Annals of nuclear medicine
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Pulmonary single photon emission computed tomography-computed tomography (SPECT-CT) fusion images provide objective and comprehensive assessment of pulmonary function and morphology relationships at cross-sectional lungs. This article reviewed the noteworthy findings of lung pathophysiology in wide-spectral lung disorders, which have been revealed on SPECT-CT fusion images in 8 years of experience. The fusion images confirmed the fundamental pathophysiologic appearance of lung low CT attenuation caused by airway obstruction-induced hypoxic vasoconstriction and that caused by direct pulmonary arterial obstruction as in acute pulmonary thromboembolism (PTE). ⋯ The fusion images showed occasional unexpected perfusion defects in normal lung areas on CT in chronic obstructive pulmonary diseases and interstitial lung diseases, indicating the ability of perfusion SPECT superior to CT for detection of mild lesions in these disorders. The fusion images showed frequent "steal phenomenon"-induced perfusion defects extending to the surrounding normal lung of arteriovenous fistulas and those at normal lungs on CT in hepatopulmonary syndrome. Comprehensive assessment of lung function-CT morphology on fusion images will lead to more profound understanding of lung pathophysiology in wide-spectral lung disorders.
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Neuroimaging in ischemic stroke continues to be one of the most developing fields in nuclear medicine. Many studies have established the efficacy of blood flow and metabolism measurements in acute ischemic stroke. Although the release of recombinant tissue plasminogen activator in clinical practice has minimized the use of SPECT or PET in the first few hours of ischemic stroke onset, implementing these techniques into a set of initial examinations is still beneficial to exclude risky patients for reperfusion therapy beyond several hours after onset. ⋯ Ischemic penumbra can be visualized by means of perfusion imaging, central type benzodiazepine receptor imaging, and hypoxy imaging. In the later phase of subacute ischemic stroke, inflammation and apoptosis can be visualized by means of peripheral-type benzodiazepine receptor imaging and annexin V imaging, respectively. Imaging of the penumbra and cellular responses will help evaluate the effects of drugs and interventions for ischemic stroke, suggesting its potential as a marker of the efficacy of future therapeutic regimens.