Dual energy film subtraction technique for detecting calcification in solitary pulmonary nodules.

Kruger, Robert A.; Armstrong, J D; Sorenson, JA; Niklason, Loren T.

doi:10.1148/radiology.140.1.7017812

Cited by 31 publications

(14 citation statements)

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“…Despite these promising results, these systems have not gained wide acceptance because of inconsistent image quality or difficulties in handling or processing of the images [4,5,6].…”

Section: Introductionmentioning

confidence: 99%

Clinical results of CsI-detector-based dual-exposure dual energy in chest radiography

et al. 2003

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The aim of this study was to compare the sensitivity and specificity of digital chest radiography alone with digital chest radiography combined with dual-energy chest radiography in the detection of small non-calcified pulmonary nodules. Standard and dual-energy radiographs were obtained with a flat-panel digital chest system. Four radiologists reviewed digital posteroanterior chest radiographs in random order either alone or in conjunction with dual-energy soft tissue and bone images. Twenty patients with a total of 59 pulmonary nodules (median 0.5 cm, range 0.3-2.5 cm) confirmed by computed tomography (HU < or =100) were included. A level of confidence for each diagnosis was documented using a rating scale of 1-5. Brunner and Langer's test was performed for statistical analysis. Subgroup analysis was performed for nodules greater than 1 cm, 1-0.5 cm, and <0.5 cm. For posteroanterior chest radiography, sensitivity was 33%, positive predictive value 83%, specificity 81%, and negative predictive value 30%. Review in conjunction with dual-energy images resulted in a sensitivity of 42%, positive predictive value 88%, specificity 85%, and negative predictive value 34%. The increase of nodule detection overall as well as for different size categories was significant (p<0.05). The increase of the confidence level rating was also significant (p<0.001). Dual energy added to standard posteroanterior chest radiography significantly improves the sensitivity, specificity, and confidence in detection of small non-calcified pulmonary nodules.

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“…Despite these promising results, these systems have not gained wide acceptance because of inconsistent image quality or difficulties in handling or processing of the images [4,5,6].…”

Section: Introductionmentioning

confidence: 99%

Clinical results of CsI-detector-based dual-exposure dual energy in chest radiography

et al. 2003

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“…A specific advantage of the dual-exposure technique is the better energy separation compared to single-shot techniques employing copper or aluminum filters between two detectors (2,3,10,12,18). Appropriate energy separation has been identified as the most important factor influencing image quality in dual-energy techniques (9).…”

Section: Discussionmentioning

confidence: 99%

Effect of dose on image quality in a detector‐based dual‐exposure, dual‐energy system for chest radiography

et al. 2005

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“…[18][19][20][21] In the energy range of interest for CT, the energy dependence of the x-ray linear attenuation coefficients, which are functions of elemental composition and density, is determined by the energy dependent probability of Compton and photoelectric interactions ͑i.e., two basis functions͒. With dual-energy measurements, theoretically, two ͑or more than two, if additional constraints are imposed, e.g., Ref.…”

Section: Introductionmentioning

confidence: 99%

Material separation in x‐ray CT with energy resolved photon‐counting detectors

et al. 2011

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Purpose: The objective of the study was to demonstrate that, in x-ray computed tomography ͑CT͒, more than two types of materials can be effectively separated with the use of an energy resolved photon-counting detector and classification methodology. Specifically, this applies to the case when contrast agents that contain K-absorption edges in the energy range of interest are present in the object. This separation is enabled via the use of recently developed energy resolved photoncounting detectors with multiple thresholds, which allow simultaneous measurements of the x-ray attenuation at multiple energies. Methods: To demonstrate this capability, we performed simulations and physical experiments using a six-threshold energy resolved photon-counting detector. We imaged mouse-sized cylindrical phantoms filled with several soft-tissue-like and bone-like materials and with iodine-based and gadolinium-based contrast agents. The linear attenuation coefficients were reconstructed for each material in each energy window and were visualized as scatter plots between pairs of energy windows. For comparison, a dual-kVp CT was also simulated using the same phantom materials. In this case, the linear attenuation coefficients at the lower kVp were plotted against those at the higher kVp. Results: In both the simulations and the physical experiments, the contrast agents were easily separable from other soft-tissue-like and bone-like materials, thanks to the availability of the attenuation coefficient measurements at more than two energies provided by the energy resolved photon-counting detector. In the simulations, the amount of separation was observed to be proportional to the concentration of the contrast agents; however, this was not observed in the physical experiments due to limitations of the real detector system. We used the angle between pairs of attenuation coefficient vectors in either the 5-D space ͑for non-contrast-agent materials using energy resolved photon-counting acquisition͒ or a 2-D space ͑for contrast agents using energy resolved photon-counting acquisition and all materials using dual-kVp acquisition͒ as a measure of the degree of separation. Compared to dual-kVp techniques, an energy resolved detector provided a larger separation and the ability to separate different target materials using measurements acquired in different energy window pairs with a single x-ray exposure. Conclusions: We concluded that x-ray CT with an energy resolved photon-counting detector with more than two energy windows allows the separation of more than two types of materials, e.g., soft-tissue-like, bone-like, and one or more materials with K-edges in the energy range of interest. Separating material types using energy resolved photon-counting detectors has a number of advantages over dual-kVp CT in terms of the degree of separation and the number of materials that can be separated simultaneously.

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Dual energy film subtraction technique for detecting calcification in solitary pulmonary nodules.

Cited by 31 publications

References 0 publications

Clinical results of CsI-detector-based dual-exposure dual energy in chest radiography

Clinical results of CsI-detector-based dual-exposure dual energy in chest radiography

Effect of dose on image quality in a detector‐based dual‐exposure, dual‐energy system for chest radiography

Material separation in x‐ray CT with energy resolved photon‐counting detectors

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