Classification of Jaw Bone Cysts and Necrosis via the Processing of Orthopantomograms

The authors analyze the design of a method for automatized evaluation of parameters in orthopantomographic images capturing pathological tissues developed in human jaw bones. The main problem affecting the applied medical diagnostic procedures consists in low repeatability of the performed evaluation. This condition is caused by two aspects, namely subjective approach of the involved medical specialists and the related exclusion of image processing instruments from the evaluation scheme. The paper contains a description of the utilized database containing images of cystic jaw bones; this description is further complemented with appropriate schematic repre¬sentation. Moreover, the authors present the results of fast automatized segmentation realized via the live-wire method and compare the obtained data with the results provided by other segmentation techniques. The shape parameters and the basic statistical quantities related to the distribution of intensities in the segmented areas are selected. The evaluation results are provided in the final section of the study; the authors correlate these values with the subjective assessment carried out by radiologists. Interestingly, the paper also comprises a discussion presenting the possibility of using selected parameters or their combinations to execute automatic classification of cysts and osteonecrosis. In this context, a comparison of various classifiers is performed, including the Decision Tree, Naive Bayes, Neural Network, k-NN, SVM, and LDA classifica¬tion tools. Within this comparison, the highest degree of accuracy (85% on the average) can be attributed to the Decision Tree, Naive Bayes, and Neural Network classifier

Enhancement Gradient Pulse Waveforms in MR Tomography

Abstract-The magnetic resonance (MR) imaging techniques of tomography and spectroscopy are exploited in many applications. For the MR instruments to function properly it is necessary to maintain a high quality of homogeneity of the fundamental magnetic field. The pre-emphasis compensation of the generated gradient field increases the homogeneity of the generated magnetic field and reduces the minimum switching times of the gradients. This enables measuring the MR images of incisions in the human body, the relaxation properties of nuclei, self-diffusion processes, flows of liquids and movements of solids faster and more accurately

Processing of MR Slices of Temporomandibular Disc for 3D Visualization

Abstract-This article deals with a segmentation of MR images in temporomandibular joint (TMJ) area. The TMJ belongs to small but the most overloaded joint of the human body. It consists of the head of the mandible and articular foss

Analysis of EPI phase correction with low flip‐angle excitation to reduce the required minimum TE: Application to whole‐brain, submillimeter‐resolution fMRI at 3 T

Echo planar imaging is used widely for its imaging speed. However, its applications often suffer from ghost artifacts. In the community, an approach using three navigator echoes is used commonly for the artifact correction. Although this scheme is effective, as the matrix size increases for high‐resolution imaging, the navigator echoes can contribute significantly to increasing the “required minimum TE.” To overcome this issue, this work proposes the use of an alternative navigator echo scheme called the “TR‐external” scheme.The TR‐external scheme reduces the required minimum TE by allocating an additional excitation loop for the navigator echoes before every main excitation loop. In this work, a detailed analysis on the TR‐external scheme was performed to assess its performance in comparison to the standard scheme. Visual fMRI was performed to check the feasibility of using the TR‐external scheme for detecting functional signals.The performance of the TR‐external scheme was comparable with that of the standard scheme in terms of the SNR, elimination of ghost artifacts, and the BOLD detection. For a given matrix size (288 × 288), the TR‐external scheme allowed a substantially shorter TE (5.94 ms) compared with the standard scheme, which resulted in a higher SNR. Furthermore, this feature enabled the submillimeter‐resolution (0.73 × 0.73 mm2) fMRI measurement with a favorable TE (35 ms) at 3 T. The fMRI results revealed that activated voxels are well localized along the cortical ribbon.A TR‐external scheme for EPI phase correction was implemented at 3 T. Its feasibility for submillimeter‐resolution fMRI was successfully demonstrated

MRI-Based Visualization of the Relaxation Times of Early Somatic Embryos

The large set of scientific activities supported by MRI includes, among others, the research of water and mineral compounds transported within a plant, the investigation of cellular processes, and the examination of the growth and development of plants. MRI is a method of major importance for the measurement of early somatic embryos (ESE) during cultivation, and in this respect it offers several significant benefits discussed within this paper. We present the following procedures: non-destructive measurement of the volume and content of water during cultivation; exact three-dimensional differentiation between the ESEs and the medium; investigation of the influence of ions and the change of relaxation times during cultivation; and multiparametric segmentation of MR images to differentiate between embryogenic and non-embryogenic cells. An interesting technique consists in two-parameter imaging of the relaxation times of the callus; this method is characterized by tissue changes during cultivation at a microscopic level, which can be monitored non-destructively