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Objective@#The aim of this study was to investigate the effect of changes in nasal tip protrusion on the sense of upper lip protrusion in different populations and to provide a reference for the improvement of soft tissue beauty.@*Methods @# Informed consent and portrait authorization were obtained from the model. A female model whose face met the criteria was selected, and a 3D model of her was obtained using a 3D stereo camera. Based on the original model, ZBRUSH2019 software was used to simulate changes in nose tip protrusion. Then, 9 segments of facial dynamic rotation videos were produced, and an electronic questionnaire was created through a questionnaire website to evaluate the effect of different nose tip protrusions on perceived upper lip protrusion. Randomly selected orthodontic patients, orthodontics professionals and general adults completed the electronic questionnaire. In the questionnaire, a Visual Analog Scale was used to evaluate the perceived degree of protrusion of the upper lip. The higher the score, the more prominent the upper lip of the model in the image. The questionnaire data were statistically analyzed using a generalized linear mixed model. @*Results @#As the nasal tip position became progressively more retracted, the subjects' upper lip protrusion scores increased. Among male subjects, the results showed that the general population thought that the upper lip protrusion was higher than the patients did when the nasal tip protrusion was +6 mm and +4.5 mm (P = 0.023, P = 0.047). When the nasal tip protrusion was +6 mm, the scores of the general population were higher than those of the orthodontics professionals (P = 0.023). However, when the nasal tip variable was -6 mm, their score was lower than that of the patients (P = 0.003), and there was no significant difference in other retest distances between groups (P>0.05).@*Conclusion @#When the protrusion of the nasal tip decreased, the three groups experienced a visual illusion of upper lip protrusion. When the nasal tip protrusion is too large, the general population perceived the visual illusion of the upper lip protrusion as being more obvious.
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OBJECTIVE: To demonstrate that human visual illusion can contribute to sub-endocardial dark rim artifact in contrast-enhanced myocardial perfusion magnetic resonance images.MATERIALS AND METHODS: Numerical phantoms were generated to simulate the first-passage of contrast agent in the heart, and rendered in conventional gray scale as well as in color scale with reduced luminance variation. Cardiac perfusion images were acquired from two healthy volunteers, and were displayed by the same gray and color scales used in the numerical study. Before and after k-space windowing, the left ventricle (LV)-myocardium boarders were analyzed visually and quantitatively through intensity profiles perpendicular the boarders.RESULTS: k-space windowing yielded monotonically decreasing signal intensity near the LV-myocardium boarder in the phantom images, as confirmed by negative finite difference values near the board ranging −1.07 to −0.14. However, the dark band still appears, which is perceived by visual illusion. Dark rim is perceived in the in-vivo images after k-space windowing that removed the quantitative signal dip, suggesting that the perceived dark rim is a visual illusion. The perceived dark rim is stronger at peak LV enhancement than the peak myocardial enhancement, due to the larger intensity difference between LV and myocardium. In both numerical phantom and in-vivo images, the illusory dark band is not visible in the color map due to reduced luminance variation.CONCLUSION: Visual illusion is another potential cause of dark rim artifact in contrast-enhanced myocardial perfusion MRI as demonstrated by illusory rim perceived in the absence of quantitative intensity undershoot.
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PURPOSE: To report a case of the Heidenhain variant of sporadic Creutzfeldt-Jakob disease (CJD), predominantly characterized by visual impairment at onset. CASE SUMMARY: History-taking, ophthalmologic examination, neurologic examination, cerebrospinal fluid examination including 14-3-3 protein analysis, and brain MRI were performed in a 48-year-old man with progressive visual loss and a visual field defect. These symptoms were accompanied by visual illusion and macropsia. Neurologic examination revealed relatively rapidly progressing cognitive impairment, ataxia, aphasia, and myoclonus. The 14-3-3 protein was detectable in otherwise normal CSF samples. The diffusion weighted brain MRI showed increased signal intensity in both occipital lobes, the basal ganglia, the temporal and frontal lobes. He was clinically diagnosed as having a Heidenhain variant of sporadic CJD. CONCLUSIONS: In a patient with a rapidly progressive visual loss, visual field defects, visual illusion, and neurologic abnormalities including progressive dementia, ataxia, aphasia, and myoclonus, the Heidenhain variant of CJD should be considered. Because prions, a cause of CJD, exhibit unusual resistance to conventional chemical and physical decontamination methods, it is necessary to have an appropriate management scheme to prevent the spread of infection.