Journal of nuclear medicine : official publication, Society of Nuclear Medicine
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Biomarkers can be used to characterize disease status or predict disease behavior. Cancer biomarkers have typically relied on assays of blood or tissue; however, molecular imaging has a promising and complementary role as a cancer biomarker. This "Focus on Molecular Imaging" article reviews the current role of biomarkers to direct cancer clinical trials and clinical practice, along with current and future cancer biomarker applications of molecular imaging.
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Comparative Study
Contrast-enhanced PET/MR imaging versus contrast-enhanced PET/CT in head and neck cancer: how much MR information is needed?
Considering PET/MR imaging as a whole-body staging tool, scan time restrictions in a single body area are mandatory for the cost-effective clinical operation of an integrated multimodality scanner setting. It has to be considered that (18)F-FDG already acts as a contrast agent and that under certain circumstances MR contrast may not yield additional clinically relevant information. The concept of the present study was to understand which portions of the imaging information enhance the sensitivity and specificity of the hybrid examination and which portions are redundant. ⋯ The results of the present study provide evidence that PET/MR imaging can serve as a legitimate alternative to PET/CT in the clinical workup of patients with head and neck cancers. Intravenous MR contrast medium may be applied only if the exact tumor extent or infiltration of crucial structures is of concern (i.e., preoperatively) or if perineural spread is anticipated. In early assessment of the response to therapy, in follow-up examinations, or in a whole-body protocol for non-head and neck tumors, T2w PET/MR imaging may be sufficient for coverage of the head and neck. The additional MR scanning time may instead be used for advanced MR techniques to increase the specificity of the hybrid imaging examination.
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Multicenter Study
Quantitative volumetric CT-histogram analysis in N-staging of 18F-FDG-equivocal patients with lung cancer.
Lung cancer often coexists with acute and chronic lung diseases such as chronic obstructive pulmonary disease. Therefore, mediastinal lymph nodes may be false-positive on (18)F-FDG PET because of the inflammatory disease alone. Nevertheless, (18)F-FDG PET/CT is the primary imaging modality used for staging patients with lung cancer, including nodal status. The purpose of this study was to evaluate whether volumetric CT histogram analysis can improve the characterization of lymph nodes on PET/CT staging of patients with lung cancer. ⋯ Three-dimensional histogram analysis is a promising and potentially valuable imaging surrogate for N-stage stratification in patients with lung cancer with unclear glucose uptake during (18)F-FDG PET imaging. In cases of equivocal (18)F-FDG PET status, this technique might potentially bridge the diagnostic gap between noninvasive techniques and invasive lymph node sampling and could help improve the yield of core biopsies.
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PET performed after 2 cycles of chemotherapy (PET2) allows prediction of outcome in most patients with Hodgkin lymphoma (HL). Visual analysis using a 5-point scale was proposed to assess PET response, but a semiquantitative approach using maximum standardized uptake value (SUVmax) reduction between baseline and interim PET was shown to be superior to the 5-point scale in patients with diffuse large B-cell lymphoma and may also improve the accuracy of interim PET interpretation in HL. To compare the clinical usefulness of both methods in HL patients, we analyzed PET2 according to visual and ΔSUVmax criteria in a retrospective single-center study. ⋯ Semiquantitative analysis was more accurate than visual analysis based on the 5-point scale to interpret PET2 and predict the outcome of HL patients. These encouraging results warrant further confirmation in larger and prospective series.
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Clinical Trial
Thoracic staging in lung cancer: prospective comparison of 18F-FDG PET/MR imaging and 18F-FDG PET/CT.
Therapeutic decisions in non-small cell lung cancer (NSCLC) patients depend on the tumor stage. PET/CT with (18)F-FDG is widely accepted as the diagnostic standard of care. The purpose of this study was to compare a dedicated pulmonary (18)F-FDG PET/MR imaging protocol with (18)F-FDG PET/CT for primary and locoregional lymph node staging in NSCLC patients using histopathology as the reference. ⋯ (18)F-FDG PET/MR imaging using a dedicated pulmonary MR imaging protocol, compared with (18)F-FDG PET/CT, does not provide advantages in thoracic staging in NSCLC patients.