Feasibility of real time dual-energy imaging based on a flat panel detector for coronary artery calcium quantification

Xu, Tingfa; Ducote, Justin L.; Wong, Jerry; Molloi, Sabee

doi:10.1118/1.2198942

Cited by 28 publications

(45 citation statements)

References 43 publications

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“…This will also allow for higher absorber thickness and for absorber materials with higher absorption efficiency, such as mercuric iodide. Energy-selective readout and photon-counting modes are further options that will allow for dual-energy imaging and for higher dose efficiency [54,55].…”

Section: Potential Future Developmentsmentioning

confidence: 99%

Flat-detector computed tomography (FD-CT)

2007

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Flat-panel detectors or, synonymously, flat detectors (FDs) have been developed for use in radiography and fluoroscopy with the defined goal to replace standard X-ray film, filmscreen combinations and image intensifiers by an advanced sensor system. FD technology in comparison to X-ray film and image intensifiers offers higher dynamic range, dose reduction, fast digital readout and the possibility for dynamic acquisitions of image series, yet keeping to a compact design. It appeared logical to employ FD designs also for computed tomography (CT) imaging. Respective efforts date back a few years only, but FD-CT has meanwhile become widely accepted for interventional and intraoperative imaging using C-arm systems. FD-CT provides a very efficient way of combining two-dimensional (2D) radiographic or fluoroscopic and 3D CT imaging. In addition, FD technology made its way into a number of dedicated CT scanner developments, such as scanners for the maxillo-facial region or for micro-CT applications. This review focuses on technical and performance issues of FD technology and its full range of applications for CT imaging. A comparison with standard clinical CT is of primary interest. It reveals that FD-CT provides higher spatial resolution, but encompasses a number of disadvantages, such as lower dose efficiency, smaller field of view and lower temporal resolution. FD-CT is not aimed at challenging standard clinical CT as regards to the typical diagnostic examinations; but it has already proven unique for a number of dedicated CT applications, offering distinct practical advantages, above all the availability of immediate CT imaging in the interventional suite or the operating room.

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Section: Potential Future Developmentsmentioning

confidence: 99%

Flat-detector computed tomography (FD-CT)

2007

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“…Dual-energy subtraction uses digital processing techniques that both subtract soft tissue structures and optimize visualization of calcified structures, including calcified atherosclerotic plaques. Applying dual-energy subtraction techniques to digital fluoroscopy and real-time video digital radiography, researchers have successfully created methods of CAC quantification [15,16]. However, these techniques have variable and more extensive radiation doses based on time of exposure.…”

Section: Introductionmentioning

confidence: 99%

Assessment of Coronary Artery Calcium Using Dual-Energy Subtraction Digital Radiography

et al. 2011

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Cardiovascular disease is the leading cause of global mortality, yet its early detection remains a vexing problem of modern medicine. Although the computed tomography (CT) calcium score predicts cardiovascular risk, relatively high cost ($250-400) and radiation dose (1-3 mSv) limit its universal utility as a screening tool. Dual-energy digital subtraction radiography (DE; <$60, 0.07 mSv) enables detection of calcified structures with high sensitivity. In this pilot study, we examined DE radiography's ability to quantify coronary artery calcification (CAC). We identified 25 patients who underwent non-contrast CT and DE chest imaging performed within 12 months using documented CAC as the major inclusion criteria. A DE calcium score was developed based on pixel intensity multiplied by the area of the calcified plaque. DE scores were plotted against CT scores. Subsequently, a validation cohort of 14 additional patients was independently evaluated to confirm the accuracy and precision of CAC quantification, yielding a total of 39 subjects. Among all subjects (n = 39), the DE score demonstrated a correlation coefficient of 0.87 (p < 0.0001) when compared with the CT score. For the 13 patients with CT scores of <400, the correlation coefficient was -0.26. For the 26 patients with CT scores of ≥400, the correlation coefficient yielded 0.86. This pilot study demonstrates the feasibility of DE radiography to identify patients at the highest cardiovascular risk. DE radiography's accuracy at lower scores remains unclear. Further evaluation of DE radiography as an inexpensive and low-radiation imaging tool to diagnose cardiovascular disease appears warranted.

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“…Sequential soft-tissue images can be obtained by a combination of the dual-energy subtraction technique and a dynamic FPD [18]. If target motion can be tracked in sequential soft-tissue images, the tracking accuracy could be improved without implantation of any special markers, such as a clip or a metallic sphere.…”

Section: Introductionmentioning

confidence: 99%

Sequential dual-energy subtraction technique with a dynamic flat-panel detector (FPD): primary study for image-guided radiation therapy (IGRT)

Tanaka

Sanada

Matsui

et al. 2008

Radiol Phys Technol

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A sequential dual-energy subtraction technique for image-guided radiation therapy (IGRT) was developed. Here, we report on a computerized method for creating sequential soft-tissue images and the accuracy of tracking targets on the images obtained, in comparison to conventional fluoroscopic images. Two sets of sequential chest images during respiration of a normal subject were obtained with X-rays of different energy separately with a flat-panel detector (FPD). Sequential soft-tissue images were created from the two sets of sequential images consisting of real-time images and reference template images, respectively. The creation of sequential soft-tissue images consisted of three steps: one-to-one image correspondence of the two sequential images, image registration, and image subtraction in each frame. Motion tracking of lung vessels was then performed by the template-matching technique. For evaluation of the accuracy of motion tracking on the sequential soft-tissue images, the results were compared with those on the original sequential images. Sequential soft-tissue images provided more accurate tracking than the original images (P < 0.01). There was no significant error throughout all frames in the soft-tissue images, whereas the rib shadow introduced a tracking error in the original images. The maximum errors were 4.1 +/- 0.3 mm in the sequential soft-tissue images and 28.1 +/- 20.0 mm in the original images. In conclusion, sequential soft-tissue images were helpful for tracking of a target affected by respiratory motion. Dual-energy subtraction has the potential to improve the accuracy of IGRT without implanted markers.

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Feasibility of real time dual-energy imaging based on a flat panel detector for coronary artery calcium quantification

Cited by 28 publications

References 43 publications

Flat-detector computed tomography (FD-CT)

Flat-detector computed tomography (FD-CT)

Assessment of Coronary Artery Calcium Using Dual-Energy Subtraction Digital Radiography

Sequential dual-energy subtraction technique with a dynamic flat-panel detector (FPD): primary study for image-guided radiation therapy (IGRT)

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