Interpretation and clinical management of patients with "Fixed" myocardial perfusion defects : A call for quantifying endocardial-to-epicardial distribution of blood flow

Nuclear medicine imaging methods of early radiation-induced cardiotoxicity: a ten-year systematic review

Introduction

Radiotherapy has significantly improved cancer survival rates, but it also comes with certain unavoidable complications. Breast and thoracic irradiation, for instance, can unintentionally expose the heart to radiation, leading to damage at the cellular level within the myocardial structures. Detecting and monitoring radiation-induced heart disease early on is crucial, and several radionuclide imaging techniques have shown promise in this regard.

Method

In this 10-year review, we aimed to identify nuclear medicine imaging modalities that can effectively detect early cardiotoxicity following radiation therapy. Through a systematic search on PubMed, we selected nineteen relevant studies based on predefined criteria.

Results

The data suggest that incidental irradiation of the heart during breast or thoracic radiotherapy can cause early metabolic and perfusion changes. Nuclear imaging plays a prominent role in detecting these subclinical effects, which could potentially serve as predictors of late cardiac complications.

Discussion

However, further studies with larger populations, longer follow-up periods, and specific heart dosimetric data are needed to better understand the relationship between early detection of cardiac abnormalities and radiation-induced heart disease.

Takotsubo cardiomyopathy induced by acute coronary syndrome: A case report

Takotsubo cardiomyopathy (TC) can be provoked by various triggers. It should be differentiated from acute coronary syndrome (ACS). Herein, we report a case of TC triggered by ACS. An 80-year-old woman was referred to the emergency room because of prolonged chest pain and ST-segment elevations. Echocardiography demonstrated left ventricular apical ballooning, findings suggestive of TC rather than ACS. Emergency coronary angiography revealed severe stenosis of the first diagonal branch of the left anterior descending coronary artery with distal flow delay. Recanalization of the diagonal branch was achieved by stent implantation and her chest pain was resolved. Cardiac magnetic resonance imaging showed increased signal intensities in the apex and the inner layer of the anterior wall on fat-suppressed, T2-weighted imaging. The present case highlights the importance of recognizing TC in relation to ACS not only as a differential diagnosis but also as a possibly concomitant condition unless clinical features fit one diagnosis.

Learning objective

Takotsubo cardiomyopathy can be provoked by various conditions and differentiated from acute coronary syndrome based on the presence or absence of coronary artery stenosis. Our case highlights the importance of acknowledging that takotsubo cardiomyopathy may be induced by acute coronary syndrome.

Complementary role of computed tomography angiography with fixed perfusion defects on SPECT myocardial perfusion imaging

Purpose

We present this case series exploring the complementary role of coronary computed tomography angiography (CCTA) to SPECT myocardial perfusion imaging (MPI) in the detection of myocardial necrosis.

Methods

A cardiac hybrid imaging database search identified 144 patients with a previous history of ST-segment elevation myocardial infarction treated with coronary revascularization. CCTA and MPI scans were evaluated to determine whether CCTA had an added value to MPI in detecting myocardial necrosis.

Results

Five patients with patent stents and/or bypass grafts and both fixed perfusion defects on MPI and sub-endocardial hypo-perfusion on CCTA were identified. The extent and location of the perfusion defects were closely correlated between the CCTA and SPECT MPI images.

Conclusion

In this series, CCTA and SPECT MPI were found to play a complementary role in the assessment of fixed perfusion defect, with CCTA adding specificity to the diagnosis of myocardial necrosis.

Non-invasive Imaging in Patients With Chronic Total Occlusions of the Coronary Arteries-What Does the Interventionalist Need for Success?

Chronic total occlusion (CTO) of coronary arteries is a common finding in patients with known or suspected coronary artery disease (CAD). Although tremendous advances have been made in the interventional treatment of CTOs over the past decade, correct patient selection remains an important parameter for achieving optimal results. Non-invasive imaging can make a valuable contribution. Ischemia and viability, two major factors in this regard, can be displayed using echocardiography, single-photon emission tomography, positron emission tomography, computed tomography, and cardiac magnetic resonance imaging. Each has its own strengths and weaknesses. Although most have been studied in patients with CAD in general, there is an increasing number of studies with positive preselectional factors for patients with CTOs. The aim of this review is to provide a structured overview of the current state of pre-interventional imaging for CTOs.