Comparison of low-contrast detail perception on storage phosphor radiographs and digital flat panel detector images

Peer, Siegfried; Neitzel, Ulrich; Giacomuzzi, Salvatore; Peer, R.; Gassner, Eva; Steingruber, Iris; Jaschke, Werner

doi:10.1109/42.918474

Cited by 20 publications

(12 citation statements)

References 14 publications

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“…Even DR obtained with 50% less dose was still found to be superior for structures in the high attenuation areas of the mediastinum, while most structures in the lung were judged equivalent. Our results are concordant with those reported by Peer and co-workers, who also found, in a contrastdetail experiment, that the advantages of DR over CR are particularly apparent for the delineation of low-contrast structures at lower dose levels [5]. The performance differences we found in that subjective preference study favor more strongly the DR system compared with the results of the previously reported phantom study [11].…”

Section: Discussionsupporting

confidence: 95%

“…A multitude of studies has been performed in recent years, which all showed substantial potential for dose reduction [1][2][3][4][5][6][7][8][9]. The amount of dose reduction, however, varied between 20 and 50%.…”

Section: Discussionmentioning

confidence: 99%

“…As a result, multiple studies have shown that considerable dose reduction is feasible without significant loss of diagnostic information. The reported degree of possible dose reduction, however, is quite variable, with results ranging from 20% to 50% [1][2][3][4][5][6][7][8][9]. Differences in these results appear to be dependent on the level of acquisition dose, the reference technique used for comparison (conventional film or CR), the statistical analysis applied (ROC or preference study), and the type of lesions studied (phantom or clinical set-up).…”

Section: Introductionmentioning

confidence: 92%

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Direct detector radiography versus dual reading computed radiography: feasibility of dose reduction in chest radiography

et al. 2006

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The image quality of dual-reading computed radiography and dose-reduced direct radiography of the chest was compared in a clinical setting. The study group consisted of 50 patients that underwent three posteroanterior chest radiographs within minutes, one image obtained with a dual read-out computed radiography system (CR; Fuji 5501) at regular dose and two images with a flat panel direct detector unit (DR; Diagnost, Philips). The DR images were obtained with the same and with 50% of the dose used for the CR images. Images were evaluated in a blinded side-by-side comparison. Eight radiologists ranked the visually perceivable difference in image quality using a three-point scale. Then, three radiologists scored the visibility of anatomic landmarks in low and high attenuation areas and image noise. Statistical analysis was based on Friedman tests and Wilcoxon rank sum tests at a significance level of P<0.05. DR was judged superior to CR for the delineation of structures in high attenuation areas of the mediastinum even when obtained with 50% less dose (P<0.001). The visibility of most pulmonary structures was judged equivalent with both techniques, regardless of acquisition dose and speed level. Scores for image noise were lower for DR compared with CR, with the exception of DR obtained at a reduced dose. Thus, in this clinical preference study, DR was equivalent or even superior to the most modern dual read-out CR, even when obtained with 50% dose. A further dose reduction does not appear to be feasible for DR without significant loss of image quality.

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Section: Discussionsupporting

confidence: 95%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 92%

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Direct detector radiography versus dual reading computed radiography: feasibility of dose reduction in chest radiography

et al. 2006

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“…88,[105][106][107] Contrast-detail analysis is an efficient means to complete these studies, since a given C-D plot often requires only a single image and minimal time commitments by professional readers. Some C-D studies in radiography seek to optimize the tradeoff between image contrast and x-ray dose to the patient by extending the analysis to include total dose levels.…”

Section: Contrast-detail Analysis In Medical Imagingmentioning

confidence: 99%

“…This technique was introduced to medical imaging in the 1970's and has since been used extensively for CT 78-81 magnetic resonance imaging, 82 ultrasound, 83 mammography, 84,85 fluoroscopy, 86 whole body x-ray systems, 87 as well as imaging displays. 88,89 This technique is used to quantify the combined performance of the imaging system and the image reader in detecting objects representing a clinically relevant range of sizes and contrasts within a domain, focusing on assessing the lower limits of each possible range. 90,91 A C-D graph of minimum detectable contrast level for all sizes of objects provides limiting data on two major regimes of system operation, namely 1. the spatial resolution for high contrast objects ͑high contrast, small object size͒, and 2. the lower level of contrast detectable for larger-sized objects.…”

Section: Contrast-detail Curvesmentioning

confidence: 99%

Image analysis methods for diffuse optical tomography

et al. 2006

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Three major analytical tools in imaging science are summarized and demonstrated relative to optical imaging in vivo. Standard resolution testing is optimal when infinite contrast is used and hardware evaluation is the goal. However, deep tissue imaging of absorption or fluorescent contrast agents in vivo often presents a different problem, which requires contrast-detail analysis. This analysis shows that the minimum detectable sizes are in the range of 1/10 the outer diameter, whereas minimum detectable contrast values are in the range of 10 to 20% relative to the continuous background values. This is estimated for objects being in the center of the domain being imaged, and as the heterogeneous region becomes closer to the surface, the lower limit on size and contrast can become arbitrarily low and more dictated by hardware specifications. Finally, if human observer detection of abnormalities in the images is the goal, as is standard in most radiological practice, receiver operating characteristic (ROC) curve and location receiver operating characteristic curve (LROC) are used. Each of these three major areas of image interpretation and analysis are reviewed in the context of medical imaging as well as how they are used to quantify the performance of diffuse optical imaging of tissue.

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Image quality and radiation dose in planar imaging — Image quality figure of merits from the CDRAD phantom

Konst

Weedon‐Fekjær

Båth

2019

J Applied Clin Med Phys

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Purpose A contrast‐detail phantom such as CDRAD is frequently used for quality assurance, optimization of image quality, and several other purposes. However, it is often used without considering the uncertainty of the results. The aim of this study was to assess two figure of merits (FOM) originating from CDRAD regarding the variations of the FOMs by dose utilized to create the x‐ray image. The probability of overlapping (assessing an image acquired at a lower dose as better than an image acquired at a higher dose) was determined. Methods The CDRAD phantom located underneath 12, 20, and 26 cm PMMA was imaged 16 times at five dose levels using an x‐ray system with a flat‐panel detector. All images were analyzed by CDRAD Analyser, version 1.1, which calculated the FOM inverse image quality figure (IQFinv) and gave contrast detail curves for each image. Inherent properties of the CDRAD phantom were used to derive a new FOM h, which describes the size of the hole with the same diameter and depth that is just visible. Data were analyzed using heteroscedastic regression of mean and variance by dose. To ease interpretation, probabilities for overlaps were calculated assuming normal distribution, with associated bootstrap confidence intervals. Results The proportion of total variability in IQFinv, explained by the dose (R2), was 91%, 85%, and 93% for 12, 20, and 26 cm PMMA. Corresponding results for h were 91%, 89%, and 95%. The overlap probability for different mAs levels was 1% for 0.8 vs 1.2 mAs, 5% for 1.2 vs 1.6 mAs, 10% for 1.6 vs 2.0 mAs, and 10% for 2.0 mAs vs 2.5 mAs for 12 cm PMMA. For 20 cm PMMA, it was 0.5% for 10 vs 16 mAs, 13% for 16 vs 20 mAs, 14% for 20 vs 25 mAs, and 14% for 25 vs 32 mAs. For 26 cm PMMA, the probability varied from 0% to 6% for various mAs levels. Even though the estimated probability for overlap was small, the 95% confidence interval (CI) showed relatively large uncertainties. For 12 cm PMMA, the associated CI for 0.8 vs 1.2 mAs was 0.1–3.2%, and the CI for 1.2 vs 1.6 mAs was 2.1–7.8%. Conclusions Inverse image quality figure and h are about equally related to dose level. The FOM h, which describes the size of a hole that should be seen in the image, may be a more intuitive FOM than IQFinv. However, considering the probabilities for overlap and their confidence intervals, the FOMs deduced from the CDRAD phantom are not sensitive to dose. Hence, CDRAD may not be an optimal phantom to differentiate between images acquired at different dose levels.

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Comparison of low-contrast detail perception on storage phosphor radiographs and digital flat panel detector images

Cited by 20 publications

References 14 publications

Direct detector radiography versus dual reading computed radiography: feasibility of dose reduction in chest radiography

Direct detector radiography versus dual reading computed radiography: feasibility of dose reduction in chest radiography

Image analysis methods for diffuse optical tomography

Image quality and radiation dose in planar imaging — Image quality figure of merits from the CDRAD phantom

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