ABSTRACT
The recent technical developments in multislice computed tomography (MSCT), with ECG retro-gated image reconstruction, have elicited great interest in the possibility of accurate non-invasive imaging of the coronary arteries. The latest generation of MSCT systems with 8-16 rows of detectors permits acquisition of the whole cardiac volume during a single 15-20 s breath-hold with a submillimetric definition of the images and an outstanding signal-to-noise ratio. Thus the race which, between MSCT, electron beam computed tomography and cardiac magnetic resonance imaging, can best provide routine and reliable imaging of the coronary arteries in clinical practice has recommenced. Currently available MSCT systems offer different options for both cardiac image acquisition and reconstruction, including multiplanar and curved multiplanar reconstruction, three-dimensional volume rendering, maximum intensity projection, and virtual angioscopy. In our preliminary experience including 176 patients suffering from known or suspected coronary artery disease, MSCT was feasible in 161 (91.5%) and showed a sensitivity of 80.4% and a specificity of 80.3%, with respect to standard coronary angiography, in detecting critical stenosis in coronary arteries and artery or venous bypass grafts. These results correspond to a positive predictive value of 58.6% and a negative predictive value of 92.2%. The true role that MSCT is likely to play in the future in non-invasive coronary imaging is still to be defined. Nevertheless, the huge amount of data obtainable by MSCT along with the rapid technological advances, shorter acquisition times and reconstruction algorithm developments will make the technique stronger, and possible applications are expected not only for non-invasive coronary angiography, but also for cardiac function and myocardial perfusion evaluation, as an all-in-one examination.
Subject(s)
Coronary Angiography/methods , Tomography, X-Ray Computed/methods , Artificial Intelligence , Coronary Angiography/trends , Coronary Disease/diagnosis , Electrocardiography , Europe/epidemiology , Humans , Image Processing, Computer-Assisted/methods , Image Processing, Computer-Assisted/trends , Reproducibility of Results , Tomography, X-Ray Computed/trends , United States/epidemiologySubject(s)
Collateral Circulation , Leriche Syndrome/diagnostic imaging , Leriche Syndrome/physiopathology , Tomography, Spiral Computed , Aorta/diagnostic imaging , Aorta/physiopathology , Blood Flow Velocity , Exercise Test , Femoral Artery/diagnostic imaging , Femoral Artery/physiopathology , Humans , Iliac Artery/diagnostic imaging , Iliac Artery/physiopathology , Intermittent Claudication/diagnostic imaging , Intermittent Claudication/physiopathology , Male , Middle Aged , Ultrasonography, Doppler, Color , Vascular PatencyABSTRACT
PURPOSE: To evaluate the physical imaging characteristics of an indirect digital radiography system used for general radiography. MATERIAL AND METHODS: The performance of the two 41x41 cm2 CsI:Tl/a-Si flat-panel detectors of a GE-Revolution XR/d digital radiography system was evaluated. Signal uniformity, dose linearity, pre-sampling and expectation Modulation Transfer Function (MTF), Noise Power Spectrum (NPS) and Detective Quantum Efficiency (DQE) were measured at 70 kVp, varying the incident dose levels, according to IEC 62220-1. The effects of anti-scatter grid on NPS were also studied. RESULTS: Both detectors have a limiting spatial resolution of 2.5 lp/mm set by the pixel pitch. Raw images demonstrated fairly good uniformity, excellent repeatability and linearity. Without the grid in the anode-cathode direction, for an 8 mGy incident dose, both pre-sampling and EMTF were greater than 0.5 and 0.2 for spatial frequencies of 1 and 2 lp/mm, respectively. At the same dose and frequencies, for one detector, DQE was greater than 0.61 and 0.20; for the other one, DQE was greater than 0.41 and 0.18. DISCUSSION AND CONCLUSIONS: The two detector panels showed different DQE curves. Namely, the table detector DQE was excellent at low dose levels but its performance appeared to degrade with increasing doses, both in mean values and in shape, whereas the wall stand detector DQE appeared to depend less strongly on dose. In any case, the DQE values obtained from this study were higher than those reported in the literature for storage phosphor Computed Radiography systems.
Subject(s)
Radiographic Image Enhancement/instrumentation , Technology Assessment, Biomedical , Humans , SiliconABSTRACT
A significant improvement in the noninvasive evaluation of coronary anatomy has been obtained after the introduction of the new high-speed multislice computed tomography systems. Images are reconstructed using retrospective ECG-gated protocol along with contrast analysis and three-dimensional display algorithms. The 8 detectors and the reduced tube rotation time of last-generation scanners allow the coverage of the entire heart during a single breath-hold following an intravenous bolus of 120 ml of nonionic contrast. Faster computer software offers submillimeter resolution reconstructions and increased post-processing capabilities, such as quantitative angiography, virtual angioscopy, and calcium score evaluation. At least in this phase of technical development the visualization of side branches of coronary vessels seems to advantage multislice computed tomography with respect to nuclear magnetic resonance and electron-beam computed tomography in the challenge for clinical noninvasive evaluation of coronary microcirculation.
