scholarly journals Image Quality Evaluation of a Digital Radiography System Made in Thailand

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Udomchai Techavipoo ◽  
Nattawut Sinsuebphon ◽  
Sakunrat Prompalit ◽  
Saowapak Thongvigitmanee ◽  
Walita Narkbuakaew ◽  
...  
Keyword(s):  
Image Quality ◽  
Digital Radiography ◽  
Technology Development ◽  
Image Resolution ◽  
Average Score ◽  
Body Parts ◽  
High Contrast ◽  
Low Contrast ◽  
Contrast Image ◽  
Better Than

Background. The National Science and Technology Development Agency (NSTDA) in Thailand researched and prototyped digital radiography systems under the brand name BodiiRay aiming for sustainable development and affordability of medical imaging technology. The image restoration and enhancement were implemented for the systems. Purpose. The image quality of the systems was evaluated using images from phantoms and from healthy volunteers. Methods. The survey phantom images from BodiiRay and other two commercial systems using the exposure settings for the chest, the abdomen, and the extremity were evaluated by three experience observers in terms of the high-contrast image resolution, the low-contrast image detectability, and the grayscale differentiation. The volunteer images of the chests, the abdomens, and the extremities from BodiiRay were evaluated by three specialized radiologists based on visual grading on 5-point scaled questionnaires for the anatomy visibility, the image quality satisfaction, and the diagnosis confidence in using the images. Results. BodiiRay phantom results were similar to those from the commercial systems. The overall performance averaged across the exposure settings showed that BodiiRay was slightly better than Fujifilm FDR Go in the low-contrast detectability ( p = 0.033 ) and in the grayscale differentiation ( p = 0.004 ). It was also slightly better than Siemens YSIO Max in the high-contrast resolution ( p = 0.018 ). The images of chest, pelvis, and hand phantoms illustrated comparable visual quality. For volunteer images, the percentage of the images scored ≥4 ranged from 61% to 99%, 23% to 92%, and 96% to 99% for the chest, abdomen, and extremity images, respectively. The average score ranged from 3.63 to 4.46, 3.18 to 4.21, and 4.41 to 4.51 for the chest, abdomen, and extremity images, respectively. Conclusion. The phantom image results showed the comparability of these systems. The clinical evaluation showed BodiiRay images provided sufficient image qualities for digital radiography of these body parts.

How Good is Too Good? A Subjective Study on Over Enhancement of Images

2021 ◽  
Vol 2021 (29) ◽  
pp. 83-88
Author(s):  
Sahar Azimian ◽  
Farah Torkamani Azar ◽  
Seyed Ali Amirshahi
Keyword(s):  
Image Quality ◽  
High Contrast ◽  
Current Image ◽  
Low Contrast ◽  
Image Dataset ◽  
Long Time ◽  
Reference Images ◽  
Subjective Study ◽  
Contrast Image

For a long time different studies have focused on introducing new image enhancement techniques. While these techniques show a good performance and are able to increase the quality of images, little attention has been paid to how and when overenhancement occurs in the image. This could possibly be linked to the fact that current image quality metrics are not able to accurately evaluate the quality of enhanced images. In this study we introduce the Subjective Enhanced Image Dataset (SEID) in which 15 observers are asked to enhance the quality of 30 reference images which are shown to them once at a low and another time at a high contrast. Observers were instructed to enhance the quality of the images to the point that any more enhancement will result in a drop in the image quality. Results show that there is an agreement between observers on when over-enhancement occurs and this point is closely similar no matter if the high contrast or the low contrast image is enhanced.

scholarly journals The difference in dose and image quality between magnification methods used after the introduction of larger 60-inch operator screens

BJR|Open ◽  
2020 ◽  
Vol 2 (1) ◽  
pp. 20190044
Author(s):  
Hywel Mortimer-Roberts ◽  
Michael R Rees
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Communication Systems ◽  
Image Resolution ◽  
Low Contrast ◽  
Test Tool ◽  
Reduce Radiation Dose ◽  
The Difference ◽  
Picture Archiving And Communication ◽  
Area Product

Objective: To determine whether the use of display matrix magnification on larger operator screens without the use of conventional magnification can reduce radiation dose to the patient, and what effect it would have on image quality. Methods: The kerma-area product (KAP) resulting from standard projections in cardiac angiography were measured when an anthropomorphic phantom was imaged using conventional magnification method and display matrix magnification. The image quality was also evaluated by three observers using a TOR 18FG test tool for both magnification method. Results: The mean radiation KAP for the seven views with conventional magnification was 36.65 µGy m−2 whilst a reduction in KAP of 20.4% is possible using display matrix magnification (p < 0.05). The image resolution during acquisition was identical between both methods and only slightly reduced for the display matrix (1.6 LP mm−1) compared to conventional magnification (1.8 LP mm−1) when images were stored and retrieved on a Picture Archiving and Communication Systems (PACS) system. Both methods retained the same low-contrast detectability to PACS, with only a slight increase in detectability of 18 for display matrix magnification compared to 17 for conventional. Conclusion: Using display matrix magnification instead of conventional equipment magnification significantly reduces radiation does in all standard cardiac views without reducing image quality for the operator. This reduction in radiation dose is significant (p < 0.05) for the patients. The resolution did not change during acquisition, but contrast improved slightly (0.9% threshold contrast), but lost resolution of 0.2 LP mm−1 when archived to PACS. Advances in knowledge: This is a new method of reducing significant dose to the patient during cardiology examinations and may encourage further studies in other fluoroscopy lead examination to see if it could work for them.

scholarly journals Quantifying the Utility of Low Resolution Brain Imaging:: Treatment of Infant Hydrocephalus

2021 ◽  
Author(s):  
Joshua Harper ◽  
Venkateswararao Cherukuri ◽  
Tom O'Riley ◽  
Mingzhao Yu ◽  
Edith Mbabazi-Kabachelor ◽  
...  
Keyword(s):  
Deep Learning ◽  
Image Quality ◽  
Treatment Planning ◽  
Image Resolution ◽  
Learning Enhancement ◽  
Low Contrast ◽  
Substantial Risk ◽  
Noise Ratio ◽  
Hydrocephalus Treatment ◽  
Post Hoc

As low-field MRI technology is being disseminated into clinical settings, it is important to assess the image quality required to properly diagnose and treat a given disease. In this post-hoc analysis of an ongoing randomized clinical trial, we assessed the diagnostic utility of reduced-quality and deep learning enhanced images for hydrocephalus treatment planning. Images were degraded in terms of resolution, noise, and contrast between brain and CSF and enhanced using deep learning algorithms. Both degraded and enhanced images were presented to three experienced pediatric neurosurgeons accustomed to working in LMIC for assessment of clinical utility in treatment planning for hydrocephalus. Results indicate that image resolution and contrast-to-noise ratio between brain and CSF predict the likelihood of a useful image for hydrocephalus treatment planning. For images with 128x128 resolution, a contrast-to-noise ratio of 2.5 has a high probability of being useful (91%, 95% CI 73% to 96%; P=2e-16). Deep learning enhancement of a 128x128 image with very low contrast-to-noise (1.5) and low probability of being useful (23%, 95% CI 14% to 36%; P=2e-16) increases CNR improving the apparent likelihood of being useful, but carries substantial risk of structural errors leading to misleading clinical interpretation (CNR after enhancement = 5; risk of misleading results = 21%, 95% CI 3% to 32%; P=7e-11). Lower quality images not customarily considered acceptable by clinicians can be useful in planning hydrocephalus treatment. We find substantial risk of misleading structural errors when using deep learning enhancement of low quality images. These findings advocate for new standards in assessing acceptable image quality for clinical use.

scholarly journals Assessment of task-based image quality for abdominal CT protocols linked with national diagnostic reference levels

2021 ◽  
Author(s):  
Anaïs Viry ◽  
Christoph Aberle ◽  
Thiago Lima ◽  
Reto Treier ◽  
Sebastian T. Schindera ◽  
...  
Keyword(s):  
Image Quality ◽  
Dose Level ◽  
Renal Stones ◽  
Dose Optimization ◽  
High Contrast ◽  
Diagnostic Reference Levels ◽  
Reference Levels ◽  
Low Contrast ◽  
Ct Scanners ◽  
High Level

Abstract Objectives To assess task-based image quality for two abdominal protocols on various CT scanners. To establish a relationship between diagnostic reference levels (DRLs) and task-based image quality. Methods A protocol for the detection of focal liver lesions was used to scan an anthropomorphic abdominal phantom containing 8- and 5-mm low-contrast (20 HU) spheres at five CTDIvol levels (4, 8, 12, 16, and 20 mGy) on 12 CTs. Another phantom with high-contrast calcium targets (200 HU) was scanned at 2, 4, 6, 10, and 15 mGy using a renal stones protocol on the same CTs. To assess the detectability, a channelized Hotelling observer was used for low-contrast targets and a non-prewhitening observer with an eye filter was used for high contrast targets. The area under the ROC curve and signal to noise ratio were used as figures of merit. Results For the detection of 8-mm spheres, the image quality reached a high level (mean AUC over all CTs higher than 0.95) at 11 mGy. For the detection of 5-mm spheres, the AUC never reached a high level of image quality. Variability between CTs was found, especially at low dose levels. For the search of renal stones, the AUC was nearly maximal even for the lowest dose level. Conclusions Comparable task-based image quality cannot be reached at the same dose level on all CT scanners. This variability implies the need for scanner-specific dose optimization. Key Points • There is an image quality variability for subtle low-contrast lesion detection in the clinically used dose range. • Diagnostic reference levels were linked with task-based image quality metrics. • There is a need for specific dose optimization for each CT scanner and clinical protocol.

OPTIMISATION OF PATIENT DOSE AND IMAGE QUALITY IN FLUOROSCOPICALLY GUIDED CERVICAL SPINE SURGERY: A PHANTOM-BASED STUDY

2018 ◽  
Vol 184 (2) ◽  
pp. 237-247 ◽  
Author(s):  
Vasileios I Metaxas ◽  
Gerasimos A Messaris ◽  
George D Gatzounis ◽  
George S Panayiotakis
Keyword(s):  
Image Quality ◽  
Spinal Surgery ◽  
Patient Dose ◽  
Skin Dose ◽  
High Contrast ◽  
Operational Parameters ◽  
High Definition ◽  
Low Contrast ◽  
Cervical Spine Surgery ◽  
Noise Ratio

Abstract The purpose of the current study was to provide useful data, which may help neurosurgeons to manage the patient dose and image quality in spinal surgery procedures, utilising a phantom and a test object. The kerma area product, cumulative dose (CD) and entrance surface dose (ESD) rate on the phantom and image intensifier were measured, for selectable fields of view (FOVs), fluoroscopy modes, two geometric magnifications and various phantom thicknesses. The images were subjectively evaluated regarding low-contrast detectability and high-contrast resolution. Signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), high-contrast spatial resolution (HCSR) and figure of merit (FOM) values were also estimated. The ESD rates increased with increasing phantom thickness, when using electronic or geometric magnification, continuous or high-definition fluoroscopy (HDF). The observers’ evaluation showed relatively slight changes in image quality when pulsed fluoroscopy was used. SNR, CNR and HCSR values decreased with increasing phantom thicknesses, while remained almost constant when using pulsed fluoroscopy. SNR and HCSR improved in HDF, while the CNR remained almost constant only for the FOVs 23 and 17 cm. By applying electronic magnification, this resulted in improved HCSR. FOM values decreased in HDF, with increasing phantom thickness and using electronic magnification. For the ‘thinnest’ patients, CD may overestimate skin dose by 25% than the actual values. Geometric magnification resulted in improved FOM, especially for low-dose fluoroscopy and FOV 23 cm. The knowledge of the increments in dose values, image quality and FOM indices concerning phantom thickness may help neurosurgeons to optimise spinal surgery procedures by selecting the appropriate operational parameters, which could contribute toward the establishment of a radiation protection culture.

Limulus vision in the ocean day and night: Effects of image size and contrast

1996 ◽  
Vol 13 (1) ◽  
pp. 31-41 ◽  
Author(s):  
E. D. Herzog ◽  
M. K. Powers ◽  
R. B. Barlow
Keyword(s):  
Fold Increase ◽  
Cape Cod ◽  
Female Size ◽  
Diurnal Changes ◽  
High Contrast ◽  
Image Size ◽  
Low Contrast ◽  
Adaptive Mechanisms ◽  
Horseshoe Crabs ◽  
Better Than

AbstractMale horseshoe crabs, Limulus polyphemus, use their eyes to locate mates day and night. We investigated their ability to detect targets of different size and contrast in a mating area of Buzzards Bay, Cape Cod, MA. We found that males can see large, high-contrast targets better than small, low-contrast ones. For targets of the same size, animals must be about 0.1 m closer to a low-contrast target to see it as well as a high-contrast one. For targets of the same contrast, animals must be approximately 0.2 m closer to a small target to see it as well as one twice as large. A decrease of 0.05 steradians in the size of the retinal image of a target can be compensated by a four-fold increase in contrast. About 60% of the animals detect black targets subtending 0.110 steradians (equivalent to an adult female viewed from about 0.56 m), while only 20% detect targets subtending 0.039 steradians. This study shows that horseshoe crabs maintain about constant contrast sensitivity under diurnal changes in light intensity in their natural environment. As a consequence of circadian and adaptive mechanisms in the retina, male horseshoe crabs can detect female-size objects about equally well day and night.

New IQI for Digital Radiography

2007 ◽  
Author(s):  
Masako Mori ◽  
Toshibumi Kashiwa ◽  
Yoshimitsu Aoki
Keyword(s):  
Image Quality ◽  
Digital Radiography ◽  
Image Resolution ◽  
Nuclear Industry ◽  
Pair Type ◽  
Line Pair ◽  
Welded Structures ◽  
Testing Conditions ◽  
Imaging Parameters ◽  
Radiographic Testing

Radiographic Test (RT) has been widely used in industries to detect inner defects of welded structures or any other significant components. Especially in the nuclear industry, film radiography is the dominant and standardized procedure in performing radiographic testing. Lately emphasis is on digital radiography. One of the most serious concerns for digitization is the lack of image resolution standardizing device like resolution gauge which would determine imaging parameters such as modular transfer function (MTF). This paper proposes line pair type image quality indicator (IQI) corresponding to the current IQIs for both hole and wire type. The advantage of this IQI is to enable easier calibration of testing conditions and quantification of digital RT image quality with required MTF that should be clearly defined in the examination procedures. Furthermore, to acquire “resolution-ensured” digital image of existing RT films, we developed line pair type standardization film. Prototypes of line pair type IQI and line pair type standardization film are currently in the validation study and trial implementing process. These results are also reported in this paper.

scholarly journals Controlling contrast and luma of digital images by transformation of pixel brightness through power function

2020 ◽  
Vol 2020 (2) ◽  
pp. 70-76
Author(s):  
Alexey Raukhvarger ◽  
Vladislav Vladimirovich Martyanov
Keyword(s):  
Image Processing ◽  
Simple Model ◽  
Power Function ◽  
Digital Image ◽  
Function Analysis ◽  
Low Contrast ◽  
Pixel Brightness ◽  
Image Details ◽  
Contrast Image ◽  
Better Than

The article considers the possibility of controlling the brightness and contrast of the digital image by transformation of the pixel brightness through the power function. Analysis of the parameters of the converted images on the simple model of dark low contrast image has been carried out. The preferred values of parameters and possible ranges of brightness and contrast are determined. The results of transformation of the dark low contrast images compared with the results of image processing by other methods (approximated by reduction of a histogram to a uniform distribution and a television algorithm) are investigated. It has been stated that the parameters of the considered transformation can be chosen, so that the improvement of the distinguishability of the image details will be much better than using the methods with which the comparison is made.

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