Electron Beam Computed Tomography Research Articles

Determining Magnetic Field Close to Air-Bearing Surface by Projection Electron-Beam Tomography and Fourier Extrapolation

The magnetic field of a recording head is measured by projection electron-beam tomography with a resolution of about ten nanometers, and the magnetic field closer to the sample surface than the mea...

Frequent Premature Ventricular Contractions in an Orbital Spaceflight Participant

Commercial spaceflight participants on orbital flights typically are older than career astronauts and they often have medical conditions that have not been studied at high g or in microgravity. This is a case report of a 56-yr-old orbital spaceflight participant with essential tremor and frequent premature ventricular contractions that occurred at rates up to 7000 per day. Before training and spaceflight, he was required to complete extensive clinical investigations to demonstrate normal cardiac structures and the absence of cardiac pathology. The evaluation included signal averaged ECG, transthoracic stress echocardiography, exercise tolerance tests, electrophysiological studies, cardiac MRI, electron beam CT, Holter monitoring, and overnight oximetry. While no cardiac pathology was demonstrated, the Russian medical team required that the PVCs be treated prior to training and spaceflight. For the initial flight, a selective beta-1 receptor beta blocker was used and for the second a calcium channel blocker was used in combination with a nonselective beta blocker for tremor control. Analogue environment testing assured that this combination of medications was compatible. The spaceflight participant's PVCs were incompletely suppressed with a low-dose selective beta-1 blocker, but were well suppressed by a calcium channel blocker. He tolerated in-flight periodic use of a nonselective beta blocker in combination with a calcium channel blocker. In-flight ECG and blood pressure monitoring results were normal, and an ECG obtained midmission and on landing day showed successful PVC suppression. He did not have any cardiac difficulty with launch, on-orbit operations, entry, or recovery

Relationship between decreased bone mineral density and subclinical atherosclerosis in postmenopausal women

Objectives The study aimed to compare measurements of coronary artery calcification (CAC) and bone mineral density (BMD) in postmenopausal women.Methods The CAC of the women was measured with electron beam tomography using a GE Imatron C150 XP EBT scanner. Subjects with calcium scores above 0 were classified as CAC(+); those without detectable coronary calcium were classified as CAC(−). BMD was measured by dual-energy X-ray absorptiometry (DEXA). Patients were divided into two groups, depending on the T scores of their lumbar spine, into those with normal bone and those with osteopenia-osteoporosis.Results The proportions of patients classified as CAC(+) were 20% in the normal group and 60% in the osteopenia-osteoporosis group (p = 0.037). BMD values in L1–4 were 1.13 ± 2.29 and 0.98 ± 2.79 g/cm2 in the normal group and osteopenia-osteoporosis group, respectively and the mean total CAC scores were 1.34 ± 1.2 and 69.0 ± 20.5, respectively. The CAC scores of patients with osteopenia-osteoporosis were significantly higher compared with those of the normal group (p = 0.014).Conclusion The study shows that postmenopausal women with decreased bone mineral density may have higher risk of subclinical coronary atherosclerosis.

CT diagnosis of cardiac rhabdomyoma in childhood

Objective To investigate the CT findings of cardiac rhabdomyoma in childhood. Methods Five children with cardiac rhabdomyoma confirmed by operation was retrospectively analysed. Enhanced electron beam CT (EBCT) was performed in 4 children and enhanced 64-slice helical CT (MSCT) scan was performed in 1 infant. Three dimensional reconstruction was applied for the full display of the lesions based on the transverse section images. Results ( 1 ) Multiple masses or nodules originated from atrioventricular septum were observed in 4 children including 1 nodule from the anterior walls of the left and right ventricles. A mass was derived from the mitral valve in 1 infant (2) The CT value of the lesions after enhancement ranged from 80 to 180 HU and was similar to neighbouring left ventricular myocardium. (3) The ventricular outlet obstruction was found in 3 children including 1 infant with pericardial effusion and pulmonary inflamation of the right lower lobe. Conclusion The rhabdomyoma should be considered first when masses or nodules originated from atrioventricular septum and with the enhancement similar to neigbouring left ventricular myocardium in children. Key words: Heart neoplasms; Rhabdomyoma; Child; Tomography, X-ray computed

Skin Fluorescence Correlates Strongly with Coronary Artery Calcification Severity in Type 1 Diabetes

Coronary artery calcification (CAC) is more severe and occurs at an earlier age in type 1 diabetes. Risk factors for this subclinical marker of atherosclerotic burden, like coronary artery disease (CAD) itself, are not fully identified. One postulated mechanism for the increased CAC observed in type 1 diabetes is the accumulation of advanced glycation end products (AGEs). As certain collagen AGEs fluoresce, skin intrinsic fluorescence (SIF) can act as a novel marker of levels of collagen AGEs. We thus sought to determine the relationship between skin intrinsic fluorescence and CAC in type 1 diabetes. One hundred five participants in the Pittsburgh Epidemiology of Diabetes Complications study of childhood-onset (age <17 years) type 1 diabetes who had previously undergone electron beam tomography scanning for CAC (80 of whom had follow-up data) had SIF measurements taken using the SCOUT DM (VeraLight, Inc., Albuquerque, NM). Mean age and diabetes' duration were 49 and 40 years, respectively, at the time of SIF measurement. Seventy-one percent of the study participants had some measurable CAC that was univariately (but not after age adjustment) cross-sectionally associated with SIF (odds ratio = 2.51, 1.37-4.59). However, for CAC severity using natural logarithmically transformed scores, SIF was both univariately (P < 0.0001) and multivariably (P = 0.03) associated with CAC. This relationship was independent of age, a history of CAD, renal function, or renal damage. Receiver operator characteristic analyses revealed that the discriminative ability of SIF to detect CAC went from an area under the curve of 71% for the presence of any CAC to 85% for those with a CAC score >400. The relationship between SIF and CAC appears stronger with more severe calcification. Given the strong relationship of CAC with CAD this finding has important implications and suggests that SIF maybe a useful marker of CAC/CAD risk and potentially a therapeutic target.

A 50-Year-Old Woman With a History of Atrial Fibrillation Presents With Acute Dyspnea and Pleuritic Chest Pain

A 50-Year-Old Woman With a History of Atrial Fibrillation Presents With Acute Dyspnea and Pleuritic Chest Pain

Effects of mandibular advancement on upper airway dimension and collapsibility in patients with obstructive sleep apnea using dynamic upper airway imaging during sleep

The objective of this study was to evaluate the effects of mandibular advancement on oropharyngeal dimension and collapsibility and reveal the predominate site of change produced by mandibular advancement in patients with obstructive sleep apnea (OSA). Sixteen adults (13 males and 3 females) with symptomatic mild to severe OSA participated. Custom-made silicone mandibular positioners were used to keep the mandible at 67% of maximum advancement. Changes in the oropharyngeal size and collapsibility with mandibular advancement were evaluated using ultrafast computed tomography taken during wakefulness and midazolam-induced sleep. Cross-sectional areas were assessed using electron beam tomography at 4 levels: high retropalatal (HRP), low retropalatal (LRP), high retroglossal (HRG), and low retroglossal (LRG). During sleep, the minimum cross-sectional areas decreased 36.5%, 67.8%, 75.5%, and 65.8% at each level of HRP, LRP, HRG, and LRG respectively, as compared with those measured during wakefulness. Mandibular advancement during sleep increased 75.7%, 141.3%, 128.1%, and 119.9% at each level. The oropharynx showed 70.3%, 110.4%, 140.3%, and 156.9% increase in the Collapsibility Indices during sleep at each level of HRP, LRP, HRG, and LRG, respectively, compared with wakefulness. However, collapsibility indices decreased 29.1%, 23.2%, 21.4%, and 34.1% at each level with mandibular advancement. Mandibular advancement increases oropharyngeal diameter and decreases oropharyngeal collapsibility during midazolam-induced sleep respiration at the retropalatal as well as the retroglossal region in most patients with OSA.

Tecnologias para investigação da DAC: relação entre publicações científicas e utilização clínica

Although some evidence suggests an association between a technology exposure in the literature and its dissemination in clinical practice, few studies have evaluated such association. To analyze whether the pattern of scientific publication on two competitive technologies used in the assessment of coronary artery disease (CAD) reflects what occurs in clinical practice. The number of scientific articles published annually in the medical literature (global scientific interest in technology) on two technologies used in the assessment of CAD was evaluated: electron beam computed tomography (EBCT) and multidetector computed tomography (MDCT). The number of countries that annually publish scientific articles about these technologies (geographic interest in the technology) was also analyzed. The EBCT showed a peak of "global scientific interest" in 2001, with 127 published articles. After this peak, the "global scientific interest" decreased by around 50% in 2008. In opposition, the "global scientific interest" for MDCT progressively increased up to 2007, with 454 articles published in that year. The "geographic scientific interest" by EBCT showed a peak in 2002, with 14 countries publishing about this technology. After this peak, the "geographic scientific interest" decreased by almost 25% up to 2008, with 11 countries publishing about this technology. In opposition, the "geographic scientific interest" by MDCT progressively increased up to 2008, with 37 countries publishing articles about it. The medical scientific literature is compatible with the substitution of EBCT by MDCT in the assessment of CAD.

History of hot flashes and aortic calcification among postmenopausal women

Menopausal hot flashes are considered largely a quality-of-life issue. However, emerging research also links hot flashes to cardiovascular risk. In some investigations, this risk is particularly apparent among women using hormone therapy. The aim of this study was to determine whether a longer history of reported hot flashes over the study period was associated with greater aortic and coronary artery calcification. Interactions with hormone therapy use were examined in an exploratory fashion. Participants included 302 women participating in the Healthy Women Study, a longitudinal study of cardiovascular risk during perimenopause and postmenopause, which was initiated in 1983. Hot flashes (any/none) were assessed when women were 1, 2, 5, and 8 years postmenopausal. Electron beam tomography measures of coronary artery calcification and aortic calcification were completed in 1997-2004. Associations between the number of visits with report of hot flashes, divided by the number of visits attended, and aortic or coronary artery calcification (transformed) were examined in linear regression models. Interactions by hormone therapy use were evaluated. Among women using hormone therapy, a longer history of reported hot flashes was associated with increased aortic calcification, controlling for traditional cardiovascular risk factors (b = 2.87, SE = 1.21, P < 0.05). There were no significant associations between history of hot flashes and coronary artery calcification. Among postmenopausal women using hormone therapy, a longer history of reported hot flashes measured prospectively was associated with increased aortic calcification, controlling for traditional cardiovascular risk factors. Hot flashes may signal adverse cardiovascular changes among certain postmenopausal women.

Usefulness of enhanced computed tomography in the diagnosis of pulmonary thromboembolism

Pulmonary thromboembolism (PTE) was diagnosed in 22 patients at Saga Medical School between 1981 and 1994. Enhanced computed tomography (CT) was done in 8 patients, and filling defects in the central pulmonary artery were identified in 6. Parenchymal shadows (wedge shaped shadows, subpleural consolidation, or nodular shadow's) were noted in 5. When enhanced CT was done during acute severe respiratory failure in 3 patients, pulmonary artery filling defects were found in all. These findings suggest that enhanced CT is useful as a diagnostic tool for acute PTE with respiratory failure. Electron beam CT may be a sensitive and specific means of diagnosing PTE because it can be done quickly and without breath-holding. We conclude that enhanced CT should be used as the first diagnostic procedure in patients with severe respiratory failure who may have PTE.

Dual-plane ultrafast limited-angle electron beam x-ray tomography

Electron beam x-ray tomography is an imaging technique, which can provide cross-sectional images of an object of interest with about 1 mm spatial resolution at frame rates of up to 10,000 frames per second. As a non-intrusive method it is especially suited for studying multiphase flows. For this purpose we devised an experimental limited-angle scan setup which utilizes linear beam deflection to generate radiographic projections. This setup was employed in the study of gas–liquid flow in an experimental flow loop operated at different liquid and gas flow rates. Electron-beam tomography images were compared with image data of a wire-mesh sensor. The latter is a fast but intrusive imaging device which is commonly used in gas–liquid flow imaging and achieves comparable frame rates but at lower spatial resolution. As a novelty we implemented a dual-plane limited-angle electron beam x-ray tomography which allows us to gain information about the phase velocities using cross-correlation data analysis.

Distribution matters: Diagnostic value of coronary plaque in distal segments

Cardiac computed tomography (CT) has become a valuable tool for quantification of coronary artery plaque, whether calcified or not, because its extent is strongly related to the severity of angiographic obstructive coronary artery disease (CAD) and identifies subjects at increased risk of future coronary events at preclinical stages of the disease. 1 Detrano R. Guerci A.D. Carr J.J. Bild D.E. Burke G. Folsom A.R. Liu K. Shea S. Szklo M. Bluemke D.A. O'Leary D.H. Tracy R. Watson K. Wong N.D. Kronmal R.A. Coronary calcium as a predictor of coronary events in four racial or ethnic groups. N Engl J Med. 2008; 358: 1336-1345 Crossref PubMed Scopus (2121) Google Scholar , 2 Miller J.M. Rochitte C.E. Dewey M. Arbab-Zadeh A. Niinuma H. Gottlieb I. Paul N. Clouse M.E. Shapiro E.P. Hoe J. Lardo A.C. Bush D.E. de Roos A. Cox C. Brinker J. Lima J.A. Diagnostic performance of coronary angiography by 64-row CT. N Engl J Med. 2008; 359: 2324-2336 Crossref PubMed Scopus (1492) Google Scholar , 3 Budoff M.J. Dowe D. Jollis J.G. Gitter M. Sutherland J. Halamert E. Scherer M. Bellinger R. Martin A. Benton R. Delago A. Min J.K. Diagnostic performance of 64-multidetector row coronary CT angiography for evaluation of coronary artery stenosis in individuals without known coronary artery disease: results from the prospective multicenter ACCURACY (Assessment by Coronary CT Angiography of Individuals Undergoing Invasive Coronary Angiography) trial. J Am Coll Cardiol. 2008; 52: 1724-1732 Abstract Full Text Full Text PDF PubMed Scopus (1697) Google Scholar , 4 Hoffmann U. Bamberg F. Chae C.U. Nichols J.H. Rogers I.S. Seneviratne S.K. Truong Q.A. Cury R.C. Abbara S. Shapiro M.D. Moloo J. Butler J. Ferencik M. Lee H. Jang I.K. Parry B.A. Brown D.F. Udelson J.E. Achenbach S. Brady T.J. Nagurney J.T. Coronary CT Angiography For Early Triage of Patients with Acute Chest Pain: the ROMICAT (Rule Out Myocardial Infarction Using Computed Assisted Tomography) trial. J Am Coll Cardiol. 2009; 53: 1642-1650 Abstract Full Text Full Text PDF PubMed Scopus (456) Google Scholar Early pathoanatomic, 5 Montenegro M.R. Eggen D.A. Topography of atherosclerosis in the coronary arteries. Lab Invest. 1968; 18: 586-593 PubMed Google Scholar histomorphometric, 6 Mautner G.C. Mautner S.L. Froehlich J. Feuerstein I.M. Proschan M.A. Roberts W.C. Doppman J.L. Coronary artery calcium: assessment with electron beam CT and histomorphometric correlation. Radiology. 1994; 192: 619-623 Crossref PubMed Scopus (319) Google Scholar and cardiac CT-based 7 Schmermund A. Baumgart D. Adamzik M. Ge J. Grönemeyer D. Seibel R. Sehnert C. Görge G. Haude M. Erbel R. Comparison of EBCT and intracoronary ultrasound in detecting calcified and non-calcified plaques in patients with acute coronary syndromes and no or minimal to moderate angiographic coronary artery disease. Am J Cardiol. 1998; 81: 141-146 Abstract Full Text Full Text PDF PubMed Scopus (86) Google Scholar studies found consistent evidence that advanced atherosclerotic lesions are most frequently located at the proximal left anterior descending coronary artery followed by the left circumflex and right coronary arteries. The prevalence of atherosclerotic lesions is lower within distal segments, particularly the left coronary artery. Similarly, the rate of progression of coronary plaque was found to be highest in the proximal left coronary artery, whereas plaque progression was more uniform throughout the right coronary artery. 5 Montenegro M.R. Eggen D.A. Topography of atherosclerosis in the coronary arteries. Lab Invest. 1968; 18: 586-593 PubMed Google Scholar , 8 Schmermund A. Baumgart D. Möhlenkamp S. Kriener P. Pump H. Grönemeyer D. Seibel R. Erbel R. Natural history and topographic pattern of progression of coronary calcification in symptomatic patients: an electron-beam CT study. Arterioscler Thromb Vasc Biol. 2001; 21: 421-426 Crossref PubMed Scopus (122) Google Scholar

Impact of Medical Therapy on Atheroma Volume Measured by Different Cardiovascular Imaging Modalities

Atherosclerosis is a systemic disease that affects most vascular beds. The gold standard of atherosclerosis imaging has been invasive intravascular ultrasound (IVUS). Newer noninvasive imaging modalities like B-mode ultrasound, cardiac computed tomography (CT), positron emission tomography (PET), and magnetic resonance imaging (MRI) have been used to assess these vascular territories with high accuracy and reproducibility. These imaging modalities have lately been used for the assessment of the atherosclerotic plaque and the response of its volume to several medical therapies used in the treatment of patients with cardiovascular disease. To study the impact of these medications on atheroma volume progression or regression, imaging modalities have been used on a serial basis providing a unique opportunity to monitor the effect these antiatherosclerotic strategies exert on plaque burden. As a result, studies incorporating serial IVUS imaging, quantitative coronary angiography (QCA), B-mode ultrasound, electron beam computed tomography (EBCT), and dynamic contrast-enhanced magnetic resonance imaging have all been used to evaluate the impact of therapeutic strategies that modify cholesterol and blood pressure on the progression/regression of atherosclerotic plaque. In this review, we intend to summarize the impact of different therapies aimed at halting the progression or even result in regression of atherosclerotic cardiovascular disease evaluated by different imaging modalities.

Lactation and Maternal Measures of Subclinical Cardiovascular Disease

To examine the relationship between lactation and subclinical cardiovascular disease in a population free of clinical cardiovascular disease. We conducted a cross-sectional analysis of 297 women who reported at least one live birth on enrollment in the Study of Women Across the Nation-Heart Study. Participants were mothers aged 45-58 years who were free of clinical cardiovascular disease. History of lactation was self-reported. Electron beam tomography was used to assess coronary and aortic calcification. B-mode ultrasonography was used to assess carotid adventitial diameter, intima-media thickness, and carotid plaque. Multivariable linear and logistic regression models were used to estimate whether lactation was independently associated with markers of subclinical cardiovascular disease. In unadjusted models, compared with mothers who had breastfed all of their children for at least 3 months, mothers who had not breastfed were more likely to have coronary artery calcification (17% compared with 32%), aortic calcification (17% compared with 39%), carotid plaque (10% compared with 18%), and larger carotid adventitial diameters (mean+/-standard deviation 6.63+/-0.59 compared with 6.87+/-0.60 mm). After adjusting for measures of socioeconomic status and lifestyle and family history variables, mothers who had not breastfed remained more likely to have aortic calcification (odds ratio [OR] 3.85, 95% confidence interval [CI] 1.47-10.00) and coronary artery calcification (OR 2.78, 95% CI 1.05-7.14) than mothers who had consistently breastfed. After further adjustment for body mass index and traditional risk factors for cardiovascular disease, mothers who had not breastfed remained more likely to have aortic calcification than mothers who had consistently breastfed (OR 5.26, 95% CI 1.47-20.00). Mothers who do not breastfeed their infants seem to be at increased risk of vascular changes associated with future cardiovascular disease. II.

The SHAPE Paradigm

Atherosclerosis is a chronic immunoinflammatory disease trigerred by lipoprotein retention in the subendothelium and produces its most serious manifestations by triggering arterial thrombosis when the plaque ruptures or erodes.1 Atherothrombotic cardiovascular disease remains the leading cause of death in the West and is achieving similar dubious distinction in developing countries.2 Atherosclerosis begins at a young age, but it remains clinically silent for a long time and the majority of clinical manifestations occur later in life. Despite considerable progress, regrettably 50% of life-threatening acute cardiovascular events occur in previously asymptomatic individuals. Identifying individuals at risk for future cardiovascular events affords an opportunity for risk reduction and thus remains a major imperative for healthcare professionals. In 2006 the SHAPE (Society for Heart Attack Prevention and Education) Task Force introduced an algorithm incorporating noninvasive screening for subclinical atherosclerosis to augment risk factor–based risk stratification in asymptomatic subjects between the ages of 45 to 75 in men and 55 to 75 in women, excluding those at very low risk or at high risk.3 In June 2009, the Texas Governor Rick Perry signed off on the Texas Heart Attack Prevention Bill introduced by Rep Rene Oliveira, mandating health-benefit plans to cover noninvasive screening for subclinical atherosclerosis. This bill grew out of the 2006 SHAPE Task Force guidelines and became effective September 1, 2009; an earlier version of the bill had been rejected in 2007. This generated a mixed reaction from healthcare professionals and others, much of which played out in the media. The critics argued that such an action is inappropriate because: (1) the SHAPE guidelines were created by an ad hoc group and had not been explicitly endorsed by the American College of Cardiology (ACC) or the American Heart Association (AHA), and (2) SHAPE guidelines are not based on randomized clinical …

Concomitant Atherosclerotic Disease Detected by Whole-Body MR Angiography in Relation to Coronary Artery Calcification in Patients with Coronary Artery Disease

Patients with coronary artery disease (CAD) show a high prevalence for concomitant atherosclerotic peripheral arterial disease (PAD). On the other hand, PAD seems to be an additional risk factor for cardiac events. We evaluated the correlation between arterial pathologies as found in whole-body MR angiography and coronary artery calcification (CAC) detected by electron beam computed tomography (EBCT) and multislice CT (MSCT). Two hundred and twenty-eight patients (161 men; 67 women) with suspicion for CAD/known CAD underwent whole-body contrast-enhanced MR angiography (wb-ce-MRA) and EBCT/MSCT. An atherosclerosis index was calculated for each patient Index = (40)Sigma(n=1) w(i) with w(i) being the grading of the stenosis of the i (ten) of 40 arteria segments (grade: 0 - no plaque; 1 - plaque - < or = 50 % stenosis; 2 - > 50 % stenosis - < or = 90 % stenosis; 3 - > 90 % stenosis - < 100 % stenosis; 4 - occlusion). Correlations between CAC and atherosclerosis index were performed. Wb-ce MRA and CAC correlate only moderately in this population. An atherosclerosis index 8 renders a positive predictive value for a CAC 100 of 63.3 %. An atherosclerosis index as defined in this study does not fully correlate with the extent of CAD as revealed by catheter angiography or EBCT/MSCT, but it might theoretically mirror the increased risk by PAD. It thus might be a promising complementary parameter for the prediction of cardiac events. Future studies need to show its possible additional predictive impact.

Improvement in coronary endothelial function is independently associated with a slowed progression of coronary artery calcification in type 2 diabetes mellitus

To examine a relationship between alterations of structure and function of the arterial wall in response to glucose-lowering therapy in type 2 diabetes mellitus (DM) after a 1-year follow-up (FU). In DM (n = 22) and in healthy controls (n = 17), coronary artery calcification (CAC) was assessed with electron beam tomography and carotid intima-media thickness (IMT) with ultrasound, whereas coronary function was determined with positron emission tomography-measured myocardial blood flow (MBF) at rest, during cold pressor testing (CPT), and during adenosine stimulation at baseline and after FU. The decrease in plasma glucose in DM after a mean FU of 14 +/- 1.9 months correlated with a lower progression of CAC and carotid IMT (r = 0.48, P < or = 0.036 and r = 0.46, P < or = 0.055) and with an improvement in endothelium-related DeltaMBF to CPT and to adenosine (r = 0.46, P < or = 0.038 and r = 0.36, P < or = 0.056). After adjusting for metabolic parameters by multivariate analysis, the increases in DeltaMBF to CPT after glucose-lowering treatment remained a statistically significant independent predictor of the progression of CAC (P < or = 0.001 by one-way analysis of variance). In DM, glucose-lowering treatment may beneficially affect structure and function of the vascular wall, whereas the observed improvement in endothelium-related coronary artery function may also mediate direct preventive effects on the progression of CAC.

A model for quantitative correction of coronary calcium scores on multidetector, dual source, and electron beam computed tomography for influences of linear motion, calcification density, and temporal resolution: A cardiac phantom study

The objective of this study is to quantify the influence of linear motion, calcification density, and temporal resolution on coronary calcium determination using multidetector computed tomography (MDCT), dual source CT (DSCT), and electron beam tomography (EBT) and to find a quantitative method which corrects for the influences of these parameters using a linear moving cardiac phantom. On a robotic arm with artificial arteries with four calcifications of increasing density, a linear movement was applied between 0 and 120 mm/s (step of 10 mm/s). The phantom was scanned five times on 64-slice MDCT, DSCT, and EBT using a standard acquisition protocol. The average Agatston, volume, and mass scores were determined for each velocity, calcification, and scanner. Susceptibility to motion was quantified using a cardiac motion susceptibility (CMS) index. Resemblance to EBT and physical volume and mass was quantified using a Delta index. Increasing motion artifacts were observed at increasing velocities on all scanners, with increasing severity from EBT to DSCT to 64-slice MDCT. The calcium score showed a linear dependency on motion from which a correction factor could be derived. This correction factor showed a linear dependency on the mean calcification density with a good fit for all three scoring methods and all three scanners (0.73 < or = R2 < or = 0.95). The slope and offset of this correction factor showed a linear dependency on temporal resolution with a good fit for all three scoring methods and all three scanners (0.83 < or = R2 < or = 0.98). CMS was minimal for EBT and increasing values were observed for DSCT and highest values for 64-slice MDCT. CMS was minimal for mass score and increasing values were observed for volume score and highest values for Agatston score. For all densities and scoring methods DSCT showed on average the closest resemblance to EBT calcium scores. When using the correction factor, CMS index decreased on average by 15% and Delta index decreased by 35%. Calcium scores determined on DSCT and 64-slice MDCT are highly susceptible to motion as compared to EBT. The mass score is less susceptible to motion compared to volume and Agatston score. Calcium scores determined on DSCT bear a closer resemblance to EBT obtained calcium scores than 64-slice MDCT. In addition, the calcium score is highly dependent on the average density of individual calcifications and the dependency of the calcium score on motion showed a linear behavior on calcification density. From these relations, a quantitative method could be derived which corrects the measured calcium score for the influence of linear motion, mean calcification density, and temporal resolution.

Cardiac CT: the missing piece of the puzzle

Until a few years ago, conventional coronary angiography was the only technique which could explore coronary arteries. Although magnetic resonance imaging offered some promise, computed tomography coronary angiography (CTCA) really opened a window for the non-invasive assessment of the coronary arteries. CTCA has rapidly became a real clinical tool, albeit with some important limitations (e.g. radiation dose and heart rate). Finally, CTCA is becoming a routine part of chest CT. The paper deals with the clinical validation of a new CTCA geometry [1]. Compared with all previous algorithms, in this case the CT algorithm/geometry is a “hybrid”. First, there was electron-beam CT with prospective ECG triggering. Then, there was spiral CT with retrospective ECG gating. Recently, prospective ECG triggering was introduced to reduce the radiation dose. With this “prospectively ECG-triggered high-pitch spiral acquisition”, the two optimal techniques of cardiac synchronization are merged together [2]. In order to achieve this CT geometry, a mandatory requirement is extremely high temporal resolution (to provide the minimum of 180° required for one image), which for CT means <100 ms (in hardware). The average radiation dose for such CTCA is 0.8-0.9 mSv, the lowest ever reported. This was first possible with dual-source CT systems, but all CT manufacturers are coming up with their own solutions. One major limitation still remains for CTCA, which is related to heart rate. In order to obtain the best image quality, a low and regular heart rate should be achieved (probably <60-65 bpm). However, this is nothing new, since all the development of CTCA has been performed with the extensive and aggressive use of beta-blockers [3]. For all generations of CT technology, the statement concerning heart rate, “the lower the better”, has been a mantra for CT users. In addition, the re-introduction of prospective ECG triggering recently determined a “revival” of beta-blockers. This newmode for CT data acquisition is a revolution and may cause another paradigm shift. In other words: the possibility to examine the heart with 0.8-0.9 mSv (within ∼300ms in total) and/or the possibility to examine the thorax with 1.2-1.4 mSv and have data about the heart “for free”. With this technology, any chest CT may become a CTof the heart with a radiation exposure lower than ever before. In the cardiology community this will require some time to be understood. Within radiology, this is even more usual. Just This commentary refers to the article doi:10.1007/s00330-009-1558-4

Does imaging help with preventing extrusion?

AbstractBoth clinical and radiological methods can be used for early detection of resorption in OOKP patients; this is influential in preventing serious complications such as extrusion and endophthalmitis. Radiologically, use of either multidetector computed tomography (MDCT) or electron beam tomography (EBT) is valuable in identifying laminar resorption. A novel approach was recently adopted in Sussex Eye Hospital, using volume rendering software in processing previously obtained MDCT images, to calculate volume of the OOKP lamina rather than 2D measurements. We present the results of an observational retrospective case series study to illustrate the use of this approach. We describe how it can be used to calculate percentage change in volume of the lamina over time and how this can be correlated with clinical laminar resorption. We will also discuss further recommendations to build upon this advance.