Brain and whole-body FDG-PET in diagnosis, treatment monitoring and long-term follow-up of primary CNS lymphoma.

BACKGROUND: Positron emission tomography (PET) with F-18-labeled fluorodeoxyglucose (FDG) provides remarkable accuracy in detection, treatment monitoring and follow-up of systemic malignant lymphoma. Its value in the management of patients with primary central nervous system lymphoma (PCNSL) is less clear. PATIENTS AND METHODS: In a prospective trial, 42 FDG-PET examinations were performed in ten immunocompetent patients with newly diagnosed or recurrent PCNSL before and repeatedly during and after the treatment. Brain and whole body FDG-PET were compared to brain MRI and extra-cerebral CT, respectively. RESULTS: Before the treatment, 6 of 10 patients had congruent findings on FDG-PET and MRI of the brain. Three patients had lesions on brain MRI, not detected by FDG-PET. One patient had additional FDG-PET positive lesions inconspicuous in MRI. The follow-up suggested FDG-PET to be false positive in these lesions. After the treatment, brain PET was in agreement with MRI in 6 of 8 patients. In the remaining 2 patients there were persistent lesions in brain MRI whereas FDG-uptake was reduced to normal values. In the long-term follow-up of 5 patients (63-169 weeks), 3 patients retained normal in both PET and MRI. In 2 patients a new focal pathologic FDG-uptake was detected 69 and 52 weeks after the end of the treatment. In one of these patients, recurrence was confirmed by MRI not until 9 weeks after PET. CONCLUSIONS: Brain FDG-PET may contribute valuable information for the management of PCNSL, particularly in the assessment of the treatment response. Integration of FDG-PET into prospective interventional trials is warranted to investigate prognostic and therapeutic implications.

Increased serotonin transporter availability in the brainstem of migraineurs.

For decades, serotonin has been speculated to play a major role in migraine pathophysiology. The central serotonergic system is located in the raphe nuclei and the adjacent reticular formation in the brainstem. Recently, radioligands targeting the brain serotonin transport protein (SERT) have been developed. We used the highly specific SERT-radioligand (123)I-ADAM [2-((2-((dimethylamino) methyl)phenyl)thio)-5-iodophenylamine] to test the hypothesis of the mesopontine serotonergic system being involved in the pathophysiology of migraine. Nineteen migraine patients and 10 healthy, age- and sex-matched controls were enrolled. The neuroimaging study was performed interictally during the pain-free interval. Single Photon Emission Computed Tomography (SPECT)-images were coregistered with MRI-scans. Region of interest (ROI)-analysis revealed a highly significant increase of (123)I-ADAM uptake in the mesopontine brainstem of migraineurs (p < 0.001). In contrast, (123)IADAM uptake in the thalamus did not differ significantly between migraineurs and controls. Our study demonstrates for the first time a significant increase of brainstem SERT-availability in migraineurs, suggesting a dysregulation of the brainstem serotonergic system. It remains to be elucidated whether the altered SERT-availability is causally related to migraine pathophysiology or whether it reflects secondary pathophysiological mechanisms.

A concept for the clinical implementation of sentinel lymph node biopsy in patients with breast carcinoma with special regard to quality assurance.

The development of standardized and reproducible clinical pathways is an important precondition for quality assurance in medicine, especially if a new method has not yet been ultimately validated. Sentinel lymph node biopsy (SLNB) is a widely accepted new surgical procedure in the treatment of early breast carcinoma. However, numerous steps of the method and details of the technique are not standardized and, thus, hamper quality assurance for SLNB. The German Society of Senology appointed an interdisciplinary consensus committee to work out guidelines for the standardized performance and quality-assured implementation of SLNB on a nationwide, homogeneous standard. The committee consisted of surgeons, gynecologists, radiooncologists, nuclear physicians, oncologists, and pathologists. Relevant questions related to patient selection, lymphatic mapping, surgery, histopathologic work-up, further local and systemic treatment decisions, patient information, training, and follow-up were evaluated with respect to clinical evidence, objectivity, and reproducibility. Clinical pathways were developed on the basis of this analysis. Requirements to the performing institutions and surgeons were defined.

[Dependence of uniformity on the radionuclide in SPECT: test methods]. / Abhängigkeit der Homogenität vom Radionuklid bei SPECT: Methoden der Uberprüfung.

The aim of this study was to investigate test methods to clarify whether the non-uniformity of a gamma camera depends on individual radionuclides, and whether it is necessary to measure a separate correction matrix for each radionuclide used in single photon emission computed tomography (SPECT). Two methods were devised to verify the nuclide-dependence of the gamma camera. In order to test the energy correction of the detectors, the first approach was based on the evaluation of the intrinsic non-uniformity and on the production of images with asymmetrical energy window. The second method was based on the production of correction matrices for different radionuclides, as well as on the subsequent application to phantom data that were also generated with different radionuclides. The investigation of a dualhead gamma camera produced the same results with both methods. One detector head was found to be weakly dependent on the radionuclide, due to the insufficient quality of energy correction. In this case, the phantom or patient data should be corrected using a uniformity correction matrix measured with the same radionuclide. The second detector remained nuclide-independent; in this case the uniformity correction matrix acquired for only one radionuclide was sufficient.