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ABSTRACT: Stress and rest myocardial perfusion imaging using computed tomography (CT) can be accurately and safely performed. CT angiography allows for the anatomic visualization of coronary lesions and the components of atherosclerotic plaque, whereas according to currently available data, CT perfusion imaging improves the diagnostic accuracy for detecting ischemic lesions. However, the radiation exposure and contrast load that are involved cannot be neglected. Owing to the limited number of trials that have been published so far, and the fact that they used a wide variety of image acquisition and stress protocols, a standard acquisition protocol for CT perfusion imaging still needs to be found and evaluated in larger multicenter trials. Therefore, CT perfusion imaging, as opposed to other modalities such as magnetic resonance perfusion, SPECT, or positron emission tomography, cannot yet be regarded as clinical routine, but may be considered in patients with contraindications for other imaging modalities.
Herz 04/2013; · 0.92 Impact Factor
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ABSTRACT: In the 20years since its introduction, radial access for diagnostic and interventional coronary procedures has been well
validated in countless scientific studies. Nevertheless, the use of this access route varies greatly among—and even within—countries.
Fear of the unknown may make some experienced interventionalists hesitant to adopt the transradial approach in spite of its
proven advantages. In our review, we describe practical aspects of the transradial access, such as the role of Allen’s test
in patient selection and considerations on the optimal puncture technique of the radial artery. Catheter selection, anatomic
variations which may complicate access, as well as strategies to avoid and/or manage possible complications are outlined.
Finally, we review the literature on the reduction of access site complications by adopting the transradial approach. Even
in interventions for acute myocardial infarction, transradial access can be used safely and effectively. In addition to a
reduced rate of access site complications, a reduction in overall in-hospital major adverse cardiac events has been demonstrated.
The advantage regarding access site complications could be seen even when closure devices were utilized for transfemoral procedures.
Etwa 20Jahre nach Einführung des transradialen Zugangs für Herzkatheteruntersuchungen und Koronarinterventionen sind die
Vorteile dieses Verfahrens im Vergleich zum transfemoralen Vorgehen gut untersucht; dennoch kommt es unterschiedlich häufig
zur Anwendung. In dieser Arbeit werden praktische Aspekte des transradialen Zugangs dargestellt, die Bedeutung des Allen-Tests
bei der Auswahl geeigneter Patienten und die optimale Punktionstechnik der A.radialis. Anatomische Varianten der A.radialis
können Probleme verursachen und müssen bedacht werden. Zur Koronarangiographie werden üblicherweise Standardkatheter wie beim
transfemoralen Vorgehen verwendet. Komplikationen sind bei der Beachtung von wenigen, wichtigen Grundregeln selten und können
in der Regel sicher gehandhabt werden. In klinischen Untersuchungen wurde gezeigt, dass Blutungen im Rahmen von Koronarinterventionen
mit einem schlechteren Outcome verbunden sind. Durch die Anwendung des transradialen Zugangs können Blutungen an der Punktionsstelle
signifikant verringert werden. Auch bei akuten Myokardinfarkten kann der transradiale Zugang sicher eingesetzt werden; im
Vergleich zur transfemoralen Technik ließ sich nicht nur eine geringere Komplikationsrate an der Punktionsstelle, sondern
auch ein besseres kardiovaskuläres Outcome nachweisen. Selbst beim Einsatz von Verschlusssystemen im Rahmen des femoralen
Zugangs zeigte sich bezüglich der Komplikationsrate ein Vorteil für den transradialen Zugang.
KeywordsTransradial catheterization–Radial access–Radial artery–Acute myocardial infarction–Complications
SchlüsselwörterTransradiale Katheterisierung–Radialer Zugang–Arteria radialis–Akuter Myokardinfarkt–Komplikationen
Herz 04/2012; 36(5):386-395. · 0.92 Impact Factor
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W Wuest,
K Anders,
A Schuhbaeck,
M S May,
S Gauss,
M Marwan,
M Arnold,
S Ensminger,
G Muschiol,
W G Daniel,
M Uder, S Achenbach
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ABSTRACT: Transcatheter Aortic Valve Implantation (TAVI) is an alternative to surgical valve replacement in high risk patients. Angiography of the aortic root, aorta and iliac arteries is required to select suitable candidates, but contrast agents can be harmful due to impaired renal function. We evaluated ECG-triggered high-pitch spiral dual source Computed Tomography (CT) with minimized volume of contrast agent to assess aortic root anatomy and vascular access.
42 patients (82 ± 6 years) scheduled for TAVI underwent dual source (DS) CT angiography (CTA) of the aorta using a prospectively ECG-triggered high-pitch spiral mode (pitch = 3.4) with 40 mL iodinated contrast agent. We analyzed aortic root/iliac dimensions, attenuation, contrast to noise ratio (CNR), image noise and radiation exposure.
Aortic root/iliac dimensions and distance of coronary ostia from the annulus could be determined in all cases. Mean aortic and iliac artery attenuation was 320 ± 70 HU and 340 ± 77 HU. Aortic/iliac CNR was 21.7 ± 6.8 HU and 14.5 ± 5.4 HU using 100 kV (18.8 ± 4.1 HU and 8.7 ± 2.6 HU using 120 kV). Mean effective dose was 4.5 ± 1.2 mSv.
High-pitch spiral DSCTA can be used to assess the entire aorta and iliac arteries in TAVI candidates with a low volume of contrast agent while preserving diagnostic image quality.
European Radiology 08/2011; 22(1):51-8. · 3.22 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: In the 20 years since its introduction, radial access for diagnostic and interventional coronary procedures has been well validated in countless scientific studies. Nevertheless, the use of this access route varies greatly among--and even within--countries. Fear of the unknown may make some experienced interventionalists hesitant to adopt the transradial approach in spite of its proven advantages. In our review, we describe practical aspects of the transradial access, such as the role of Allen's test in patient selection and considerations on the optimal puncture technique of the radial artery. Catheter selection, anatomic variations which may complicate access, as well as strategies to avoid and/or manage possible complications are outlined. Finally, we review the literature on the reduction of access site complications by adopting the transradial approach. Even in interventions for acute myocardial infarction, transradial access can be used safely and effectively. In addition to a reduced rate of access site complications, a reduction in overall in-hospital major adverse cardiac events has been demonstrated. The advantage regarding access site complications could be seen even when closure devices were utilized for transfemoral procedures.
Herz 08/2011; 36(5):386-95. · 0.92 Impact Factor
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ABSTRACT: To compare in vivo DNA lesions induced during helical and sequential coronary computed tomography angiography (CTA) and to evaluate the effect of CT parameters on double-strand break (DSB) levels.
Thirty-six patients were examined with various CT protocols and modes (helical scan, n = 27; sequential scan, n = 9) either using a 64-slice dual-source or a 128-slice CT system. Blood samples were obtained before and 30 min after CT. Lymphocytes were isolated, stained against the phosphorylated histone variant γ-H2AX, and DSBs were visualised by using fluorescence microscopy.
DSB yields 30 min after CTA ranged from 0.04 to 0.71 per cell and showed a significant correlation to DLP (ρ = 0.81, p < 0.00001). Median DSB yield and median DLP were significantly lower after sequential compared to helical CT examinations (0.11 vs. 0.37 DSBs/cell and 249 vs. 958 mGy cm, p < 0.00001). Additional calcium scoring led to an increase in DLP (p = 0.15) and DSB levels (p = 0.04). DSB levels normalised to the DLP showed a significant correlation to the attenuation of the blood (ρ = 0.53, p = 0.01) and a negative correlation to the body mass index of the patients (ρ = -0.37, p = 0.06).
γ-H2AX immunofluorescence microscopy allows one to determine dose-related effects on x-ray-induced DSB levels and to consider individual factors which cannot be monitored by physical dose measurements.
European Radiology 12/2010; 20(12):2917-24. · 3.22 Impact Factor
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ABSTRACT: Spiral CT angiography (CTA) of the coronaries using low-pitch scanning and ECG-gated image reconstruction is a robust method for detecting or excluding relevant coronary plaque. However, the resulting dose exposure is considerable. The aim of the present study was to evaluate image quality and artifacts as well as to record dose values for sequential coronary CTA using a 128-slice scanner with a temporal resolution of 150 ms.
20 patients with a regular heart rate and without contraindications for oral/I.V. beta blockers, who were referred for CTA of the coronaries for exclusion or detection of relevant plaques, were examined by sequential CTA with the following parameters: 120 kV, 200 ref mAs, collimation 2 x 64 x 0.6, table feed of 34.5 mm at a detector width of 38.4 mm. A total acquisition time of 380 ms per table position allowed for mild shifting of the reconstruction window within the cardiac cycle of +/- 5 %. 50 ml of contrast agent were injected at 5 ml/s followed by a 50 ml split bolus (20 % contrast). The individual start delay was determined by a test bolus scan (10 ml contrast + 50 ml saline flush at 5 ml/s). The image quality for each segment, coronary artery, and patient was determined on a 4-point scale. Dose values were estimated based on the individual dose length product as provided by the scanner's patient protocol. Artifacts were evaluated to determine the cause (calcium vs. motion).
All patients received beta blocker pretreatment. The mean heart rate was 62 +/- 5 beats/min. 5 % (13 / 286) of all segments in 5 / 20 patients were rated as non-diagnostic. The mean dose length product was 213 mGy x cm, and the mean effective dose was 3.6 mSv. Calcifications were the major cause of non-diagnostic images. However breathing or other motion artifacts occurred as well.
In select patients with effective heart rate control and thorough instruction for breath hold compliance, sequential CTA of the coronaries using a 128-slice scanner with a temporal resolution of 150 ms is technically feasible. The resulting effective dose values are clearly below those of spiral coronary CT scans.
RöFo - Fortschritte auf dem Gebiet der R 05/2009; 181(4):332-8. · 2.76 Impact Factor
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ABSTRACT: Due to the technical advance of multislice cardiac CT and the recently introduced dual source CT, the acquisition times for cardiac CT exams are < 10 sec. At the same time the assessment of left ventricular function is possible. However, in many patients a complete right ventricular outwash is noted, leading to insufficient septal delineation. Studies were able to demonstrate that contrast media (CM) mixed in the saline chaser bolus is sufficient for significantly better visualization of septal structures. The aim of this study was to investigate whether this dual flow concept works as well for 64-slice and dual source CT angiography using only 20 % CM in the saline chaser bolus.
97 patients were included in this prospective study. 47 patients underwent 64-slice CT coronary angiography. 80 cc were administered at 5 cc/sec as the main bolus followed by a 50 cc saline chaser bolus containing 20 % contrast media. The other 50 patients were examined using dual source CT. They received a CM protocol adapted for the scan time with the identical saline/CM chaser bolus. The datasets were quantitatively examined in defined ROIs along the septum and in the right ventricle with respect to the density. The septal delineation was qualitatively analyzed and both groups were compared. In a final step the density was measured in the proximal and distal RCA as well as in the LAD and also compared.
Using the protocol adapted for the scan time, significantly less CM was used. No significant difference was able to be found regarding the septal delineation or coronary enhancement.
The study shows that the dual flow concept allows for robust septal delineation regardless of the CM injection protocol used as long as a 20 % saline chaser bolus is used. A CM protocol adapted for the scan time also leads to significant CM reduction at equal image quality.
RöFo - Fortschritte auf dem Gebiet der R 04/2009; 181(4):324-31. · 2.76 Impact Factor
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ABSTRACT: As a result of rapid advances in CT technology, including dual source CT, cardiac CT exams at high heart rates are feasible, making pediatric cardiac CT in congenital heart disease possible. Dose concerns and patient size variability make general recommendations difficult. The aim of this study was to investigate which scanner settings are suitable for multiple weight groups to provide dose-optimized scanning.
All 12 patients underwent a contrast-enhanced gated dual source CT exam. A maximum of 2 ml/kg body weight or 60 ml contrast was applied. Scanner settings at 80 and 120 kV, as well as weight-adapted mAs settings were used in an iterative fashion. Datasets were assessed for image quality and dose-optimized scan parameters were established via class comparison. In a final step a table was created as a recommendation for cardiac CT in children corresponding to their body weight. Strategies for optimized contrast application with hand vs. manual injection were explored.
In all children diagnostic image quality was obtained. In children < 60 kg, 80 kV can be used, in all others 100 kV is sufficient. The eff. mAs varied from 362 mAs to 30 mAs depending on body weight. Retrospectively a significant dose reduction would have been possible in 6 / 12 patients. Cardiac CT can be performed between 0.6 and 3.2 mSv in a pediatric population.
The present study shows that dual source cardiac CT is a potential diagnostic alternative in children with congenital heart disease without excessive radiation exposure or contrast media application.
RöFo - Fortschritte auf dem Gebiet der R 04/2009; 181(4):339-48. · 2.76 Impact Factor
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RSNA, Chicago, USA; 11/2008
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ABSTRACT: Assessment of left ventricular function is possible in contrast-enhanced cardiac CT data sets. However, rapid ventricular motion especially in systole can lead to artifacts. Dual Source Computed Tomography (DSCT) has high temporal resolution which effectively limits motion artifact. We therefore assessed the accuracy of DSCT to detect regional left ventricular wall motion abnormalities in comparison to invasive cine angiocardiography.
We analyzed DSCT data sets of 50 patients (39 male, 11 female, mean age: 61+/-10 years) which were acquired after intravenous injection of 55-70 mL contrast agent (rotation time: 330 ms, collimation: 2 mm x 64 mm x 0.6 mm, 120 kV, 380 mAs, ECG-correlated tube current modulation). 10 data sets consisting of transaxial slices with a slice thickness of 1.5 mm, an increment of 1.0 mm and a matrix of 256 x 256 pixels were reconstructed at 10 time instants during the cardiac cycle (0-90% in 10% increments). The data sets were analyzed visually by two independent readers, using standard left ventricular planes, concerning regional wall motion abnormalities. DSCT was verified in a blinded fashion against cine ventriculography performed during cardiac catheterization (RAO and LAO projection), using a 7-segment model. Analysis was performed on a per-patient (presence of at least one hypo-, a- or dyskinetic segment) and on a per-segment basis.
Concerning the presence of a wall motion abnormality, the two observers agreed in 340/350 segments (97%) and 48/50 patients (96%). In invasive cine angiocardiography, 22 of 50 patients displayed at least one segment with abnormal contraction. To detect these patients, DSCT showed a sensitivity of 95% (21/22), specificity of 96% (27/28), positive predictive value of 95% and negative predictive value of 96%. Out of a total of 350 left ventricular segments, 66 segments had abnormal contraction in cine angiocardiography (34 hypokinetic, 26 akinetic, 6 dyskinetic). For detection of these segments, DSCT had a sensitivity of 88% (58/66), specificity of 98% (278/284), positive predictive value of 91% (58/64) and negative predictive value of 97% (278/286).
DSCT allows the detection of regional wall motion abnormalities with high interobserver agreement as well as high sensitivity and specificity. Whereas sensitivity and positive predictive value were higher in a per-patient- in comparison to a per-segment-based analysis, specificity, negative predictive value and interobserver agreement did not differ considerably between both analyzing methods.
European journal of radiology 08/2008; 72(1):85-91. · 2.65 Impact Factor
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ABSTRACT: In coronary CT angiography (CTA), both high-grade stenoses and total occlusions of a coronary artery may appear as a complete interruption of the contrast-enhanced lumen. Parameters to differentiate between occlusions and stenoses have not been systematically assessed. We evaluated 40 consecutive patients with a lesion demonstrating complete interruption of the contrast-enhanced lumen in coronary CTA and in whom invasive coronary angiography was available. Length of the vessel segment without luminal contrast enhancement; luminal enhancement proximal, in and distal to the lesion; degree of coronary remodelling; and the degree of lesion calcification were assessed by a blinded observer unaware of the invasive angiogram. Mean length of complete occlusions (n = 20; range 4-54 mm; mean 16.6 +/- 3.5 mm) was significantly longer than for high-grade stenoses (n = 20; 2-8 mm; mean 4.6 +/- 1.7 mm, p < 0.001). A lesion length > or = 9 mm was 100% specific and 70% sensitive for an occlusion. No significant differences were found for vessel enhancement in or distal to the lesion, remodelling index or degree of calcification. Lesion length is the only parameter that may differentiate complete occlusions and high-grade stenoses in coronary CTA. For lesions > or = 9 mm, an occlusion is very likely.
European Radiology 07/2008; 18(12):2770-5. · 3.22 Impact Factor
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ECR, Vienna, Austria; 03/2008
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ABSTRACT: Multidetector CT (MDCT) is a reliable tool to assess and quantify calcified plaque in coronary arteries. Only very limited information is available concerning the accuracy of MDCT for evaluating non-calcified plaque. We determined the interobserver variability for measuring non-calcified plaque volumes in the three main coronary arteries using 64-slice computed tomography.
We retrospectively evaluated data sets of 41 patients who received a 64-slice CT scan (Sensation 64, Siemens Forchheim, Germany, 330 msec rotation, 0.6 mm collimation, 60 ml contrast agent i. v. at 5 ml/sec) due to suspected stable coronary artery disease. The patients showed presence of non-calcified plaque in the proximal part of at least one main coronary artery. The image quality was defined on the basis of a 4-point rating scale. Two independent and blinded investigators measured the plaque volume of the non-calcified plaque by manually tracing plaque areas in contiguous cross-sectional reconstructions rendered along the vessel centerline using a slice thickness of 1 mm and an increment of 0.5 mm. The interobserver variability was evaluated and the influence of plaque volume and image quality on interobserver variability was determined.
The mean volume of non-calcified plaque was 157 +/- 85 mm (3), 76 +/- 43 mm (3) and 133 +/- 80 mm (3) for the LAD, LCX and RCA, respectively (LAD vs. LCX: p < 0.01; LAD vs. RCA: p = 0.33; LCX vs. RCA: p < 0.01). There was a mean absolute difference in plaque volume between the two observers of 23 +/- 15 mm (3), of 20 +/- 9 mm (3) and of 38 +/- 21 mm (3), which corresponds to a mean interobserver variability of 17 +/- 10 %, 29 +/- 13 % and 32 +/- 13 % for the LAD, LCX and RCA, respectively (LAD vs. LCX: p < 0.01; LAD vs. RCA: p < 0.01; LCX vs. RCA: p = 0.87). A significant inverse correlation between interobserver variability and the extent of the plaque volume (r = - 0.48; p = 0.01) was found. Interobserver variability was dependent on image quality: The highest image quality was observed in the LAD (2.4 +/- 0.5), while the image quality in the LCX (2.1 +/- 0.7) and the RCA (2.0 +/- 0.6) was lower.
Interobserver variability for the quantification of non-calcified plaque volumes in 64-slice MDCT is substantial. Interobserver variability in the LAD was significantly lower than in the LCX and the RCA. This might be due to a larger mean plaque volume and better image quality in the LAD than in other coronary arteries.
RöFo - Fortschritte auf dem Gebiet der R 09/2007; 179(9):953-7. · 2.76 Impact Factor
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DMW - Deutsche Medizinische Wochenschrift 05/2007; 132(14):768-9. · 0.53 Impact Factor
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DMW - Deutsche Medizinische Wochenschrift 05/2007; 132(14):769-70. · 0.53 Impact Factor
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DMW - Deutsche Medizinische Wochenschrift 05/2007; 132(14):750-6. · 0.53 Impact Factor
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ECR, Vienna, Austria; 02/2007
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MICCAI, Copenhagen, Denmark; 01/2006
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Heart (British Cardiac Society) 01/2005; 90(12):1477-8. · 4.22 Impact Factor
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ABSTRACT: New cardiovascular imaging modalities, including computed tomography (CT), magnetic resonance (MR) imaging and real-time three-dimensional echocardiography, have great potential for providing important and additional information concerning cardiac function and pathology. With significant and extremely fast technical improvements, non-invasive cardiac imaging has become a focal point in the diagnosis of cardiac disease. Thereby CT has been shown to allow the visualization of coronary arteries concerning calcifications, significant stenoses and coronary plaques, whereas MR imaging demonstrated its ability to evaluate cardiac morphology and function as well as perfusion imaging and viability assessment. As CT and MR, real-time three-dimensional echocardiography has increasingly progressed in the last years offering the potential for routine clinical application, e.g. in the evaluation of valve disease, the assessment of left ventricular thrombi or the guidance of intracardiac catheter placement. This article will provide a brief overview of each technique, possible clinical applications and their perspectives. Because both, CT and MR, have been successfully applied to visualize the coronary arteries, this article focuses on the abilities and limitations of CT and MR coronary artery imaging.
Minerva cardioangiologica 11/2004; 52(5):407-17.
