physiologic pacing. During 24 months of follow-up, pacing parameters remained stable, and no ventricular arrhythmias requiring ICD therapy were observed. This case demonstrates the feasibility of combining CSP with ICD therapy in selected patients early after mitral valve surgery. These findings are hypothesis-generating and require confirmation in prospective studies and larger clinical registries to define the broader clinical role and long-term durability of this strategy.
