Imaging the Infected Heart

One-pot green synthesis of I@CNDs-Fe3O4 hybrid nanoparticles from kelp for multi-modal imaging in vivo

Multi-modal imaging technologies are playing an increasingly important role in biomedical research. However, there remains a demanding challenge to develop biocompatible contrast agents via a simple, green synthetic route for multi-modal imaging. Here we report the synthesis and applications of a new contrast agent for triple-modal imaging, that is, iodine-containing N-doping carbon nano-dots hybridized with Fe3O4 nanoparticles (I@CNDs-Fe3O4). We develop a one-pot, environment friendly hydrothermal method to synthesize the hybrid nanoparticles, primarily using kelp as the bioresource. I@CNDs-Fe3O4 nanoparticles have been demonstrated to exhibit excellent multi-modal imaging capabilities, including wavelength-tunable fluorescent imaging, X-ray attenuation for CT imaging enhancement, and T2-Weighted MR imaging. Importantly, the formulation of the hybrid nanoparticle provides an optimal solution to address the disequilibrium of osmotic pressure caused by the conventional CT imaging contrast agents of iodine compounds. The I@CNDs-Fe3O4 nanoparticles promise important applications in multi-modal imaging technologies in vivo as a versatile and biocompatible contrast agent.

Heart Infection Prognosis Analysis by Two-dimensional Spot Tracking Imaging

Cardiovascular death is one of the leading causes worldwide; an accurate identification followed by diagnosing the cardiovascular disease increases the chance of a better recovery. Among different demonstrated strategies, imaging on cardiac infections yields a visible result and highly reliable compared to other analytical methods. Two-dimensional spot tracking imaging is the emerging new technology that has been used to study the function and structure of the heart and test the deformation and movement of the myocardium. Particularly, it helps to capture the images of each segment in different directions of myocardial strain values, such as valves of radial strain, longitudinal strain, and circumferential strain. In this overview, we discussed the imaging of infections in the heart by using the two-dimensional spot tracking.

18-Fluoro-deoxyglucose-PET/Computed Tomography in Infection and Aseptic Inflammatory Disorders: Value to Patient Management

This communication is aimed specifically at exploring the possible practical advantages and potentials of 18-fluoro-deoxyglucose (FDG)-PET/ computed tomography (CT) that could translate into routine management of patients with infection and aseptic inflammatory disorders. From viewpoint of patient management, the applications can be classified into two broad categories, based upon primary intent of the investigation: [a] Diagnostic (eg, pyrexia of unknown origin and other localized infectious processes) and [b] Undertaking this as part of objective imaging assessment of early treatment response and thereby tailoring/altering therapy (eg, systemic infectious and non-infectious inflammatory diseases). Over the last decade, this promising FDG-PET/CT application has been debated and there is need to make systematic approach for defining its value to patient management.

The pivotal role of FDG-PET/CT in modern medicine

The technology behind positron emission tomography (PET) and the most widely used tracer, 2-deoxy-2-[18F]fluoro-D-glucose (FDG), were both conceived in the 1970s, but the latest decade has witnessed a rapid emergence of FDG-PET as an effective imaging technique. This is not least due to the emergence of hybrid scanners combining PET with computed tomography (PET/CT). Molecular imaging has enormous potential for advancing biological research and patient care, and FDG-PET/CT is currently the most widely used technology in this domain. In this review, we discuss contemporary applications of FDG-PET and FDG-PET/CT as well as novel developments in quantification and potential future indications including the emerging new modality PET/magnetic resonance imaging.

¹⁸F-FDG PET/CT diagnosis of unexpected extracardiac septic embolisms in patients with suspected cardiac endocarditis

PURPOSE

Acute infective endocarditis is a potentially life-threatening disease. Its outcome strongly depends on systemic embolization and extracardiac infections. When present, these conditions usually lead to a more aggressive therapeutic approach. However, the diagnosis of peripheral septic embolism is very challenging. (18)F-Fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT has proven to be accurate for the detection of inflammatory diseases and occult infections. The aim of this study was to assess the added value of (18)F-FDG PET/CT in the detection of extracardiac embolisms in the evaluation of patients with suspected valvular endocarditis (VE).

METHODS

Seventy-one patients with suspected infective endocarditis, enrolled between June 2010 and December 2012, underwent (18)F-FDG PET/CT with the standard procedure on a dedicated PET/CT scanner. Extracardiac findings were subsequently evaluated with other imaging procedures.

RESULTS

Of the 71 patients with suspicion of infective endocarditis, we found unexpected extracardiac findings in 17 patients (24%) without any clinical suspicion. Extracardiac findings were subsequently evaluated with other imaging procedures.

CONCLUSION

PET/CT detected unexpected extra sites of infection in 24% of cases, leading to changes in therapeutic management in a very relevant percentage of patients. These findings may have important therapeutic implications.

Positron emission tomography/computed tomography for diagnosis of prosthetic valve endocarditis: increased valvular 18F-fluorodeoxyglucose uptake as a novel major criterion

OBJECTIVES

This study sought to determine the value of (18)F-fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) for diagnosing prosthetic valve endocarditis (PVE).

BACKGROUND

The diagnosis of PVE remains challenging. In PVE cases, initial echocardiography is normal or inconclusive in almost 30%, leading to a decreased diagnostic accuracy for the modified Duke criteria.

METHODS

We prospectively studied 72 consecutive patients suspected of having PVE. All of the patients were subjected to clinical, microbiological, and echocardiographic evaluation. Cardiac PET/CT was performed at admission. The final diagnosis was defined according to the clinical and/or pathological modified Duke criteria determined during a 3-month follow-up.

RESULTS

Thirty-six patients (50%) exhibited abnormal FDG uptake around the site of the prosthetic valve. The sensitivity, specificity, positive predictive value, negative predictive value, and global accuracy were as follows (95% confidence interval): 73% (54% to 87%), 80% (56% to 93%), 85% (64% to 95%), 67% (45% to 84%), and 76% (63% to 86%), respectively. Adding abnormal FDG uptake around the prosthetic valve as a new major criterion significantly increased the sensitivity of the modified Duke criteria at admission (70% [52% to 83%] vs. 97% [83% to 99%], p = 0.008). This result was due to a significant reduction (p < 0.0001) in the number of possible PVE cases from 40 (56%) to 23 (32%).

CONCLUSIONS

The use of (18)F-FDG PET/CT was helpful for diagnosing PVE. The results of this study support the addition of abnormal FDG uptake as a novel major criterion for PVE.