European journal of nuclear medicine and molecular imaging
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Eur. J. Nucl. Med. Mol. Imaging · May 2009
[18F]FDG PET/CT in the diagnosis of malignant peripheral nerve sheath tumours in neurofibromatosis type-1.
The detection of malignant peripheral nerve sheath tumours (MPNSTs) in patients with neurofibromatosis 1 (NF1) remains a clinical challenge. The purpose of this study was to evaluate the use of [(18)F]2-fluoro-2-deoxy-D-glucose PET/CT (FDG PET/CT with early and delayed imaging) in patients with symptomatic neurofibromas, to revalidate current cut-off values for identification of malignant change within neurofibromas and to examine the relationship between SUV and tumour grade. ⋯ FDG PET/CT is a highly sensitive and specific imaging modality for the diagnosis of MPNST in NF1 patients. We recommend performing early (90 min) and delayed imaging at 4 h for accurate lesion characterization and using a cut-off SUVmax of 3.5 on delayed imaging to achieve maximal sensitivity.
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Eur. J. Nucl. Med. Mol. Imaging · Apr 2009
FDG-PET/CT imaging in the management of HIV-associated multicentric Castleman's disease.
To evaluate the role of FDG-PET/CT scanning in the management of HIV-associated multicentric Castleman's disease (MCD) a rare lymphoproliferative disorder associated with infection by human herpesvirus 8 (HHV8). ⋯ Despite the small number of patients, in HIV-positive individuals with active MCD, FDG-PET scans more frequently detected abnormal uptake than CT scans detected enlarged lymph nodes. FDG-PET scanning has a useful role in the management of HIV-associated MCD in selecting appropriate sites for biopsy, and in staging and monitoring these lymphoproliferations.
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Eur. J. Nucl. Med. Mol. Imaging · Apr 2009
FDG-PET imaging in HIV-infected subjects: relation with therapy and immunovirological variables.
To characterise tissue sites of immune activation and HIV replication we performed FDG-PET in ART-treated and ART-naive HIV-infected individuals. Specific aims were to establish whether HIV-infected patients can be differentiated on the basis of the detection of specific locations of viral replication, even in the presence of an apparently optimal immunovirological response to ART, and whether these FDG-PET findings can be related to immunovirological variables and AIDS history status. ⋯ The emergence, in our study, of a correlation between the percentage of CD8+/CD38+/RO+ T cells (well established markers of progression to AIDS independently of CD4+ T lymphocytes) and positive FDG-PET in ART-naive patients is a novel finding that seems to confer prognostic value on FDG uptake. FDG uptake is strongly associated with response to ART independently of a previous AIDS diagnosis. Notably, no differences were observed between ART-treated subjects classed as immunological responders and those classed as non responders. Data herewith indicate that FDG uptake and immunological variables are unrelated when ART is being administered. This is evidence of the complementarity of immunological and FDG measures. FDG uptake is a sensitive marker of disease state and its relation with CD8+/CD38+/CD45RO+ T cells indicates that it can be considered a marker of disease status. The lack of a correlation between FDG uptake and immunological variables in patients under ART warrants further investigation.
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Eur. J. Nucl. Med. Mol. Imaging · Mar 2009
ReviewMultimodality imaging: an update on PET/CT technology.
Since their introduction in 2001, PET/CT systems have gained wide acceptance primarily due to their inherent ability to combine functional and structural information about the underlying disease state of the patient in a single imaging session. Their significance has also been documented with regard to their short imaging times, which minimize patient anxiety and image blurring due to patient motion. In the past seven years, PET/CT systems have replaced dedicated PET systems as the imaging modality of choice for diagnostic evaluation of oncology patients. ⋯ Recent improvements in instrumentation are highlighted together with some outstanding issues that arise for specific PET/CT applications. These are followed by a description of some of the more common clinical applications of PET/CT imaging such as staging malignant disease, treatment planning, and monitoring therapy response. Finally, the future developments of PET/CT systems with regard to sensitivity, resolution, and new radiopharmaceuticals are discussed. The article concludes by presenting some issues concerning the next stage in the future of PET imaging, namely PET/MRI.
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Hybrid imaging is now widely accepted in cancer imaging with increasing use of PET/CT in clinical practice. The advantages of MRI compared to CT with respect to radiation exposure and soft-tissue lesion contrast, as well as the possibility of performing more sophisticated assessment of tissue chemistry, have stimulated interest in the development of hybrid PET/MR imaging systems. ⋯ To realize the unique potential advantages of combined PET/MRI, we believe that PET/MRI devices should be designed to be a complementary tool running in parallel with PET/CT. The use of PET/CT for whole-body screening could identify lesions requiring more detailed anatomical and biological characterization. Selection of only those patients and those lesions for which this information is critical for treatment selection and planning will provide efficient and easily justified use of what will, for the foreseeable future, be an expensive and limited resource.