MISM: A Medical Image Segmentation Metric for Evaluation of Weak Labeled Data

Performance measures are an important tool for assessing and comparing different medical image segmentation algorithms. Unfortunately, the current measures have their weaknesses when it comes to assessing certain edge cases. These limitations arise when images with a very small region of interest or without a region of interest at all are assessed. As a solution to these limitations, we propose a new medical image segmentation metric: MISm. This metric is a composition of the Dice similarity coefficient and the weighted specificity. MISm was investigated for definition gaps, an appropriate scoring gradient, and different weighting coefficients used to propose a constant value. Furthermore, an evaluation was performed by comparing the popular metrics in the medical image segmentation and MISm using images of magnet resonance tomography from several fictitious prediction scenarios. Our analysis shows that MISm can be applied in a general way and thus also covers the mentioned edge cases, which are not covered by other metrics, in a reasonable way. In order to allow easy access to MISm and therefore widespread application in the community, as well as reproducibility of experimental results, we included MISm in the publicly available evaluation framework MISeval.

Evaluation of the Availability of Nursing Quality Indicators in German FHIR Implementations

Standardized nursing data sets facilitate data analysis and help to improve nursing research and quality management in Germany. Recently, governmental standardization approaches have favored the FHIR standard and helped to define it as the state of the art for healthcare interoperability and data exchange. In this study, we identify common data elements used for nursing quality research purposes by analyzing nursing quality data sets and databases. We then compare the results with current FHIR implementations in Germany to find most relevant data fields and overlaps. Our results show that most of the patient focused information has already been modelled in national standardization efforts and FHIR implementations. However, representation of data fields describing nursing staff related information, such as experience, workload or satisfaction, is missing or lacking.

The RCX Extension Hub: A Resource for Implementations Extending the R Adaption of the Cytoscape Exchange Format

Public repositories provide access to biological networks for investigations, and subsequently serve to distribute the network encoded biomedical and even clinically relevant results. However, inclusion of complementary information requires data structures and implementations customized to the integrated data for network representation, usage in supporting application, and extending analysis functionality. Partitioning of this information into individual aspects of a network facilitates compatibility and reusability of the network-based results, but also requires support and accessibility of the extensions and their implementations. The RCX extension hub offers overview and access to extensions of the Cytoscape exchange format implemented in R. The hub supports the realization of self-customized extension through guides, example implementations, and a template for the creation of R extension packages.

Adaptation of HL7 FHIR for the Exchange of Patients' Gene Expression Profiles

High-throughput technologies, especially gene expression analyses can accurately capture the molecular state in patients under different conditions. Thus, their application in clinical routine gains increasing relevance and fosters patient stratification towards individualized treatment decisions. Electronic health records already evolved to capture genomic data within clinical systems and standards like FHIR enable sharing within, and even between institutions. However, FHIR only provides profiles tailored to variations in the molecular sequence, while expression patterns are neglected although being equally important for decision making. Here we provide an exemplary implementation of gene expression profiles of a microarray analysis of patients with acute myeloid leukemia using an adaptation of the FHIR genomics extension. Our results demonstrate how FHIR resources can be facilitated in clinical systems and thereby pave the way for usage for the aggregation and exchange of transcriptomic data in multi-center studies.

Data-dependent visualization of biological networks in the web-browser with NDExEdit

Networks are a common methodology used to capture increasingly complex associations between biological entities. They serve as a resource of biological knowledge for bioinformatics analyses, and also comprise the subsequent results. However, the interpretation of biological networks is challenging and requires suitable visualizations dependent on the contained information. The most prominent software in the field for the visualization of biological networks is Cytoscape, a desktop modeling environment also including many features for analysis.

A further challenge when working with networks is their distribution. Within a typical collaborative workflow, even slight changes of the network data force one to repeat the visualization step as well. Also, just minor adjustments to the visual representation not only need the networks to be transferred back and forth. Collaboration on the same resources requires specific infrastructure to avoid redundancies, or worse, the corruption of the data. A well-established solution is provided by the NDEx platform where users can upload a network, share it with selected colleagues or make it publicly available.

NDExEdit is a web-based application where simple changes can be made to biological networks within the browser, and which does not require installation. With our tool, plain networks can be enhanced easily for further usage in presentations and publications. Since the network data is only stored locally within the web browser, users can edit their private networks without concerns of unintentional publication. The web tool is designed to conform to the Cytoscape Exchange (CX) format as a data model, which is used for the data transmission by both tools, Cytoscape and NDEx. Therefore the modified network can be directly exported to the NDEx platform or saved as a compatible CX file, additionally to standard image formats like PNG and JPEG.

Relations in biological research are often visualized as networks. For instance, if two proteins interact with each other during a certain process, the corresponding network would show two nodes connected by one edge. But the fact that the interaction between the two exists, may not be enough. With established software solutions like Cytoscape we can add all the information we have about our nodes and their interaction to our data foundation. Furthermore, we can change the visual appearance of our nodes and their interaction based on this information.

For example, if our network contains 20 nodes, that all interact with each other, but the strength of these interactions each range between 0 and 1, we can illustrate that by making the edges wider for strong interactions and slimmer for weak interactions. Thus, our visualization is enriched with valuable information. As of now these data-dependent modifications can only be made with a desktop client.

We introduce NDExEdit, a web-based solution for visualization changes to networks that conform to the CX data format. It allows us to import networks directly from the NDEx platform and apply changes to the visualization—including all types of mappings, one of which was briefly described above.

Perspective on Code Submission and Automated Evaluation Platforms for University Teaching

We present a perspective on platforms for code submission and automated evaluation in the context of university teaching. Due to the COVID-19 pandemic, such platforms have become an essential asset for remote courses and a reasonable standard for structured code submission concerning increasing numbers of students in computer sciences. Utilizing automated code evaluation techniques exhibits notable positive impacts for both students and teachers in terms of quality and scalability. We identified relevant technical and non-technical requirements for such platforms in terms of practical applicability and secure code submission environments. Furthermore, a survey among students was conducted to obtain empirical data on general perception. We conclude that submission and automated evaluation involves continuous maintenance yet lowers the required workload for teachers and provides better evaluation transparency for students.

Implementation of Gene Expression Profiles in the HL7 FHIR Standard

Gene expression profiles can capture significant molecular differences paving the way toward precision medicine. However, clinical standards like FHIR only provide encoding of molecular sequence variations, even so, expression patterns are equally important for decision making. Here we provide an exemplary implementation of gene expression profiles of a microarray analysis using an adaption of the FHIR Genomics extension. Our results demonstrate how FHIR resources can be facilitated in bioinformatics-based decision support systems or used for the aggregation of molecular genetics data in multi-center clinical trials.

MISeval: A Metric Library for Medical Image Segmentation Evaluation

Correct performance assessment is crucial for evaluating modern artificial intelligence algorithms in medicine like deep-learning based medical image segmentation models. However, there is no universal metric library in Python for standardized and reproducible evaluation. Thus, we propose our open-source publicly available Python package MISeval: a metric library for Medical Image Segmentation Evaluation. The implemented metrics can be intuitively used and easily integrated into any performance assessment pipeline. The package utilizes modern DevOps strategies to ensure functionality and stability. MISeval is available from PyPI (miseval) and GitHub: https://github.com/frankkramer-lab/miseval.

RCX-an R package adapting the Cytoscape Exchange format for biological networks

Motivation

The Cytoscape Exchange (CX) format is a JSON-based data structure designed for the transmission of biological networks using standard web technologies. It was developed by the network data exchange, which itself serves as online commons to share and collaborate on biological networks. Furthermore, the Cytoscape software for the analysis and visualization of biological networks contributes structure elements to capture the visual layout within the CX format. However, there is a fundamental difference between data handling in web standards and R. A manual conversion requires detailed knowledge of the CX format to reproduce and work with the networks.

Results

Here, we present a software package to create, handle, validate, visualize and convert networks in CX format to standard data types and objects within R. Networks in this format can serve as a source for biological knowledge and also capture the results of the analysis of those while preserving the visual layout across all platforms. The RCX package connects the R environment for statistical computing with outside platforms for storage and collaboration, as well as further analysis and visualization of biological networks.

Availability

RCX is a free and open-source R package, available on Bioconductor from release 3.15 (https://bioconductor.org/packages/RCX) and via GitHub (https://github.com/frankkramer-lab/RCX).

Supplementary information

Supplementary data are available at Bioinformatics Advances online.

Comprehensive Analysis of Chemical Structures That Have Been Tested as CFTR Activating Substances in a Publicly Available Database CandActCFTR

Background: Cystic fibrosis (CF) is a genetic disease caused by mutations in CFTR, which encodes a chloride and bicarbonate transporter expressed in exocrine epithelia throughout the body. Recently, some therapeutics became available that directly target dysfunctional CFTR, yet research for more effective substances is ongoing. The database CandActCFTR aims to provide detailed and comprehensive information on candidate therapeutics for the activation of CFTR-mediated ion conductance aiding systems-biology approaches to identify substances that will synergistically activate CFTR-mediated ion conductance based on published data. Results: Until 10/2020, we derived data from 108 publications on 3,109 CFTR-relevant substances via the literature database PubMed and further 666 substances via ChEMBL; only 19 substances were shared between these sources. One hundred and forty-five molecules do not have a corresponding entry in PubChem or ChemSpider, which indicates that there currently is no single comprehensive database on chemical substances in the public domain. Apart from basic data on all compounds, we have visualized the chemical space derived from their chemical descriptors via a principal component analysis annotated for CFTR-relevant biological categories. Our online query tools enable the search for most similar compounds and provide the relevant annotations in a structured way. The integration of the KNIME software environment in the back-end facilitates a fast and user-friendly maintenance of the provided data sets and a quick extension with new functionalities, e.g., new analysis routines. CandActBase automatically integrates information from other online sources, such as synonyms from PubChem and provides links to other resources like ChEMBL or the source publications. Conclusion: CandActCFTR aims to establish a database model of candidate cystic fibrosis therapeutics for the activation of CFTR-mediated ion conductance to merge data from publicly available sources. Using CandActBase, our strategy to represent data from several internet resources in a merged and organized form can also be applied to other use cases. For substances tested as CFTR activating compounds, the search function allows users to check if a specific compound or a closely related substance was already tested in the CF field. The acquired information on tested substances will assist in the identification of the most promising candidates for future therapeutics.

ndexr-an R package to interface with the network data exchange

Motivation

Seamless exchange of biological network data enables bioinformatic algorithms to integrate networks as prior knowledge input as well as to document resulting network output. However, the interoperability between pathway databases and various methods and platforms for analysis is currently lacking. The Network Data Exchange (NDEx) is an open-source data commons that facilitates the user-centered sharing and publication of networks of many types and formats.

Results

Here, we present a software package that allows users to programmatically connect to and interface with NDEx servers from within R. The network repository can be searched and networks can be retrieved and converted into igraph-compatible objects. These networks can be modified and extended within R and uploaded back to the NDEx servers.

Availability and implementation

ndexr is a free and open-source R package, available via GitHub (https://github.com/frankkramer-lab/ndexr) and Bioconductor (http://bioconductor.org/packages/ndexr/).

Contact

florian.auer@med.uni-goettingen.de.

Supplementary information

Supplementary data are available at Bioinformatics online.

Small vessel disease, but neither amyloid load nor metabolic deficit, is dependent on age at onset in Alzheimer's disease

BACKGROUND

There is controversy concerning whether Alzheimer's disease (AD) with early onset is distinct from AD with late onset with regard to amyloid pathology and neuronal metabolic deficit. We hypothesized that compared with patients with early-onset AD, patients with late-onset AD have more comorbid small vessel disease (SVD) contributing to clinical severity, whereas there are no differences in amyloid pathology and neuronal metabolic deficit.

METHODS

The study included two groups of patients with probable AD dementia with evidence of the AD pathophysiologic process: 24 patients with age at onset <60 years old and 36 patients with age at onset >70 years old. Amyloid deposition was assessed using carbon-11-labeled Pittsburgh compound B positron emission tomography, comorbid SVD was assessed using magnetic resonance imaging, and neuronal metabolic deficit was assessed using fluorodeoxyglucose positron emission tomography. Group differences of global and regional distribution of pathology were explored using region of interest and voxel-based analyses, respectively, carefully controlling for the influence of dementia severity, apolipoprotein E genotype, and in particular SVD. The pattern of cognitive impairment was determined using z scores of the subtests of the Consortium to Establish a Registry for Alzheimer's Disease Neuropsychological Assessment Battery.

RESULTS

Patients with late-onset AD showed a significantly greater amount of SVD. No statistically significant differences in global or regional amyloid deposition or neuronal metabolic deficit between the two groups were revealed. However, when not controlling for SVD, subtle differences in fluorodeoxyglucose uptake between early-onset AD and late-onset AD groups were detectable. There were no significant differences regarding cognitive functioning.

CONCLUSIONS

Age at onset does not influence amyloid deposition or neuronal metabolic deficit in AD. The greater extent of SVD in late-onset AD influences the association between neuronal metabolic deficit and clinical symptoms.

Homology-based inference sets the bar high for protein function prediction

BACKGROUND

Any method that de novo predicts protein function should do better than random. More challenging, it also ought to outperform simple homology-based inference.

METHODS

Here, we describe a few methods that predict protein function exclusively through homology. Together, they set the bar or lower limit for future improvements.

RESULTS AND CONCLUSIONS

During the development of these methods, we faced two surprises. Firstly, our most successful implementation for the baseline ranked very high at CAFA1. In fact, our best combination of homology-based methods fared only slightly worse than the top-of-the-line prediction method from the Jones group. Secondly, although the concept of homology-based inference is simple, this work revealed that the precise details of the implementation are crucial: not only did the methods span from top to bottom performers at CAFA, but also the reasons for these differences were unexpected. In this work, we also propose a new rigorous measure to compare predicted and experimental annotations. It puts more emphasis on the details of protein function than the other measures employed by CAFA and may best reflect the expectations of users. Clearly, the definition of proper goals remains one major objective for CAFA.

A large-scale evaluation of computational protein function prediction

A report on the results of the first large-scale community-based critical assessment of protein function annotation (CAFA) experiment.

Automated annotation of protein function is challenging. As the number of sequenced genomes rapidly grows, the overwhelming majority of protein products can only be annotated computationally. If computational predictions are to be relied upon, it is crucial that the accuracy of these methods be high. Here we report the results from the first large-scale community-based critical assessment of protein function annotation (CAFA) experiment. Fifty-four methods representing the state of the art for protein function prediction were evaluated on a target set of 866 proteins from 11 organisms. Two findings stand out: (i) today's best protein function prediction algorithms substantially outperform widely used first-generation methods, with large gains on all types of targets; and (ii) although the top methods perform well enough to guide experiments, there is considerable need for improvement of currently available tools.

Tumor shrinkage assessed by volumetric MRI in the long-term follow-up after stereotactic radiotherapy of meningiomas

PURPOSE

To evaluate tumor volume reduction in the follow-up of meningiomas after fractionated stereotactic radiotherapy (FSRT) or linac radiosurgery (RS) by using magnetic resonance imaging (MRI).

PATIENTS AND METHODS

In 59 patients with skull base meningiomas, gross tumor volume (GTV) was outlined on contrast-enhanced MRI before and median 50 months (range 11-92 months) after stereotactic radiotherapy. MRI was performed as an axial three-dimensional gradient-echo T1-weighted sequence at 1.6 mm slice thickness without gap (3D-MRI). Results were compared to the reports of diagnostic findings.

RESULTS

Mean tumor size of all 59 meningiomas was 13.9 ml (0.8-62.9 ml) before treatment. There was shrinkage of the treated meningiomas in all but one patient. Within a median volumetric follow-up of 50 months (11-95 months), an absolute mean volume reduction of 4 ml (0-18 ml) was seen. The mean relative size reduction compared to the volume before radiotherapy was 27% (0-73%). Shrinkage measured by 3D-MRI was greater at longer time intervals after radiotherapy. The mean size reduction was 17%, 23%, and 30% (at < 24 months, 24-48 months, and 48-72 months).

CONCLUSION

By using 3D-MRI in almost all patients undergoing radiotherapy of a meningioma, tumor shrinkage is detected. The data presented here demonstrate that volumetric assessment from 3D-MRI provides additional information to routinely used radiologic response measurements. After FSRT or RS, a mean size reduction of 25-45% can be expected within 4 years.

Computer-assisted detection of pulmonary embolism: performance evaluation in consensus with experienced and inexperienced chest radiologists

The value of a computer-aided detection tool (CAD) as second reader in combination with experienced and inexperienced radiologists for the diagnosis of acute pulmonary embolism (PE) was assessed prospectively. Computed tomographic angiography (CTA) scans (64 x 0.6 mm collimation; 61.4 mm/rot table feed) of 56 patients (31 women, 34-89 years, mean = 66 years) with suspected PE were analysed by two experienced (R1, R2) and two inexperienced (R3, R4) radiologists for the presence and distribution of emboli using a five-point confidence rating, and by CAD. Informed consent was obtained from all patients. Results were compared with an independent reference standard. Inter-observer agreement was calculated by kappa, confidence assessed by ROC analysis. A total of 1,116 emboli [within mediastinal (n = 72), lobar (n = 133), segmental (n = 465) and subsegmental arteries (n = 455)] were included. CAD detected 343 emboli (sensitivity = 30.74%, correct-positive rate = 6.13/patient; false-positive rate = 4.1/patient). Inter-observer agreement was good (R1, R2: kappa = 0.84, 95% CI = 0.81-0.87; R3, R4: kappa = 0.79, 95% CI = 0.76-0.81). Extended inter-observer agreement was higher in mediastinal and lobar than in segmental and subsegmental arteries (kappa = 0.84-0.86 and kappa = 0.51-0.58 for mediastinal/lobar and segmental/subsegmental arteries, respectively P < 0.05). Agreement between experienced and inexperienced readers was improved by CAD (kappa = 0.60-0.62 and kappa = 0.69-0.72 before and after CAD consensus, respectively P < 0.05). The experienced outperformed the inexperienced readers (Az = 0.95, 0.93, 0.89 and 0.86 for R1-4, respectively, P < 0.05). CAD significantly improved overall performances of readers 3 and 4 (Az = 0.86 for R3, R4 and Az = 0.89 for R3, R4 with CAD, P < 0.05), by enhancing sensitivities in segmental/subsegmental arteries. CAD improved experienced readers' sensitivities in segmental/subsegmental arteries (sens. = 0.93 and 0.90 for R1, R2 before and 0.97 and 0.94 for R1, R2 after CAD consensus, P < 0.05), without significant improvement of their overall performances (P > 0.05). Particularly inexperienced readers benefit from consensus with CAD data, greatly improving detection of segmental and subsegmental emboli. This system is advocated as a second reader.

Technical improvement of pO(2) measurements in breast cancer: investigation of the feasibility in patients and in vitro validation of the method

PURPOSE

Investigating tumor oxygenation in breast cancer with the Eppendorf device is hampered by the deep location and inadequate fixation of the tumor within the breast. In order to ensure the correct site of pO(2) measurements, guiding aids were introduced and the reliability of the refined method was evaluated.

MATERIAL AND METHODS

For guidance of the needle electrode, a metal trocar was inserted up to the tumor rim. Its positioning and all transtumoral tracks of the needle electrode were monitored continuously by ultrasonography. Thus, 150 tumor measurements in 148 patients were evaluated. In a phantom, the possible influence of the metal trocar was assessed and the measurements of two histographs with five different needle electrodes were compared.

RESULTS

In 88% of measurements (132/150) complete or partial sonographic demarcation of the tumor was possible. 83.2% of the tracks (437/525) could be controlled by ultrasonography. Overall, in 60% of measurements (90/150) all values derived reliably from within the tumor. In vitro, an influence of the metal trocar on the measurements could be excluded. Differences between histographs were in accordance with tolerance limits.

CONCLUSION

From theoretical considerations and the phantom experiments a significant negative impact of the technical modifications could be excluded. Instead, the method described here showed to be beneficial in measuring tumor oxygenation in breast tumors. The authors strongly advise to consider exclusively intratumoral pO(2) values as proven by ultrasonography for oxygenation profiling, as in 40% of all measurements the origin of single pO(2) values or tracks was questionable.

Automated CT volumetry of pulmonary metastases: the effect of a reduced growth threshold and target lesion number on the reliability of therapy response assessment using RECIST criteria

The purpose of this study was to evaluate the reproducibility of CT-volumetric tumour response assessment of pulmonary metastasis using variable volume change thresholds (VCT) and target lesions with response evaluation criteria in solid tumours (RECIST). Fifty consecutive patients with pulmonary metastases undergoing follow-up multislice CT under chemotherapy were assessed for response to chemotherapy with modifications to RECIST: (1) decreasing the percentual VCT for diagnosis of tumour response (range = 70%-20%), (2) reducing the number of target lesions (range = 1-5). Continuous and categorical observer agreements were tested by Bland and Altman and extended (kappa(e)) or non-weighted kappa (kappa) and correlated with percentual VCT to predict observer agreement. A total of 202 metastases were evaluated (average volume = 522.4 mm(3) +/- 902.4 mm(3)). General agreement on treatment response was very high (kappa(e) = 0.93-1), but was reduced with VCT < 35% (kappa(e) < 0.95). Kappa correlation with VCT values was strong (r=0.94-0.96; p< or =0.0002). Average confidence decreased significantly at VCT < 45% (p < 0.01) and agreement on stable disease at VCT < 35% (kappa(e) < 0.95; p < 0.01). Reduction of target lesions (n < 3; VCT = 35%) resulted in decreased reader confidence (for n = 1: kappa = 0.49; p < 0.05). Agreement for evaluation of treatment response was robust using VCT > or =35% and > or =3 metastases. This may translate into shortening of follow-up intervals or enable for response assessment with tumours displaying minimal volume change.

Rectal carcinoma: high-spatial-resolution MR imaging and T2 quantification in rectal cancer specimens

PURPOSE

To prospectively compare high-spatial-resolution T1-weighted, T2-weighted, and intermediate-weighted spectral fat-saturated magnetic resonance (MR) imaging for the differentiation of tumor from fibrosis and for delineation of rectal wall layers in rectal cancer specimens.

MATERIALS AND METHODS

The local ethics committee approved the protocol, and written informed consent was obtained from each patient. Thin-section high-spatial-resolution MR imaging was performed in specimens obtained from 23 patients (16 men, seven women; median age, 64 years; age range, 39-84 years) immediately after resection. Seven patients underwent neoadjuvant treatment. T1-weighted spin-echo, T2-weighted fast spin-echo, and intermediate-weighted spectral fat-saturated MR images were obtained in the transverse plane. Differences in signal intensity between tumor and fibrosis and between tumor and rectal wall layers were evaluated by using visual scoring and measurements of T2 relaxation time. Statistical differences were evaluated by using the Wilcoxon signed rank test and a mixed-model regression analysis. All images were compared with whole-mount histopathologic slices (n = 86).

RESULTS

T2-weighted MR images provided the best differentiation between tumor and fibrosis (P < .001). Mean visual signal intensity scores were -1.8 for T2-weighted MR images, -1.4 for intermediate-weighted spectral fat-saturated MR images, and -0.2 for T1-weighted MR images. T2 relaxation times were 97 msec +/- 4.6 for tumor and 70 msec +/- 3.8 for fibrosis (P < .001). Substantial overlap was noted between the tumor and the circular layer of the muscularis propria (97 msec +/- 2.1), and less overlap was noted between the tumor and the longitudinal layer of the muscularis propria (88 msec +/- 1.6).

CONCLUSION

T2-weighted MR imaging provides superior delineation of rectal wall layers and better differentiation of tumor from fibrosis in rectal cancer specimens compared with T1-weighted MR imaging and intermediate-weighted spectral fat-saturated MR imaging by using thin-section high-spatial-resolution sequences.

Inadequacy of manual measurements compared to automated CT volumetry in assessment of treatment response of pulmonary metastases using RECIST criteria

The purpose of this study was to compare relative values of manual unidimensional measurements (MD) and automated volumetry (AV) for longitudinal treatment response assessment in patients with pulmonary metastases. Fifty consecutive patients with pulmonary metastases and repeat chest multidetector-row CT (median interval=2 months) were independently assessed by two radiologists for treatment response using Response Evaluation Criteria In Solid Tumours (RECIST). Statistics included relative measurement errors (RME), intra-/interobserver correlations, limits of agreement (95% LoA), and kappa. A total of 202 metastases (median volume=182.22 mm(3); range=3.16-5,195.13 mm(3)) were evaluated. RMEs were significantly higher for MD than for AV (intraobserver RME=2.34-3.73% and 0.15-0.22% for MD and AV respectively; P<0.05. Interobserver RME=3.53-3.76% and 0.22-0.29% for MD and AV respectively; P<0.05). Overall correlation was significantly better for AV than for MD (P<0.05). Intraobserver 95% LoAs were -1.85 to 1.75 mm for MD and -11.28 to 9.84 mm(3) for AV. The interobserver 95% LoA were -1.46 to 1.92 mm for MD and -11.17 to 9.33 mm(3) for AV. There was total intra-/interobserver agreement on response using AV (kappa=1). MD intra- and interobserver agreements were 0.73-0.84 and 0.77-0.80 respectively. Of the 200 MD response ratings, 28 (14/50 patients) were discordant. Agreement using MD dropped significantly from total remission to progressive disease (P<0.05). We therefore conclude that AV allows for better reproducibility of response evaluation in pulmonary metastases and should be preferred to MD in these patients.

Computer-assisted detection of pulmonary nodules: performance evaluation of an expert knowledge-based detection system in consensus reading with experienced and inexperienced chest radiologists

To evaluate the performance of experienced versus inexperienced radiologists in comparison and in consensus with an interactive computer-aided detection (CAD) system for detection of pulmonary nodules. Eighteen consecutive patients (mean age: 62.2 years; range 29-83 years) prospectively underwent routine 16-row multislice computed tomography (MSCT). Four blinded radiologists (experienced: readers 1, 2; inexperienced: readers 3, 4) assessed image data against CAD for pulmonary nodules. Thereafter, consensus readings of readers 1+3, reader 1+CAD and reader 3+CAD were performed. Data were compared against an independent gold standard. Statistical tests used to calculate interobserver agreement, reader performance and nodule size were Kappa, ROC and Mann-Whitney U. CAD and experienced readers outperformed inexperienced readers (Az=0.72, 0.71, 0.73, 0.49 and 0.50 for CAD, readers 1-4, respectively; P<0.05). Performance of reader 1+CAD was superior to single reader and reader 1+3 performances (Az=0.93, 0.72 for reader 1+CAD and reader 1+3 consensus, respectively, P<0.05). Reader 3+CAD did not perform superiorly to experienced readers or CAD (Az=0.79 for reader 3+CAD; P>0.05). Consensus of reader 1+CAD significantly outperformed all other readings, demonstrating a benefit in using CAD as an inexperienced reader replacement. It is questionable whether inexperienced readers can be regarded as adequate for interpretation of pulmonary nodules in consensus with CAD, replacing an experienced radiologist.

Thêta-Cream® versus Bepanthol® Lotion in Breast Cancer Patients under Radiotherapy

BACKGROUND AND PURPOSE

In radiotherapy of the breast following breast-conserving surgery, the adverse reaction predominantly found is confined to the skin. After phase II studies, Thêta-Cream, containing CM Glucan, Hydroxyprolisilan C und Matrixyl as active substances, was said to have prophylactic properties of preventing acute radiation side effects in skin tissue. In a prospective randomized study, Thêta-cream was compared with standard skin care using Bepanthol lotion.

PATIENTS AND METHODS

20 breast cancer patients were randomly assigned to use Thêta-Cream or Bepanthol lotion during radiotherapy. At 0, 30, and 50 Gy, acute skin toxicity was scored with a modified RTOG scoring system. The patients' content with the skin care and the technical assistants' content with the skin marks were recorded.

RESULTS

For single aspects of toxicity and their sums in defined skin areas, no differences in median and range between study groups were found. The maximal toxicity anywhere in the breast averaged in a moderate erythema, mild elevation of skin temperature, no desquamation in both groups. Mild itchiness and sporadic efflorescences were more frequently seen with Thêta-Cream. According to a ranking of anonymized breast photos at 50 Gy by independent investigators, side effects were equal. Patients' content was high with both skin care regimens (1.25 on a scale from 0 to 10). With Thêta-Cream a trend toward worse skin marks was noted. Adverse events exclusively occurred in Thêta-Cream users: suspected allergic reaction once, and the necessity for resimulation twice.

CONCLUSION

In direct comparison with dexpanthenol-containing lotion, no advantage for Thêta-Cream was found. Higher costs and problems with skin marks prevent a general recommendation.

One year follow up of macular translocation with 360 degree retinotomy in patients with age related macular degeneration

AIM

To evaluate the benefits of macular translocation with 360 degree retinotomy in patients with exudative age related macular degeneration (ARMD).

METHODS

A consecutive interventional case series was performed on patients who underwent macular translocation between June 1997 and January 2000 at the department of ophthalmology, University of Aachen, Germany. A retrospective pilot study was set up with a minimum follow up of 12 months in 39 consecutive patients with subfoveal choroidal neovascularisation secondary to ARMD. The surgical technique included pars plana vitrectomy, induction of retinal detachment, 360 degree retinotomy, removal of the choroidal neovascular membranes (CNVM), macular translocation, peripheral laser retinopexy, and silicone oil endotamponade.

RESULTS

18 patients showed predominantly occult CNVM, six patients had predominantly classic CNVM, and 15 showed subretinal haemorrhage. At the 12 month follow up 13 patients (33%) showed an improvement in visual acuity of more than three lines (logMAR scale), 18 patients (46%) retained stable visual acuity with a change of equal or less than three lines (logMAR scale), and eight patients (21%) showed a decrease in visual acuity of more than three lines (logMAR scale). Recurrence of CNVM was observed in three (8%) eyes at 5-11 months postoperatively. Other complications included proliferative vitreoretinopathy with retinal detachment (n=10), peripheral epiretinal membranes (n=9), macular pucker (n=2), corneal decompensation (n=2), and hypotony (n=11). 18 patients (46%) complained about persistent diplopia.

CONCLUSION

Macular translocation surgery is able to maintain or improve distant vision in the majority of patients with exudative ARMD. Proliferative vitreoretinopathy and diplopia are the two major complications. A prospective randomised controlled trial comparing macular translocation with observation for patients with the occult form of exudative ARMD may be justified.