Cryoconites from Alpine glaciers: Radionuclide accumulation and age estimation with Pu and Cs isotopes and 210Pb.

Cryoconites ("cold dust", derived from the Greek) are aeolian sediments accumulated on glacier surfaces. In cryoconites from the surface of the Stubacher Sonnblickkees, a temperate Austrian glacier, extremely high activity concentrations of artificial and natural radionuclides were found. Artificial radionuclides stem from two clearly distinguishable sources, global fallout from the nuclear weapons testing era deposited over a period of years until roughly 1966 and the fallout from Chernobyl in 1986, which was essentially deposited as a single input during one week. Anthropogenic radionuclides identified were 137Cs, 134Cs, 238Pu, 239+240Pu, 90Sr, 241Am, 60Co, 125Sb, 154Eu, and 207Bi. The naturally occurring radionuclides detected were the long-lived radon decay product 210Pb, the primordial radionuclide 4 K and the cosmogenic 7Be. Isotopic ratios of 134Cs/137Cs and 239+240Pu/238Pu were used to separate the nuclide inventory into the contributions of the two aforementioned sources, which show varying degrees of mixing and provide information on the mixing age of the cryoconites. Since isotopic ratios of Pu often have high uncertainties due to low absolute concentrations, age estimation based on this method can be quite inaccurate. Additional information about the age of cryoconites was obtained through analysis of 210Pb, which is constantly deposited over time.

Combined PET/MRI: Global Warming-Summary Report of the 6th International Workshop on PET/MRI, March 27-29, 2017, Tübingen, Germany.

The 6th annual meeting to address key issues in positron emission tomography (PET)/magnetic resonance imaging (MRI) was held again in Tübingen, Germany, from March 27 to 29, 2017. Over three days of invited plenary lectures, round table discussions and dialogue board deliberations, participants critically assessed the current state of PET/MRI, both clinically and as a research tool, and attempted to chart future directions. The meeting addressed the use of PET/MRI and workflows in oncology, neurosciences, infection, inflammation and chronic pain syndromes, as well as deeper discussions about how best to characterise the tumour microenvironment, optimise the complementary information available from PET and MRI, and how advanced data mining and bioinformatics, as well as information from liquid biomarkers (circulating tumour cells and nucleic acids) and pathology, can be integrated to give a more complete characterisation of disease phenotype. Some issues that have dominated previous meetings, such as the accuracy of MR-based attenuation correction (AC) of the PET scan, were finally put to rest as having been adequately addressed for the majority of clinical situations. Likewise, the ability to standardise PET systems for use in multicentre trials was confirmed, thus removing a perceived barrier to larger clinical imaging trials. The meeting openly questioned whether PET/MRI should, in all cases, be used as a whole-body imaging modality or whether in many circumstances it would best be employed to give an in-depth study of previously identified disease in a single organ or region. The meeting concluded that there is still much work to be done in the integration of data from different fields and in developing a common language for all stakeholders involved. In addition, the participants advocated joint training and education for individuals who engage in routine PET/MRI. It was agreed that PET/MRI can enhance our understanding of normal and disrupted biology, and we are in a position to describe the in vivo nature of disease processes, metabolism, evolution of cancer and the monitoring of response to pharmacological interventions and therapies. As such, PET/MRI is a key to advancing medicine and patient care.

Single mode 4.3 kW output power from a diode-pumped Yb-doped fiber amplifier.

We investigate the average power scaling of two diode-pumped Yb-doped fiber amplifiers emitting a diffraction-limited beam. The first fiber under investigation with a core diameter of 30 µm was able to amplify a 10 W narrow linewidth seed laser up to 2.8 kW average output power before the onset of transverse mode instabilities (TMI). A further power scaling was achieved using a second fiber with a smaller core size (23µm), which allowed for a narrow linewidth output power of 3.5 kW limited by stimulated Brillouin scattering (SBS). We mitigated SBS using a spectral broadening mechanism, which allowed us to further increase the output power to 4.3 kW only limited by the available pump power. Up to this power level, a high slope efficiency of 90% with diffraction-limited beam quality and without any sign of TMI or stimulated Raman scattering for a spectral dynamic range of higher than -80 dB was obtained.

Comparison of volumetric and functional parameters in simultaneous cardiac PET/MR: feasibility of volumetric assessment with residual activity from prior PET/CT.

OBJECTIVE: To compare cardiac left ventricular (LV) parameters in simultaneously acquired hybrid fluorine-18-fluorodeoxyglucose ([18F] FDG) positron emission tomography/magnetic resonance imaging (PET/MRI) in patients with residual tracer activity of upstream PET/CT. METHODS: Twenty-nine patients (23 men, age 58±17 years) underwent cardiac PET/MRI either directly after a non-cardiac PET/CT with homogenous cardiac [18F] FDG uptake (n=20) or for viability assessment (n=9). Gated cardiac [18F] FDG PET and cine MR sequences were acquired simultaneously and evaluated blinded to the cross-imaging results. Image quality (IQ), end-diastolic (LVEDV), end-systolic volume (LVESV), ejection fraction (LVEF) and myocardial mass (LVMM) were measured. Pearson correlation and intraclass correlation coefficient (ICC), regression and a Bland-Altman analysis were assessed. RESULTS: Except LVMM, volumetric and functional LV parameters demonstrated high correlations (LVESV: r=0.97, LVEDV: r=0.95, LVEF: r=0.91, LVMM: r=0.87, each p<0.05), but wide limits of agreement (LOA) for LVEDV (-25.3-82.5ml); LVESV (-33.1-72.7ml); LVEF (-18.9-14.8%) and LVMM (-78.2-43.2g). Intra- and interobserver reliability were very high (ICC≥0.95) for all parameters, except for MR-LVEF (ICC=0.87). PET-IQ (0-3) was high (mean: 2.2±0.9) with significant influence on LVMM calculations only. CONCLUSION: In simultaneously acquired cardiac PET/MRI data, LVEDV, LVESV and LVEF show good agreement. However, the agreement seems to be limited if cardiac PET/MRI follows PET/CT and only the residual activity is used. KEY POINTS: • [ 18 F] FDG PET-MRI is feasible with residual [ 18 F] FDG activity in patients with homogenous cardiac uptake. • Cardiac volumes and function assessed by PET/MRI show good agreement. • LVEDV and LVESV are underestimated; PET overestimates LVMM and LVEF. • Cardiac PET and MRI data correlate better when acquired simultaneously than sequentially. • PET and MRI should not assess LV parameters interchangeably.

[Head and Neck Cancer in Pregnancy - Recommendations for Diagnosis and Therapy With Case Report]. / Kopf-Hals-Krebs in der Schwangerschaft ­ Empfehlungen zu Diagnostik und Therapie mit Fallbericht.

Objective: The diagnosis of cancer in pregnancy is rare, but might become more relevant even for head and neck cancer patients due to a shift of age of primipara towards the last third of reproductive years. Unsureness exists about the risk and benefit of diagnostic and therapeutic cancer modalities for the unborn and established recommendations are still missing. But, according to recent data, even multimodal therapeutic approaches (e. g. surgery, radiation, chemotherapy) seem possible in face of pregnancy and should be traded against the risk of prematurity. Material and Methods: Our findings are discussed on the basis of a case report of a pregnant woman with advanced carcinoma of the outer ear canal and therapy options are formulated. Results: Sufficient performed diagnostic modalities do not reach imperilling uterus dosages. A growing number of case reports und studies did not detect any developmental disadvantage of children of prenatal exposed mothers by radiation or chemotherapy, whereas long-term impairments of premature infants are proven. Conclusion: In cancer in pregnancy, an immediate start of well-established therapy modalities like surgery and/or cisplatin-based chemoradiation seems to be possible without unjustifiable risks for the unborn.

Narrow linewidth, single mode 3 kW average power from a directly diode pumped ytterbium-doped low NA fiber amplifier.

We report on a newly designed and fabricated ytterbium-doped large mode area fiber with an extremely low NA (~0.04) and related systematic investigations on fiber parameters that crucially influence the mode instability threshold. The fiber is used to demonstrate a narrow linewidth, continuous wave, single mode fiber laser amplifier emitting a maximum output power of 3 kW at a wavelength of 1070 nm without reaching the mode-instability threshold. A high slope efficiency of 90 %, excellent beam quality, high temporal stability, and an ASE suppression of 70 dB could be reached with a signal linewidth of only 170 pm.

Using Machine Learning to Estimate Global PM2.5 for Environmental Health Studies.

With the increasing awareness of health impacts of particulate matter, there is a growing need to comprehend the spatial and temporal variations of the global abundance of ground-level airborne particulate matter (PM2.5). Here we use a suite of remote sensing and meteorological data products together with ground based observations of PM2.5 from 8,329 measurement sites in 55 countries taken between 1997 and 2014 to train a machine learning algorithm to estimate the daily distributions of PM2.5 from 1997 to the present. We demonstrate that the new PM2.5 data product can reliably represent global observations of PM2.5 for epidemiological studies. An analysis of Baltimore schizophrenia emergency room admissions is presented in terms of the levels of ambient pollution. PM2.5 appears to have an impact on some aspects of mental health.

Combined PET/MR: The Real Work Has Just Started. Summary Report of the Third International Workshop on PET/MR Imaging; February 17-21, 2014, Tübingen, Germany.

This paper summarises the proceedings and discussions at the third annual workshop held in Tübingen, Germany, dedicated to the advancement of the technical, scientific and clinical applications of combined PET/MRI systems in humans. Two days of basic scientific and technical instructions with "hands-on" tutorials were followed by 3 days of invited presentations from active researchers in this and associated fields augmented by round-table discussions and dialogue boards with specific themes. These included the use of PET/MRI in paediatric oncology and in adult neurology, oncology and cardiology, the development of multi-parametric analyses, and efforts to standardise PET/MRI examinations to allow pooling of data for evaluating the technology. A poll taken on the final day demonstrated that over 50 % of those present felt that while PET/MRI technology underwent an inevitable slump after its much-anticipated initial launch, it was now entering a period of slow, progressive development, with new key applications emerging. In particular, researchers are focusing on exploiting the complementary nature of the physiological (PET) and biochemical (MRI/MRS) data within the morphological framework (MRI) that these devices can provide. Much of the discussion was summed up on the final day when one speaker commented on the state of PET/MRI: "the real work has just started".

Late enhanced computed tomography in Hypertrophic Cardiomyopathy enables accurate left-ventricular volumetry.

OBJECTIVES: Late enhancement (LE) multi-slice computed tomography (leMDCT) was introduced for the visualization of (intra-) myocardial fibrosis in Hypertrophic Cardiomyopathy (HCM). LE is associated with adverse cardiac events. This analysis focuses on leMDCT derived LV muscle mass (LV-MM) which may be related to LE resulting in LE proportion for potential risk stratification in HCM. METHODS: N=26 HCM-patients underwent leMDCT (64-slice-CT) and cardiovascular magnetic resonance (CMR). In leMDCT iodine contrast (Iopromid, 350 mg/mL; 150mL) was injected 7 minutes before imaging. Reconstructed short cardiac axis views served for planimetry. The study group was divided into three groups of varying LV-contrast. LeMDCT was correlated with CMR. RESULTS: The mean age was 64.2 ± 14 years. The groups of varying contrast differed in weight and body mass index (p < 0.05). In the group with good LV-contrast assessment of LV-MM resulted in 147.4 ± 64.8 g in leMDCT vs. 147.1 ± 65.9 in CMR (p > 0.05). In the group with sufficient contrast LV-MM appeared with 172 ± 30.8 g in leMDCT vs. 165.9 ± 37.8 in CMR (p > 0.05). Overall intra-/inter-observer variability of semiautomatic assessment of LV-MM showed an accuracy of 0.9 ± 8.6 g and 0.8 ± 9.2 g in leMDCT. All leMDCT-measures correlated well with CMR (r > 0.9). CONCLUSIONS: LeMDCT primarily performed for LE-visualization in HCM allows for accurate LV-volumetry including LV-MM in > 90% of the cases. KEY POINTS: • LeMDCT of relatively low contrast allows for LV planimetry in HCM. • The correlation of leMDCT-based LV volumetry with gold-standard CMR was excellent (r > 0.9). • LeMDCT requires approximately 2.0mL/kgBW of dye to achieve acceptable contrast.

The EuroNet paediatric hodgkin network - modern imaging data management for real time central review in multicentre trials.

Since 2007, children and adolescents with Hodgkin lymphomas are treated in the Europe-wide EuroNet-PHL trials. A real time central review process for stratification of the patients enhances quality control and efficient therapy management. This process includes reading of all cross-sectional-images. Since reference evaluation is time critical, a fast, easy to handle and safe data transfer is important. In addition, immediate and constant access to all the data has to be guaranteed in case of queries and for regulatory reasons. To meet the mentioned requirements the EuroNet Paediatric Hodgkin Data Network (funded by the European Union - Project Number: 2007108) was established between 2008 and 2011. A respective tailored data protection plan was formulated. The aim of this article is to describe the networks' mode of operation and the advantages for multi-centre trials that include centralized image review.

Outcome of immediate interventions in acute dysfunctional hemodialysis fistulas.

PURPOSE: To analyze the efficacy of interventions in acute dysfunctional hemodialysis fistulas, if intervention is performed immediately as recommended by European Best Practice Guidelines for Hemodialysis. MATERIALS AND METHODS: Over 3 years, all (n = 280) patients with an acute dysfunctional hemodialysis fistula were immediately referred to angiography, irrespective of the time of day. Angiography and, if possible, interventional revision (n = 241) were performed. Three groups of interest were established: interventionalist's experience (high/low), time of day (routine hours: 7 am-4 pm/emergency hours: 4 pm-7 am), lesion type (stenosis/fibrosclerotic occlusion/thrombotic occlusion/combined stenosis+thrombotic occlusion). For statistical analysis corresponding success rates, chi-square tests (p < 0.025) and logistic regression analysis (p < 0.05) were calculated. RESULTS: The total success rate was 62 % (149/241). The success rates were: interventionalist experience high/low 71 % (79/111)/54 % (70/130), p = 0.022; time of day routine/emergency hours 68 % (93/136)/53 % (56/105), p = 0.017; lesion type stenosis/fibrosclerotic occlusion/thrombotic occlusion/combined stenosis+occlusion 82 % (94/104)/39 % (13/33)/18 % (6/33)/59 % (36/61), p < 0.001. Relevant variables due to logistic regression analysis were high experience and the lesion types stenosis and combined stenosis+occlusion with odds ratios 2.300 (p = 0.012), 12.053 (p < 0.001), 3.189 (p = 0.003). CONCLUSION: Unrestricted implementation of immediate interventions in acute dysfunctional hemodialysis fistulas requires permanent availability of experienced interventionalists. The lesion types fibrosclerotic occlusion and thrombotic occlusion offer poor success rates for interventional revision.

Integration of FDG-PET/CT into external beam radiation therapy planning: technical aspects and recommendations on methodological approaches.

UNLABELLED: This work addresses the clinical adoption of FDG-PET/CT for image-guided radiation therapy planning (RTP). As such, important technical and methodological aspects of PET/CT-based RTP are reviewed and practical recommendations are given for routine patient management and clinical studies. First, recent developments in PET/CT hardware that are relevant to RTP are reviewed in the context of quality control and system calibration procedures that are mandatory for a reproducible adoption of PET/CT in RTP. Second, recommendations are provided on image acquisition and reconstruction to support the standardization of imaging protocols. A major prerequisite for routine RTP is a complete and secure data transfer to the actual planning system. Third, state-of-the-art tools for image fusion and co-registration are discussed briefly in the context of PET/CT imaging pre- and post-RTP. This includes a brief review of state-of-the-art image contouring algorithms relevant to PET/CT-guided RTP. Finally, practical aspects of clinical workflow and patient management, such as patient setup and requirements for staff training are emphasized. PET/CT-guided RTP mandates attention to logistical aspects, patient set-up and acquisition parameters as well as an in-depth appreciation of quality control and protocol standardization. CONCLUSION: Upon fulfilling the requirements to perform PET/CT for RTP, a new dimension of molecular imaging can be added to traditional morphological imaging. As a consequence, PET/CT imaging will support improved RTP and better patient care. This document serves as a guidance on practical and clinically validated instructions that are deemed useful to the staff involved in PET/CT-guided RTP.

Accumulation of anthropogenic radionuclides in cryoconites on Alpine glaciers.

Cryoconites are airborne sediments which accumulate on the surface of glaciers. In samples of cryoconites a temperate Austrian glacier high activity concentrations of anthropogenic radionuclides were found, which stem from global and Chernobyl fallouts. Radionuclides identified were (137)Cs, (134)Cs, (238)Pu, (239+240)Pu, (90)Sr, (241)Am, (60)Co, (154)Eu, (207)Bi, and (125)Sb. Given the approximately known isotopic ratios, Cs and Pu can be separated into the contributions of either source of origin. Published (137)Cs/(134)Cs and (239+240)Pu/(238)Pu ratios were used for the discrimination of the Dachstein-glacier cryoconites according to their origin from global or Chernobyl fallout. Two different groups of cryoconites were identified, an older population dominated by nuclear weapons fallout and a younger one with predominant Chernobyl fallout. With those data a simple model was formulated to demonstrate the transition and mixing of these two populations on the glacier surface.

Impact of vasoactive intestinal polypeptide and gastrin-releasing peptide on small bowel microcirculation and mucosal injury after hepatic ischemia/reperfusion in rats.

BACKGROUND AND AIMS: Alterations in microvascular perfusion of the intestine after hepatic ischemia/reperfusion have been suggested as an important cause of postoperative septic complications. We therefore investigated small bowel microcirculation and mucosal injury after liver ischemia/reperfusion in a rat model. Furthermore, we analyzed the effects of the regulatory peptides vasoactive intestinal polypeptide and gastrin-releasing peptide for their splanchnic vasoactivity. METHODS: Hepatic ischemia was induced by clamping of the left hepatic artery and vein for 40 min, followed by 60 min of reperfusion. The control group was treated similarly, but without clamping of the liver vessels. Ten minutes after clamping of the hepatic vessels, vasoactive intestinal polypeptide or gastrin-releasing peptide, respectively, were continuously infused intravenously in the experimental groups. Small bowel microcirculation and mucosal injury were assessed using intravital microscopy and the Chiu-score, respectively. RESULTS: The functional capillary density of the small intestine following ischemia and reperfusion of the left hepatic lobe significantly decreased compared to normal controls in both the mucosa and the smooth intestinal muscle. Red blood cell velocity decreased, whereas leukocyte-endothelium adherence, stasis index and the mucosal injury score increased. Administration of vasoactive intestinal polypeptide resulted in an increase of functional capillary density in the mucosa and of the red blood cell velocity and a decrease in the stasis index. The mucosal injury score was significantly higher in reperfused animals without treatment. The application of gastrin-releasing peptide resulted in an isolated increase of the red blood cell velocity. Leukocyte adherences could not be altered by the regulatory peptides. CONCLUSION: We conclude that hepatic ischemia/reperfusion injury leads to significant alterations of small bowel microcirculation and mucosal injury. Vasoactive intestinal polypeptide and gastrin-releasing peptide attenuate the damage in a different manner.

Expression of E-selectin and its transcripts during intestinal ischemia-reperfusion injury in pigs.

BACKGROUND: Ischemia-reperfusion injury (IRI) can result in severe organ dys- or nonfunction. Interaction of leukocytes and endothelial cells mediated by E-selectin appears to be a key step for disturbed microcirculation. Therefore we studied gene and protein expression as well as localization of E-selectin during intestinal IRI. METHODS: Intestinal tissue samples were obtained from extracorporeal perfused intestines (cold ischemia time [CIT] 2 or 20 hours, each n = 5) and additionally in intestinal transplanted pigs (CIT 2 or 20 hours, each n = 1). Mucosal damage was graded according to the Chiu classification. E-selectin mRNA was determined by PCR and quantitative RT-PCR. Localization of E-selectin mRNA was performed by in situ hybridization and of the protein by immunohistochemistry. RESULTS: Histologically, mucosal damage occurred during reperfusion and was earlier and more severe after 20 hours of CIT. E-selectin mRNA expression was detected by PCR already after laparotomy and was elevated after reperfusion. Interestingly, mRNA expression was already increased after 20 hours of CIT. E-selectin mRNA was localized to the luminal surface of muscular, submucosal, and mucosal endothelial cells and the protein was detected on submucosal arterial endothelium as early as 2 hours after reperfusion. CONCLUSION: Prolongation of CIT results in more severe mucosal damage during reperfusion, which is associated with protein expression of E-selection that might be used as a marker for activated endothelial cells. Increased E-selectin mRNA at end of 20 hours of CIT might indicate a preactivated state of endothelial cells potentially triggered by bacterial translocation or products.

Kinetics and localization of interleukin-2, interleukin-6, heat shock protein 70, and interferon gamma during intestinal-rerfusion injury.

BACKGROUND: Intestinal ischemia-reperfusion injury (IRI) represents an exaggerated inflammatory cascade with a complex pathophysiology. IL-2, IL-6, HSP70, and INF-gamma are mediators of the inflammatory process. Therefore, we investigated their kinetics and localization during intestinal IRI. METHODS: Pig intestinal specimens were obtained during cold preservation (cold ischemia time 2 hours) and extracorporeal perfusion. Mucosal damage was graded according to the Chiu classification. MRNA expression was determined by Northern blot (IL-2, IL-6, IFN-gamma) or by quantitative RT-PCR (IL-6, HSP70) and localized by in situ hybridization. RESULTS: Histologically, mucosal damage occurred during reperfusion. Expression of IL-2 mRNA was up-regulated after HTK perfusion and was highest at the start and 7 hours after reperfusion. Expression of IL-6 mRNA increased at 2 hours after reperfusion and HSP70 at 3 hours after reperfusion. IFN-gamma mRNA was expressed after HTK perfusion, with expression of this cytokine increasing to 1 hour after the start of reperfusion, and decreasing thereafter. IL-2 mRNA was localized to endothelial cells (EC) and leukocytes and in close relation to ganglion cells (GC): IL-6 mRNA in EC, smooth muscle cells (SMC), and GC: HSP70 mRNA in EC and SMC; and IFN-gamma mRNA in leukocytes. CONCLUSION: IL-2, IL-6, HSP70, and INF-gamma are parameters of early mRNA expression during intestinal IRI. EC, SMC, leukocytes, and GC have been identified as sources of transcripts that might afford potential targets for intervention strategies to attenuate IRI.

Reduction of severe ischemia/reperfusion injury in rat kidney grafts by a soluble P-selectin glycoprotein ligand.

BACKGROUND: Inflammatory leukocyte-endothelium interactions, mediated by selectins, contribute to renal ischemia/reperfusion (I/R) injury. We examined the influence of the soluble P-selectin glycoprotein ligand 1 (sPSGL) on early I/R-induced changes in a rat kidney transplantation model with long cold ischemia. METHODS: After 24 hr of cold storage, syngeneic kidneys were grafted into bilaterally nephrectomized rats. Before transplantation, recipients received either 1 mg/kg of sPSGL or vehicle (n=8 per group). Six hours after reperfusion, grafts were removed for light microscopy and immunohistochemistry. Capillary blood flow was measured under a fluorescence microscope by using the concentric-circles method. RESULTS: A greater proportion, 74.7+/-7.2% (sPSGL) vs. 28+/-7.4% (controls), of all dye-labeled outer medullary capillaries appeared in the 12-microm radius (P<0.01), indicating dense blood flow, whereas 7.6+/-2.9% vs. 43.3+/-9.7%, respectively, appeared in the 60-microm radius (P<0.05), indicating rarefied blood flow. In the sPSGL-treated group, the extent of severe tubular damage within the inner stripe of the outer medulla was lower compared with controls (37.5+/-8.3% vs. 78.4+/-3.5%, P<0.01). Outer medullary heat shock protein 72 expression was 14.5+/-1.6% in the sPSGL-treated group compared with 9.6+/-1.4% in controls (P<0.05). The number of infiltrating polymorphonuclear leukocytes was similar in both groups. Treatment with sPSGL had no influence on the serum creatinine level. CONCLUSIONS: Our data suggest that impairment of outer medullary blood flow is crucial in I/R injury of kidney grafts with prolonged cold storage. Reduction of capillary blood flow perturbations by sPSGL protects tubular cells from severe structural damage. Blocking early selectin-mediated leukocyte adhesion may have therapeutic implications in improving the prognosis of renal transplants with severe I/R injury.

Androblastoma of the ovary: clinical, diagnostic and histopathologic features.

Androblastomas of Sertoli-Leydig cell tumors of the ovaries are classified into the group of sex cord stromal tumors and represent an extremely rare form of tumor (0.2% of all ovarian tumors) in women. Their malignant potential is lower than that of epithelial ovarian cancer. They cause signs of virilization, although these are not obligatory. In many cases secondary amenorrhea is the only symptom of the disease. This leads to an intensive search for the source of the disorder. Frequently only the elevated production of androgens gives a preoperative clue to the tumor type. The recommendation to include the measurement of androgen levels in the routine diagnosis of secondary amenorrhea must therefore be endorsed. The tumors are usually sonographically identifiable; in differential diagnosis, hyperandrogenemia of other origins (e.g., Cushing's disease, adrenal hyperplasia, pituitary adenoma, other causes of ovarian and adrenal androgen hypersecretion, intersexuality, medically induced androgenization) have to be ruled out. In view of the good prognosis, the therapy of choice consists simply in adnexectomy of the affected side. With regular measurement of serum androgen levels an effective control of the course of the disorder is possible. A conclusive pathological diagnosis is difficult as heterologous tumors and mixed tumors exist and, furthermore, other tumor types are capable of imitating Sertoli-Leydig cell tumors.