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Biomedical subjects

C Münzenmayer

Publications and source records attributed to C Münzenmayer.

4 recordsLinked to original sources
PubMed2005

[Experiences with 'optical' biopsies of leukoplakia of the vocal folds].

BACKGROUND: It is often difficult to distinguish leucoplakia from carcinoma or chronic laryngitis. In this study, we examined if color texture optical biopsies are able to detect leukoplakia reliably and to distinguish this from normal vocal fold tissue. METHODS: 25 images from patients with a normal larynx and 25 images from patients with leucoplakia were analysed retrospectively. The images were recorded with a rigid 90 degrees -laryngoscope (Wolf Typ 4450.571) during a clinical setting and were recorded by a S-VHS-videorecorder. With a software program (InSegT), regions with leucoplakia, normal tissue and suspicious tissue were manually marked. Within each marked region, the use of color texture analysis numeric features were calculated to characterize the surface in texture and color. Color histogramms (HST), Sum- and Difference histogramms (S/D), Statistical Geometric Features (SGF) and Grey-Value-Dependent-Matrix (GLDM) were used. PATIENTS: 29 women and 21 men (age 18 to 81 years, average of 53 years), who were examined in our clinic from 10/1999 - 8/2003, took part in this study. RESULTS: The automatized classification for color texture analysis resulted in 71 % for leucoplakia and 97 % for normal tissue. CONCLUSION: Optical biopsies can contribute to find the correct diagnosis. However, classification results must still get better when optical biopsies should be used in clinical practice.

Adolescent↗
PubMed2004

A semantic approach to segmentation of overlapping objects.

OBJECTIVES: This paper aims at introducing a novel approach for segmentation of overlapping objects and at demonstrating its applicability to medical images. METHODS: This work details a novel approach enhancing the known theory of full-segmentation of an image into regions by lifting it to a semantic segmentation into objects. Our theory allows the formal description of partitioning an image into regions on the first level and allowing the occurrence of overlaps and occlusions of objects on a second, semantic level. Possible applications for the use of this 'semantical segmentation' are the analysis of radiographs and micrographs. We demonstrate our approach by the example of segmentation and separation of overlapping cervical cells and cell clusters on a set of 787 image pairs of registered PAP- and DAPI-stained micrographs. The semantical cell segmentation yielding areas of cell plasmas and nuclei are compared to a manual segmentation of the same images, where 2212 cells have been labeled. A direct comparison of over and under-segmentation between the two segmentation sets yields a mean difference value of 10.15% for the nuclei and 10.80% for the plasma. RESULTS: Using the proposed theory of semantical segmentation of images in combination with adequate models of the image contents, our approach allows identifying, separating and distinguishing several overlapping, occluding objects in medical images. Applying the proposed theory to the application of cervical cell segmentation from overlapping cell clusters and aggregates, it can be seen that it is possible to formally describe the complex image contents. CONCLUSIONS: The proposed method of semantical segmentation is a mighty tool and under the assumption of the subtractive transparency model can be used in different medical image processing applications such as radiology and microscopy. By using alternative models to solve the ambiguities attached to overlaps and occlusions, further fields of application can be addressed.

Algorithms↗
PubMed1998

Design and preliminary evaluation of an extraoral Gow-Gates guiding device.

Incidence of unsuccessful anesthesia with the Gow-Gates mandibular block may be greater than that for the inferior alveolar nerve block until the administrator gains experience with this technique. The aim of this study was to develop a support instrument for the Gow-Gates mandibular block in an attempt to make the described procedure easier and more precise, especially for beginners. In a preliminary clinical experiment 40 patients were anesthetized with this new device; a control group of 40 patients was anesthetized without the instrument. The operators were 80 dental students without previous clinical experience in the Gow-Gates technique. In the experimental group 39 (97.5%) of the 40 patients were provided with complete anesthesia. In the control group 31 (77.5%) of the 40 patients were completely anesthetized. It appears that the new device allows a great level of success with the Gow-Gates mandibular block, irrespective of the clinical experience of the operator.

Anesthesia, Dental↗