Annals of nuclear medicine
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Regional cerebral blood flow (CBF), cerebral blood volume, oxygen extraction fraction (OEF), and cerebral metabolic rate of oxygen (CMRO2) can be estimated from C15O, H(2)15O, and 15O2 tracers and positron emission tomography (PET) using an autoradiographic (ARG) method. Our objective in this study was to optimize the scan time for 15O2 gas study for accurate estimation of OEF and CMRO2. ⋯ The optimal scan time of 15O2 inhalation study with the ARG method was concluded to be 3 min from taking into account for maintaining the S/N ratio and the quantification of accurate OEF and CMRO2.
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Studies have suggested that ischemia-induced diastolic dysfunction persists longer than systolic dysfunction. We examined whether global left ventricular (LV) diastolic function during stress testing assessed by 16-frame gated myocardial perfusion single-photon emission computed tomography (SPECT) is useful as an indicator of myocardial ischemia. ⋯ Altered global LV diastolic function during stress assessed by 16-frame gated myocardial perfusion SPECT is useful for the detection of myocardial ischemia. However, similar findings are observed in patients with cardiac dysfunction but without detectable ischemia. Our findings do suggest that tests should be performed with caution to determine whether ischemia exists on the basis of altered global LV function after stress in patients with cardiac dysfunction.
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Drug-induced pneumonitis is a serious and an unpredictable side effect of chemotherapy in patients with malignant lymphoma. We present the case of a 51-year-old man who developed drug-induced pneumonitis during chemotherapy for non-Hodgkin's lymphoma in which pneumonitis was detected earlier by 18F-fluorodeoxyglucose positron emission tomography (18F-FDG-PET) than by high-resolution computed tomography (HRCT). ⋯ Mild dyspnea appeared 3 days after PET, and additional HRCT revealed patchy ground-glass opacities disseminated with the appearance of interlobular septum thickening. Drug-induced pneumonitis was finally diagnosed, and treatment was initiated. 18F-FDG-PET can be an imaging modality for detecting drug-induced pneumonitis at an extremely early stage in which HRCT is incapable of revealing any abnormal changes.
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Positron emission tomography (PET) using (18)F-fluoro-2-deoxy-D -glucose (FDG) has a limitation in detecting cerebral metastases; however, the feasibility of detection by inline PET/computed tomography (CT) system remains unknown. We evaluated the accuracy of FDG-PET/CT of body imaging protocol for the detection of cerebral metastases when compared with PET alone and CT alone. ⋯ Even with an integrated PET/CT scanner of body imaging protocol, the sensitivity of cerebral metastases remained unsatisfactory. To assess intracranial lesions, MR scanning should still be considered.
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(123)I-metaiodobenzylguanidine (MIBG) myocardial scintigraphy is a useful tool for differentiating idiopathic Parkinson's disease (PD) from parkinsonism (PS) caused by other disorders. However, cardiac MIBG uptake is affected by various causes. Alternatively, hypoperfusion in the occipital lobe of PD is reported recently. ⋯ MIBG parameters (H/M) correlated positively with occipital hypoperfusion in PD. In the differential diagnosis between PD and PS, although its usefulness might be limited, analysis of rCBF in the occipital lobe added to (123)I-MIBG myocardial imaging can be recommended.