scholarly journals Evaluation of Non-Uniform Image Quality Caused by Anode Heel Effect in Digital Radiography Using Mutual Information

Entropy ◽  
2021 ◽  
Vol 23 (5) ◽  
pp. 525
Author(s):  
Ming-Chung Chou
Keyword(s):  
Image Quality ◽  
Mutual Information ◽  
Digital Radiography ◽  
Positive Correlation ◽  
Normalized Mutual Information ◽  
Digital Radiographs ◽  
Radiography System ◽  
The Impact ◽  
Heel Effect

Anode heel effects are known to cause non-uniform image quality, but no method has been proposed to evaluate the non-uniform image quality caused by the heel effect. Therefore, the purpose of this study was to evaluate non-uniform image quality in digital radiographs using a novel circular step-wedge (CSW) phantom and normalized mutual information (nMI). All X-ray images were acquired from a digital radiography system equipped with a CsI flat panel detector. A new acrylic CSW phantom was imaged ten times at various kVp and mAs to evaluate overall and non-uniform image quality with nMI metrics. For comparisons, a conventional contrast-detail resolution phantom was imaged ten times at identical exposure parameters to evaluate overall image quality with visible ratio (VR) metrics, and the phantom was placed in different orientations to assess non-uniform image quality. In addition, heel effect correction (HEC) was executed to elucidate the impact of its effect on image quality. The results showed that both nMI and VR metrics significantly changed with kVp and mAs, and had a significant positive correlation. The positive correlation is suggestive that the nMI metrics have a similar performance to the VR metrics in assessing the overall image quality of digital radiographs. The nMI metrics significantly changed with orientations and also significantly increased after HEC in the anode direction. However, the VR metrics did not change significantly with orientations or with HEC. The results indicate that the nMI metrics were more sensitive than the VR metrics with regards to non-uniform image quality caused by the anode heel effect. In conclusion, the proposed nMI metrics with a CSW phantom outperformed the conventional VR metrics in detecting non-uniform image quality caused by the heel effect, and thus are suitable for quantitatively evaluating non-uniform image quality in digital radiographs with and without HEC.

Effects of Projections on Radiation Dose for and Image Quality of Chest Digital Radiography for Children

2021 ◽  
Vol 17 ◽  
Author(s):  
Hongrong Xu ◽  
Bo Liu ◽  
Jinhua Cai ◽  
Huan Zheng ◽  
Helin Zheng ◽  
...  
Keyword(s):  
Body Mass Index ◽  
Image Quality ◽  
Radiation Dose ◽  
Body Mass ◽  
Digital Radiography ◽  
Old Patients ◽  
Dose Area Product ◽  
The Impact ◽  
Field Area

Background: Until now few studies have specially validated whether the sex, body mass index, or imaging projections of pediatric patients undergoing chest digital radiography (DR) affect the radiation dose and image quality. Introduction: To investigate the impact of different photography positions on radiation dose for and image quality of chest DR for 3-4-year-old children. Method: One-hundred twenty 3-4-year-old patients who required chest DR were included. The patients were divided into 3 groups, with 40 patients in each group: supine anterior-posterior projection (APP), standing APP and posterior-anterior projection (PAP). The dose area product (DAP) and entrance surface dose (ESD) values for every patient were recorded after each exposure. The visual grading analysis score (VGAS) was used to evaluate image quality. Result: The DAP and ESD values for the standing PAP and APP groups were significantly lower than those for the supine APP group (0.19 ± 0.04 dGy cm2 and 0.05 ± 0.01 mGy vs 0.25 ± 0.05 dGy cm2 and 0.08 ± 0.01 mGy, P<0.05, respectively). Additionally, the VGAS for the standing APP group was significantly lower than those for the standing PAP and supine APP groups (28.58 ± 0.96 vs 29.08 ± 0.94 and 29.03 ± 0.80, P<0.05, respectively), whereas the pulmonary field area for the standing PAP group was significantly higher than those for the standing and supine APP groups (118.95 ± 16.81 cm2 vs 105.65 ± 14.76 cm2 and 105.24 ± 16.32 cm2, P<0.05, respectively). However, there were no statistically significant differences in DAP, ESD, VGAS, pulmonary field area and body mass index between the male and female patients in the three groups (P>0.05, respectively). Conclusion: The standing PAP should be the first projection choice for chest DR for 3-4-year-old children; compared with the supine and standing APP, the standing PAP may improve image quality and decrease the required radiation dose.

scholarly journals Modeling and image quality enhancement for dynamic compressive imaging system

2021 ◽  
Vol 15 ◽  
pp. 174830262110080
Author(s):  
Changjun Zha* ◽  
Qian Zhang* ◽  
Huimin Duan
Keyword(s):  
Image Quality ◽  
Imaging System ◽  
Quality Enhancement ◽  
Target Image ◽  
Compressive Imaging ◽  
Image Quality Enhancement ◽  
System A ◽  
Single Column ◽  
The Impact

Traditional single-pixel imaging systems are aimed mainly at relatively static or slowly changing targets. When there is relative motion between the imaging system and the target, sizable deviations between the measurement values and the real values can occur and result in poor image quality of the reconstructed target. To solve this problem, a novel dynamic compressive imaging system is proposed. In this system, a single-column digital micro-mirror device is used to modulate the target image, and the compressive measurement values are obtained for each column of the image. Based on analysis of the measurement values, a new recovery model of dynamic compressive imaging is given. Differing from traditional reconstruction results, the measurement values of any column of vectors in the target image can be used to reconstruct the vectors of two adjacent columns at the same time. Contingent upon characteristics of the results, a method of image quality enhancement based on an overlapping average algorithm is proposed. Simulation experiments and analysis show that the proposed dynamic compressive imaging can effectively reconstruct the target image; and that when the moving speed of the system changes within a certain range, the system reconstructs a better original image. The system overcomes the impact of dynamically changing speeds, and affords significantly better performance than traditional compressive imaging.

scholarly journals Impact of depression on quality of life in systemic lupus erythematosus patients

2021 ◽  
Vol 57 (1) ◽  
Author(s):  
Eman M. Khedr ◽  
Rania M. Gamal ◽  
Sounia M. Rashad ◽  
Mary Yacoub ◽  
Gellan K. Ahmed
Keyword(s):  
Quality Of Life ◽  
Systemic Lupus Erythematosus ◽  
Lupus Erythematosus ◽  
Short Form ◽  
Systemic Lupus ◽  
Positive Correlation ◽  
Depressed Patients ◽  
Sf 36 ◽  
The Impact

Abstract Background Depression is common in systemic lupus erythematosus (SLE) and is an unmeasured risk factor, yet its symptoms can be neglected in standard disease evaluations. The purpose of this study was to assess the frequency and the impact of depression on quality of life in SLE patients. We recruited 32 patients with SLE and 15 healthy control volunteers in the study. The following investigations were undertaken in each patient: clinical and rheumatologic assessment, SLE Disease Activity Index-2k (SLEDAI-2k), Beck Depression Inventory (BDI), Short-Form Health Survey (SF-36) questionnaire, and routine laboratory tests. Results There was a high percentage of depression (46.9%) in the SLE patients. Regarding quality of life (SF-36), there were significant affection of the physical and mental composite summary domains (PCS and MCS) scores in lupus patients compared with controls (P < 0.000 for both) with the same significant in depressed compared with non-depressed patients. SF-36 subscales (physical function, limit emotional, emotional wellbeing, and social function) were significantly affected in depressed lupus patients compared with non-depressed patients. There was a significant negative correlation between the score of MCS domain of SF-36 with BDI (P < 0.000) while positive correlation between SLEDAI score with depression score. In contrast, there were no significant correlations between MCS or PCS with age, duration of illness, or SLEDAI-2K. Conclusions Depression is common in SLE patients and had a negative impact on quality of life particularly on MCS domain and positive correlation with disease severity score. Trial registration This study was registered on clinical trial with registration number: NCT03165682 https://clinicaltrials.gov/ct2/show/NCT03165682 on 24 May 2017.

Impact of total variation regularized expectation maximization reconstruction on the image quality of 68Ga-PSMA PET: a phantom and patient study

2021 ◽  
pp. 20201356
Author(s):  
Feng-Jiao Yang ◽  
Shu-Yue Ai ◽  
Runze Wu ◽  
Yang Lv ◽  
Hui-Fang Xie ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Image Quality ◽  
Total Variation ◽  
Expectation Maximization ◽  
Image Noise ◽  
Psma Pet ◽  
Pet Ct ◽  
Digital Pet ◽  
The Impact

Objectives: To investigate the impact of total variation regularized expectation maximization (TVREM) reconstruction on the image quality of 68Ga-PSMA-11 PET/CT using phantom and patient data. Methods: Images of a phantom with small hot sphere inserts and 20 prostate cancer patients were acquired with a digital PET/CT using list-mode and reconstructed with ordered subset expectation maximization (OSEM) and TVREM with seven penalisation factors between 0.01 and 0.42 for 2 and 3 minutes-per-bed (m/b) acquisition. The contrast recovery (CR) and background variability (BV) of the phantom, image noise of the liver, and SUVmax of the lesions were measured. Qualitative image quality was scored by two radiologists using a 5-point scale (1-poor, 5-excellent). Results: The performance of CR, BV, and image noise, and the gain of SUVmax was higher for TVREM 2 m/b groups with the penalization of 0.07 to 0.28 compared to OSEM 3 m/b group (all p < 0.05). The image noise of OSEM 3 m/b group was equivalent to TVREM 2 and 3 m/b groups with a penalization of 0.14 and 0.07, while lesions’ SUVmax increased 15 and 20%. The highest qualitative score was attained at the penalization of 0.21 (3.30 ± 0.66) for TVREM 2 m/b groups and the penalization 0.14 (3.80 ± 0.41) for 3 m/b group that equal to or greater than OSEM 3 m/b group (2.90 ± 0.45, p = 0.2 and p < 0.001). Conclusions: TVREM improves lesion contrast and reduces image noise, which allows shorter acquisition with preserved image quality for PSMA PET/CT. Advances in knowledge: TVREM reconstruction with optimized penalization factors can generate higher quality PSMA-PET images for prostate cancer diagnosis.

THE IMPACT OF HEAD POSITIONING ON THE IMAGE QUALITY OF MULTI-DETECTOR COMPUTED TOMOGRAPHY

2021 ◽  
pp. 2150050
Author(s):  
Yang-Ting Hsu ◽  
Jo-Chi Jao
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Control Group ◽  
Ct Scanner ◽  
Head Ct ◽  
Radiologic Technologists ◽  
Head Positioning ◽  
The Impact ◽  
Multi Detector Computed Tomography

Radiologic technologists face various types of patients during multi-detector computed tomography (CT) examinations. In emergency departments, it is common to have patients who cannot follow instructions for the examinations. The asymmetric axial view of the head CT might affect the correctness of the clinician’s diagnosis. This study aimed to assess the impact of head positioning on the image quality of head CT using two phantoms. All scans were performed on a 16-slice CT scanner. In the control group, the tilted angle of the phantoms was 0[Formula: see text], and no multiplanar reconstruction (MPR) was performed. In the experimental groups, the tilted angles of the phantoms were 5[Formula: see text], 10[Formula: see text] and 15[Formula: see text], respectively, and MPR was performed afterwards. The results showed that if the head was tilted during the head CT examinations, image asymmetry and artifacts appeared without MPR. After MPR, one phantom showed that there were significant differences and the other phantom showed no significant differences quantitatively in image symmetry and artifacts between experimental groups and the control group, while both phantoms showed no significant differences qualitatively in image symmetry and artifacts between experimental groups and the control group. Although MPR can correct the image asymmetry and artifacts caused by tilted head positioning to some extent, it consumes time. Therefore, technologists should position the head as exactly as possible when performing head CT examinations.

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