Effects of differences in pixel size on image characteristics of digital intraoral radiographic systems: a physical and visual evaluation

Author(s):  
Hiroshi Watanabe ◽  
Tohru Kurabayashi
2020 ◽  
Vol 49 (6) ◽  
pp. 20190378
Author(s):  
Taku Kuramoto ◽  
Shinya Takarabe ◽  
Kazutoshi Okamura ◽  
Kenshi Shiotsuki ◽  
Yusuke Shibayama ◽  
...  

Objectives: To quantify and validate the effect of pixel size on a digital intraoral radiographic system according to International Electrotechnical Commission standards through physical and visual evaluations. Methods: The digital intraoral radiographic system used was the photostimulable phosphor imaging plate and scanner system. The system had three image capture modes: high-speed (HS), high-resolution (HR), and super high-resolution (SHR) with different pixels. The physical characteristics of the system were evaluated using presampled modulation transfer function (MTF) and the normalized noise power spectrum (NNPS). An aluminum (Al) step phantom with different depths of holes was used to acquire images under various exposure conditions. The average number of perceptible holes from all steps was plotted against each exposure dose. The results were compared to analyze the effects of pixel size on image quality of intraoral radiographs. Results: The MTF was slightly higher with SHR than with HR and HS. The NNPS with SHR showed about a 40% decrease in magnitude compared to HS. The total number of perceptible holes in the Al step phantom was higher with SHR than with HS and HR in all exposure conditions. Conclusions: The MTF and NNPS obtained with different pixel size could be quantified by physical evaluation, and the differences were visually validated with Al step phantom. The SHR mode has the potential to decrease the radiation dose without compromising the image quality.


2014 ◽  
Vol 24 (2) ◽  
pp. 67-76 ◽  
Author(s):  
Thomas Watterson ◽  
Lynn Marty Grames

The American Speech-Language-Hearing Association (ASHA) has developed Knowledge and Skills (KAS) recommendations for evaluation of the larynx and swallowing function but the evaluation of velopharyngeal (VP) function has never been addressed. This article will review previous documents that have addressed general endoscopic knowledge and skills and develop a case for a new KAS that specifically addresses visualization and evaluation of the VP mechanism. The new KAS document will delineate and explain the relationship between speech evaluation and visual evaluation of VP physiology. The unique skills required of the speech-language pathologist for this kind of evaluation will be discussed.


1994 ◽  
Author(s):  
George A. Geri ◽  
Don R. Lyon ◽  
Yehoshua Y. Zeevi
Keyword(s):  

2005 ◽  
Vol 44 (01) ◽  
pp. 29-32 ◽  
Author(s):  
I. Garai ◽  
J. Varga ◽  
G. Szücs ◽  
Z. Galajda ◽  
C. András ◽  
...  

Summary Aim: We investigated the circulatory characteristics of patients suffering of primary and secondary Raynaud’s syndrome. Patients, methods: We examined 106 patients presenting with the classical symptoms of Raynaud’s syndrom (47 primary, 59 secondary) by hand perfusion scintigraphy developed by our Department of Nuclear Medicine. After visual evaluation we analyzed the images semiquantitatively, using the finger to palm ratio. We statistically compared the patients with primary and those with secondary Raynaud’s syndrome. Results: By visual evaluation we constated regional perfusion disturbances in 42 from 59 patients with secondary Raynaud’s syndrome. However, this was observed in only 3 from 47 patients with the primary form of this disease. This difference was statistically significant (p <0.001). Semiquantitative analysis showed that the finger/palm ratios (FPR) were significantly lower (p <0.05) for the patients with primary Raynaud’s syndrome. No differences in the FPR values concerning sex or right and left side. Conclusion: The hand perfusion scintigraphy with 99mTc-DTPA is a noninvasive, cost effective diagnostic tool, which objectively reflects the global and regional microcirculatory abnormalities of the hands, and provides quantitative data for follow-up.


1993 ◽  
Author(s):  
KELLY PARMLEY ◽  
JOHN DANNENHOFFER, III ◽  
NIGEL WEATHERILL

2020 ◽  
pp. 139-144
Author(s):  
E.O. Orlova

The author reveals the understanding of the nomination of urban microtoponyms as a communication method within the community: preservation and transfer of culturally significant meanings. The signs of creativity are shown in Veliky Novgorod urbanonyms: deviation from stereotypes, overcoming schemes and a combination of associative elements. The use of words-images expressiveness is shown as a leading feature of Novgorod microtoponymics. The article describes the word-image characteristics which are the basis of urbanonyms.


2021 ◽  
Vol 421 ◽  
pp. 244-259
Author(s):  
Hao Xiong ◽  
Yuan Yan Tang ◽  
Fionn Murtagh ◽  
Leszek Rutkowski ◽  
Shlomo Berkovsky

2021 ◽  
pp. 100233
Author(s):  
Koki Nakao ◽  
Shinya Inazumi ◽  
Toshiaki Takaue ◽  
Shigeaki Tanaka ◽  
Takayuki Shinoi

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