Journal of nuclear medicine : official publication, Society of Nuclear Medicine
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Accurate γ-photon attenuation correction (AC) is essential for quantitative PET/MRI as there is no simple relation between MR image intensity and attenuation coefficients. Attenuation maps (μ-maps) can be derived by segmenting MR images and assigning attenuation coefficients to the compartments. Ultrashort-echo-time (UTE) sequences have been used to separate cortical bone and air, and the Dixon technique has enabled differentiation between soft and adipose tissues. Unfortunately, sequential application of these sequences is time-consuming and complicates image registration. ⋯ The UTILE MRI sequence enables the generation of MRI-based 4-class μ-maps without anatomic priors, yielding results more similar to CT-based results than can be obtained with 3-class segmentation only.
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Whether (18)F-FDG PET can detect inflammation in the coronary arteries remains controversial. We examined (18)F-FDG uptake at the culprit sites of acute myocardial infarction (AMI) after percutaneous coronary stenting (PCS) by coregistering PET and coronary CT angiography (CTA). ⋯ Systematic fusion of (18)F-FDG PET and coronary CTA demonstrated increased culprit site (18)F-FDG uptake more commonly in patients with AMI than in patients with stable CAD. However, this approach failed to detect increased signal at the culprit site in nearly half of AMI patients, highlighting the challenging nature of in vivo coronary artery plaque metabolic imaging. Nonetheless, our findings suggest that imaging of coronary artery inflammation is feasible, and further work evaluating (18)F-FDG uptake in high-risk coronary plaques prior to rupture would be of great interest.
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Clinical Trial
Multifunctional profiling of non-small cell lung cancer using 18F-FDG PET/CT and volume perfusion CT.
The aim of this study was to investigate correlations between glucose metabolism registered by (18)F-FDG PET/CT and tumor perfusion quantified by volume perfusion CT and immunohistochemical markers Ki67 and microvessel density (MVD) in patients with non-small cell lung cancer (NSCLC). ⋯ (18)F-FDG uptake correlates with Ki67, whereas BF, BV, and K(trans) correlate with MVD. Therefore, (18)F-FDG uptake and perfusion parameters provide complementary functional information. An improved tumor profiling will be beneficial for both prognosis and therapy response evaluation in these tumors.
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Patients with obstructive hypertrophic cardiomyopathy (HCM) exhibit elevated left ventricular outflow tract gradients (LVOTGs) and appear to have a worse prognosis than those with nonobstructive HCM. The aim of this study was to evaluate whether patients with obstruction, compared with nonobstructive HCM, demonstrate significant differences in PET parameters of microvascular function. ⋯ Maximal wall thickness was identified as the strongest predictor of impaired dipyridamole-induced hyperemia and flow reserve in our study, whereas outflow tract obstruction was not an independent determinant.
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(90)Y radioembolization (selective internal radiation therapy [SIRT]) has emerged as a valuable therapeutic option in unresectable, chemotherapy-refractory hepatic metastases from breast cancer. The objective of the present study was to evaluate (18)F-FDG PET/CT for predicting survival in these patients. ⋯ The change in SUV(max) as assessed by (18)F-FDG PET/CT before and 3 mo after SIRT was identified as the only independent predictor of survival in patients with hepatic metastases of breast cancer.