The Gateway to a Bright Future

I became the chairman of the Japanese Society of Nuclear Cardiology in June 2022. This society was established in 1998, and through the excellent leadership of the many great chairmen, it is now recognized as a major academic society in Japan. The field of cardiac diagnostic imaging is very important in nuclear medicine, and I hope to help make further developments in this area.

According to the WHO report, ischemic heart disease is the leading cause of death worldwide. The number of ischemic heart disease patients is also expected to increase in the future, and early diagnosis is required for effective treatments. Nuclear cardiology will play an increasingly important role in this diagnostic imaging. In Japan, coronary revascularization by catheter intervention (PCI) for ischemic heart disease is used more widely than coronary aorta bypass surgery (CABG). However, it is important to prove the presence of physiological ischemia prior to coronary revascularization. Cardiac nuclear imaging plays a critical role in this process.

In 2020, the results of the Initial Invasive or Conservative Strategy for Stable Coronary Disease (ISCHEMIA) large-scale clinical trial were published. This study provided important new data on ischemia assessment and treatment strategies.

Careful selection of the non-invasive imaging modalities is required to determine the indications for coronary revascularization. However, although non-invasive cardiac imaging methods such as FFR-CT, stress MRI, and stress echocardiography have been performed for ischemia diagnosis, the optimal method remains controversial. Each test has a different ischemic index, and even in the same case, the evaluation of ischemia differs depending on the test used.

The presence or absence of physiological ischemia should be carefully examined using non-invasive tests. It is also important to select and use CT, MRI, echocardiogram, and cardiac nuclear medicine appropriately, as well as combinations of these modalities. This will aid in new discoveries.

There has been remarkable technological progress in diagnostic imaging equipment. Conventional Anger-type SPECT cameras are replacing semiconductor detectors, and PET scanners are increasing used worldwide. Such innovations have greatly advanced the assessment of myocardial blood flow. In particular, the coronary flow reserve (CFR), which is used to evaluate coronary microcirculatory disorders, can now be assessed non-invasively.

Note that cardiac nuclear imaging examination is also useful for diagnosing non-ischemic heart disease. The nuclear imaging test should be regarded as a functional imaging test, rather than a morphological test. The utility of this test was recently reported in diagnosis of cardiac amyloidosis and cardiac sarcoidosis, and it is becoming an essential examination for differential diagnosis of non-ischemic cardiomyopathy. Furthermore, we must consider what cardiologists require from nuclear cardiac diagnostic imaging and meet their needs. For that purpose, it is necessary to work in collaboration with various academic societies through joint meetings including symposiums.

Because of the COVID-19 pandemic, the world is now subject to unparalleled restrictions on social life. This has restricted our academic activities and opportunities for face-to-face discussions. Additionally, many medical institutions spend a lot of effort to prevent COVID-19 infection, and most hospitals are in a state of emergency. Thus, it is often difficult for patients, including those with heart disease, to receive appropriate imaging tests. This is a serious situation, and we hope that the COVID-19 pandemic will be resolved soon. 　Nevertheless, even under these circumstances, we continue to have global discussions online and continued medical research. This is amazing, and I think all healthcare professionals should be proud of these achievements.

Thank you.