Search

The purpose of this study was to assess segment image quality at high heart rates using 16-slice computed tomography and differential reconstruction for major coronary vessels. According to the following protocol, 16-slice CT coronary angiography in 46 patients with a mean heart rate of 86.3+/-11.8 was reconstructed. At three transverse planes, preview series were obtained and motion artifacts evaluated in 5% increments from 0-95% within the cardiac cycle. Relying on image quality in the previews, reconstructions were performed at three z-positions for each patient. Segment image quality was assessed in terms of artifacts and visibility. The effects of heart rate and trigger delay on image quality were analyzed. Optimal image quality was achieved at 25 to 35% of the cardiac cycle for the left circumflex (CX) and right coronary artery (RCA) or 30 to 40% for the left main (LM) and left anterior descending artery (LAD). Sixteen-slice CT and differential reconstruction produced good image quality with a low percentage of motion-degraded proximal and middle segments (8.8%). Grades were 1.5 for the LM, 1.9 for the LAD, 2.0 for the CX and 2.3 for the RCA. At high heart rates, good image quality of the coronary arteries is achieved by 16-slice CT and a sophisticated reconstruction strategy at peak to late systole.

The broad introduction of multi-slice CT by all major vendors in 1998 was a milestone with regard to extended volume coverage, improved axial resolution and better utilization of the tube output. New clinical applications such as CT-examinations of the heart and the coronary arteries became possible. Despite all promising advances, some limitations remain for 4-slice CT systems. They come close to isotropic resolution, but do not fully reach it in routine clinical applications. Cardiac CT-examinations require careful patient selection. The new generation of multi-slice CT-systems offer simultaneous acquisition of up to 16 sub-millimeter slices and improved temporal resolution for cardiac examinations by means of reduced gantry rotation time (0.4 s). In this overview article we present the basic technical principles and potential applications of 16-slice technology for the example of a 16-slice CT-system (SOMATOM Sensation 16, Siemens AG, Forchheim). We discuss detector design and dose efficiency as well as spiral scan- and reconstruction techniques. At comparable slice thickness, 16-slice CT-systems have a better dose efficiency than 4-slice CT-systems. The cone-beam geometry of the measurement rays requires new reconstruction approaches, an example is the adaptive multiple plane reconstruction, AMPR. First clinical experience indicates that sub-millimeter slice width in combination with reduced gantry rotation-time improves the clinical stability of cardiac examinations and expands the spectrum of patients accessible to cardiac CT. 16-slice CT-systems have the potential to cover even large scan ranges with sub-millimeter slices at considerably reduced examination times, thus approaching the goal of routine isotropic imaging.

In the past 2 years mechanical multidetector-row CT (MDCT) systems with simultaneous acquisition of four slices and half-second scanner rotation have become widely available. Data acquisition with these scanners allows for considerably faster coverage of the heart volume compared with single-slice scanning. This increased scan speed can be used for retrospective gating together with 1-mm collimated slice widths and allows coverage of the entire cardiac volume in one breath hold. Initial results from studies in correlation with intracoronary ultrasound suggest that MDTC technology not only offers the possibility to visualize intracoronary stenoses non-invasively but also to differentiate plaque morphology. This is especially the case with the next generation of 16-row multidetector CT. An increased number of simultaneously acquired slices and sub-millimeter collimation for cardiac applications allows true isotropic scanning with high temporal resolution. Contrast-enhanced MDTC is a promising non-invasive technique for the detection, visualization, and characterization of stenotic artery disease. It could act as a gate keeper prior to cardiac catherization and finally replace conventional diagnostic modalities.

Paclitaxel, a potent anti-tumor agent, shifts the cytoskeleton equilibrium towards assembly of altered and extraordinarily stable microtubules. These cellular modifications lead to reduced proliferation, migration, and signal transduction. It is highly lipophilic, which promotes a rapid cellular uptake, and has a long-lasting effect in the cell due to the structural alteration of the cytoskeleton. This makes paclitaxel a promising candidate for local drug delivery intended to address the proliferative and migratory processes involved in restenosis. In this article, results of our in vitro and in vivo studies with paclitaxel are presented. Cell culture experiments with monocultures of human arterial smooth muscle cells as well as co-cultures with human endothelial cells showed that paclitaxel leads to an almost complete growth inhibition within a dose range of 1.0-10.0 mumol/l, even after a short (20 min) single dose application. The comparison of an active, semi-active, and passive delivery system (porous balloon, microporous balloon, and double balloon) favored the double balloon for the following in vivo experiments. Tubulin staining and electron microscopy enabled visualization of paclitaxel-induced vessel wall alterations. In the rabbit model, locally delivered paclitaxel resulted in reduced neointima formation and enlargement in vessel size; in the pig model, however, after stenting, this inhibition was not significant. Both reduced proliferation and enlargement in vessel size contribute to a preservation of vessel shape and are likely to be caused by a structural alteration of the cytoskeleton, which is also supported by vascular contraction force experiments.

Background The antineoplastic compound paclitaxel (Taxol) causes an increased assembly of extraordinarily stable microtubules. The present study was designed to characterize the effects of paclitaxel on proliferation and migration of human arterial smooth muscle cells (haSMCs) in vitro and on neointima formation in an in vivo experimental rabbit model. Methods and Results Both monocultures of haSMCs and cocultures with human arterial endothelial cells (haECs) were used. Cell growth after 4, 8, and 14 days was determined in the absence or presence of platelet-derived growth factor-AB (PDGF-AB), basic fibroblast growth factor (bFGF), or thrombin. Nonstop paclitaxel exposure, as well as single-dose applications of paclitaxel for 24 hours or even 20 minutes (0.1 to 10.0 μmol/L), caused a complete and prolonged inhibition of haSMC growth up to day 14, with an IC 50 of 2.0 nmol/L. Mitogens or cocultures with stimulating haECs did not significantly attenuate paclitaxel-induced effects. Immunohistochemistry showed characteristic cytoskeletal changes predominantly in the microtubule network. Additionally, in 20 male New Zealand White rabbits, intimal plaques were produced by electrical stimulation. In 10 animals, paclitaxel was locally applied by use of microporous balloons. Histologically, the intima wall area, wall thickness, and degree of stenosis were reduced significantly in paclitaxel-treated animals compared with controls. Conclusions Our data show that paclitaxel inhibits haSMC proliferation and migration in a dose-dependent manner in monocultures and cocultures even in the presence of mitogens. Furthermore, paclitaxel prevents neointima formation in rabbits after balloon angioplasty. The long-lasting effect after just several minutes’ exposure time makes this lipophilic substance a promising candidate for local antiproliferative therapy of restenosis.

Koronararteriensystem: Verdacht auf koronare Herzerkrankung (KHK) [1, 2, 3, 4] und koronare Anomalien [5]. Aufnahme der Herzmorphologie: Erkrankungen des Perikards, angeborene Herzerkrankungen [6]. Status nach koronaren Therapiemasnahmen: Status nach Nachbeobachtung nach koronarer Bypasschirurgie [7] oder Status nach perkutanen koronaren Interventionen (Darstellung von Stents [8]). Postoperative Phase nach grosen chirurgischen Eingriffen am Herzen, wenn die Koronarien mitbetroffen sind, etwa bei Ersatz der Aorta ascendens mit Reimplantation der Koronarostien. Notfallmasige Untersuchung auf mogliche Koronarbeteiligung, z.B. bei Typ A-Dissektion der Aorta ascendens.

Die CT-Angiographie (CTA) ist ein relativ neues Verfahren, dass insbesondere seit der Einfuhrung der 32–64 Zeilengeneration nochmals eine erhebliche Entwicklung erfahren hat. Derzeit fehlen noch grose Multizenterstudien, sodass noch keine definitive, klinisch nachgewiesene Indikation fur die CT-Angiographie existiert. Konsens besteht allerdings daruber, dass die koronare CTA bei Verdacht auf Anomalien der Koronararterien die Methode der Wahl darstellt [1]. Auserdem zeigt sich zunehmend, dass die Methode einen hohen negativen pradiktiven Wert besitzt und daher signifikante Stenosen der Koronarien ausschliesen kann [2,3]. Fur alle anderen moglichen Indikationen, einschlieslich Beurteilung der koronaren Plaquelast und deren Verlaufskontrolle, gibt es im Moment noch keine gesicherten Indikationen im Sinne der Evidenz-basierten Medizin. Mogliche Indikationsgebiete sind: 1. Verdacht auf angeborene Anomalien der Koronararterien 2. Ausschluss signifikanter Koronarstenosen bei Patienten mit niedrigem bis masigem Risiko einer KHK, wenn atypische Symptome vorliegen und/oder wenn Belastungs-EKG, Echokardiographie oder myokardiale Szintigraphie nicht aussagekraftig waren. 3. Beobachtung nach Intervention an den Koronarien, um Re-Stenosen auszuschliesen 4. Beobachtung von Patienten mit hamodynamisch nicht wirksamen atherosklerotischen Veranderungen der Koronarwand und von Plaques, um das Fortschreiten oder die Ruckbildung der Plaqueausdehnung vor oder wahrend einer medikamentosen Behandlung zu untersuchen. 5. Untersuchung von Thromben in der rechten Kammer oder im rechten Vorhof, wenn andere Methoden (Echo oder MRT) nicht verfugbar sind oder keine klare Diagnose erlauben. 6. Seltene Indikationen: koronare Aneurysmata wie z.B. beim Kawasaki-Syndrom oder genetisch bedingte Erkrankungen wie das Marfanoder Loeys-Dietz-Syndrom

Pulmonalatresie mit Ventrikelseptumdefekt Fallotsche Tetralogie und andere zyanotische Herzfehler Transposition der grosen Arterien Doppelter Aortenbogen Aortenisthmusstenose Pulmonalvenenfehlmundung

1. Atypischer Brustschmerz 2. Erhohte D-Dimer-Werte 3. Unklare Atemnot 4. Nachkontrolle bei Patienten mit bekannter Lungenembolie 5. Pravention fur Patienten mit tiefer Venenthrombose und hohem Risiko fur Lungenembolie 6. CAVE: ≫Organisatorische Missbrauchsindikation≪

Die Thorax-Ubersichtsaufnahme ist aufgrund der VerfUgbarkeit und der exzellenten Kosten-Nutzen-Relation die haufigste verwendete Untersuchungsmethode in der Diagnostik der infektiosen Lungenerkrankungen. Allerdings ist ihre Zuverlassigkeit durch eine grose Interobserver-Variabilitat in der radiologischen Interpretation limitiert [1]. Die Rolle der Computertomographie und der High-Resolution-CT (HRCT) ist aufgrund der Uberlegenen Detektion und Charakterisation pulmonaler Infiltrate gut etabliert.

We present a performance evaluation of a recently introduced dual-source computed tomography (DSCT) system equipped with two X-ray tubes and two corresponding detectors, mounted onto the rotating gantry with an angular offset of 90 degrees . We introduce the system concept and derive its consequences and potential benefits for electrocardiograph [corrected] (ECG)-controlled cardiac CT and for general radiology applications. We evaluate both temporal and spatial resolution by means of phantom scans. We present first patient scans to illustrate the performance of DSCT for ECG-gated cardiac imaging, and we demonstrate first results using a dual-energy acquisition mode. Using ECG-gated single-segment reconstruction, the DSCT system provides 83 ms temporal resolution independent of the patient's heart rate for coronary CT angiography (CTA) and evaluation of basic functional parameters. With dual-segment reconstruction, the mean temporal resolution is 60 ms (minimum temporal resolution 42 ms) for advanced functional evaluation. The z-flying focal spot technique implemented in the evaluated DSCT system allows 0.4 mm cylinders to be resolved at all heart rates. First clinical experience shows a considerably increased robustness for the imaging of patients with high heart rates. As a potential application of the dual-energy acquisition mode, the automatic separation of bones and iodine-filled vessels is demonstrated.

The objective of this study was to evaluate the accuracy of electrocardiography (ECG)-gated 16-slice multidetector-row computed tomography (MDCT) in detection of stenosis of bypass grafts and native coronary arteries in patients who have undergone coronary artery bypass grafting (CABG). ECG-gated contrast-enhanced MDCT using 12 x 0.75-mm collimation was performed in 20 patients with recurrent angina 4.75 years after undergoing CABG. A total of 50 grafts, 16 arterial and 34 venous, were examined. All graft and coronary segments were evaluated for stenosis in comparison with conventional coronary angiography (CCA). Among the 80 arterial graft segments, 62 could be assessed (77.5%). Sensitivity, specificity, and positive and negative predictive values for stenosis were 96.2%, 97.2%, 96.2%, and 97.2%, respectively. In a total of 180 venous graft segments, 167 could be assessed. Sensitivity, specificity, and positive and negative predictive values for stenosis were 98.5%, 93.9%, 91.8%, and 98.9%, respectively. MDCT could assess 179 of 260 native coronary artery segments (68.8%). Sensitivity, specificity, and positive and negative predictive values for stenosis were 92.1%, 76.9%, 87.5%, and 84.7%, respectively. Sixteen-slice MDCT provides excellent image quality and diagnostic accuracy in detection of graft and coronary artery lesions in patients with suspected graft dysfunction.

Eighty-four patients with suspected coronary artery disease were studied to determine the accuracy of noninvasive coronary angiography using a multidetector computed tomographic scanner with 64- x 0.6-mm collimation and 330-ms gantry rotation. All coronary artery segments with a diameter >1.5 mm were assessed with respect to stenoses >50% decreased diameter. Results were compared with quantitative coronary angiographic findings. After exclusion of unevaluable coronary segments (4%), multidetector computed tomography demonstrated a sensitivity of 93%, a specificity of 97%, and a negative predictive value of 100% in a per-segment analysis. In a per-artery analysis, 15 of 336 arteries (4%) were unevaluable. Sensitivity and specificity in evaluable arteries were 95% and 93%, respectively. In a per-patient analysis (81 of 84 patients included), sensitivity and specificity were 96% and 91%, respectively.

ObjectivesWe sought to evaluate graft patency, flow, and flow reserve in patients with minimally invasive direct coronary artery bypass surgery of internal thoracic artery grafts by a combined magnetic resonance protocol with a phase-contrast technique and magnetic resonance angiography.MethodsAt 1.5 T (Magnetom Sonata, Siemens), 30 symptomatic patients with 30 left internal thoracic artery grafts were examined 6 years after minimally invasive surgical intervention. Navigator-gated magnetic resonance angiography and contrast-enhanced FLASH-3D magnetic resonance angiography (0.2 mmol gadopentate–diethylene triamine pentetic acid [Gd-DTPA]/kg body weight) was used to assess bypass patency. Phase-contrast flow measurements with retrospective gating were performed in the internal thoracic artery grafts at rest and after stress induction with dipyridamole (0.57 mg/kg body weight). Graft patency was evaluated by means of multidetector computed tomography (Sensation 16, Siemens).ResultsInternal thoracic artery grafts were occluded in 5 of 30 patients. In 6 patients the anastomosis to the left anterior descending artery was highly stenotic (>70%) at multidetector computed tomography. In patients with regular grafts (multidetector computed tomography), a significant improvement of graft flow (P < .001) and diastolic/systolic peak velocity ratio (P < .001) after stress induction was detected. Magnetic resonance angiography combined with flow reserve measurements could differentiate between occluded-stenotic and regular minimally invasive direct coronary artery bypass grafts.ConclusionsMagnetic resonance imaging allows a combined assessment of bypass patency and flow with flow reserve in patients after the minimally invasive direct coronary artery bypass operation. The protocol of this study might be applicable for the evaluation of graft status in symptomatic patients after revascularization.

The aim of this study was to compare different representation models of surface-rendered virtual bronchoscopy. 10 consecutive patients with inoperable primary lung tumors underwent thin-section spiral computed tomography. The structures of interest, the tracheobronchial system and anatomical and pathological thoracic structures were segmented using an interactive threshold interval volume-growing segmentation algorithm and visualized with the aid of a color-coded surface rendering method. For virtual bronchoscopy, the tracheobronchial system was visualized using a triangle-surface rendering model, a shaded-surface rendering model and a transparent shaded-surface rendering model. The triangle-surface rendering model allowed optimum detailed spatial representation of the dimensions of extraluminal anatomical and pathological mediastinal structures. As the lumen of the tracheobronchial system was less well defined, the rendering model was of limited use for depiction of the airway surface. The shaded-surface rendering model facilitated an optimum assessment of the airway surface, but the mediastinal structures could not be depicted. The transparent shaded-surface rendering model provides simultaneous adequate to optimum visualization and assessment of the intraluminal airway surface and the extraluminal mediastinal structures as well as a quantitative assessment of the spatial relationship between these structures. Fast data acquisition with a multi-slice detector spiral computed tomography scanner and the use of virtual bronchoscopy with the transparent shaded-surface rendering model obviate the need for time consuming detailed analysis and presentation of axial source images by providing improved the diagnostic imaging of endotracheal and endobronchial diseases and offering a useful alternative to fiberoptic bronchoscopy.

4-slice CT scanners have shown limitations in clinical application for noninvasive coronary CT angiography (CTA). We evaluate advances in ECG-gated scanning of the heart and the coronary arteries with recently introduced 16-slice CT equipment (SOMATOM Sensation 16, Siemens, Forchheim, Germany).The technical principles of ECG-gated cardiac scanning, scan parameters, and detector design of the new scanner are presented. ECG-gated scan and image reconstruction techniques and ECG-controlled dose modulation ("ECG pulsing") for a reduction of the patient dose are described, key parameters for image quality and simulation results presented, and phantom studies and initial patient experience discussed. The impact of reduced gantry rotation time (0.42 s) on temporal resolution and initial estimations of the patient dose are presented.Extensions of ECG-gated reconstruction algorithms used for 4-slice CT provide adequate image quality for up to 16 slices. For each detector collimation different slice widths are available for retrospective reconstruction with well-defined slice sensitivity profiles (SSPs). For coronary CTA the heart can be covered with 0.75 mm collimation within a 20-s breathhold. The best possible spatial resolution is 0.5 x 0.5 x 0.6 mm. For 0.42 s gantry rotation time, temporal resolution reaches its optimum (105 ms) at a heart rate of 81 bpm. Effective patient dose for coronary CTA is 4-5 mSv using ECG-pulsed acquisition.The clinical performance of coronary CTA by means of spatial resolution, temporal resolution and scan time is substantially improved with the evaluated 16-slice CT scanner. Also, display of smaller coronary segments and instent visualization are substantially improved.

Percutaneous transluminal coronary angioplasty is an accepted treatment for coronary artery disease. The major limitation, however, is the high incidence of restenosis which limits the long-term benefit of this intervention. Paclitaxel is a new antiproliferative agent that has generated considerable scientific interest since it was introduced in clinical trials in the early 1980s. Recent in vitro studies have shown that paclitaxel has considerable antiproliferative activity in human coculture systems. In the present study the efficacy of paclitaxel was investigated after development of an intimal plaque by electrical stimulation and additional cholesterol diet and subsequent balloon angioplasty in 63 New Zealand White rabbits. Local drug delivery of paclitaxel was accomplished in 30 rabbits with a porous balloon catheter (35 holes, hole diameter 75 microm, 2.5 mm catheter diameter). Paclitaxel was administered locally with 4 ml (solution 10(-5) mol/L) using an injection pressure of 2 atm. To study the extent of restenosis and morphological changes, the animals were sacrificed 7, 28 or 56 days after intervention. After staining procedures quantification of SMC proliferation, intimal macrophages and morphological analyses were performed. Paclitaxel plasma concentrations were measured using HPLC technique. One week after balloon angioplasty the arteries treated with local paclitaxel delivery showed an insignificant trend towards a reduction in intimal smooth muscle cell proliferation (untreated 8.4 +/- 4.9 % vs paclitaxel treated 2.4 +/- 2.4 %, p = NS). However, this resulted in a significant reduction of stenosis degree of 66 % 8 weeks after intervention compared to the untreated group (untreated 41 +/- 18 % vs paclitaxel treated 14 +/- 11 %, p = 0.005). In conclusion, locally delivered paclitaxel prevented neointimal thickening in the rabbit carotid artery after balloon angioplasty. Local paclitaxel treatment may therefore be a clinical option for the prevention of restenosis after coronary interventions. However, further preclinical studies have to prove long-term efficacy and safety.

Coronary artery disease (CAD) is the leading killer in Europe and the United States. CAD accounted for almost 600,000 deaths in Europe in 1998. Although many patients initially present with symptoms, about half of all patients have no symptoms before their sudden death. Thus, a screening test for CAD might help stratify coronary risk in asymptomatic adults. Since its introduction in 1983, electron beam computed tomography scanning (EBCT) has been proposed as a means of coronary calcium assessment for screening. However, direct visualization of the epicardial coronary arteries is necessary to establish the presence and focal severity of lumen disease. Selective coronary angiography is the only clinical method to accurately visualize and quantify coronary artery anatomy in vivo. This. method provides exceptional spatial resolution and a general road map of the coronary system. More than one million diagnostic catheterizations are performed in the United States each year. Selective coronary angiography is expensive and requires at least a brief hospital stay and a period of observation for several hours after the procedure. A convenient noninvasive and safe means to perform coronary angiography clearly would be of clinical benefit. Promising results have been reported for EBCT with a decent sensitivity and specificity in the detection of coronary artery stenoses [12, 16]. A major caveat of this method is, however, the high incidence of motion artifacts, leading to uninterpretable images [1, 4]. This limitation might now be overcome by the emergence of superfast multislice CT (MSCT) technology with spiral scanning at high temporal (125 ms) and superior spatial (10 1p/cm) resolution [11].

Background: The microtubule stabilizing compound paclitaxel has proved to have potent antiproliferative effects on smooth muscle cells both in vitro and in vivo. It induces cellular modifications that result in reduced proliferation, migration and signal transduction by shifting the cellular microtubule equilibrium towards assembly. We therefore reasoned that a visualization of the altered cytoskeleton could enable an evaluation of the drug effects following local drug delivery. Methods and results: 3 catheters – the porous balloon, the microporous balloon and the double balloon catheter – were chosen for this study representing the spectrum from passive to active, pressure-driven delivery. After the induction of a defined plaque in the right carotid arteries of 40 New Zealand rabbits by electrical stimulation, 32 animals underwent balloon dilatation and 8 animals served as pre-interventional control group with electrostimulation only. In 24 animals (n = 8 in each group) subsequent local paclitaxel delivery (10 μmol/L) was performed. 8 animals served as control with angioplasty only. Vessels were excised 1 week following intervention. Immunohistochemistry with antibodies against bromodeoxyuridine, alpha-actin, macrophages, von Willebrand factor and α-tubulin was performed. Cytoskeletal changes were analyzed by electron microscopy. Tubulin staining and electron microscopy revealed changes with distinct staining patterns for the different catheters. Specific catheter-induced injuries could be identified for the porous and double balloon catheter. Intimal proliferation, percentage of macrophages and extent of injury favor the double balloon catheter for local paclitaxel delivery. Conclusions: The alterations of the cytoskeleton induced by paclitaxel allowed for the detection of drug action by staining of tubulin and electron microscopy. This enables an evaluation of transfer, distribution and drug effects directly in the vasculature without marker substances. The double balloon catheter appears to be best suited for local paclitaxel therapy.

Background Diarrhea is common in patients with Crohn's disease and may be accompanied by acid base disorders, most commonly metabolic acidosis due to intestinal loss of bicarbonate. Case Presentation Here, we present a case of severe metabolic alkalosis in a young patient suffering from M. Crohn. The patient had undergone multiple resections of the intestine and suffered from chronic kidney disease. He was now referred to our clinic for recurrent acute kidney injury, the nature of which was pre-renal due to profound volume depletion. Renal failure was associated with marked hypochloremic metabolic alkalosis which only responded to high volume repletion and high dose blockade of gastric hypersecretion. Intestinal failure with stomal fluid losses of up to 5.7 litres per day required port implantation to commence parenteral nutrition. Fluid and electrolyte replacement rapidly improved renal function and acid base homeostasis. Conclusions This case highlights the important role of gastrointestinal function to maintain acid base status in patients with Crohn's disease.

To methodically evaluate the reproducibility and accuracy of coronary arterial calcification measurements by using spiral multi-detector row and electron-beam computed tomography (CT) with a beating heart phantom.A phantom was built to mimic a beating heart with coronary arteries and calcified plaques. The simulated vessels moved in a pattern similar to that of a beating heart. The phantom operated at a variety of pulse rates (0-140 beats per minute). The phantom was repeatedly scanned in various positions by using various protocols with electron-beam and multi-detector row CT scanners to assess interexamination variability. Statistical analysis was performed to determine significant differences in interexamination variability for various acquisition protocols.Electrocardiographically (EKG) gated volume coverage with spiral multi-detector row CT (2.5-mm collimation) and overlapping image reconstruction (1-mm increment) was found to significantly improve the reliability of coronary arterial calcium quantification, especially for small plaques (P.05). Mean interexamination variability was reduced from 35% +/- 6 (SD) (Agatston score, standard electron-beam CT) to 4% +/- 2 (P.05) (volumetric score, spiral EKG-gated multi-detector row CT).By coupling retrospective gating with nearly isotropic volumetric imaging data, spiral multi-detector row CT provides better input data for quantification of coronary arterial calcium volume. Multi-detector row CT allows precise and repeated measurement of coronary arterial calcification, with low interexamination variability.