Software system for calibrating examiners in cephalometric point identification.

INTRODUCTION: The literature has shown that subjective concepts lead to interobserver variations in the definitions and identifications of cephalometric landmarks. Observers must be trained and calibrated to conduct scientific research using cephalometric comparisons. In this study, we aimed to develop and test a computational model called Cyclops cephalometry in radiographic cephalometry training and calibration. METHODS: This system uses the concepts of evaluation process managers, examiners, and testers, thus affording uniformity in cephalometric evaluations. The system was tested with 5 orthodontists and 5 postgraduate students who located 28 landmarks in 10 lateral cephalometric radiographs before and after training. RESULTS: Before training, the Student t test showed significant differences (P <0.05) in accuracy between the orthodontists and the students (71.4% and 54.9%, respectively). However, considerable improvement in accuracy was observed after training in both groups (86.5% and 83%, respectively), without significant differences (P = 0.30) between groups. Users of the system agreed about its usability aspects such as effectiveness, efficiency, and satisfaction. CONCLUSIONS: This model was shown to be a useful and efficient tool in the calibration process, and might be helpful in various comparative cephalometric investigations.

Recording and reenactment of collaborative diagnosis sessions using DICOM.

This paper presents a radiological collaborative tool capable of direct manipulation of Digital Imaging and Communications in Medicine (DICOM) images on both sides, and also recording and reenacting of a recorded session. A special collaborative application protocol formerly developed was extended and used as basis for the development of collaborative session recording and playback processes. The protocol is used today for real-time radiological meetings through the Internet. This new standard for collaborative sessions makes possible other uses for the protocol, such as asynchronous collaborative sessions, decision regulation, auditing, and educational applications. Experimental results are given which compare this protocol with other popular collaborative approaches. Comparison of these results shows that the proposed protocol performs much better than other approaches when run under controlled conditions.

Comparative study of linear measurements performed in magnetic resonance and computed tomography images with the aid of an image realignment software / Estudo comparativo de medidas realizadas em imagens por ressonância magnética e por tomografia computadorizada com auxílio de um software de realinhamento de imagens

The aim of this study was to compare linear measurements of implant sites performed in magnetic resonance and computed tomography images with the aid of an image alignment software. Four patients from the Dental Implant Research and Teaching Center of Universidade Federal de Santa Catarina, Florianópolis, Brazil, were submitted to both computed tomography and magnetic resonance scans. An image realignment software was used to allow measuring the exact same sites on the images of both modalities. A total of eighty linear measuremensts of the posterior regions and twelve linear measurement of the anterior regions were performed with each modality. Measurements were carried out by one calibrated observer. Observer's reproducibility was higher than 97% (Dalberg's error). Student's t-test was used to compare the results of the height of the alveolar process in the computed tomography and magnetic resonance images. There was no statistically significant differences between the measurements performed in the computed tomography and magnetic resonance images (p = 0.4136). with a strong correlation between them (r = 0.8346). Similarly, there was no statistically significant differences between the measurements produced by the two modalities when the analysis discriminated the anterior and posterior regions (p = 0.7801 and p = 0.4381, respectively), with a strong correlation between the measurements in the posterior region of the jaws (r = 0.8547), and a weak correlation in the anterior region (r = 0.5472). Linear measurements of the alveolar process obtained from magnetic resonance and computed tomography images are comparable.

A computational method for the estimation of atrophic changes in Alzheimer's disease and mild cognitive impairment.

Early diagnosis and objective monitoring of disease progression are essential for the development of therapeutic strategies in Alzheimer's disease (AD). Current techniques are mainly based on semi-objective measures such as neuropsychological tests and a physician's magnetic resonance imaging (MRI) inspection. We have developed a computational method for automatic and unbiased assessment of the brain's state of atrophy from MRI. Sixty-eight high-resolution MRI scans were acquired from 25 AD patients (age: 69.8+/-7.5), 16 mild cognitive impairment (MCI) patients (67.6+/-9.1) and 27 control subjects (64.9+/-8.8). On the basis of the computations we were able to recognize MCI subjects with a sensitivity of 81% and a specificity of 80% in a group of MCIs and controls using a linear classifier. To date, comparable results have only been received by manual labelling or human inspection. Our calculations are light weighted and can be applied on usual workstations in everyday clinical practice. Each step can be understood and applied by the physicians, independent of their computer knowledge. The applied image analysis process produces visual maps of atrophic changes as intermediate steps of the calculations. These can be helpful for the physician during inspection of the brain. The proposed analysis has the potential to improve AD diagnosis and treatment, especially in early its stages, and could also be used to monitor disease progression in therapeutic trials.