Irene Schmidtmann

Diagnostic ability of retinal ganglion cell complex, retinal nerve fiber layer, and optic nerve head measurements by Fourier-domain optical coherence tomography

PurposeTo evaluate the diagnostic ability of Fourier-domain optical coherence tomography (FD-OCT) measurements in glaucoma patients, patients with ocular hypertension, and normal subjects.MethodsNinety-three participants with open-angle glaucoma (OAG), 58 patients with ocular hypertension (OHT), and 60 healthy control subjects were included in the study. All study participants underwent FD-OCT imaging. Retinal ganglion cell complex (GCC), macular thickness, peripapillary retinal nerve fiber layer thickness (RFNL), and optic nerve head parameters (ONH) were measured in each participant. The diagnostic ability was evaluated using area under the receiver operating characteristics curves (AUROC).ResultsGlaucoma patients showed a significant reduction in GCC and macular retinal thickness compared to patients with OHT and normal subjects. No differences in GCC were found between the patients with OHT and normal subjects. The best diagnostic ability in the comparison between glaucoma and normal subjects after adjusting for age was found for cup-to-disc ratio (AUROC = 0.848), RNFL average thickness (AUROC = 0.828), and GCC global loss volume (AUROC = 0.805). The diagnostic power of the best GCC, RNFL, and ONH parameter did not show differences beyond random variation (p > 0.05).ConclusionsImaging of the GCC using FD-OCT (RTVue-100) has a comparable diagnostic ability to RNFL and ONH measurements in distinguishing between glaucoma patients and healthy subjects. No differences were found between patients with OHT and normal subjects with regard to ONH, RNFL, and GCC parameters.

SPM-based count normalization provides excellent discrimination of mild Alzheimer's disease and amnestic mild cognitive impairment from healthy aging

Statistical comparisons of [(18)F]FDG PET scans between healthy subjects and patients with Alzheimers disease (AD) or amnestic mild cognitive impairment (aMCI) using Statistical Parametric Mapping (SPM) usually require normalization of regional tracer uptake via ROIs defined using additional software. Here, we validate a simple SPM-based method for count normalization. FDG PET scans of 21 mild, 15 very mild AD, 11 aMCI patients and 15 age-matched controls were analyzed. First, we obtained relative increases in the whole patient sample compared to controls (i.e. areas relatively preserved in patients) with proportional scaling to the cerebral global mean (CGM). Next, average absolute counts within the cluster with the highest t-value were extracted. Statistical comparisons of controls versus three patients groups were then performed using count normalization to CGM, sensorimotor cortex (SMC) as standard, and to the cluster-derived counts. Compared to controls, relative metabolism in aMCI patients was reduced by 15%, 20%, and 23% after normalization to CGM, SMC, and cluster-derived counts, respectively, and 11%, 21%, and 25% in mild AD patients. Logistic regression analyses based on normalized values extracted from AD-typical regions showed that the metabolic values obtained using CGM, SMC, and cluster normalization correctly classified 81%, 89% and 92% of aMCI and controls; classification accuracies for AD groups (very mild and mild) were 91%, 97%, and 100%. The proposed algorithm of fully SPM-based count normalization allows for a substantial increase of statistical power in detecting very early AD-associated hypometabolism, and very high accuracy in discriminating mild AD and aMCI from healthy aging.

Evaluation of the McGrath® Series 5 videolaryngoscope after failed direct laryngoscopy*

Unanticipated difficulties during tracheal intubation and failure to intubate are among the leading causes of anaesthesia‐related morbidity and mortality. Using the technique of video laryngoscopy, the alignment of the oral and pharyngeal axes to facilitate tracheal intubation is unnecessary. In this study we evaluated the McGrath® Series 5 videolaryngoscope for tracheal intubation in 61 patients who exhibited Cormack and Lehane grade 3 or 4 laryngoscopies with a Macintosh laryngoscope. Using the McGrath resulted in an improved glottic view, compared to Macintosh laryngoscope. Laryngoscopy was improved by one grade in 10%, by two grades in 80% and by three grades in 10% of cases (p < 0.0001). The success rate for intubation was 95% with the McGrath. These results suggest that the McGrath videolaryngoscope can be used with a high success rate to facilitate tracheal intubation in difficult intubation situations.

Performance of the C-MAC video laryngoscope in patients after a limited glottic view using Macintosh laryngoscopy

We applied the C‐MAC videolaryngoscope in 52 consecutive patients who were found to have an unexpected Cormack and Lehane grade‐3 (n = 49) and grade‐4 (n = 3) laryngeal view with the Macintosh laryngoscope. The glottic view improved in 49 (94%) patients using the C‐MAC. Tracheal intubation was successful in 49 of 52 patients (94%). In one patient, tracheal intubation failed using the C‐MAC despite the presence of a Cormack and Lehane grade‐2. These results suggest that the C‐MAC videolaryngoscope has a role as a rescue device in cases of an initially difficult laryngeal view.

Ascorbic Acid Reduces Noise‐Induced Nitric Oxide Production in the Guinea Pig Ear

Objectives: Noise‐induced hearing loss can be caused, among other causes, by increased nitric oxide (NO) production in the inner ear leading to nitroactive stress and cell destruction. Some studies in the literature suggest that the degree of hearing loss (HL) could be reduced in an animal model through ascorbic acid supplementation. To identify the effect of ascorbic acid on tissue‐dependent NO content in the inner ear of the guinea pig, we determined the local NO production in the organ of Corti and the lateral wall separately 6 hours after noise exposure.

Effects of record linkage errors on registry-based follow-up studies

The importance of reliable record linkage for high quality-population-based disease registration is widely recognized. Systematic methodologic work is lacking, however, on the effects of record linkage errors on the use of disease registries for epidemiologic purposes. The present paper provides algebraic models describing the effects of record linkage errors on monitoring survival of registered patients, which is commonly performed by matching registry records against a database of death certificates, and on registry-based incidence follow-up of external cohorts. Homonym errors, that is, erroneous linkage of records that pertain to distinct individuals, lead to underestimation of survival of registered patients and to overestimation of disease incidence among external cohorts linked to the registry, while synonym errors, that is, failure to link notifications on the same individual, have opposite effects. The magnitude of effects of record linkage errors are illustrated with numerical examples.

Four color-measuring devices compared with a spectrophotometric reference system

OBJECTIVES The objective of this study was to compare the L*C*h° color coordinates of dental color-measuring devices with those of a spectrophotometric reference system. METHODS The International Commission on Illumination (CIE) L*C*h° color coordinates of ceramic samples, matching the colors of the VITA Linearguide, were recorded using four color-measuring devices (VITA Easyshade (A), VITA Easyshade compact (B), Degudent Shadepilot (C), X-Rite Shadevision (D)) and a spectrophotometric reference system under standardized test conditions. The intraclass correlation coefficients, regression lines with coefficients of determination, and mean deviations of the dental color-measuring devices from the spectrophotometric reference system were calculated. RESULTS All of the devices had high intraclass correlation coefficients, between 0.979 and 1.000. Nearly all measurements, except the hue values of devices A, B, and D, showed coefficients of determination close to 1.0 over the range of measurements for L*C*h° color coordinates. Similarly, all of the devices had coefficients of determination near the optimum value of 1.0. Devices C and D produced regression line slopes near the optimum value of 1.0 and intercepts close to the optimum value of zero. Only the L* coordinate measurements of devices A and B and the h° coordinate measurements of device B differed not significantly from the spectrophotometric reference values. CONCLUSIONS The electronic dental color-measuring devices tested showed excellent repeatability, but some devices showed substantial deviations in color coordinate values from the spectrophotometric reference system. Devices C and D showed higher precision than devices A and B.

Completeness and timeliness: Cancer registries could/should improve their performance.

UNLABELLED Cancer registries must provide complete and reliable incidence information with the shortest possible delay for use in studies such as comparability, clustering, cancer in the elderly and adequacy of cancer surveillance. Methods of varying complexity are available to registries for monitoring completeness and timeliness. We wished to know which methods are currently in use among cancer registries, and to compare the results of our findings to those of a survey carried out in 2006. METHODS In the framework of the EUROCOURSE project, and to prepare cancer registries for participation in the ERA-net scheme, we launched a survey on the methods used to assess completeness, and also on the timeliness and methods of dissemination of results by registries. We sent the questionnaire to all general registries (GCRs) and specialised registries (SCRs) active in Europe and within the European Network of Cancer Registries (ENCR). RESULTS With a response rate of 66% among GCRs and 59% among SCRs, we obtained data for analysis from 116 registries with a population coverage of ∼280 million. The most common methods used were comparison of trends (79%) and mortality/incidence ratios (more than 60%). More complex methods were used less commonly: capture-recapture by 30%, flow method by 18% and death certificate notification (DCN) methods with the Ajiki formula by 9%. The median latency for completion of ascertainment of incidence was 18 months. Additional time required for dissemination was of the order of 3-6 months, depending on the method: print or electronic. One fifth (21%) did not publish results for their own registry but only as a contribution to larger national or international data repositories and publications; this introduced a further delay in the availability of data. CONCLUSIONS Cancer registries should improve the practice of measuring their completeness regularly and should move from traditional to more quantitative methods. This could also have implications in the timeliness of data publication.

Correlation of cone beam computed tomography (CBCT) findings in the maxillary sinus with dental diagnoses: a retrospective cross-sectional study

This study was conducted to assess the coincidence of mucosal hyperplasia in the maxillary sinus and related clinical diagnoses of posterior maxillary teeth found in cone beam computed tomography (CBCT) scans. A total of 204 patients who underwent CBCT examinations between 2006 and 2008 were evaluated retrospectively. Clinical and CBCT findings were correlated using patient records. Absolute frequencies, odds ratios (OR), and 95% confidence intervals (95% CI) were calculated for statistical evaluations. There was a pronounced association between periodontitis and radiological signs of sinusitis. Basal mucosal wall thickening was more likely in patients with decayed and non-vital teeth compared to patients with sound teeth (OR = 5.2; 95% CI = 1.2–23.1). Basal mucosal wall thickening was also more likely than total mucosal thickening (OR = 10.4; 95% CI = 2.6–42.2). Patients with decayed and endodontically treated teeth were more likely to exhibit involvement of the basal wall (OR = 9.2; 95% CI = 3.3–25.2) than were patients with healthy teeth. CBCT examinations revealed a correlation between basal mucosal thickening in the maxillary sinus and decayed posterior maxillary teeth or periodontitis. Chronic symptoms involving the sinuses are one of the most common reasons for patients to consult physicians. One reason for chronic orofacial pain is the prevalence of undiagnosed sinus conditions.

Irregularity of the posterior corneal surface after curved interface femtosecond laser-assisted versus microkeratome-assisted descemet stripping automated endothelial keratoplasty.

Purpose: During donor tissue preparation for Descemet stripping automated endothelial keratoplasty (DSAEK), either microkeratome or femtosecond laser can be used for intrastromal cutting. We compared morphological and functional outcomes after DSAEK using both cutting techniques. Methods: In this retrospective study, 22 uneventful DSAEK surgeries were reviewed. Eight donor corneas were prepared for DSAEK using the VisuMax femtosecond laser (Carl Zeiss Meditec AG, Jena, Germany). Fourteen corneas were processed using an Amadeus II microkeratome (Ziemer Ophthalmic Systems AG, Port, Switzerland). The postoperative best spectacle-corrected visual acuity was measured. Furthermore, corneal optical coherence tomography scans (RTVue; Optovue, Fremont, CA) were conducted and analyzed for graft cornea thickness and posterior surface irregularities using regression analysis (SPSS; IBM, Chicago, IL) on a second-order polynomial curve as a model for the posterior surface. Results: The graft thickness was 166.3 ± 58.2 &mgr;m (mean ± SD) in the femtosecond laser group and 172.7 ± 48.2 &mgr;m in the microkeratome group. The best-corrected visual acuity of 0.48 ± 0.20 (logarithm of the minimum angle of resolution) in the femtosecond laser group was significantly poorer when compared with 0.33 ± 0.11 in the microkeratome group (P = 0.038). Moreover, the root mean square error between the posterior corneal surface and an ideal parabola surface was significantly higher in the femtosecond laser group (9.9 ± 2.2 &mgr;m) than in the microkeratome group (5.7 ± 2.2 &mgr;m; P < 0.001). Conclusions: Our study underlines the current superiority of a microkeratome-assisted preparation of the stromal–endothelial lamella before DSAEK surgery compared with the curved interface femtosecond laser-assisted processing.