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The conventional rationale that uses per cent diameter reduction to assess diffuse coronary artery disease is not appropriate because no normal reference segments exist. In a recent publication, we have proposed a theoretical model based on physical principles that relate the various morphological and haemodynamic parameters (cross-sectional area, length,(More)
The problems associated with visual interpretation of coronary arteriograms have been well-documented. There is a need for more physiologic means of assessing coronary artery stenosis during routine coronary arteriography. Volumetric coronary blood flow assessed as a function of time can be a valuable aid in the analysis of functional significance of(More)
RATIONALE AND OBJECTIVES There are well-known limitations to the use of visual estimation to assess the severity of coronary artery disease and luminal stenosis. This is especially true in the case of an intermediate coronary lesion (30%-70% diameter stenosis), where coronary arteriography is very limited in distinguishing ischemia-producing intermediate(More)
The scatter and veiling glare distribution in images acquired with a digital subtraction angiography imaging system was estimated using a digital filtration and a beam-stop technique. The digital filtration technique utilizes exposure parameters and image gray levels to estimate scatter-glare intensity based on previous phantom measurements. The beam-stop(More)
To quantify the trade-offs of dose and image quality among pre-loaded automatic exposure control (AEC) options in digital mammography, two AEC tables from the Hologic Selenia digital mammography system were compared: the default AEC "table 0" and AEC "table 1". Realistically-shaped phantoms consisting of tissue-equivalent material of various thicknesses(More)
Some digital radiography (DR) detectors and software allow for remote download of exam statistics, including image reject status, body part, projection, and exposure index (EI). The ability to have automated data collection from multiple DR units is conducive to a quality control (QC) program monitoring institutional radiographic exposures. We have(More)
PURPOSE It is possible to measure the patient surface dose non-invasively using radiolucent dosimeters. However, the patient size specific weighted dose remains unknown. We attempted to study the weighted dose to surface dose relationship as the patient size varies in abdominal CT. METHODS Seven abdomen phantoms (CIRS TE series) simulating patients from(More)
PURPOSE To measure energy-specific CT number and effective Z accuracy for a variety of simulated tissues and to measure iodine concentration accuracy, using Gemstone Spectral Imaging (GSI). METHODS We used a GE CT 750HD scanner and CIRS electron density phantom; the phantom is solid water with inserts simulating lung, bone, and soft tissues and has a(More)
PURPOSE To study optimal dose dictated by consistent low contrast detectability for various patient sizes in abdominal CT. METHODS Seven realistically shaped tissue-equivalent abdomen phantoms (CIRS TE01-TE08) were utilized. Helical scans were performed on each phantom with GE 750 HD and Siemens mCT 64 at different dose levels. The images were(More)
CT dose optimization is typically guided by pixel noise or contrast-to-noise ratio that does not delineate low contrast details adequately. We utilized the statistically defined low contrast detectability to study its relationship to dose and lesion size in abdominal CT. A realistically shaped medium sized abdomen phantom was customized to contain a(More)