Journal of nuclear medicine : official publication, Society of Nuclear Medicine
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Attenuation correction (AC) of PET images with helical CT (HCT) in PET/CT matches only the spatial resolution of CT and PET, not the temporal resolution. We therefore proposed the use of respiration-averaged CT (ACT) to match the temporal resolution of CT and PET and evaluated the improvement of tumor quantification in PET images of the thorax with ACT. ⋯ The high rate of misalignment suggested a potential mismatch between the HCT and the PET data with the limited-breath-hold CT protocol. In the comparison of HCT and ACT, significant differences (>50%) in SUV were attributable to different breathing states between HCT and PET. The PET data corrected by ACT did not show breathing artifacts, suggesting that ACT may be more accurate than HCT for AC of the PET data.
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The value of PET or PET/CT with (18)F-FDG for the staging of penile cancer has yet to be determined. The objective of this study was to investigate the pattern of (18)F-FDG uptake in the primary malignancy and its metastases and to determine the diagnostic value of (18)F-FDG PET/CT in the staging and restaging of penile cancer. ⋯ According to our results, the main indication for (18)F-FDG PET in the primary staging or follow-up of penile cancer patients may be the prognostically crucial search for lymph node metastases. With the use of a PET/CT unit, the additional information provided by CT may be especially useful for planning surgery. Implementing (18)F-FDG PET and PET/CT in future staging algorithms may lead to a more precise and stage-appropriate therapeutic strategy. Furthermore, invasive procedures with a high morbidity rate, such as general bilateral lymphadenectomy, may be avoided.
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Small-animal PET has opened the way for imaging (18)F-FDG uptake in murine tumor models, but the need for anesthesia raises concern over its potential influence on (18)F-FDG kinetics. We thus investigated such effects on cultured cells and on tumor-bearing mice after short- and long-term fasting. ⋯ Xy/Ke anesthesia markedly elevates blood (18)F-FDG activity and reduces tumor uptake ratios through inhibition of insulin release in mice kept fasting 4 h, whereas pentobarbital induces a similar but less severe response through insulin resistance. These metabolic effects, however, are substantially attenuated after 20 h of fasting. Hence both the choice of anesthetic and the duration of fasting have important effects on (18)F-FDG kinetics and PET images of tumor-bearing mice and should be considered when such studies are performed.
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Clinical Trial Controlled Clinical Trial
Semiquantitative 67Ga scintigraphy as an indicator of response to and prognosis after corticosteroid treatment in idiopathic interstitial pneumonia.
The prognosis in some forms of idiopathic interstitial pneumonia (IIP), especially idiopathic pulmonary fibrosis (IPF) and fibrotic nonspecific interstitial pneumonia (NSIP), is still poor. A minority of patients will respond to immunosuppressive treatment. In patients with IPF or fibrotic NSIP, pulmonary (67)Ga scintigraphy may be useful for predicting response to therapy and prognosis. The objective of the present study was to evaluate whether semiquantitative (67)Ga scintigraphy can be used to predict responsiveness to therapy with high-dose corticosteroids in a well-defined population of patients with IIP (IPF and fibrotic NSIP). ⋯ Pulmonary (67)Ga uptake cannot be used to predict response to corticosteroid treatment or prognosis in patients with IIP. Apparently, the (inflammatory) process influenced by treatment with methylprednisolone does not determine the progression of disease. This finding supports the hypothesis that although inflammation is present in IPF and fibrotic NSIP, it is neither the hallmark of the disease nor the major factor determining prognosis.
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The motor improvement derived from high-frequency deep brain stimulation (DBS) of the subthalamic nucleus (STN) in Parkinson's disease (PD) is maintained over time after surgery. The aim of the present prospective follow-up study was to assess regional cerebral blood flow (rCBF) changes related to such improvement in the long term. ⋯ Our study suggests that the long-term STN stimulation leads to improvement in neural activity in the frontal motor/associative areas. After an rCBF increase during the first months of stimulation, these regions showed a further increment in the later phase, which was accompanied by an increased activity in subcortical structures. The correlation between motor improvement and rCBF increase in higher order motor cortical areas suggests that even in the long term, as well as in the short term, the STN-DBS achieves its therapeutic benefit by restoring the activity within these cortical regions.