Electronic Zoom Research Articles

Applying Peer Tutor Learning and Interactive Case Methods in Online Learning: Its Effect on Student Activities and Learning Outcomes

<p style="text-align:justify">The purpose of this study was to increase student activity and learning outcomes by applying peer tutor learning methods combined with interactive case methods in online learning mode through Electronic Learning Aid (ELENA) and Zoom meeting. This study was carried out with a classroom action research (CAR) design in three cycles of implementation. This study was carried out in the even semester of 2020/2021 in the Cost Accounting course. Data collection methods used are documentation, observation, and tests. Student learning activities in online learning through ELENA and Zoom meetings have been recorded to show changes and improvements in the quality of student learning activities. The data analysis method used is quantitative descriptive analysis. The application of the peer tutor learning with the interactive case methods has been going well through the Zoom meeting and ELENA and is able to have an impact on student activities and learning outcomes in the Cost Accounting course. The increase in student learning activities can be seen in the increased ability of students to ask questions, provide responses or answers, and express opinions or ideas during lectures. Student learning outcomes also experienced a significant increase, which was 7.5%. Students who act as tutors can carry out their duties well.</p>

Development And Symbiosis of a Chlorella Strain in Natural and Extreme Conditions of The Aquatic Environment

The article studies the influence of natural and extreme conditions of the aquatic environment on the development and symbiosis of a strain of the unicellular planktonic green microalgae Chlorella vulgaris BIN, 6-10 microns in size. The studies were carried out in 2019, 2020 on the basis of laboratory analysis of samples taken at a depth of 10 cm from 15 control points of the Nizhny Fermsky pond of the Federal State Budgetary Educational Institution of Higher Education RSAU-Moscow Agricultural Academy named after K.A. Timiryazev, and in an open aquarium (bioreactor) with a volume of 50 liters in which, using the Arduino hardware and software complex, the temperature and lighting optimal for the growth of microalgae of the Chlorella vulgaris BIN strain were automatically maintained, as well as biochemical and physical conditions for the growth and development of microalgae were simulated strain Chlorella vulgaris BIN. In a separate study, completed in January 2020, the development and symbiosis of chlorella with unicellular and multicellular aquatic organisms was studied in an open aquarium with artificial lighting and temperature maintenance, in the presence of a critically large amount of macro and microelements used by the microalga of the Chlorella vulgaris BIN strain at the growth and reproduction. To calculate the number of chlorella cells in the samples, a Goryaev two-grid camera was used, in which the identification and quantitative accounting of chlorella cells was carried out according to the results of photographs and video filming, with the resolution settings of the Bresser LCD MICRO 5MP digital microscope at 125, 500 times, and at 1000 times electronic ZOOM magnification. As a result of the work carried out, a number of limiting factors have been identified that affect the growth and development of microalgae of the Chlorella vulgaris BIN strain and associations of microorganisms that coexist in symbiosis with microalgae.

SURG-21. ENDO- AND EXOSCOPIC SURGERY FOR PEDIATRIC NEUROSURGICAL OPERATION

INTRODUCTIONRecently endo- and exoscopic surgeries have been gradually performed in neurosurgery. To improve the accuracy and safety of our endoscopic procedures, we are currently trialing 4K or 8K systems. Here we report our experience of endo- and exoscopic procedures for pediatric neurosurgery.METHODSWe retrospectively identified 22 patients (15 males, 7 females; mean age, 9.2 years) who underwent surgery for sellar lesions and intraventricular or intraparenchymal lesions with an endo- or exoscopic procedure at our institute between 2010 and 2020. We used a full HD endoscope system (Storz) and an organic electroluminescence (EL) monitor (Sony), and a 4K system (Sony and Olympus). VITOM 3D (Storz) was used as the exoscope. Videoscope (Olympus) was used as a flexible scope for intraventricular tumors.RESULTSWe performed surgical procedures as 11 biopsies, 6 third ventriculostomies, 5 resections, and 3 fenestrations. The full HD system with organic EL monitor presented high color contrast. We could easily distinguish between tumor microstructure and the normal structure with the 4K system comparing to full HD. Moreover, electronic zoom function enabled us to discriminate tumor boundaries without having to move the endoscope closer. As a result, we could delineate the surgical working space. VITOM 3D was simple to sharpen the focus on the wider surgical field, similar to the application of an operating microscope.CONCLUSIONIn pediatric neurosurgery, an endo- or exoscope enables clear visual recognition of a boundary between tumor and normal area.

Realities of practical andragogy in the condition of the COVID-19 pandemic: migration pedagogy in Ukraine

The purpose of this article is to make recommendations for the organization of adult education in quarantine conditions: exchange of experience.The article identifies that "Lifelong Learning" is one of the priorities of society in all countries, focusing on such potentials of andragogy as promoting the social adaptation of adults and addressing issues of labor migration. In the conditions of COVID-19, an effective form of work was interactive communication through e-mail, work in Viber-groups and the use of the electronic platform ZOOM for distance lectures. It has been proven, that the methods of work of a teacher and an andragogue are not identical: adult learners and full-time university students are different mental subjects of education. The theory and methodology of teaching economic disciplines in these two varieties are very different. The authors present the results of the analysis of modern scientific sources, which testify in favor of the need for further development of andragogical learning technologies. The experiment of this study and comparative analysis was not planned, it took place for objective reasons, caused by the COVID-19 pandemic. The obtained results in practical andrаgogy are useful for teachers-practitioners, andragogues, employment services - especially in cases of force majeure in adult education (COVID and others) and for quality administrative control over the learning process in extreme conditions or at a distance operating mode

Технология Zoom как эффективный инструмент для дистанционного обучения в преподавании английского языка студентам медикам

The paper presents issues associated with the introduction of effective educational technologies to distance learning a foreign language at the university. The review of the author’s use of Zoom technology in medical education is presented. The current problems of introduction of distance learning technologies in teaching English language to medical students are determined. The experience of distance learning for teaching medical students a foreign language by the electronic educational resource Zoom is described.

ПІДХІД ДО ВИБОРУ ПРОГРАМНО-ТЕХНІЧНОЇ ТА ОБҐРУНТУВАННЯ ТЕХНОЛОГІЧНОЇ ОСНОВИ СТВОРЕННЯ ІНТЕРАКТИВНОЇ КАРТИ ПРИРОДНО-ЗАПОВІДНОГО ФОНДУ УКРАЇНИ В ПОЛТАВСЬКІЙ ОБЛАСТІ

Author’s approach to the choice of software and technological basis for compilation a thematic interactive map of the Natural Reserve Fund of Ukraine (NRFU) in Poltava region was offered in the article. The content of relevant key concepts and tendencies of their progressive development under the conditions of scientific-and-technological advance were revealed. On the basis of working in a full-featured and multifunctional geoinformation systems (GIS) environment practical experience, the criteria for the selection of application software products suitable for the thematic interactive maps compilation, taking into account the peculiarities of information and software of the created database of NRFU objects were determined. They were: free distribution; freedom of manipulation with functionality; dynamic development; extended documentation support; interoperability. It was selected full-featured GIS – QGIS, the most optimal GIS that was installed on the technical system or that would be used to obtain a thematic interactive map of the NRF in Poltava region. For the most part, it was characterized the content of the corresponding cartographic working out, which consists of more than 200 objects, divided into 4 main categories of national and local importance (national nature park; nature reserve of national importance; natural monuments, botanical gardens and parks of national importance; territories and local nature reserve fund objects) that were displayed with the dot, line, and plane symbols in a certain electronic map-full zoom mode. The main principles of forming of the technical and technological component in the algorithm of compilation the modern types of cartographic works were determined and adapted to the interactive specified region NRF map development. There was constructed a structural and graphical model, which represented the system settings of the most active elements of the process, determining the technological way to obtain the eventual result (a product in the form of a cartographic product or service), and was carried out with the help of the necessary tools, organized into a corresponding technological scheme.

Efficacy of narrow-band imaging for detecting intestinal metaplasia in adult patients with symptoms of dyspepsia

Introduction and objectiveAtrophy and intestinal metaplasia are early phenotypic markers in gastric carcinogenesis. White light endoscopy does not allow direct biopsy of intestinal metaplasia due to a lack of contrast of the mucosa. Narrow-band imaging is known to enhance the visibility of intestinal metaplasia, to reduce sampling error, and to increase the diagnostic yield of endoscopy for intestinal metaplasia in Asian patients. The aim of our study was to validate the diagnostic performance of narrow-band imaging using 1.5× electronic zoom endoscopy (with no high magnification) to diagnose intestinal metaplasia in Mexican patients. Materials and methodsA retrospective cohort study was conducted on consecutive patients with dyspeptic symptoms at a private endoscopy center within the time frame of January 2015 to December 2016. ResultsA total of 338 patients (63±8.4 years of age, 40% women) were enrolled. The prevalence of H. pylori infection was 10.9% and the incidence of intestinal metaplasia in the gastric antrum and corpus was 23.9 and 5.9%, respectively. Among the patients with intestinal metaplasia, 65.3% had the incomplete type, 42.7% had multifocal disease, and one third had extension to the gastric corpus. Two patients had low-grade dysplasia. The sensitivity of white light endoscopy was 71.2%, with a false negative rate of 9.9%. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of narrow-band imaging (with a positive light blue crest) were 85, 98, 86.8, 97.7, and 87.2%, respectively. ConclusionThe prevalence of H. pylori infection and intestinal metaplasia in dyspeptic Mexican patients was not high. Through the assessment of the microsurface structure and light blue crest sign, non-optical zoom narrow-band imaging had high predictive values for detecting intestinal metaplasia in patients from a general Western setting.

Comparison between image quality in electronic zoom and geometric magnification in digital mammography.

Magnification mammography is performed to enhance the visibility of small structures at the expense of relatively high radiation dose as a complementary examination to standard mammography. The introduction of post-processing capabilities and the widespread use of digital mammography has promoted some controversy in the last decade on whether similar visibility can be achieved using electronic zoom. The aim of this study is to compare the visibility of small structures in images obtained by the two techniques stated above for different exposure conditions. Images of a Fluke Biomedical Model 18-220 Mammography Accreditation Phantom were obtained using standard techniques and geometric magnification, using a digital mammography unit, with different exposure factors. Three different target/filter combinations (Mo/Mo,Mo/Rh,Rh/Rh), variable kVp (26-32), and automatic exposure control were used. Images obtained using standard technique were electronically zoomed and compared to the corresponding magnification mammograms. Comparisons were based on the visibility of structures evaluated by five senior technologist with extensive experience in mammography. Statistical analysis was performed using non-parametric tests. Visibility of structures was not affected by the kV used for a given target/filter combination for both techniques (p > 0.065). Target/filter combination of Mo/Mo provided better visibility of micro-calcification and fibers (p < 0.026) in geometric magnification technique and Mo/Rh in the digital zoom technique. No significant differences were observed in the visibility of simulated breast masses. The overall image score was significantly higher (p < 0.001) for geometric magnification over the digital zoom for Mo/Mo & Rh/Rh combinations. Although sufficient image quality was maintained in electronically zoomed images, geometric magnification provided better overall visualization of structures in the phantom.

Tu1443 New Generation Flexible Spectral Imaging Color Enhancement Is Useful to Predict Histology of Small Colorectal Polyps

Prediction of colon polyp histology is decisive as small non advanced adenoma may be discarded after resection and hyperplastic lesions may be left in place. The NICE classification system for NBI endoscopy and magnification has been shown to be effective in prediction of histology. There is only little data for the flexible spectral imaging color enhancement (FICE. Newest generation of endoscopes have over mega pixel CMOS sensors that allow FICE aligned with electronic zoom without loss of image quality. With this new technology, histology prediction may easily be possible during standard colonoscopy without using optical zoom endoscopes.

Calcifications in the Breast and Digital Breast Tomosynthesis

Our study was to compare the clarity with which calcifications are seen on conventional mammography (CM) with the same calcifications on digital breast tomosynthesis (DBT). We define clarity as the sharpness, contrast, and diagnostic quality by which the calcifications were depicted. In a HIPPA compliant Institutional Review Board approved study, 3,000 women volunteered to have both a screening mammogram and a DBT study. A total of 119 sequential cases with relevant calcifications (not clearly benign) were reviewed. Two board certified, dedicated, breast imaging radiologists reviewed the CM and DBT images in an unblinded paired comparison. Only the mediolateral oblique (MLO) projection was available for the DBT studies. The MLO and craniocaudal projections were reviewed using the 2D images. Window and leveling, and electronic zoom were permitted. Unlimited time was allowed to provide a subjective assessment as too how well the calcifications were seen, from a diagnostic perspective, when the two studies were evaluated side-by-side. In 41.6% of the cases, the readers felt that calcifications were seen with superior clarity on DBT. In 50.4% of the cases, the visibility of calcifications was the same for DBT and CM, and in 8% of the cases, calcifications were seen with greater clarity on CM than DBT. In 92% of the cases, the clarity with which calcifications were seen on DBT was equal to or better than for CM and in almost half, the clarity on DBT was judged to be better than for CM. Our analysis shows that calcifications can be demonstrated with equal or greater clarity on DBT as on CM, thus allowing for comparable, and, perhaps, improved interpretive analysis of detected calcifications.

A Kinase Anchor Protein 150 (AKAP150)-associated Protein Kinase A Limits Dendritic Spine Density

The A kinase anchor protein AKAP150 recruits the cAMP-dependent protein kinase (PKA) to dendritic spines. Here we show that in AKAP150 (AKAP5) knock-out (KO) mice frequency of miniature excitatory post-synaptic currents (mEPSC) and inhibitory post-synaptic currents (mIPSC) are elevated at 2 weeks and, more modestly, 4 weeks of age in the hippocampal CA1 area versus litter mate WT mice. Linear spine density and ratio of AMPAR to NMDAR EPSC amplitudes were also increased. Amplitude and decay time of mEPSCs, decay time of mIPSCs, and spine size were unaltered. Mice in which the PKA anchoring C-terminal 36 residues of AKAP150 are deleted (D36) showed similar changes. Furthermore, whereas acute stimulation of PKA (2-4 h) increases spine density, prolonged PKA stimulation (48 h) reduces spine density in apical dendrites of CA1 pyramidal neurons in organotypic slice cultures. The data from the AKAP150 mutant mice show that AKAP150-anchored PKA chronically limits the number of spines with functional AMPARs at 2-4 weeks of age. However, synaptic transmission and spine density was normal at 8 weeks in KO and D36 mice. Thus AKAP150-independent mechanisms correct the aberrantly high number of active spines in juvenile AKAP150 KO and D36 mice during development.

Comparaison entre le zoom numérique et l’agrandissement géométrique dans l’étude des foyers de microcalcifications en mammographie numérique

With the advent of digital mammography with electronic zoom capabilities, we have sought to determine the need for geometric magnification for the evaluation of clusters of microcalcifications. Eighty-eight clusters of microcalcifications were reviewed by two experienced radiologists using electronic zoom (ZOOM) and geometric magnification (MAG). The following criteria were evaluated: image quality, shape and number of microcalcifications, size and shape of the clusters. The clusters were classified based on malignancy risk using the BI-RADS criteria. Histological results from macrobiopsy or surgery as well as 2 year follow-up were used as reference for statistical analysis. Sensitivity (100% for MAG and 90% for ZOOM), specificity (52% versus 39%), positive predictive value (51% versus 44%) and negative predictive value (100% versus 88%) were superior for geometric magnification compared to electronic zoom irrespective of the reviewer but without reaching statistical significance. However, image quality was significantly superior with geometric magnification (p<<0.05). In addition, reviewers were more confident in their interpretation of geometric magnification images. Geometric magnification remains necessary in routine clinical practice for the characterization of microcalcifications and BI-RADS classification.

On the Suitability of SIFT Technique to Deal with Image Modifications Specific to Confocal Scanning Laser Microscopy

Computer vision tasks such as recognition and classification of objects and structures or image registration and retrieval can provide significant information when applied to microscopy images. Recently developed techniques for the detection and description of local features make the extraction and description of local image features that are invariant to various changes possible. The invariance and robustness of feature detection and description techniques play a key role in the design and implementation of object recognition, image registration, or image mosaicing applications. The scale-invariant feature transform (SIFT) technique is a widely used method for the detection, description, and matching of image features. In this article we present the results of our experiments regarding the repeatability of SIFT features, and to the precision of the SIFT feature matching, under image modifications specific to confocal scanning laser microscopy (CSLM). We have analyzed the behavior of SIFT while changing the pinhole aperture, photomultiplier gain, laser beam power, and electronic zoom. Our experiments, conducted on CSLM images, show that the SIFT technique is able to match detected key points between images acquired at different values of the acquisition parameters with good precision and represents a consistent tool for computer vision applications in CSLM.

Can electronic zoom replace magnification in mammography? A comparative Monte Carlo study

Magnification, which is considered to be a relatively high "dose cost" mammographic technique, is a complementary examination performed on women exhibiting breast complaints or abnormalities. Particular attention is given to the imaging procedure as the primary aim is to confirm the existence of suspected abnormalities, despite the additional dose. The introduction of post-processing capabilities and the widespread use of digital mammography promoted some controversy in the last decades on whether electronic zoom performed on the derived initial screening mammogram can effectively replace this technique. This study used Monte Carlo simulation methods to derive simulated screening mammograms produced under several exposure conditions, aiming to electronically magnify and compare them to the corresponding magnification mammograms. Comparison was based on quantitative measurements of image quality, namely contrast to noise ratio (CNR) and spatial resolution. Results demonstrated that CNR was higher for geometric magnification compared to the case of electronic zooming. The percentage difference was higher for lesions of smaller radius and achieved 29% for 0.10 mm details. Although spatial resolution is maintained high in the zoomed images, when investigating microcalcifications of 0.05 mm radius or less, only with geometric magnification can they be visualised.

Coloscopie : mieux détecter et mieux caractériser

The endoscopic analysis of the colonic lumen with a flexible tube began around1960, at first with a gastrocamera, then with a fibrocolonoscope. After 1990, the electronic imaging brought a three points revolution with increased resolution of the image, transfer of the image on a television monitor giving access to multiple observers, electronic image processing. The recent colonoscopes have an increased resolution with more pixels in the Charged Coupled Device (CCD) sensor, a High Definition Television (HDTV) image and an electronic and/or optical zoom for magnification. Colonoscopy is now often performed in a similar environment to that of surgery. Therapeutic applications justify a strict strategy for endoscopic diagnosis. At first, detection of the lesion in standard vision, then characterization with the help of chromoscopy for the evaluation of morphology and with the help of magnification for the evaluation of the pit pattern. Then, comes the time for treatment decision between abstention, endoscopic resection or surgery. The legitimacy of the management is controlled in retrospective by the analysis of the tissue samples. Recent alternatives to colonoscopy (3D radiological imaging, colon capsule) should not invalidate the priority attributed to colonoscopy which associates treatment to the early detection of colorectal cancer and precursors.

Impact of Wide-Angle, High-Definition Endoscopy in the Diagnosis of Colorectal Neoplasia: A Randomized Controlled Trial

It is essential to optimize standard colonoscopy technique to be able to increase polyp detection. We sought to compare the performance of colonoscopy using a high-definition, wide-angle endoscope (HDE) versus a standard colonoscope (SC) for the detection of colorectal neoplasia. All consecutive consenting adult patients referred from primary care centers were included and randomly assigned at a 1:1 ratio to undergo HDE or SC. Times to reach and withdraw from the cecum were measured. Morphology, size, location, and pathologic diagnosis of each polyp were recorded. Sample size calculation resulted in a total of 682 patients needed. A total of 693 consecutive patients fulfilled all inclusion criteria (73 excluded owing to insufficient bowel preparation). Each arm included 310 patients with no baseline characteristic differences. Time to reach the cecum was slightly superior for SC (8.9 +/- 4.8 minutes vs 8.2 +/- 4.5 minutes; P = .055). Pathology examination was feasible in 418 lesions (272 adenomas, 109 hyperplastic polyps, and 37 inflammatory lesions). Both techniques detected a similar number and type of lesions, and there were no differences in the distribution along the colon, in the degree of dysplasia, or morphology of adenomas. The per-patient basis analyses demonstrated that there were no differences between the 2 arms of the study in the detection rates of polyps (SC, 0.84 +/- 1.59; HDE, 0.83 +/- 1.30), adenomas (0.45 +/- 1.07 vs 0.43 +/- 0.87), small adenomas (0.22 +/- 0.71 vs 0.28 +/- 0.78), flat adenomas (0.30 +/- 0.91 vs 0.21 +/- 0.63), or hyperplastic polyps (0.16 +/- 0.50 vs 0.18 +/- 0.54). HDE did not detect significantly more colorectal neoplasia than SC.

Focus on Photonics and Imaging

Focus on Photonics and Imaging

Contribution of the Carboxyl Terminus of the VPAC1 Receptor to Agonist-induced Receptor Phosphorylation, Internalization, and Recycling

When exposed to vasoactive intestinal peptide (VIP), the human wild type VPAC1 receptor expressed in Chinese hamster ovary (CHO) cells is rapidly phosphorylated, desensitized, and internalized in the endosomal compartment and is not re-expressed at the cell membrane within 2 h after agonist removal. The aims of the present work were first to correlate receptor phosphorylation level to internalization and recycling, measured by flow cytometry and in some cases by confocal microscopy using a monoclonal antibody that did not interfere with ligand binding, and second to identify the phosphorylated Ser/Thr residues. Combining receptor mutations and truncations allowed identification of Ser250 (in the second intracellular loop), Thr429, Ser435, Ser448 or Ser449, and Ser455 (all in the distal part of the C terminus) as candidates for VIP-stimulated phosphorylation. The effects of single mutations were not additive, suggesting alternative phosphorylation sites in mutated receptors. Replacement of all of the Ser/Thr residues in the carboxyl-terminal tail and truncation of the domain containing these residues completely inhibited VIP-stimulated phosphorylation and receptor internalization. There was, however, no direct correlation between receptor phosphorylation and internalization; in some truncated and mutated receptors, a 70% reduction in phosphorylation had little effect on internalization. In contrast to results obtained on the wild type and all of the mutated or truncated receptors that still underwent phosphorylation, internalization of the severely truncated receptor was reversed within 2 h of incubation in the absence of the agonist. Receptor recovery was blocked by monensin, an endosome inhibitor.

A Magnified Narrow-Band Imaging (NBI) Improves Pretreatment Endoscopic Evaluation of the Early Gastric Cancers

Aim: The narrow-band imaging (NBI) is a newly developed device which brings about an information of the microvascular structure of GI mucosa. An aim of this study is to investigate the usefulness of the magnified NBI for more accurate endoscopic diagnosis of the early gastric cancer. Patients and Methods: We observed endoscopically 132 early gastric cancers with the magnified NBI from January to October, 2004. An Olympus electronic zoom endoscope Q240Z with a lucent hood on its tip was used in this study. The magnified NBI patterns of the cancers were collated with the histology of the resected cancers. Results: The appearances of the magnified NBI were classified as follws; fine-network, oval, spiral, and irregular patterns. Well-differentiated adenocarcinomas typically showed fine-network pattern (sensitivity: 55%, specificity: 98%, n = 113). Moderately differentiated adenocarcinomas typically showed oval or spiral pattern (sensitivity: 58%, specificity: 90%, n = 6). Poorly differentiated adenocarcinomas typically showed irregular pattern (sensitivity: 90%, specificity: 96%, n = 13). The margin of the cancer was more clearly defined in cases of depressed type (“IIc”) early gastric cancer. However, in cases of elevated type (“IIa”) early gastric cancer, the margin was not so clearly demarcated. Cancers invading the submucosal layer (“depth sm”, n = 14) had a tendency to show dilated capillary patterns, which were rarely observed in the case of cancers remaining in the mucosal layer (“depth m”, n = 118). Conclusion: The magnified NBI observation was useful for the pretreatment histological evaluation of the early gastric cancer and for the accurate demarcation of the margin of the depressed type (IIc) of early gastric cancers. Aim: The narrow-band imaging (NBI) is a newly developed device which brings about an information of the microvascular structure of GI mucosa. An aim of this study is to investigate the usefulness of the magnified NBI for more accurate endoscopic diagnosis of the early gastric cancer. Patients and Methods: We observed endoscopically 132 early gastric cancers with the magnified NBI from January to October, 2004. An Olympus electronic zoom endoscope Q240Z with a lucent hood on its tip was used in this study. The magnified NBI patterns of the cancers were collated with the histology of the resected cancers. Results: The appearances of the magnified NBI were classified as follws; fine-network, oval, spiral, and irregular patterns. Well-differentiated adenocarcinomas typically showed fine-network pattern (sensitivity: 55%, specificity: 98%, n = 113). Moderately differentiated adenocarcinomas typically showed oval or spiral pattern (sensitivity: 58%, specificity: 90%, n = 6). Poorly differentiated adenocarcinomas typically showed irregular pattern (sensitivity: 90%, specificity: 96%, n = 13). The margin of the cancer was more clearly defined in cases of depressed type (“IIc”) early gastric cancer. However, in cases of elevated type (“IIa”) early gastric cancer, the margin was not so clearly demarcated. Cancers invading the submucosal layer (“depth sm”, n = 14) had a tendency to show dilated capillary patterns, which were rarely observed in the case of cancers remaining in the mucosal layer (“depth m”, n = 118). Conclusion: The magnified NBI observation was useful for the pretreatment histological evaluation of the early gastric cancer and for the accurate demarcation of the margin of the depressed type (IIc) of early gastric cancers.

Effects of magnification and zooming on depth perception in digital stereomammography: an observer performance study

We are evaluating the application of stereoscopic imaging to digital mammography. In the current study, we investigated the effects of magnification and zooming on depth perception. A modular phantom was designed which contained six layers of 1-mm-thick Lexan plates, each spaced 1 mm apart. Eight to nine small, thin nylon fibrils were pasted on each plate in horizontal or vertical orientations such that they formed 25 crossing fibril pairs in a projected image. The depth separation between each fibril pair ranged from 2 to 10 mm. A change in the order of the Lexan plates changed the depth separation of the two fibrils in a pair. Stereoscopic image pairs of the phantom were acquired with a GE full-field digital mammography system. Three different phantom configurations were imaged. All images were obtained using a Rh target/Rh filter spectrum at 30 kVp tube potential and a ±3° stereo shift angle. Images were acquired in both contact and 1.8X magnification geometry and an exposure range of 4 to 63 mAs was employed. The images were displayed on a Barco monitor driven by a Metheus stereo graphics board and viewed with LCD stereo glasses. Five observers participated in the study. Each observer visually judged whether the vertical fibril was in front of or behind the horizontal fibril in each fibril pair. It was found that the accuracy of depth discrimination increased with increasing fibril depth separation and x-ray exposure. The accuracy was not improved by electronic display zooming of the contact stereo images by 2X. Under conditions of high noise (low mAs) and small depth separation between the fibrils, the observers' depth discrimination ability was significantly better in stereo images acquired with geometric magnification than in images acquired with a contact technique and displayed with or without zooming. Under our experimental conditions, a 2 mm depth discrimination was achieved with over 60% accuracy on contact images with and without zooming, and with over 90% accuracy on magnification images. This study indicates that stereoscopic imaging, especially with magnification, may be useful for visualizing the spatial distribution of microcalcifications in a cluster and for differentiating overlapping tissues from masses on mammograms.