真鍋 徳子

With the increasing use of contrast-enhanced CT, optimizing the iodinated contrast medium (ICM) dose while maintaining diagnostically adequate image quality is essential to mitigate potential adverse effects on patients, the environment, and public health, as well as to reduce medical costs and address potential supply shortages. Multi-energy CT technologies including dual-energy CT and photon-counting detector CT enable data acquisition at multiple energy spectra, allowing for material characterization beyond the capabilities of conventional single-energy CT. Recent technical advancements and the growing adoption of these technologies in clinical practice have enhanced patient care across various diagnostic tasks. Among the spectral-based imaging options offered by multi-energy CT, virtual monoenergetic imaging holds significant promise for substantial ICM dose reduction due to the drastic improvement in iodine contrast at lower energy levels. This article aims to provide an overview of multi-energy CT technology and its utility for ICM dose optimization across various clinical indications, while also discussing current issues and related topics.

Diagnosing the cause of post-acute sequelae of COVID-19 (PASC, also known as long COVID)-related chest pain is often challenging in patients with a low pre-test probability of coronary artery disease. In a retrospective review of 273 consecutive patients who presented to the cardiovascular outpatient unit for cardiovascular PASC at the Hokkaido Cardiovascular Hospital, Japan, 8 patients were suspected to have vasospastic angina (VSA) and underwent acetylcholine provocation testing, 5 of whom (1.8%, 5/273) were newly diagnosed with VSA. Although the causal relationship between VSA and PASC should be studied further, the present study suggests that VSA can be a potential cause of chest pain in patients with PASC.

Myocarditis is a heterogeneous disease with diverse etiologies and clinical trajectories. Traditionally, its diagnosis has been guided by the Dallas criteria, which focus on histopathological features. Clinically, myocarditis is categorized as acute or chronic based on the duration since symptom onset. However, recent expert consensus, particularly in Western countries, has redefined myocarditis as either acute myocarditis or chronic inflammatory cardiomyopathy, including inflammatory dilated cardiomyopathy, reflecting advancements in viral genome analysis and histopathology. In 2023, the Japanese Circulation Society proposed the concept of chronic active myocarditis, a high-risk phenotype characterized by persistent inflammation and ongoing cardiomyocyte injury. The transition from acute myocarditis to its chronic phase involves complex immune mechanisms, with sustained myocardial inflammation driving ventricular remodeling and progression to heart failure. Cardiac magnetic resonance imaging and endomyocardial biopsy remain pivotal diagnostic modalities, though their diagnostic yield varies according to disease phase. Management strategies focus on heart failure treatment, arrhythmia control, and, in select cases, immunosuppressive therapy, particularly for virus-negative inflammatory cardiomyopathy. Although antiviral therapy has shown promise, its clinical efficacy remains uncertain. Given the evolving understanding of the chronic phase of myocarditis, further research is warranted to refine the diagnostic criteria and optimize personalized therapeutic strategies. This review gives a comprehensive overview of the pathophysiology, classification, and management of chronic myocarditis, with an emphasis on emerging disease concepts and their clinical implications.

As one of the key pillars of work style reform for physicians, task shifting and sharing from radiologists to radiological technologists has been considered. In May 2021, the Radiological Technologists Act was amended, allowing for the expansion of several duties. Alongside these legal and regulatory changes, a notice from Ministry of Health, Labour and Welfare was issued, highlighting tasks to be particularly promoted under the current system prior to the amendment of the Radiological Technologists Act. These amendments authorize radiological technologists to perform advanced and specialized tasks, such as securing venous access for contrast agent administration, which require significantly higher skill levels than their traditional roles. However, the amended legislation did not include specific guidelines, rules, or considerations for the practical implementation of these new duties in daily medical practice, especially from the perspectives of patient safety and quality of care. To address this, the Japan Radiological Society, the Japanese College of Radiology, and the Japan Association of Radiological Technologists collaborated with other related societies to develop guidelines on five key topics:-Guidelines for Safe Conduct of CT/MRI Contrast-Enhanced Examinations: Considering the expanded scope of practice for radiological technologists. -Guidelines for Safe Conduct of Nuclear Medicine Examinations: Aligned with the expanded responsibilities of radiological technologists. -Guidelines for Clinical application of Image-Guided Radiation Therapy (IGRT). -Guidelines for Safe Conduct of Angiography and Interventional Radiology (IR): Adapted for the expanded roles of radiological technologists. -Guidelines for Reporting Findings of STAT Imaging: Addressing urgent conditions with potential impact on life prognosis.