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Technical Developments |
1 From Siemens Medical Engineering, Division CTC 2, An der Lände 1, 91301 Forchheim, Germany (B.O., T.F., K.K.R.); the Departments of Clinical Radiology (C.B., U.J.S., M.F.R.) and Medicine I (A.K.), Klinikum Grosshadern, University of Munich, Germany; the Institute of Diagnostic Radiology, University of Tübingen, Germany (A.F.K.); and the Institute of Diagnostic Radiology, University of Erlangen-Nürnberg, Germany (U.B.). Received October 22, 1999; revision requested November 24; revision received February 7, 2000; accepted March 29. Address correspondence to B.O. (e-mail: Bernd.Ohnesorge@med.siemens.de).
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ABSTRACT |
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 TOP ABSTRACT INTRODUCTIONMATERIALS AND METHODS RESULTSDISCUSSIONAPPENDIX AAPPENDIX BREFERENCES |
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Index terms: Computed tomography (CT), technology, 51.12114, 51.12115, 51.12117, 51.12118, 54.12114, 54.12115, 54.12117, 54.12118 • Computed tomography (CT), thin-section, 51.12118, 54.12118 • Coronary vessels, calcification, 54.81 • Coronary vessels, CT, 54.12114, 54.12115, 54.12117, 54.12118 • Heart, CT, 51.12114, 51.12115, 51.12117, 51.12118
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INTRODUCTION |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODS RESULTSDISCUSSIONAPPENDIX AAPPENDIX BREFERENCES |
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Mechanical multisection CT systems with simultaneous acquisition of four sections, half-second scanner rotation, and 250-msec maximum temporal resolution recently have become available for general-purpose scanning. Multisection acquisition with these scanners allows for considerably faster coverage of the cardiac volume, compared with single-section scanning. This increased scanning speed allows use of thinner collimated sections and thus increases the z resolution of thin-section examinations such as CT angiography of the coronary arteries.
We investigated this application for acquiring ECG-synchronized multisection spiral scans with heart rate–dependent table feed (pitch) adaptation. For this, we used dedicated spiral algorithms that provide 250-msec temporal resolution and cardiac phase-selective image reconstruction (eg, in the diastolic phase with the least cardiac motion). By using such a data set, 3D reconstructions in incrementally shifted phases of the cardiac cycle allow for multiphase functional (cine) evaluations. The first clinical results for which we used this technology to perform thin-section CT angiography of the coronary arteries and to generate 3D and multiphase depictions of the heart are presented in this article.
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MATERIALS AND METHODS |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODS RESULTSDISCUSSIONAPPENDIX AAPPENDIX BREFERENCES |
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This reconstruction technique combines partial scan reconstruction and multisection spiral weighting to compensate for table movement and to provide a well-defined section sensitivity profile. During multisection spiral weighting, a single-section partial scan data segment is generated for each image of the continuous volume. The single-section partial scan data segment is then reconstructed by using an algorithm that provides a temporal resolution of half the rotation time within a centered field of view. A detailed description of the two steps of the multisection cardiac volume reconstruction algorithm—multisection spiral weighting and partial scan reconstruction—can be found in Appendix A.
ECG-Gated Volume Reconstruction with Heart Rate–dependent Pitch Limitation
For retrospectively ECG-gated reconstruction by means of the multisection cardiac volume reconstruction algorithm, each image is reconstructed by using a multisection partial scan data segment with an arbitrary temporal relation to the R wave of the ECG trace. Image reconstruction during different cardiac phases is feasible by shifting the start point of image reconstruction relative to the R wave. For a given start position, a stack of images at different z positions covering a small subvolume of the heart can be reconstructed owing to multisection data acquisition.
Figure 1 shows an example of how the cardiac volume is successively covered with stacks of transverse images (shaded stacks) reconstructed in consecutive cardiac cycles. All image stacks are reconstructed at identical time-points during the cardiac cycle. At the same time, the four detector sections travel along the z axis relative to the patient table. In each stack, single-section partial scan data segments are generated with equidistant spacing in the z direction, depending on the selected image reconstruction increment. Continuous volume coverage can be achieved only when the spiral pitch is adapted to the heart rate to avoid gaps between image stacks that are reconstructed by using data from different cardiac cycles. To achieve full volume coverage, the image stacks reconstructed in subsequent cardiac cycles must cover all z positions. Thus, the pitch, which can be used for image acquisition, is limited by the patient’s R-R interval, as described in Appendix B.
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Written informed consent was obtained from each patient after the nature of the procedure had been explained fully. Contrast material–enhanced CT angiography of the coronary arteries was performed in seven patients according to a protocol approved by the internal review boards of the participating clinical institutions. Nonenhanced scans were obtained for evaluation of coronary calcification in three patients with fast heart rates or arrhythmia. For these studies, institutional review board approval was not required, since these patients underwent CT for clinical indications as part of the clinical work-up for their coronary arterial disease.
Multisection CT Examination Protocols and ECG-Gating Techniques
Spiral CT scan data were obtained by using a multisection CT system (SOMATOM VolumeZoom; Siemens, Forchheim, Germany) with simultaneous acquisition of four sections. The patients’ ECG signals were recorded during the multisection spiral scanning to be able to match the spiral acquisition to specific phases of the cardiac cycle (eg, to the diastolic phase) (8–10).
With retrospective ECG gating, only data acquired within a predefined interval of the cardiac cycle are used for image reconstruction. These intervals are determined relative to the R waves of the ECG signal by means of an arbitrary phase parameter. The following phase-selection strategies can be used (Fig 2).
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Absolute-delay.—Fixed delay times after onset of the R wave define the start point of the reconstruction data interval.
Absolute-reverse.—Fixed times prior to the onset of the next R wave define the start point of the reconstruction data interval.
By means of defining different phase parameters for reconstruction of the same spiral scan data set, images can be reconstructed in incrementally shifted cardiac phases. In our study, we wanted to evaluate the suitability of the different ECG-gating techniques for generation of images in the diastolic and systolic phases of the cardiac cycle.
For this purpose, the multisection data acquisition was obtained by using a 500-msec full rotation time, which resulted in 250-msec temporal resolution, and 4 x 1-mm or 4 x 2.5-mm collimated sections: 4 x S mm indicates simultaneous acquisition of four sections with S mm collimated width of each section. To evaluate the suitability of our spiral scanning and reconstruction techniques for 3D scoring of coronary calcifications by using volume image data (11,12), nonenhanced spiral scans for coronary calcium scoring were obtained by using 3-mm sections (section width, 3 mm; collimated section width, 2.5 mm) and a 1-mm image reconstruction increment in three patients.
Seven patients with known cardiac disease were examined by using contrast-enhanced scanning protocols to investigate the potential of our technique for performing CT angiography of the coronary arteries and for functional cardiac imaging. Two scanning protocols—two patients with 3-mm sections and five patients with 1.25-mm sections—were tested to evaluate the potential improvement in 3D image quality that may be attained with 1.25-mm versus the 3-mm sections that are used routinely for coronary CT angiography by using electron-beam CT (5,13,14). For each patient, the appropriate spiral pitch was determined prior to the examination by using Equation (B2) in Appendix B, with an estimation of the minimum heart rate that was to be expected during the scan. Images were reconstructed at 1-mm image increments for 3-mm sections (section width, 3 mm; collimated section width, 2.5 mm) and at 0.5-mm image increments for 1.25-mm sections (section width, 1.25 mm; collimated section width, 1 mm).
For both protocols, iopromide (Ultravist 300; Schering, Berlin, Germany) was injected intravenously at a flow rate of 3 mL/sec. For optimal contrast, the optimal delay times between start of injection of contrast material and start of scanning were determined individually for each patient by injecting a 10-mL test bolus. After injection of the test bolus, sequential images were acquired every 1.5 seconds without table feed. Optimal delay times were determined by means of visually evaluating the contrast enhancement in the aortic root.
The reconstructed volume image data sets were depicted on a workstation (Insight, Neo Imagery Technologies, City of Industry, Calif; 3D-Virtuoso, Siemens) by using volume rendering and multiplanar reformation.
Two independent observers (C.B., A.K.) evaluated the image data. For nonenhanced scanning protocols, they assessed whether calcified lesions could be imaged clearly and free of motion artifacts in the diastolic cardiac phase. For coronary CT angiographic protocols, the observers evaluated the diagnostic value of the image data for diagnosis of coronary arterial disease or other cardiac diseases in the selected patient population. The potential for functional imaging was assessed qualitatively on the basis of reconstructions during systole and diastole that were depicted on comparable multiplanar reformation and volume-rendered images.
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RESULTS |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODS RESULTSDISCUSSIONAPPENDIX AAPPENDIX BREFERENCES |
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Figure 3 shows two representative images obtained in patient C, who had calcifications in the left main and circumflex coronary arteries. Owing to the short R-R interval in this patient, a spiral pitch of 2.5 was used (Appendix B, Eq [B2]), which limited the examination time to 10 seconds for a 12-cm z volume. For this patient, the best image quality was attained by using absolute-reverse ECG gating with a reconstruction interval of 350 msec prior to the next R wave. In spite of rapid cardiac motion, the calcified coronary arteries can be identified clearly.
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In all seven patients, the cardiac anatomy, including the major coronary arterial branches, was depicted free of motion artifacts with an appropriate selection of the ECG-gating phase parameters. With 1.25-mm sections, smaller side branches could also be assessed reliably.
End-diastolic volume reconstructions were generated by using relative-delay and absolute-reverse ECG-gating techniques in the patients with rhythmic heart rates. In the patients with moderate and severe arrhythmia, we found improved volume reconstruction results in the diastolic phase by using absolute-reverse ECG gating compared with the relative-delay approach. Systolic volume reconstructions were possible with all three ECG-gating approaches. However, patient-specific approaches were required to obtain end-systolic reconstructions for each patient.
The gain in z resolution with the use of 1.25-mm sections is demonstrated in Figure 4. Figure 4a shows a sagittal multiplanar reformation image of an end-diastolic reconstruction with 3-mm sections and a 1-mm image increment. Figure 4b shows a multiplanar reformation image obtained in a plane comparable to that of an end-diastolic reconstruction in a different patient with a comparable heart rate; the image was obtained with 1.25-mm sections and a 0.5-mm image increment. In both patients, relative-delay ECG gating by using 60% of the R-R interval after onset of the R wave provided end-diastolic images free of motion artifacts. Considerable improvement in z resolution is seen in Figure 4b compared with that in Figure 4a (eg, in the assessment of calcifications in the left anterior descending coronary artery and in the depiction of the mitral valve). Despite increased scanning time (15 seconds vs 33 seconds), the "thin-section" multiplanar reformation image in Figure 4b shows homogeneous image quality throughout the entire scan.
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The main objective of performing contrast-enhanced cardiac spiral examinations with 1.25-mm sections is the noninvasive depiction of the coronary arteries, either for detection of high-grade stenosis or for follow-up investigations after percutaneous transluminal coronary angioplasty or bypass surgery. Multiplanar reformation and volume rendering were applied to the 3D image data that were reconstructed in the end-diastolic phase with the least cardiac motion.
Figure 5 shows volume-rendered images that were generated from a 3D image data set with 1.25-mm sections and 0.5-mm increment phase. End-diastolic images free of motion artifacts were obtained by means of absolute-reverse ECG gating by using a reconstruction interval of 450 msec before onset of the R wave. Cut planes were introduced to provide a direct view of the origins of the coronary arteries and the vessel course. The main coronary arterial branches—the left main, left anterior descending, circumflex, and right coronary arteries—can be seen clearly, including four stents in the left anterior descending, circumflex, and right coronary arteries. Distal to the stent in the left anterior descending coronary artery, a high-grade stenosis that was confirmed by means of coronary angiography can be identified.
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DISCUSSION |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODS RESULTSDISCUSSIONAPPENDIX AAPPENDIX BREFERENCES |
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The high spatial resolution, absence of motion artifacts, and good overall image quality of our first clinical CT images of the entire cardiac volume show that multisection spiral CT is a promising modality for the noninvasive diagnosis of cardiac disease. The scanning time needed to acquire continuous ECG-gated multisection spiral CT image data is reduced substantially compared with that for electron-beam CT by a factor of approximately 2.5 and for single-section CT by a factor of approximately 5 (19,20).
Data obtained by using 3-mm sections can be used for volumetric coronary calcium scoring (11). This alternative scoring method has the potential to improve the reproducibility of repeat calcium scoring compared with that of the conventional Agatston score (1). Phantom studies (20) have shown that nonoverlapping sequential scanning is an important contributor to the interscan variability of Agatston and volumetric calcium scores because of partial volume errors in plaque registration. ECG-gated volume coverage with multisection spiral CT and overlapping image reconstruction, however, improved the reliability of coronary calcium quantification, especially for small plaques (20). If this observation can be confirmed by means of ongoing patient studies, ECG-gated multisection spiral CT potentially can be of great value for coronary calcium screening, especially for patients receiving lipid-lowering therapy (12) and for follow-up examinations in patients after heart transplantation (21).
In contrast to sequential CT scans, the z resolution of ECG-gated spiral images with 3-mm sections can be improved by using overlapping reconstruction with 1-mm section increments. Moreover, the fast scanning speed allows coverage of the entire heart with 1.25-mm sections within a single breath hold (10 cm in 25–35 seconds). Three-dimensional reconstruction with 1.25-mm sections and submillimeter image increments allows thin-section depiction of the coronary arteries, which may be suitable for a highly accurate diagnosis of coronary arterial disease.
ECG-synchronized conventional CT scanning is also well suited for examinations of mediastinal or pulmonary vessels (16) and thin-section lung studies (22) that are often affected by blurring artifacts due to cardiac pulsations. Thus, examinations of pulmonary embolism and of aortic dissection likely will benefit from improved temporal resolution volume imaging in predefined cardiac phases.
Continuous retrospectively ECG-gated multisection volume scanning allows multiphase functional (cine) cardiac CT imaging with 3D reconstruction of the cardiac volume in incrementally shifted phases of the cardiac cycle. Future studies will have to be performed to evaluate whether reconstructions during different cardiac phases can be used for the evaluation of functional cardiac parameters. Possible applications are the functional assessment of cardiac anatomy (eg, pulmonary or mitral valve function) or determination of ventricular function parameters on the basis of reformations of long- and short-axis images of the heart. Three-dimensional volumes obtained by using 250-msec temporal resolution during phases of fast cardiac motion (ie, systolic phase) may provide adequate image quality for the evaluation of larger cardiac structures.
For special requirements, reconstruction algorithms currently are being investigated that might provide a maximal temporal resolution of 100 msec with 500-msec rotation time by sampling data for reconstruction of an individual image from different cardiac cycles (23,24). However, these algorithms rely on an adequate desynchronization of heart rate and system rotation and require a rather stable heart rate throughout the scan. These methods currently are being investigated, and their ultimate value will have to be proved in a clinical environment.
We conclude that ECG-gated CT scanning with multisection spiral acquisition and 250-msec temporal resolution can provide thin-section volume image data in arbitrary cardiac phases. Images free of motion artifacts can be obtained in the diastolic cardiac phase, even in patients with faster heart rates. Ongoing and future clinical studies will have to be performed to evaluate the suitability of this method for noninvasive screening for and diagnosis of coronary arterial disease in comparison with other invasive and noninvasive imaging modalities in a large patient population.
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APPENDIX A |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODS RESULTSDISCUSSIONAPPENDIX AAPPENDIX BREFERENCES |
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During multisection spiral weighting, a single-section partial scan data segment is generated for each image by using a partial rotation of the multisection spiral scan that covers the pertinent z position. A partial rotation covers a projection angle interval—angle interval between tube positions at the starting and ending points of tube rotation—of 180° plus the breadth of the x-ray fan. This way, a partial rotation usually covers about 240° (25). For each projection angle 
within the multisection data segment, a linear interpolation is performed between the data of those two detector sections that are in closest proximity to the desired image plane. In contrast to standard multisection interpolation techniques (16–18), each projection is treated independently. The spiral interpolation scheme for a four-section system is illustrated in Figure A1. With increasing scanning time t and increasing projection angle , the four detector sections travel along the z axis relative to the patient table. The z position is normalized to the collimated width of one detector section (SWcoll).
Each multisection fan beam projection pM(n,ßm,q) consists of four subprojections corresponding to the four detector sections that are measured at the same focus (source) position; n is the projection angle of fan beam projection n, ßm is the angle of a ray m within the fan relative to the central ray, and q is the detector number (q = 0,1,2,3). For generating an image at a given z position zima, the single-section projections p(n,ßm) are calculated by means of linear interpolation of those subprojections within the multisection projection pM that are closest to the image z position zima for a given projection angle n (Eq [A1]). The interpolation weights w(n,q) are determined according to the distances d(n,q) to zima of the subprojections that are considered for reconstruction (Eq [A2]). The spiral interpolation for some representative projection angles is demonstrated in Figure A1.
Conventional partial scan reconstruction techniques (25) result in a temporal resolution equal to the acquisition time of the partial scan, which is approximately two-thirds of the rotation time, such as 340 msec for a 500-msec rotation. We use a modified technique with a temporal resolution close to half the rotation time in a centered scan field of view. This technique is based on parallel beam reconstruction. To this end, the fan beam geometry of the partial scan data set needs to be transformed to parallel beam geometry (26). By using parallel beam geometry, an image can be reconstructed from parallel projections that cover an angle range of 180° (26).
The rebinning of a partial scan fan beam data set provides 180° of complete parallel projections, including chunks of incomplete parallel projections that consist of redundant data. Optimal temporal resolution is attained by neglecting redundant data during reconstruction. Use of only 180° complete parallel projections for reconstruction results in a temporal resolution of half the rotation time (ie, 250 msec for a 500-msec rotation) for a sufficiently centered object.
For improvement of image quality, a motion artifact suppression algorithm is included in our reconstruction. This algorithm uses part of the redundant data for a smooth transition weighting at the limits of the reconstruction interval, thus suppressing streak-type motion artifacts without degradation of temporal resolution.
Special attention was paid to the section sensitivity profiles as a major parameter of spiral image quality, which is generated by our partial scan–based spiral weighting approach. Using this approach, we found a constant relation (Eq [A3]) independent of pitch of the collimated width (SWcoll) of one detector section to the full width at half maximum, or FWHM, of the section sensitivity profile, which represents the section width (SW) of the reconstructed image:
By using the multisection cardiac volume reconstruction algorithm, it is also possible to retrospectively generate thicker sections for a certain collimated section width SWcoll than given by Equation (A3), and this can be performed in a separate reconstruction by using the same scan data. During the multisection spiral weighting step, two planar single-section partial scan data segments are generated symmetrically for each image z position zima at closely adjacent z positions: zima - 
z and zima + z (z is a small distance in the z direction). Averaging these data before performing the partial scan reconstruction step results in the reconstruction of a thicker section at the desired position zima. This technique is suited for reconstruction of images with reduced image noise for improved low-contrast resolution at the cost of reduced z resolution.
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APPENDIX B |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODS RESULTSDISCUSSIONAPPENDIX AAPPENDIX BREFERENCES |
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According to Equation (B1), the table feed is restricted to N - 1 single sections of an N-section detector within the time interval TRR + TQ, where TRR is R-R the interval and TQ is partial scanning time. Trot represents the full rotation time:
By using these principles, proper spiral weighting with two interpolation partners can be performed for all projections within the partial scan data set. Examination times can be sped up by allowing that half of the projections at the edges of the image stacks are reconstructed without interpolation by using the projection of only the nearest detector section. By using this approach, the heart rate–dependent spiral pitch is then restricted according to Equation (B2). In the example given in Figure 1, with a heart rate of 70 beats per minute (TRR = 860 msec), the pitch can then be increased from a pitch of 1.25 according to Equation (B1) to a pitch of 1.75 according to Equation (B2):
60–120 beats per minute), Equation (B2) thus restricts pitch values to a range of 1.5–3.0. In Figure 1, the slope of the four detector position lines represents the pitch that is properly limited to allow for continuous volume coverage. In the example shown, an ECG-gating approach in which a relative delay with a delay parameter of 40% was chosen, which in this case results in image reconstruction during the diastolic phase (shaded stacks). The hatched bars represent image stacks that are reconstructed from the same spiral data set, but in a different cardiac phase with a delay parameter of 90%, which in turn results in image reconstruction during the systolic phase. As seen in Figure 1, the entire cardiac volume can be reconstructed in both cardiac phases without gaps. A multiphase reconstruction for true functional volume imaging of the moving heart thus can be generated from various 3D images with incrementally shifted delay parameters within the range of 0%–100%.
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FOOTNOTES |
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Author contributions: Guarantors of integrity of entire study, B.O., A.F.K., K.K.R., M.F.R.; study concepts, B.O., A.F.K.; study design, B.O., T.F.; definition of intellectual content, B.O., T.F., A.F.K.; literature research, B.O., A.F.K.; clinical studies, C.B., A.K., U.B.; experimental studies, B.O., T.F.; data acquisition, C.B., U.J.S., A.K., U.B.; data analysis, A.K., C.B., B.O., T.F.; manuscript preparation, B.O., A.F.K., T.F., U.J.S.; manuscript editing, B.O., A.F.K., U.J.S.; manuscript review, A.F.K., M.F.R., U.J.S., K.K.R.
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REFERENCES |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODS RESULTSDISCUSSIONAPPENDIX AAPPENDIX BREFERENCES |
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C. Herzog, M. Arning-Erb, S. Zangos, K. Eichler, R. Hammerstingl, S. Dogan, H. Ackermann, and T. J. Vogl Multi-Detector Row CT Coronary Angiography: Influence of Reconstruction Technique and Heart Rate on Image Quality Radiology, January 1, 2006; 238(1): 75 - 86. [Abstract] [Full Text] [PDF]
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 G. Kohl The Evolution and State-of-the-Art Principles of Multislice Computed Tomography Proceedings of the ATS, December 1, 2005; 2(6): 470 - 476. [Abstract] [Full Text] [PDF]
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 N E Manghat, G J Morgan-Hughes, A J Marshall, and C A Roobottom Multidetector row computed tomography: imaging congenital coronary artery anomalies in adults Heart, December 1, 2005; 91(12): 1515 - 1522. [Abstract] [Full Text] [PDF]
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T Beck, C Burgstahler, A Kuettner, A F Kopp, M Heuschmid, C D Claussen, and S Schroeder Clinical use of multislice spiral computed tomography in 210 highly preselected patients: experience with 4 and 16 slice technology Heart, November 1, 2005; 91(11): 1423 - 1427. [Abstract] [Full Text] [PDF]
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S. Achenbach, D. Ropers, F.-K. Pohle, D. Raaz, J. von Erffa, A. Yilmaz, G. Muschiol, and W. G. Daniel Detection of coronary artery stenoses using multi-detector CT with 16x0.75 collimation and 375 ms rotation Eur. Heart J., October 1, 2005; 26(19): 1978 - 1986. [Abstract] [Full Text] [PDF]
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J. Kefer, E. Coche, G. Legros, A. Pasquet, C. Grandin, B. E. Van Beers, J.-L. Vanoverschelde, and B. L. Gerber Head-to-Head Comparison of Three-Dimensional Navigator-Gated Magnetic Resonance Imaging and 16-Slice Computed Tomography to Detect Coronary Artery Stenosis in Patients J. Am. Coll. Cardiol., July 5, 2005; 46(1): 92 - 100. [Abstract] [Full Text] [PDF]
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 M. Hayakawa, K. Katada, H. Anno, S. Imizu, J. Hayashi, K. Irie, M. Negoro, Y. Kato, T. Kanno, and H. Sano CT Angiography with Electrocardiographically Gated Reconstruction for Visualizing Pulsation of Intracranial Aneurysms: Identification of Aneurysmal Protuberance Presumably Associated with Wall Thinning AJNR Am. J. Neuroradiol., June 1, 2005; 26(6): 1366 - 1369. [Abstract] [Full Text] [PDF]
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T. G. Flohr, S. Schaller, K. Stierstorfer, H. Bruder, B. M. Ohnesorge, and U. J. Schoepf Multi-Detector Row CT Systems and Image-Reconstruction Techniques Radiology, June 1, 2005; 235(3): 756 - 773. [Abstract] [Full Text] [PDF]
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M. Heuschmid, A. Kuettner, S. Schroeder, T. Trabold, A. Feyer, M. D. Seemann, R. Kuzo, C. D. Claussen, and A. F. Kopp ECG-Gated 16-MDCT of the Coronary Arteries: Assessment of Image Quality and Accuracy in Detecting Stenoses Am. J. Roentgenol., May 1, 2005; 184(5): 1413 - 1419. [Abstract] [Full Text] [PDF]
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T. Nakanishi, Y. Kayashima, R. Inoue, K. Sumii, and Y. Gomyo Pitfalls in 16-Detector Row CT of the Coronary Arteries RadioGraphics, March 1, 2005; 25(2): 425 - 438. [Abstract] [Full Text] [PDF]
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B. L. Gerber, E. Coche, A. Pasquet, E. Ketelslegers, D. Vancraeynest, C. Grandin, B. E. Van Beers, and J.-L. J. Vanoverschelde Coronary Artery Stenosis: Direct Comparison of Four-Section Multi-Detector Row CT and 3D Navigator MR Imaging for Detection--Initial Results Radiology, January 1, 2005; 234(1): 98 - 108. [Abstract] [Full Text] [PDF]
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 A F Kopp, A Kuttner, T Trabold, M Heuschmid, S Schroder, and C D Claussen Multislice CT in cardiac and coronary angiography Br. J. Radiol., December 1, 2004; 77(suppl_1): S87 - S97. [Abstract] [Full Text] [PDF]
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L. K. Hofmann, K. H. Zou, P. Costello, and U. J. Schoepf Electrocardiographically Gated 16-Section CT of the Thorax: Cardiac Motion Suppression Radiology, December 1, 2004; 233(3): 927 - 933. [Abstract] [Full Text] [PDF]
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U. Hoffmann, F. Moselewski, R. C. Cury, M. Ferencik, I.-k. Jang, L. J. Diaz, S. Abbara, T. J. Brady, and S. Achenbach Predictive Value of 16-Slice Multidetector Spiral Computed Tomography to Detect Significant Obstructive Coronary Artery Disease in Patients at High Risk for Coronary Artery Disease: Patient- Versus Segment-Based Analysis Circulation, October 26, 2004; 110(17): 2638 - 2643. [Abstract] [Full Text] [PDF]
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A. Kuettner, T. Trabold, S. Schroeder, A. Feyer, T. Beck, A. Brueckner, M. Heuschmid, C. Burgstahler, A. F. Kopp, and C. D. Claussen Noninvasive detection of coronary lesions using 16-detector multislice spiral computed tomography technology: Initial clinical results J. Am. Coll. Cardiol., September 15, 2004; 44(6): 1230 - 1237. [Abstract] [Full Text] [PDF]
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P. Schoenhagen, S. S. Halliburton, A. E. Stillman, S. A. Kuzmiak, S. E. Nissen, E. M. Tuzcu, and R. D. White Noninvasive Imaging of Coronary Arteries: Current and Future Role of Multi-Detector Row CT Radiology, July 1, 2004; 232(1): 7 - 17. [Abstract] [Full Text] [PDF]
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K. Awai, D. Utsunomiya, M. Imuta, S. Shiraishi, Y. Yamashita, Y. Nishimura, N. Sato, and M. Kudo Retrospective Respiration-Gated MDCT: Initial Results in Canine Models Am. J. Roentgenol., July 1, 2004; 183(1): 79 - 81. [Full Text] [PDF]
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T. Schertler, S. Wildermuth, J. K. Willmann, H. Alkadhi, B. Marincek, and T. Boehm Effects of ECG Gating and Postprocessing Techniques on 3D MDCT of the Bronchial Tree Am. J. Roentgenol., July 1, 2004; 183(1): 83 - 89. [Abstract] [Full Text] [PDF]
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U. J. Schoepf, C. R. Becker, B. M. Ohnesorge, and E. K. Yucel CT of Coronary Artery Disease Radiology, July 1, 2004; 232(1): 18 - 37. [Abstract] [Full Text] [PDF]
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B. Desjardins and E. A. Kazerooni ECG-Gated Cardiac CT Am. J. Roentgenol., April 1, 2004; 182(4): 993 - 1010. [Full Text] [PDF]
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A. Kuettner, A. F. Kopp, S. Schroeder, T. Rieger, J. Brunn, C. Meisner, M. Heuschmid, T. Trabold, C. Burgstahler, J. Martensen, et al. Diagnostic accuracy of multidetector computed tomography coronary angiography in patients with angiographically proven coronary artery disease J. Am. Coll. Cardiol., March 3, 2004; 43(5): 831 - 839. [Abstract] [Full Text] [PDF]
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K. U. Juergens, M. Grude, D. Maintz, E. M. Fallenberg, T. Wichter, W. Heindel, and R. Fischbach Multi-Detector Row CT of Left Ventricular Function with Dedicated Analysis Software versus MR Imaging: Initial Experience Radiology, February 1, 2004; 230(2): 403 - 410. [Abstract] [Full Text] [PDF]
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K. Nieman, P. M. T. Pattynama, B. J. Rensing, R.-J. M. van Geuns, and P. J. de Feyter Evaluation of Patients after Coronary Artery Bypass Surgery: CT Angiographic Assessment of Grafts and Coronary Arteries Radiology, December 1, 2003; 229(3): 749 - 756. [Abstract] [Full Text] [PDF]
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C. Herzog, S. Dogan, T. Diebold, M. F. Khan, H. Ackermann, S. Schaller, T. G. Flohr, G. Wimmer-Greinecker, A. Moritz, and T. J. Vogl Multi-Detector Row CT versus Coronary Angiography: Preoperative Evaluation before Totally Endoscopic Coronary Artery Bypass Grafting Radiology, October 1, 2003; 229(1): 200 - 208. [Abstract] [Full Text] [PDF]
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H. K. Pannu, T. G. Flohr, F. M. Corl, and E. K. Fishman Current Concepts in Multi-Detector Row CT Evaluation of the Coronary Arteries: Principles, Techniques, and Anatomy RadioGraphics, October 1, 2003; 23(90001): S111 - 125. [Abstract] [Full Text] [PDF]
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J. A. Rumberger and L. Kaufman A Rosetta Stone for Coronary Calcium Risk Stratification: Agatston, Volume, and Mass Scores in 11,490 Individuals Am. J. Roentgenol., September 1, 2003; 181(3): 743 - 748. [Abstract] [Full Text] [PDF]
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N. Takahashi and K. T. Bae Quantification of Coronary Artery Calcium with Multi-Detector row CT: Assessing Interscan Variability with Different Tube Currents—Pilot Study Radiology, July 1, 2003; 228(1): 101 - 106. [Abstract] [Full Text] [PDF]
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 I. Shiraishi, Y. Yamamoto, S. Ozawa, A. Kawakita, K. Toiyama, T. Tanaka, K. Sakata, T. Hayano, T. Itoi, M. Yamagishi, et al. Application of helical computed tomographic angiography with differential color imaging three-dimensional reconstruction in the diagnosis of complicated congenital heart diseases J. Thorac. Cardiovasc. Surg., January 1, 2003; 125(1): 36 - 39. [Full Text] [PDF]
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K. Saito, M. Saito, S. Komatu, and K. Ohtomo Real-Time Four-dimensional Imaging of the Heart with Multi-Detector Row CT RadioGraphics, January 1, 2003; 23(1): e8 - e8. [Abstract] [Full Text]
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K Nieman, B J Rensing, R-J M van Geuns, J Vos, P M T Pattynama, G P Krestin, P W Serruys, and P J de Feyter Non-invasive coronary angiography with multislice spiral computed tomography: impact of heart rate Heart, December 1, 2002; 88(5): 470 - 474. [Abstract] [Full Text] [PDF]
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K. U. Juergens, M. Grude, E. M. Fallenberg, C. Opitz, T. Wichter, W. Heindel, and R. Fischbach Using ECG-Gated Multidetector CT to Evaluate Global Left Ventricular Myocardial Function in Patients with Coronary Artery Disease Am. J. Roentgenol., December 1, 2002; 179(6): 1545 - 1550. [Abstract] [Full Text] [PDF]
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A.F. Kopp, S. Schroeder, A. Kuettner, A. Baumbach, C. Georg, R. Kuzo, M. Heuschmid, B. Ohnesorge, K.R. Karsch, and C.D. Claussen Non-invasive coronary angiography with high resolution multidetector-row computed tomography. Results in 102 patients Eur. Heart J., November 1, 2002; 23(21): 1714 - 1725. [Abstract] [Full Text] [PDF]
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T. Giesler, U. Baum, D. Ropers, S. Ulzheimer, E. Wenkel, M. Mennicke, W. Bautz, W. A. Kalender, W. G. Daniel, and S. Achenbach Noninvasive Visualization of Coronary Arteries Using Contrast-Enhanced Multidetector CT: Influence of Heart Rate on Image Quality and Stenosis Detection Am. J. Roentgenol., October 1, 2002; 179(4): 911 - 916. [Abstract] [Full Text] [PDF]
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A. F. Kopp, B. Ohnesorge, C. Becker, S. Schroder, M. Heuschmid, A. Kuttner, R. Kuzo, and C. D. Claussen Reproducibility and Accuracy of Coronary Calcium Measurements with Multi-Detector Row versus Electron-Beam CT Radiology, October 1, 2002; 225(1): 113 - 119. [Abstract] [Full Text] [PDF]
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J. K. Willmann, D. Weishaupt, M. Lachat, R. Kobza, J. E. Roos, B. Seifert, T. F. Luscher, B. Marincek, and P. R. Hilfiker Electrocardiographically Gated Multi-Detector Row CT for Assessment of Valvular Morphology and Calcification in Aortic Stenosis Radiology, October 1, 2002; 225(1): 120 - 128. [Abstract] [Full Text] [PDF]
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 C. J Garvey and R. Hanlon Computed tomography in clinical practice BMJ, May 4, 2002; 324(7345): 1077 - 1080. [Full Text] [PDF]
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C. Hong, C. R. Becker, U. J. Schoepf, B. Ohnesorge, R. Bruening, and M. F. Reiser Coronary Artery Calcium: Absolute Quantification in Nonenhanced and Contrast-enhanced Multi-Detector Row CT Studies Radiology, May 1, 2002; (2002) 2232010919. [Abstract] [Full Text]
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S Schroeder, A F Kopp, B Ohnesorge, H Loke-Gie, A Kuettner, A Baumbach, C Herdeg, C D Claussen, and K R Karsch Virtual coronary angioscopy using multislice computed tomography Heart, March 1, 2002; 87(3): 205 - 209. [Abstract] [Full Text] [PDF]
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 N.L. Muller Computed tomography and magnetic resonance imaging: past, present and future Eur. Respir. J., February 1, 2002; 19(35_suppl): 3S - 12s. [Abstract] [Full Text] [PDF]
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P. Raggi, T. Q. Callister, and B. Cooil Calcium Scoring of the Coronary Artery by Electron Beam CT: How to Apply an Individual Attenuation Threshold Am. J. Roentgenol., February 1, 2002; 178(2): 497 - 502. [Abstract] [Full Text] [PDF]
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 T. C. Gerber, R. S. Kuzo, N. Karstaedt, G. E. Lane, R. L. Morin, P. F Sheedy II, R. E. Safford, J. L. Blackshear, and J. H. Pietan Current Results and New Developments of Coronary Angiography With Use of Contrast-Enhanced Computed Tomography of the Heart Mayo Clin. Proc., January 1, 2002; 77(1): 55 - 71. [Abstract] [PDF]
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U J Schoepf, C R Becker, R D Bruening, B M Ohnesorge, A Huber, L-G Haw, H Hildebrandt, and M F Reiser Multislice CT angiography Imaging, December 15, 2001; 13(5): 357 - 365. [Abstract] [Full Text] [PDF]
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D. S. Katz and M. Hon CT Angiography of the Lower Extremities and Aortoiliac System with a Multi-Detector Row Helical CT Scanner: Promise of New Opportunities Fulfilled Radiology, October 1, 2001; 221(1): 7 - 10. [Full Text] [PDF]
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C. Hong, C. R. Becker, A. Huber, U. J. Schoepf, B. Ohnesorge, A. Knez, R. Bruning, and M. F. Reiser ECG-gated Reconstructed Multi-Detector Row CT Coronary Angiography: Effect of Varying Trigger Delay on Image Quality Radiology, September 1, 2001; 220(3): 712 - 717. [Abstract] [Full Text] [PDF]
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 Z. A. Fayad and V. Fuster Clinical Imaging of the High-Risk or Vulnerable Atherosclerotic Plaque Circ. Res., August 17, 2001; 89(4): 305 - 316. [Abstract] [Full Text] [PDF]
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S. Achenbach, T. Giesler, D. Ropers, S. Ulzheimer, H. Derlien, C. Schulte, E. Wenkel, W. Moshage, W. Bautz, W. G. Daniel, et al. Detection of Coronary Artery Stenoses by Contrast-Enhanced, Retrospectively Electrocardiographically-Gated, Multislice Spiral Computed Tomography Circulation, May 29, 2001; 103(21): 2535 - 2538. [Abstract] [Full Text] [PDF]
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S. Schroeder, A. F. Kopp, A. Baumbach, C. Meisner, A. Kuettner, C. Georg, B. Ohnesorge, C. Herdeg, C. D. Claussen, and K. R. Karsch Noninvasive detection and evaluation of atherosclerotic coronary plaques with multislice computed tomography J. Am. Coll. Cardiol., April 1, 2001; 37(5): 1430 - 1435. [Abstract] [Full Text] [PDF]
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A. F. Kopp, S. Schroeder, A. Kuettner, M. Heuschmid, C. Georg, B. Ohnesorge, R. Kuzo, and C. D. Claussen Coronary Arteries: Retrospectively ECG-gated Multi-Detector Row CT Angiography with Selective Optimization of the Image Reconstruction Window Radiology, December 1, 2001; 221(3): 683 - 688. [Abstract] [Full Text] [PDF]
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C. Hong, C. R. Becker, U. J. Schoepf, B. Ohnesorge, R. Bruening, and M. F. Reiser Coronary Artery Calcium: Absolute Quantification in Nonenhanced and Contrast-enhanced Multi-Detector Row CT Studies Radiology, May 1, 2002; 223(2): 474 - 480. [Abstract] [Full Text] [PDF]
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340 msec; heart rate, 70 beats per minute (bpm); increment, one-third of the section width; relative-delay ECG gating; first percentage of R-R interval, 40%; second percentage of R-R interval, 90%; pitch, 1.25. TD = delay time relative to the onset of the previous R wave that determines the start point of the reconstruction data interval, z/SWcoll = z position of each collimated section.
, and the generated projections are marked with 
. Continuous table movement is compensated for by means of linear interpolation within multisection fan beam projections to generate single-section partial scan data for image z positions (zima).