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UNLABELLED: Hexamethylpropyleneamine oxime (HMPAO) SPECT and 18F-FDG PET depict similar aspects of perfusion and metabolic abnormalities in Alzheimer's disease (AD), but the correspondence between them is not known in detail. We therefore used statistical parametric mapping to detect and compare abnormal brain areas objectively and quantitatively. METHODS: Twenty-six patients with probable AD (mean age +/- SD, 66 +/- 9 y; mean Mini-Mental State Examination score, 22.5 +/- 4.2) and 6 nondemented healthy volunteers (mean age, 63 +/- 11 y) were studied with HMPAO SPECT and 18F-FDG PET. All images underwent the same processing steps, including 12-mm gaussian smoothing, spatial normalization, and z transformation with respect to normal average and SD. Thresholding of z maps was used to detect abnormal voxels. RESULTS: The overall correlation between PET and SPECT across the entire brain was significant but not close (average r = 0.43). The best correspondence was found in the temporoparietal and posterior cingulate association cortices. There, the number of abnormal voxels for PET correlated strongly with the number for SPECT (r = 0.90 at a z threshold of -2.25), but tracer uptake reductions were significantly more pronounced for PET than for SPECT. Discordant findings were most frequently seen in the temporobasal and orbitofrontal areas (PET low, SPECT high) and in the cerebellum, parahippocampal cortex, and midcingulate cortex (PET high, SPECT low). The correlation between dementia severity and the number of abnormal voxels was closer for PET than for SPECT. Separation of patients from healthy volunteers by counting the number of abnormal voxels was possible over a much wider range of z thresholds with PET than with SPECT. CONCLUSION: Correspondence between 18F-FDG PET and HMPAO SPECT is limited to the main finding of temporoparietal and posterior cingulate functional impairment in mild to moderate AD. The distinction between healthy volunteers and patients is less sensitive to threshold selection with PET than with SPECT, and findings in the frontal, temporobasal, and temporomesial cortices and in the cerebellum may differ between the 2 techniques.

For recognition and exclusion of hyper- and hypothyroidism total thyroxine, index of free thyroxine, free thyroxine and total triiodothyronine were evaluated. Among 532 strictly selected patients, corresponding to the five main thyroid out-patient groups, the four parameters were estimated simultaneously. Their sensitivity and specificity including two combinations of free thyroxine and total triiodothyronine were calculated. On the basis of an average prevalence of the five above-mentioned groups among our patients and the two most frequent interfering factors (administration of oestrogens and additional iodine intake) predictive values were assessed. The following results were obtained. 1. Differences among the various in-vitro parameters are less than generally assumed. For free thyroxine and the combination of increased free thyroxine or total triiodothyronine, sensitivity and specificity were slightly higher than for other parameters. 2. There is insufficiently substantiated probability of positive evidence of hyperthyroid and hypothyroid states being supplied by all the examined parameters if these are the only criteria relied upon. The probability of positive evidence of hyperthyroid states is only acceptable if, prior to use of in-vitro tests, the prevalence has been considerably increased by history and clinical findings. 3. The probability of exclusion of hyperthyroid states supplied by the examined parameters is high. However, despite their high negative predictive value they are insufficient for the definite exclusion of hypothyroid states if the latent types are included.

SummaryAim: For the examination of the impact on clinical practice of the guidelines for differentiated thyroid carcinoma (DTC), treatment data from the ongoing Multicenter Study Differentiated Thyroid Carcinoma (MSDS) were analyzed. Patients, methods: Patients were randomized to adjuvant external beam radiotherapy (RTx) or no RTx in addition to standard therapy in TNM stages pT4 pN0/1/x M0/x (UICC, 5th ed. 1997). All patients were to receive the same treatment regimen consisting of thyroidectomy, ablative radioiodine therapy (RIT), and a diagnostic 131I whole-body scintigraphy (WBS) 3-4 months after RIT. Results: Of 339 eligible patients enrolled between January 2000 and March 2004, 273 could be analyzed. Guideline recommendations by the German Society for Nuclear Medicine from 1999 and 1992 were complied with within 28% and 82% with regard to the interval between surgery and RIT (4 vs. 4–6 weeks), in 33% and 84% with regard to 131I activity for RIT (1-3 vs. 1-4 GBq; ± 10%), and in 16% and 60% with regard to 131I activity for WBS (15319-300 vs. 15319-400 MBq; ± 10%). Conclusions: The 1999 guideline revision appears to have had little impact on clinical practice. Further follow-up will reveal if guideline compliance had an effect on outcomes.

The effects of high cervical spinal cord stimulation (cSCS) on regional cerebral blood flow (rCBF) were investigated after experimentally induced subarachnoid haemorrhage (SAH) in rats by the means of (99m)Tc-HMPAO. The experiments were carried out on a total of 24 Wistar rats, divided in three groups [group I: control without SAH, group II: SAH, group III: SAH and cSCS]. (99m)Tc-HMPAO was administered intravenously (group II/group III) 48 hours after induction of SAH. In group III, (99m)Tc-HMPAO was given after 3 hours of cSCS. All animals were sacrificed 30 minutes after application on (99m)Tc-HMPAO. Radioactivities were determined in blood, cerebrum and cerebellum. The ratio cerebrum/blood and cerebellum/blood was calculated to ascertain "extraction rate" in the sample differentially. The following mean values were calculated for the cerebellum/blood ratio: Group I: 1.06, SD: 0.21; Group II: 0.66, SD: 0.21; Group III: 1.00, SD: 0.37. Comparing the mean values a highly significant difference could be found between group II and III (p = 0.007) and between group I and II (p = 0.0019), respectively. Calculations of the cerebrum/blood ratio revealed similar results. After SAH cSCS enhances cerebral and cerebellar blood flow in rats. Possibly, cSCD constitutes a new therapeutic approach in the treatment of disturbed regional cerebral blood flow after SAH.

Aim: The working group on positron emission tomography (PET) of the DGN (German Society of Nuclear Medicine) initiated this first survey to collect and analyse information on the practise of PET in Germany in the year 2008. Methods: A questionnaire was sent to PET performing facilities (medical practices, hospitals, university hospitals and others) for retrospective data acquisition. Details regarding the equipment and examination procedures were examined as well as indications and number of studies. In add ition, the role of PET within the diagnostic process was evaluated. Results: Responses from 65 sites were analysed, Their technical equipment consisted of 77 PET scanners (40 of them were combined PET/CT devices). About 63500 PET studies had been performed with 86% in the field of oncology, 8% in neurology and 3% in cardiology. The radiotracers were labelled with 18F in 91 % of the studies, whereas 68Ga was used in 4% and 11C in 3%. The analyses revealed lung tumours as the most investigated tumour entity, followed by malignant lymphoma, tumours of the g astro-intestinal tract and prostate cancer (about 14000, 6000, 5000 and 2000). Corresponding to the new scanners and software procedures, the number of studies with attenuation correction by CT was high (68%) and nearly all studies were reconstructed iteratively (99%). The PET images were analysed quantitatively in the majority of cases (91%). The clinical reports, which included image documentation for the greater part, were posted regularly within 3 days. However, in 70% of the sites electronic transfer possibilities were used additionally to speed up the diagnostic process. The high standard of quality was demonstrated by the fact, that 40 facilities were engaged in a tumour board. Further on, one third of the physicians had gained a PET certification awarded by the DGN. Conclusion: Relative to the high general standard of diagnostic instrumentation in Germany, PET is less established, in particular when compared with other industrialised countries such as USA and Switzerland.

FDG-PET/CT examinations combine metabolic and morphologic imaging within an integrated procedure. Over the past decade PET/CT imaging has gained wide clinical acceptance in the field of oncology. This FDG-PET/CT guideline focuses on indications, data acquisition and processing as well as documentation of FDG-PET/CT examinations in oncologic patients within a clinical and social context specific to Germany. Background information and definitions are followed by examples of clinical and research applications of FDG-PET/CT. Furthermore, protocols for CT scanning (low dose and contrast-enhanced CT) and PET emission imaging are discussed. Documentation and reporting of examinations are specified. Image interpretation criteria and sources of errors are discussed. Quality control for FDG and PET/CT-systems, qualification requirements of personnel as well as legal aspects are presented.