[Screening for glaucoma by blue light-pattern ERG and OCT--are the methods comparable?]. / Glaukomscreening mit dem blaulicht-muster-ERG und dem OCT--sind beide verfahren gleichwertig?

BACKGROUND: Up to now, several examinations are necessary to identify early glaucoma. It is also possible to analyse the peripapillary retinal nerve fibre layer thickness by means of OCT. The loss of retinal ganglion cells can be measured by pattern ERG, therefore this method could be used for the detection of early glaucoma. This study compares the results of the blue light-pattern ERG with the Stratus OCT for glaucoma early recognition. PATIENTS AND METHODS: We studied 30 healthy test persons, 20 patients with glaucoma and 20 patients with suspected glaucoma. Each group was examined using eye pressure measurements, funduscopy, perimetry, pachymetry und analysing the retinal nerve fibre layer by the Stratus OCT. The diagnostic work-up was completed by the pattern ERG and an upgrade with a blue light filtering glass. The results of the blue light-pattern ERG and the OCT ("healthy" or "pathological") were compared in a cross table and the agreement between these two raters was measured by the Cohen's kappa coefficient. RESULTS: Pattern ERG and blue light-pattern ERG decrease with advancing age. After developing an age-matched calibration graph we defined standard values up to the age of 56 years. All included subjects were classified by Stratus OCT and blue light-pattern ERG as healthy. We recognised a significant reduction of the retinal nerve fibre layer thickness and the amplitude in the pattern ERG in the cluster of glaucoma patients. For most of them, a blue light-pattern ERG could not be recorded. Nine out of 40 glaucoma suspect eyes were judged as "pathological". Regarding the amplitudes of the blue light-pattern ERG 25 of 28 eyes under suspicion of glaucoma were assigned as "healthy". With the aid of the cross table we estimated a Cohen's kappa of 0.4. The sensitivity of the blue light-pattern ERG was computed to be 70 % and the specificity to be 97.7 %. For the OCT we calculated the sensitivity to be 50 % and the specificity to be 100 %. CONCLUSION: The blue light-pattern ERG correlates in 87 % of our cases with the OCT. Healthy test persons are certainly identified just as well as definitely glaucomatous patients. To distinguish people suspected of early glaucoma the blue light-pattern ERG can be used as an additional, fast and economic diagnostic procedure.

Red tides in the Gulf of Mexico: Where, when, and why?

[1] Independent data from the Gulf of Mexico are used to develop and test the hypothesis that the same sequence of physical and ecological events each year allows the toxic dinoflagellate Karenia brevis to become dominant. A phosphorus-rich nutrient supply initiates phytoplankton succession, once deposition events of Saharan iron-rich dust allow Trichodesmium blooms to utilize ubiquitous dissolved nitrogen gas within otherwise nitrogen-poor sea water. They and the co-occurring K. brevis are positioned within the bottom Ekman layers, as a consequence of their similar diel vertical migration patterns on the middle shelf. Upon onshore upwelling of these near-bottom seed populations to CDOM-rich surface waters of coastal regions, light-inhibition of the small red tide of ~1 ug chl l(-1) of ichthytoxic K. brevis is alleviated. Thence, dead fish serve as a supplementary nutrient source, yielding large, self-shaded red tides of ~10 ug chl l(-1). The source of phosphorus is mainly of fossil origin off west Florida, where past nutrient additions from the eutrophied Lake Okeechobee had minimal impact. In contrast, the P-sources are of mainly anthropogenic origin off Texas, since both the nutrient loadings of Mississippi River and the spatial extent of the downstream red tides have increased over the last 100 years. During the past century and particularly within the last decade, previously cryptic Karenia spp. have caused toxic red tides in similar coastal habitats of other western boundary currents off Japan, China, New Zealand, Australia, and South Africa, downstream of the Gobi, Simpson, Great Western, and Kalahari Deserts, in a global response to both desertification and eutrophication.

Impact of radical operative treatment on the quality of life in women with vulvar cancer--a retrospective study.

OBJECTIVES: For patients undergoing vulva surgery the quality of life (QoL) is generally accepted as an important outcome parameter in addition to long-term survival, mortality and complication rates. Less radical operative treatment can reduce morbidity and thereby improve quality of life. This study focuses on outcome in terms of QoL in patients comparing wide local excision (WLE) with radical vulvectomy and waiver of lymphonodectomy (LNE) with inguinofemoral lymphonodectomy. METHODS: In a retrospective single-center study from 2000 to 2010, 199 patients underwent surgery for vulvar cancer. To assess QoL, the EORTC QLQ-C30 and a tumor-specific module questionnaire were sent to all patients in the follow-up period. RESULTS: Women who underwent WLE have a superior QoL with regard to global health status and physical, role, emotional and cognitive functioning than those who underwent radical vulvectomy. Less radical surgery also implies less fatigue, nausea/vomiting, pain, insomnia, appetite loss, diarrhea and financial difficulties. After radical vulvectomy 89% of patients have sexual complications. CONCLUSION: Radical operative treatment, such as radical vulvectomy, causes deterioration in the QoL of these patients. An individualized, less radical surgery must be the aim in the treatment of vulvar cancer.

Semi-automated volumetric analysis of artificial lymph nodes in a phantom study.

PURPOSE: Quantification of tumour burden in oncology requires accurate and reproducible image evaluation. The current standard is one-dimensional measurement (e.g. RECIST) with inherent disadvantages. Volumetric analysis is discussed as an alternative for therapy monitoring of lung and liver metastases. The aim of this study was to investigate the accuracy of semi-automated volumetric analysis of artificial lymph node metastases in a phantom study. MATERIALS AND METHODS: Fifty artificial lymph nodes were produced in a size range from 10 to 55mm; some of them enhanced using iodine contrast media. All nodules were placed in an artificial chest phantom (artiCHEST®) within different surrounding tissues. MDCT was performed using different collimations (1-5 mm) at varying reconstruction kernels (B20f, B40f, B60f). Volume and RECIST measurements were performed using Oncology Software (Siemens Healthcare, Forchheim, Germany) and were compared to reference volume and diameter by calculating absolute percentage errors. RESULTS: The software performance allowed a robust volumetric analysis in a phantom setting. Unsatisfying segmentation results were frequently found for native nodules within surrounding muscle. The absolute percentage error (APE) for volumetric analysis varied between 0.01 and 225%. No significant differences were seen between different reconstruction kernels. The most unsatisfactory segmentation results occurred in higher slice thickness (4 and 5 mm). Contrast enhanced lymph nodes showed better segmentation results by trend. CONCLUSION: The semi-automated 3D-volumetric analysis software tool allows a reliable and convenient segmentation of artificial lymph nodes in a phantom setting. Lymph nodes adjacent to tissue of similar density cause segmentation problems. For volumetric analysis of lymph node metastases in clinical routine a slice thickness of ≤3mm and a medium soft reconstruction kernel (e.g. B40f for Siemens scan systems) may be a suitable compromise for semi-automated volumetric analysis.

Low dose MDCT of the wrist--an ex vivo approach.

The primary objective of this study was to evaluate, if in multidetector computed tomography (MDCT) of the wrist a good image quality can be maintained while radiation dose is substantially reduced. In a second approach one solely parameter change that allows for the best trade-off between dose reduction and image quality should be identified. Twenty wrist specimens were examined with a 16-slice MDCT in different parameter combinations: 120 and 100 kV, 100, 70 and 40 electronic mAs, pitch factor 0.9 and 1.5. Images were reconstructed in four standard planes (slice thickness 1.0mm, increment 0.5mm, hard kernel) resulting into a total number of 960 images. Two observers evaluated image quality in a blinded and randomized consensus scheme. Detail quality of corticalis, spongiosa, articular surface and soft tissues was graded according to a four-point scale (1 = excellent, 2 = good, 3 = sufficient, and 4 = poor). The scan protocol with the best trade-off between radiation exposure and image quality had a parameter constellation of 100 kV, 70 electronic mAs (78 effective mAs) and a pitch of 0.9 (DLP 63 mGycm). This represented a dose reduction of 55%. A solely decrease of voltage lead to a dose reduction of 36% without any loss of image quality. An increase of the pitch factor to 1.5 and a decrease from 70 to 40 mAs caused the most distinct impairment of image quality. In MDCT of the wrist good image quality could be maintained while radiation dose was considerably reduced. A reduction of voltage offers the best result for a solely parameter change.

Lung nodule assessment in computed tomography: precision of attenuation measurement based on computer-aided volumetry.

PURPOSE: To compare the reproducibility (r) of CT value measurement of pulmonary nodules using volumetry software (LungCare, LC) and manual ROIs (mROI). MATERIALS AND METHODS: 54 artificial nodules in a chest phantom were scanned three times with CT. CT values were measured with LC and mROI. The intrascan-r was assessed with three measurements in the first scan, and the interscan-r with measurements in three consecutive scans (one observer). Intrascan-r und interobserver-r (two obs.) were assessed in the first scan and in contrast-enhanced CT of 51 nodules from 15 patients (kernels b50f and b80f). Intrascan-r and interscan-r were described as the mean range and interobserver-r as the mean difference of CT values. The significance of differences was tested using t-test and sign test. RESULTS: Reproducibility was significantly higher for volumetry-based measurements in both artificial and patient nodules (range 0.11 vs. 6.16 HU for intrascan-r, 2.22 vs. 7.03 HU for interscan-r, difference 0.11 vs. 18.42 HU for interobserver-r; patients: 1.78 vs. 13.19 HU (b50f-Kernel) and 1.88 vs. 27.4 HU (b80f-Kernel) for intrascan-r, 3.71 vs. 22.43 HU for interobserver-r). Absolute CT values differed significantly between convolution kernels (pat./mROI: 29.3 [b50f] and 151.9 HU [b80f] pat./LC: 5 [b50f] and 147 HU [b80f]). CONCLUSION: The reproducibility of volumetry-based measurements of CT values in pulmonary nodules is significantly higher and should therefore be recommended, e. g. in dynamic chest CT protocols. Reproducibility does not depend on absolute CT values.