Reduction of artefacts caused by hip implants in CT-based attenuation-corrected PET images using 2-D interpolation of a virtual sinogram on an irregular grid

Metallic prosthetic replacements, such as hip or knee implants, are known to cause strong streaking artefacts in CT images. These artefacts likely induce over- or underestimation of the activity concentration near the metallic implants when applying CT-based attenuation correction of positron emission tomography (PET) images. Since this degrades the diagnostic quality of the images, metal artefact reduction (MAR) prior to attenuation correction is required

Radionuclide Imaging of Viable Myocardium: Is it Underutilized?

Coronary artery disease is the major cause of heart failure in North America. Viability assessment is important as it aims to identify patients who stand to benefit from coronary revascularization. Radionuclide modalities currently used in the assessment of viability include 201Tl SPECT, 99mTc-based SPECT imaging, and 18F-fluorodexoyglucose (18F-FDG)-PET imaging. Different advances have been made in the last year to improve the sensitivity and specificity of these modalities. In addition, the optimum amount of viable (yet dysfunctional) myocardium is important to identify in patients, as a risk–benefit ratio must be considered. Patients with predominantly viable/hibernating myocardium can benefit from revascularization from a mortality and morbidity standpoint. However, in patients with minimal viability (predominantly scarred myocardium), revascularization risk may certainly be too high to justify revascularization without expected benefit. Understanding different radionuclide modalities and new developments in the assessment of viability in ischemic heart failure patients is the focus of this discussion