1
|
Kumar P, Bhatia M. Coronary Artery Calcium Data and Reporting System (CAC-DRS): A Primer. J Cardiovasc Imaging 2023; 31:1-17. [PMID: 36693339 PMCID: PMC9880346 DOI: 10.4250/jcvi.2022.0029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 04/23/2022] [Accepted: 06/06/2022] [Indexed: 01/26/2023] Open
Abstract
The Coronary Artery Calcium Data and Reporting System (CAC-DRS) is a standardized reporting method for calcium scoring on computed tomography. CAC-DRS is applied on a per-patient basis and represents the total calcium score with the number of vessels involved. There are 4 risk categories ranging from CAC-DRS 0 to CAC-DRS 3. CAC-DRS also provides risk prediction and treatment recommendations for each category. The main strengths of CAC-DRS include a detailed and meaningful representation of CAC, improved communication between physicians, risk stratification, appropriate treatment recommendations, and uniform data collection, which provides a framework for education and research. The major limitations of CAC-DRS include a few missing components, an overly simple visual approach without any standard reference, and treatment recommendations lacking a basis in clinical trials. This consistent yet straightforward method has the potential to systemize CAC scoring in both gated and non-gated scans.
Collapse
Affiliation(s)
- Parveen Kumar
- Department of Radiodiagnosis & Imaging, Fortis Escort Heart Institute, New Delhi, India
| | - Mona Bhatia
- Department of Radiodiagnosis & Imaging, Fortis Escort Heart Institute, New Delhi, India
| |
Collapse
|
2
|
van der Star S, de Jong DJ, Bleys RLAW, Kuijf HJ, Schilham A, de Jong PA, Kok M. Quantification of Calcium in Peripheral Arteries of the Lower Extremities: Comparison of Different CT Scanners and Scoring Platforms. Invest Radiol 2022; 57:141-147. [PMID: 34411031 DOI: 10.1097/rli.0000000000000821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES The aim of this study was to investigate the interscanner and interscoring platform variability of calcium quantification in peripheral arteries of the lower extremities. MATERIALS AND METHODS Twenty human fresh-frozen legs were scanned using 3 different computed tomography (CT) scanners. The radiation dose (CTDIvol) was kept similar for all scanners. The calcium scores (Agatston and volume scores) were quantified using 4 semiautomatic scoring platforms. Comparative analysis of the calcium scores between scanners and scoring platforms was performed by using the Friedman test; post hoc analysis was performed by using the Wilcoxon signed rank test with Bonferroni correction. RESULTS Sixteen legs had calcifications and were used for data analysis. Agatston and volume scores ranged from 12.1 to 6580 Agatston units and 18.2 to 5579 mm3. Calcium scores differed significantly between Philips IQon and Philips Brilliance 64 (Agatston: 19.5% [P = 0.001]; volume: 14.5% [P = 0.001]) and Siemens Somatom Force (Agatston: 18.1% [P = 0.001]; volume: 17.5% [P = 0.001]). The difference between Brilliance 64 and Somatom Force was smaller (Agatston: 5.6% [P = 0.778]; volume: 7.7% [P = 0.003]). With respect to the interscoring platform variability, OsiriX produced significantly different Agatston scores compared with the other 3 scoring platforms (OsiriX vs IntelliSpace: 14.8% [P = 0.001] vs Syngo CaScore: 13.9% [P = 0.001] vs iX viewer: 13.2% [P < 0.001]). For the volume score, the differences between all scoring platforms were small ranging from 2.9% to 4.0%. Post hoc analysis showed a significant difference between OsiriX and IntelliSpace (3.8% [P = 0.001]). CONCLUSIONS The use of different CT scanners resulted in notably different Agatston and volume scores, whereas the use of different scoring platforms resulted in limited variability especially for the volume score. In conclusion, the variability in calcium quantification was most evident between different CT scanners and for the Agatston score.
Collapse
Affiliation(s)
| | | | | | - Hugo J Kuijf
- Image Sciences Institute, University Medical Center Utrecht, Utrecht, the Netherlands
| | | | | | | |
Collapse
|
3
|
Coronary artery calcium: A technical argument for a new scoring method. J Cardiovasc Comput Tomogr 2019; 13:347-352. [DOI: 10.1016/j.jcct.2018.10.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 10/15/2018] [Accepted: 10/18/2018] [Indexed: 01/24/2023]
|
4
|
Tang YC, Liu YC, Hsu MY, Tsai HY, Chen CM. Adaptive Iterative Dose Reduction 3D Integrated with Automatic Tube Current Modulation for CT Coronary Artery Calcium Quantification: Comparison to Traditional Filtered Back Projection in an Anthropomorphic Phantom and Patients. Acad Radiol 2018; 25:1010-1017. [PMID: 29395796 DOI: 10.1016/j.acra.2017.12.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 12/20/2017] [Accepted: 12/23/2017] [Indexed: 01/05/2023]
Abstract
RATIONALE AND OBJECTIVES We aimed to evaluate integrated adaptive iterative dose reduction 3D (AIDR 3D) algorithm in automatic tube current modulation (ATCM) for the quantification of coronary artery calcium score (CACS) and cardiac risk stratification. MATERIALS AND METHODS A thoracic phantom with calcium inserts of known densities was scanned with filtered back projection (FBP) and AIDR 3D algorithms in small- and medium-sized phantoms. Twenty-four patients underwent two consecutive scans of CACS with FBP and AIDR 3D algorithms. The absolute Agatston score, Agatston score risk, volume score, and Agatston score percentile-based risk were compared, and concordance coefficients and agreement plots were made. RESULTS Agatston and volume scores were significantly different between the phantom sizes (P < .01). There were no significant differences in the Agatston scores between FBP and AIDR 3D for the medium phantoms (P = .25). In the patients, there were no significant differences in Agatston and volume scores between FBP and AIDR 3D (P = .06 and P = .09, respectively). The correlation coefficients of Agatston and volume scores with AIDR 3D were excellent compared to those of FBP. There were no significant differences in Agatston score risk and Agatston score percentile-based risk between FBP and AIDR 3D (P = .74 and P = 1, respectively). There was mean dose reduction of 57.8% ± 18.6% for AIDR 3D. CONCLUSION The absolute Agatston score differed between FBP and AIDR 3D reconstructions. However, the cardiac risk categorizations of the two methods were comparable. An integrated AIDR 3D algorithm with automatic tube current modulation enables radiation dose savings at a consistent noise level without sacrificing CACS.
Collapse
|
5
|
Vonder M, van der Aalst CM, Vliegenthart R, van Ooijen PMA, Kuijpers D, Gratama JW, de Koning HJ, Oudkerk M. Coronary Artery Calcium Imaging in the ROBINSCA Trial: Rationale, Design, and Technical Background. Acad Radiol 2018; 25:118-128. [PMID: 28843465 DOI: 10.1016/j.acra.2017.07.010] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 07/18/2017] [Accepted: 07/20/2017] [Indexed: 01/20/2023]
Abstract
RATIONALE AND OBJECTIVES To describe the rationale, design, and technical background of coronary artery calcium (CAC) imaging in the large-scale population-based cardiovascular disease screening trial (Risk Or Benefit IN Screening for CArdiovascular Diseases [ROBINSCA]). MATERIALS AND METHODS First, literature search was performed to review the logistics, setup, and settings of previously performed CAC imaging studies, and current clinical CAC imaging protocols of participating centers in the ROBINSCA trial were evaluated. A second literature search was performed to evaluate the impact of computed tomography parameter settings on CAC score. RESULTS Based on literature reviews and experts opinion an imaging protocol accompanied by data management protocol was created for ROBINSCA. The imaging protocol should consist of a fixed tube voltage, individually tailored tube current setting, mid-diastolic electrocardiography-triggering, fixed field-of-view, fixed reconstruction kernel, fixed slice thickness, overlapping reconstruction and without iterative reconstruction. The analysis of scans is performed with one type and version of CAC scoring software, by two dedicated and experienced researchers. The data management protocol describes the organization of data handling between the coordinating center, participating centers, and core analysis center. CONCLUSION In this paper we describe the rationale and technical considerations to be taken in developing CAC imaging protocol, and we present a detailed protocol that can be implemented for CAC screening purposes.
Collapse
Affiliation(s)
- Marleen Vonder
- University of Groningen, University Medical Center Groningen, Center for Medical Imaging North-East Netherlands (CMI-NEN), Groningen, The Netherlands
| | - Carlijn M van der Aalst
- Erasmus MC-University Medical Centre, Department of Public Health, Rotterdam, The Netherlands
| | - Rozemarijn Vliegenthart
- University of Groningen, University Medical Center Groningen, Center for Medical Imaging North-East Netherlands (CMI-NEN), Groningen, The Netherlands
| | - Peter M A van Ooijen
- University of Groningen, University Medical Center Groningen, Center for Medical Imaging North-East Netherlands (CMI-NEN), Groningen, The Netherlands; University of Groningen, University Medical Center Groningen, Department of Radiology, Groningen, The Netherlands
| | - Dirkjan Kuijpers
- University of Groningen, University Medical Center Groningen, Center for Medical Imaging North-East Netherlands (CMI-NEN), Groningen, The Netherlands; Department of Radiology, Haaglanden Medical Center Bronovo, The Hague, The Netherlands
| | - Jan Willem Gratama
- University of Groningen, University Medical Center Groningen, Center for Medical Imaging North-East Netherlands (CMI-NEN), Groningen, The Netherlands; Department of Radiology, Gelre Hospital, Apeldoorn, The Netherlands
| | - Harry J de Koning
- Erasmus MC-University Medical Centre, Department of Public Health, Rotterdam, The Netherlands
| | - Matthijs Oudkerk
- University of Groningen, University Medical Center Groningen, Center for Medical Imaging North-East Netherlands (CMI-NEN), Groningen, The Netherlands.
| |
Collapse
|
6
|
Liew G, Chow C, van Pelt N, Younger J, Jelinek M, Chan J, Hamilton-Craig C. Cardiac Society of Australia and New Zealand Position Statement: Coronary Artery Calcium Scoring. Heart Lung Circ 2017; 26:1239-1251. [DOI: 10.1016/j.hlc.2017.05.130] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 05/06/2017] [Indexed: 01/07/2023]
|
7
|
Abstract
The ability to follow changes in atherosclerotic plaque burden over time should provide an accurate measure of efficacy for different cardiovascular therapies. Coronary calcifications are associated with atherosclerotic coronary artery plaque, and the amount of coronary calcifications has been shown to correlate with the overall coronary plaque burden. The presence and extent of coronary calcifications can be assessed noninvasively by monitoring the progression of coronary calcification with electron beam tomography. With annual progression rates of 22% to 52% and a median interscan variability of only 5% to 8%, this technology provides an opportunity to monitor patients to assess the clinical efficacy of medical therapies in studies as short as 1 year. Several studies have demonstrated that the successful pharmacologic reduction of low-density lipoprotein cholesterol significantly mitigated the progression of the calcium score. Studies using serial computed tomographic scans indicate that the annual progression of coronary calcium varies between 30% and 50% in symptomatic or high-risk individuals and from 0% to 20% in patients treated effectively with lipid-lowering medication. An increased rate of progression of coronary calcium seems to indicate a substantially increased risk for adverse cardiac events, suggesting that this modality can be used to monitor the efficacy of therapy.
Collapse
Affiliation(s)
- Matthew J Budoff
- Division of Cardiology, Harbor-UCLA Medical Center Research and Education Institute, Torrance, CA 90502, USA.
| |
Collapse
|
8
|
Schindler A, Vliegenthart R, Schoepf UJ, Blanke P, Ebersberger U, Cho YJ, Allmendinger T, Vogt S, Raupach R, Fink C, Saam T, Bamberg F, Nikolaou K, Apfaltrer P. Iterative Image Reconstruction Techniques for CT Coronary Artery Calcium Quantification: Comparison with Traditional Filtered Back Projection in Vitro and in Vivo. Radiology 2014; 270:387-93. [DOI: 10.1148/radiol.13130233] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
9
|
Weininger M, Ritz KS, Schoepf UJ, Flohr TG, Vliegenthart R, Costello P, Hahn D, Beissert M. Interplatform Reproducibility of CT Coronary Calcium Scoring Software. Radiology 2012; 265:70-7. [DOI: 10.1148/radiol.12112532] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
10
|
Ebersberger U, Eilot D, Goldenberg R, Lev A, Spears JR, Rowe GW, Gallagher NY, Halligan WT, Blanke P, Makowski MR, Krazinski AW, Silverman JR, Bamberg F, Leber AW, Hoffmann E, Schoepf UJ. Fully automated derivation of coronary artery calcium scores and cardiovascular risk assessment from contrast medium-enhanced coronary CT angiography studies. Eur Radiol 2012; 23:650-7. [PMID: 22983281 DOI: 10.1007/s00330-012-2652-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Revised: 08/13/2012] [Accepted: 08/19/2012] [Indexed: 10/27/2022]
Abstract
OBJECTIVES Performance evaluation of a fully automated system for calculating computed tomography (CT) coronary artery calcium scores from contrast medium-enhanced coronary CT angiography (cCTA) studies. METHODS One hundred and twenty-seven patients (58 ± 11 years, 71 men) who had undergone cCTA as well as an unenhanced CT calcium scoring study where included. Calcium scores were computed from cCTA by an automated image processing algorithm and compared with calcium scores obtained by standard manual assessment of unenhanced CT calcium scoring studies. Results were compared vis-a-vis (1) absolute calcium score values, (2) age-, gender- and race-dependent percentiles, and (3) commonly used calcium score risk classification categories. RESULTS One hundred and nineteen out of 127 (93.7%) studies were successfully processed. Mean Agatston calcium score values obtained by traditional non-contrast CT calcium scoring studies and derived from contrast medium-enhanced cCTA did not significantly differ (235.6 ± 430.5 vs 262.0 ± 499.5; P > 0.05). Calcium score risk categories and Multi-Ethnic Study of Atherosclerosis (MESA) percentiles showed very high correlation (Spearman rank correlation coefficient = 0.97, P < 0.0001/0.95, P < 0.0001) between the two approaches. CONCLUSIONS Calcium score values automatically computed from cCTA are highly correlated with standard unenhanced CT calcium scoring studies. These results suggest a radiation dose- and time-saving potential when deriving calcium scores from cCTA studies without a preceding unenhanced CT calcium scoring study.
Collapse
Affiliation(s)
- Ullrich Ebersberger
- Department of Radiology and Radiological Science, Medical University of South Carolina, Ashley River Tower, 25 Courtenay Drive, Charleston, SC 29425-2260, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
11
|
Coronary artery calcium scoring: Influence of adaptive statistical iterative reconstruction using 64-MDCT. Int J Cardiol 2012; 167:2932-7. [PMID: 22959869 DOI: 10.1016/j.ijcard.2012.08.003] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Revised: 07/23/2012] [Accepted: 08/14/2012] [Indexed: 01/07/2023]
Abstract
OBJECTIVE Assessment of coronary artery calcification is increasingly used for cardiovascular risk stratification. We evaluated the reliability of calcium-scoring results using a novel iterative reconstruction algorithm (ASIR) on a high-definition 64-slice CT scanner, as such data is lacking. METHODS AND RESULTS In 50 consecutive patients Agatston scores, calcium mass and volume score were assessed. Comparisons were performed between groups using filtered back projection (FBP) and 20-100% ASIR algorithms. Calcium score was measured in the coronary arteries, signal and noise were measured in the aortic root and left ventricle. In comparison with FBP, use of 20%, 40%, 60%, 80%, and 100% ASIR resulted in reduced image noise between groups (7.7%, 18.8%, 27.9%, 39.86%, and 48.56%, respectively; p<0.001) without difference in signal (p=0.60). With ASIR algorithms Agatston coronary calcium scoring significantly decreased compared with FBP algorithms (837.3 ± 130.3; 802.2 ± 124.9, 771.5 ± 120.7; 744.7 ± 116.8, 724.5 ± 114.2, and 709.2 ± 112.3 for 0%, 20%, 40%, 60%, 80%, and 100% ASIR, respectively, p<0.001). Volumetric score decreased in a similar manner (p<0.001) while calcium mass remained unchanged. Mean effective radiation dose was 0.81 ± 0.08 mSv. CONCLUSION ASIR results in image noise reduction. However, ASIR image reconstruction techniques for HDCT scans decrease Agatston coronary calcium scores. Thus, one needs to be aware of significant changes of the scoring results caused by different reconstruction methods.
Collapse
|
12
|
Koos R, Brandenburg V, Mahnken AH, Muhlenbruch G, Stanzel S, Gunther RW, Floege J, Jahnen-Dechent W, Kelm M, Kuhl HP. Association of fetuin-A levels with the progression of aortic valve calcification in non-dialyzed patients. Eur Heart J 2009; 30:2054-61. [DOI: 10.1093/eurheartj/ehp158] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
|
13
|
Optimal cardiac phase for coronary artery calcium scoring on single-source 64-MDCT scanner: least interscan variability and least motion artifacts. AJR Am J Roentgenol 2008; 190:1561-8. [PMID: 18492907 DOI: 10.2214/ajr.07.3120] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE The purpose of our study was to investigate the cardiac phase with the least interscan variability and motion artifacts on coronary artery calcium studies using a 64-MDCT scanner. SUBJECTS AND METHODS Ninety-one patients with suspected coronary artery disease were scanned twice on retrospective ECG-gated helical scans. Images with 2.5-mm thickness and 1.25-mm interval at nine cardiac phases (center of cardiac phase: 40-80% in 5% increments) were reconstructed. The interscan variability of coronary artery scores (Agatston, volume, and mass) per patient and motion artifact scores per branch, subjectively assigned by motion artifact grading (1, none; 2, minor; and 3, major), were compared between cardiac phases for all patients, low (< 65 beats per minute [bpm]) and high (>or= 65 bpm) heart rate patient groups. RESULTS For all patients, two-factor factorial analysis of variance revealed that the interscan variability was different between cardiac cycles (p < 0.01); however, this was not statistically significant between scoring algorithms (p = 0.46). The least variability was obtained at 70% on Agatston (8%) and volume (7%) and at 75% on mass (7%). Adjacent categories logit model analysis revealed that the motion artifact score was the least at 75% (left anterior descending coronary artery, 1.3; left circumflex coronary artery, 1.4; and right coronary artery, 1.9 in all patients) and that a smaller difference in calcium scores between the scans led to a smaller motion artifact score (p < 0.05). CONCLUSION Middiastole reconstruction (center of cardiac phase: 70-75%), with the least interscan variability and the least motion artifacts, is recommended on 64-MDCT.
Collapse
|
14
|
Variability of coronary calcium scores throughout the cardiac cycle: implications for the appropriate use of electrocardiogram-dose modulation with retrospectively gated computed tomography. Invest Radiol 2008; 43:187-94. [PMID: 18301315 DOI: 10.1097/rli.0b013e31815cdd56] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To study how much the calcium scores at various phases throughout the cardiac cycle deviate from the score in the most motionless phase during retrospectively electrocardiogram (ECG)-gated multidetector row computed tomography (MDCT) of the heart and to evaluate how to optimize ECG-based tube current modulation so that errors in calcium scoring can be minimized while dose savings can be maximized. MATERIALS AND METHODS In 73 subjects with known or suspected coronary artery disease we performed retrospectively ECG-gated 64-detector row computed tomography for calcium scoring. Four subjects were excluded after scanning because of breathing artifacts or lack of coronary calcification. The scans of 69 subjects (46 men, mean age 62 +/- 6 years) were used for further analysis. Heart rate during the scan was recorded. In each patient, calcium scoring [Agatston score (AS), mass score (MS), and volume score, (VS)] was performed on 10 data sets reconstructed at 10%-intervals throughout the cardiac cycle. The most motionless phase was subjectively determined and used as the reference phase. For the score in each phase, deviation from the score in the reference phase was determined. An ECG-simulator was used to determine the amount of dose saving while scanning with dose modulation and applying diagnostic dose during 1 or several phases. RESULTS Mean heart rate was 63 (+/-13) beats per minute (bpm). In 51% of patients the reference phase was the 70% phase. Using the calcium score in the 70% phase (mid-diastole) instead of the reference at heart rates below 70 bpm would have induced a median score deviation of 0% [interquartile range: 0%-6% (AS, MS, and VS)] and using the calcium score in the 40% phase (end-systole) at heart rates > or =70 bpm would also have induced a median score deviation of 0% [interquartile range: 0%-7% (AS), 0%-5% (MS), and 0%-3% (VS)]. Errors in calcium scores of more than 10% occur in around 10% of subjects for all 3 scoring algorithms. Dose savings increased with lower heart rates and shorter application of diagnostic dose. CONCLUSIONS The optimum phases for dose modulation are 70% (mid-diastole) at heart rates below 70 bpm and 40% (end-systole) at heart rates above 70 bpm. Under these conditions dose saving is maximum and a median error of 0% is found for the various calcium scoring techniques with score errors of more than 10% in around 10% of subjects.
Collapse
|
15
|
The Influence of Heart Rate, Slice Thickness, and Calcification Density on Calcium Scores Using 64-Slice Multidetector Computed Tomography. Invest Radiol 2007; 42:848-55. [DOI: 10.1097/rli.0b013e318154c549] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
16
|
Schlosser T, Hunold P, Voigtländer T, Schmermund A, Barkhausen J. Coronary artery calcium scoring: influence of reconstruction interval and reconstruction increment using 64-MDCT. AJR Am J Roentgenol 2007; 188:1063-8. [PMID: 17377048 DOI: 10.2214/ajr.05.1369] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE Assessment of coronary artery calcification is increasingly used for cardiovascular risk stratification. However, a scanning protocol for modern MDCT has not been established. In this study, we evaluated the impact of the reconstruction interval within diastole and the reconstruction increment on the coronary calcium score. MATERIALS AND METHODS In 40 consecutive patients Agatston scores and volumetric scores were assessed using a 64-MDCT scanner. The patients were assigned to two groups at random with 20 patients each: in group A, collimation was 64 x 0.6 mm; in group B, it was 20 x 1.2 mm. All CT examinations were performed with retrospective ECG gating. For each patient, five data sets were created throughout diastole (50%, 55%, 60%, 65%, and 70% of the R-R interval). For each reconstruction, two data sets were calculated with a reconstruction increment of 3.0 and 1.5 mm, respectively. For all reconstructions, the mean Agatston scores and volumetric scores +/- SD and the coefficient of variance were assessed. Furthermore, for each reconstruction, patients were assigned a percentile rank that described the level of cardiovascular risk. RESULTS Four patients had to be excluded from the study because no coronary calcium was detected on any of the reconstructions. In both groups, the mean Agatston score was not significantly different between reconstruction increment 3.0 mm and reconstruction increment 1.5 mm (group A, 112.1 +/- 92.5 and 114.3 +/- 93.6, p = 0.28; group B, 164.8 +/- 203.0 and 169.4 +/- 207.9, p = 0.29, respectively). However, in two cases, very small calcified lesions in the circumflex coronary artery were only detected using a reconstruction increment of 1.5 mm. In both groups, the mean coefficient of variation was not significantly different at reconstruction increment 1.5 mm (group A, 11.4 +/- 8.2; group B, 12.5 +/- 7.6) and reconstruction increment 3.0 mm (group A, 14.8 +/- 9.3; group B, 14.2 +/- 9.1; group A, p = 0.18; group B, p = 0.48). Based on the reconstruction increment and reconstruction interval, 77% of the patients (n = 14) in group A were assigned to one risk group and 23% (n = 4) to two different risk groups according to percentile strata. In group B, 83% of the patients (n = 15) were assigned to one risk group and 17% (n = 3) to two different risk groups. In contrast to the Agatston score, the volumetric score was significantly higher in both groups at reconstruction increment 1.5 mm (group A, 105.4 +/- 78.5 mm3; group B, 153.8 +/- 182.5 mm3) compared with reconstruction increment 3.0 mm (group A, 90.0 +/- 73.11 mm3; group B, 138.2 +/- 166.8 mm3; p < 0.05). CONCLUSION Using a 64-MDCT scanner, the calcium score calculated from different reconstructions within early diastole is variable, but the difference can be minimized using overlapping slice reconstructions. The variation does not lead to a different risk estimation in most patients. In patients with mild coronary calcifications, the use of overlapping slices may help to detect small calcified plaques. Furthermore, we recommend the use of ECG-controlled tube current modulation to reduce the radiation exposure.
Collapse
Affiliation(s)
- Thomas Schlosser
- Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Hufelandstrasse 55, Essen 45122, Germany.
| | | | | | | | | |
Collapse
|
17
|
Begemann PGC, van Stevendaal U, Koester R, Mahnken AH, Koops A, Adam G, Grass M, Nolte-Ernsting C. Evaluation of the influence of acquisition and reconstruction parameters for 16-row multidetector CT on coronary calcium scoring using a stationary and dynamic cardiac phantom. Eur Radiol 2007; 17:1985-94. [PMID: 17268802 DOI: 10.1007/s00330-006-0564-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2006] [Revised: 12/03/2006] [Accepted: 12/18/2006] [Indexed: 11/24/2022]
Abstract
A calcium-scoring phantom with hydroxyapatite-filled cylindrical holes (0.5 to 4 mm) was used. High-resolution scans were performed for an accuracy baseline. The phantom was mounted to a moving heart phantom. Non-moving data with the implementation of an ECG-signal were acquired for different pitches (0.2/0.3), heart rates (60/80/95 bpm) and collimations (16 x 0.75/16 x 1.5 mm). Images were reconstructed with a cone-beam multi-cycle algorithm at a standard thickness/increment of 3 mm/1.5 mm and the thinnest possible thickness (0.8/0.4 and 2/1). Subsequently, ECG-gated moving calcium-scoring phantom data were acquired. The calcium volume and Agatston score were measured. The temporal resolution and reconstruction cycles were calculated. High-resolution scans determine the calcium volume with a high accuracy (mean overestimation, 0.8%). In the non-moving measurements, the volume underestimation ranged from about 6% (16 x 0.75 mm; 0.8/0.4 mm) to nearly 25% (16 x 1.5 mm; 3/1.5 mm). Moving scans showed increased measurement errors depending on the reconstructed RR interval, collimation, pitch, heart rate and gantry rotation time. Also, a correlation with the temporal resolution could be found. The reliability of calcium-scoring results can be improved with the use of a narrower collimation, a lower pitch and the reconstruction of thinner images, resulting in higher patient doses. The choice of the correct cardiac phase within the RR interval is essential to minimize measurement errors.
Collapse
Affiliation(s)
- Philipp G C Begemann
- Center of Diagnostic Imaging and Intervention, Department of Diagnostic and Interventional Radiology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.
| | | | | | | | | | | | | | | |
Collapse
|
18
|
Frydrychowicz A, Pache G, Saueressig U, Föll D, Kotter E, Langer M, Bley TA. Comparison of Reconstruction Intervals in Routine ECG-Pulsed 64-Row-MSCT Coronary Angiography in Frequency Controlled Patients. Cardiovasc Intervent Radiol 2006; 30:79-84. [PMID: 17086457 DOI: 10.1007/s00270-006-0010-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE In light of the increasing use and acceptance of multislice computed tomography (MSCT) coronary angiography it was the purpose of this study to compare reconstruction intervals used in a routine ECG-pulsed MSCT coronary artery angiography setting with frequency controlled patients. METHODS Examinations were performed on a Siemens Somatom Sensation 64 scanner with a total of 110 ml of contrast agent and ECG pulsing (interval from 40% to 70%) after oral application of a beta-blocker if the heart rate was higher than 65 bpm. All human subjects were referred for the evaluation of suspected coronary artery disease. Coronary artery segments were evaluated by two experienced radiologists in a consensus reading. A ranking of diagnostic image quality (from 1 (no evaluation possible) to 5 (excellent image quality)) was statistically evaluated by Wilcoxon Signed Rank Test. RESULTS In 45 patients (30 male, 15 female, age 63.8 +/- 12.1 years) we detected a significant advantage of the 60% reconstruction interval over 40%, 50%, and 70% (for each p < 0.05). In cases of sudden arrhythmia or movement during the scan, additional reconstruction intervals within the ECG-pulsed reconstruction intervals remained necessary for diagnosis. CONCLUSION In a routine diagnostic setting with frequency controlled patients and ECG pulsing the 60% reconstruction interval can be considered superior for the initial diagnosis in 64-row multislice computed tomography coronary angiography. However, further information can be derived from various reconstruction intervals such as 40% and 70%.
Collapse
Affiliation(s)
- Alex Frydrychowicz
- Department of Diagnostic Radiology, University Hospital Freiburg, Hugstetter Strasse 55, 79106 Freiburg, Germany.
| | | | | | | | | | | | | |
Collapse
|
19
|
Budoff MJ, Achenbach S, Blumenthal RS, Carr JJ, Goldin JG, Greenland P, Guerci AD, Lima JAC, Rader DJ, Rubin GD, Shaw LJ, Wiegers SE. Assessment of coronary artery disease by cardiac computed tomography: a scientific statement from the American Heart Association Committee on Cardiovascular Imaging and Intervention, Council on Cardiovascular Radiology and Intervention, and Committee on Cardiac Imaging, Council on Clinical Cardiology. Circulation 2006; 114:1761-91. [PMID: 17015792 DOI: 10.1161/circulationaha.106.178458] [Citation(s) in RCA: 998] [Impact Index Per Article: 55.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
20
|
Thomas CK, Mühlenbruch G, Wildberger JE, Hohl C, Das M, Günther RW, Mahnken AH. Coronary Artery Calcium Scoring With Multislice Computed Tomography. Invest Radiol 2006; 41:668-73. [PMID: 16896301 DOI: 10.1097/01.rli.0000233324.09603.dd] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES We sought to compare an 80-kVp coronary calcium scoring protocol with the standard protocol of 120 kVp in terms of accuracy and reproducibility and to assess its dose reduction potential. MATERIALS AND METHOD An anthropomorphic heart phantom with calcium cylinders was scanned with different tube currents at 80 kVp and 120 kVp using a 16-slice multislice CT (MSCT) scanner. An adapted threshold for 80 kVp was calculated. Accuracy and reproducibility for calcium mass, volume, and Agatston score were analyzed using F-tests. The radiation doses needed to produce artifact-free images were determined. RESULTS Accuracy (measurement errors: mass 120 kVp +4.6%, mass 80 kVp -6.9%, volume 120 kVp +78.8%, volume 80 kVp +58.2%) and reproducibility (F-tests: mass: P = 0.4998, volume: P = 0.9168, Agatston: P = 0.5422) were comparable at both tube voltages. Avoiding the appearance of artificial lesions, a CTDI(w,eff) of 10.7 mGy was needed at 120 kVp versus 4.6 mGy at 80 kVp (dose reduction of 57%). CONCLUSIONS Using an 80-kVp protocol in coronary calcium scoring, a relevant dose reduction is possible without compromising reproducibility and accuracy.
Collapse
Affiliation(s)
- Christoph K Thomas
- Department of Diagnostic Radiology, University Hospital, RWTH-Aachen University, Pauwelsstrasse 30, 52074 Aachen, Germany.
| | | | | | | | | | | | | |
Collapse
|
21
|
Mühlenbruch G, Klotz E, Wildberger JE, Koos R, Das M, Niethammer M, Hohl C, Honnef D, Thomas C, Günther RW, Mahnken AH. The accuracy of 1- and 3-mm slices in coronary calcium scoring using multi-slice CT in vitro and in vivo. Eur Radiol 2006; 17:321-9. [PMID: 16819606 DOI: 10.1007/s00330-006-0332-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2005] [Revised: 04/03/2006] [Accepted: 05/08/2006] [Indexed: 11/30/2022]
Abstract
The accuracy of coronary calcium scoring using 16-row MSCT comparing 1- and 3-mm slices was assessed. A thorax phantom with calcium cylinder inserts was scanned applying a non-enhanced retrospectively ECG-gated examination protocol: collimation 12 x 0.75 mm; 120 kV; 133 mAs(eff). Thirty-eight patients were examined using the same scan protocol. Image reconstruction was performed with an effective slice thickness of 3 and 1 mm. The volume score, calcium mass and Agatston score were determined. Image noise was measured in both studies. The volume score and calcium mass varied less than the Agatston score. The overall measured calcium mass compared to the actual calcium mass revealed a relative difference of +2.0% for 1-mm slices and -1.2% for 3-mm slices. Due to increased image noise in thinner slices in the patient study (26.1 HU), overall calcium scoring with a scoring threshold of 130 HU was not feasible. Interlesion comparison showed significantly higher scoring results for thinner slices (all P<0.001). A similar accuracy comparing calcium scoring results of 1- and 3-mm slices was shown in the phantom study; therefore, the potentially necessary increase of the patient's dose in order to achieve assessable 1-mm slices with an acceptable image-to-noise-ratio appears not to be justified.
Collapse
Affiliation(s)
- Georg Mühlenbruch
- Department of Diagnostic Radiology, University Hospital (RWTH) Aachen, Pauwelsstrasse 30, 52057 Aachen, Germany.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Horiguchi J, Yamamoto H, Hirai N, Akiyama Y, Fujioka C, Marukawa K, Fukuda H, Ito K. Variability of Repeated Coronary Artery Calcium Measurements on Low-Dose ECG-Gated 16-MDCT. AJR Am J Roentgenol 2006; 187:W1-6. [PMID: 16794121 DOI: 10.2214/ajr.05.0052] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE High reproducibility on coronary artery calcium (CAC) scoring is a key requirement in monitoring the progression of coronary atherosclerosis. Retrospective ECG-gated helical CT has been shown to be superior to prospective gating helical CT in the reproducibility of CAC measurements. However, it brings with it a high level of radiation exposure. The purpose of this study was to compare low- and standard-dose protocols in the variability of CAC scores and in image quality, thereby assessing the feasibility of low-dose retrospective ECG-gated helical CT in CAC measurements. SUBJECTS AND METHODS Eighty-six patients with CAC were scanned using a tube current setting of 100 mA once and then a tube current setting equivalent to the patient's body weight twice. CAC scores (Agatston and volume) and interscan variability were evaluated. The mean and SD of the CT attenuation values in regions of interest in the aorta were measured, and the value (mean + 2 x SD) was obtained. RESULTS A high correlation of log(10) (Agatston score + 1) was observed between sequential helical CT scans (r = 0.998). The variability in CAC measurements ranged from 11% to 12% for both the Agatston and volume scores. With the tube current equivalent to body weight, the value (mean + 2 x SD) did not exceed a CT attenuation value of 130 H. CONCLUSION Low-dose retrospective ECG-gated helical CT-yielding low variability and achieving the level of image quality needed to measure CAC-can be used to monitor patients with coronary atherosclerosis.
Collapse
Affiliation(s)
- Jun Horiguchi
- Department of Clinical Radiology, Hiroshima University Hospital, 1-2-3, Kasumi-cho, Minami-ku, Hiroshima 734-8551, Japan.
| | | | | | | | | | | | | | | |
Collapse
|
23
|
Horiguchi J, Fukuda H, Yamamoto H, Hirai N, Alam F, Kakizawa H, Hieda M, Tachikake T, Marukawa K, Ito K. The impact of motion artifacts on the reproducibility of repeated coronary artery calcium measurements. Eur Radiol 2006; 17:81-6. [PMID: 16718452 DOI: 10.1007/s00330-006-0278-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2005] [Revised: 03/17/2006] [Accepted: 04/03/2006] [Indexed: 10/24/2022]
Abstract
The purpose of this study is, using a 16-section multidetector-row helical computed tomography (MDCT) scanner with retrospective reconstruction, to compare variability in repeated coronary calcium scoring and qualitative scores of the motion artifacts. One hundred forty-four patients underwent two subsequent scans using MDCT. According to Agatston and volume algorithms, the coronary calcium scores during mid-diastole (the center corresponding to 70% of the R-R cycle) were calculated and the inter-scan variability was obtained. Motion artifacts from coronary artery calcium were subjectively evaluated and classified using a 5-point scale: 1, excellent; no motion artifacts; 2, fine, minor motion artifacts; 3, moderate, mild motion artifacts; 4, bad, severe motion artifacts; 5, poor, doubling or discontinuity. Each reading was done by vessels (left main, left descending, left circumflex and right coronary arteries) and the motion artifact score (mean of the scales) was determined per patient. The variability in the low (1.2+/-0.2) and high (2.4+/-0.6) motion artifact score groups was 7+/-6 (median, 6)% and 19+/-15 (16)% on the Agatston score (P<0.01) and 7+/-7 (6)% and 16+/-13 (14)% on the volume score (P<0.01), respectively. In conclusion, motion has a significant impact on the reproducibility of coronary calcium scoring.
Collapse
Affiliation(s)
- Jun Horiguchi
- Department of Clinical Radiology, Hiroshima University Hospital, Hiroshima 734-8551, Japan.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
24
|
Koos R, Mahnken AH, Kühl HP, Mühlenbruch G, Mevissen V, Stork L, Dronskowski R, Langebartels G, Autschbach R, Ortlepp JR. Quantification of Aortic Valve Calcification Using Multislice Spiral Computed Tomography. Invest Radiol 2006; 41:485-9. [PMID: 16625112 DOI: 10.1097/01.rli.0000208224.93467.87] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Multislice spiral computed tomography (MSCT) allows the in vivo detection of valvular calcification. The aim of this study was to validate the quantification of aortic valve calcification (AVC) by MSCT with in vitro measurements by atomic absorption spectroscopy. METHODS In 18 patients with severe aortic stenosis, 16 detector row MSCT (SOMATOM Sensation 16, Siemens, Forchheim, Germany with scan parameters as follows: 420 milliseconds tube rotation time, 12 x 0.75 mm collimation, tube voltage 120 KV) was performed before aortic valve replacement. Images were reconstructed at 60% of the RR interval with an effective slice thickness of 3 mm and a reconstruction increment of 2 mm. AVC was assessed using Agatston AVC score, mass AVC score, and volumetric AVC score. After valve replacement, the calcium content of the excised human stenotic aortic valves was determined in vitro using atomic absorption spectroscopy. RESULTS The mean Agatston AVC score was 3,842 +/- 1,790, the mean volumetric AVC score was 3,061 +/- 1,406, and mass AVC score was 888 +/- 492 as quantified by MSCT. Atomic absorption spectroscopy showed a mean true calcification mass (Ca5(PO4)3OH) of 19 +/- 8 mass%. There was a significant correlation between in vivo AVC scores determined by MSCT and in vitro mean true calcification mass (r = 0.74, P = 0.0004 for mass AVC score, r = 0.79, P = 0.0001 for volumetric AVC score and r = 0.80, P = 0.0001 for Agatston AVC score) determined by atomic absorption spectroscopy. Linear regression analysis showed a significant association between the degree of hydroxyapatite (given in mass%) in the aortic valve and the degree of AVC (R = 0.74, F = 19.6, P = 0.0004 for mass AVC score, R = 0.80, F = 29.3, P = 0.0001 for Agatston AVC score and R = 0.79, F = 27.3, P = 0.0001 for volumetric AVC score) assessed by MSCT. CONCLUSION MSCT allows accurate in vivo quantification of aortic valve calcifications.
Collapse
Affiliation(s)
- Ralf Koos
- Department of Cardiology, University Hospital RWTH Aachen, Germany.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
25
|
Ruhl KM, Das M, Koos R, Mühlenbruch G, Flohr TG, Wildberger JE, Günther RW, Mahnken AH. Variability of Aortic Valve Calcification Measurement With Multislice Spiral Computed Tomography. Invest Radiol 2006; 41:370-3. [PMID: 16523019 DOI: 10.1097/01.rli.0000197979.44181.92] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES We sought to assess the variability of aortic valve calcifications (AVCs) regarding the reconstruction window at different heart phases using multislice-spiral computed tomography. MATERIALS AND METHODS A total of 46 patients (26 men; mean age. 65 years) underwent AVC scoring with multislice-spiral computed tomography (12 x 0.75 mm, 120 kV, 133 mAseff). Image reconstruction was performed every 10% of the RR-interval (0-90%). AVC was quantified using Agatston score, calcium volume, and calcium mass. Images were assessed for least motion artifacts. Coefficients of variation and Wilcoxon test were calculated. RESULTS AVC scores are lowest at 60% and highest at 0% of the RR-interval (P < 0.001). Mean coefficients of variation were 36.2% (Agatston score), 38.7% (calcium volume), and 32.9% (calcium mass). At 60% (50-70%). minimal motion artifacts and the lowest variability of the scores were found. CONCLUSIONS AVC scores show large variability depending on the point of image reconstruction. Diastolic image reconstruction at 60% of the RR-interval is recommended.
Collapse
Affiliation(s)
- Karl M Ruhl
- Department of Diagnostic Radiology, RWTH Aachen University, Germany.
| | | | | | | | | | | | | | | |
Collapse
|
26
|
Mühlenbruch G, Wildberger JE, Koos R, Das M, Flohr TG, Niethammer M, Weiss C, Günther RW, Mahnken AH. Coronary calcium scoring using 16-row multislice computed tomography: nonenhanced versus contrast-enhanced studies in vitro and in vivo. Invest Radiol 2006; 40:148-54. [PMID: 15714089 DOI: 10.1097/01.rli.0000153024.12712.10] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES We sought to assess the agreement of coronary artery calcium score in nonenhanced and contrast-enhanced multislice-spiral computed tomography. MATERIALS AND METHODS Vessel phantoms and 36 patients underwent nonenhanced and contrast-enhanced cardiac multislice-spiral computed tomography (Sensation 16; Siemens, Germany). Reconstruction-parameters: slice thickness 3 mm, increment 2 mm, kernels B35f and B30f. The Agatston score, calcium mass, and number of lesions were calculated. Images were scored using detection thresholds of 130 Hounsfield units (HU) and 350 HU. Based on the Agatston score, risk stratification was performed. RESULTS In the phantom and patient study, altering the threshold from 130 to 350 HU led to a significant decrease in the mean Agatston score (phantom: 54.6%, patients: 66.7%) and calcium mass (33.0%, 47.0%) (B35f). Contrast-enhanced studies (threshold: 350 HU) showed an increase of the mean Agatston score (71.0%, 20.7%) and calcium mass (81.0%, 16.0%) when compared with nonenhanced scans (threshold: 350 HU). A total of 57% of all patients were assigned to different risk groups. CONCLUSIONS Contrast material may simulate calcification; therefore, calculation of the coronary calcium score from contrast-enhanced images is not reliable.
Collapse
Affiliation(s)
- Georg Mühlenbruch
- Department of Diagnostic Radiology, University Hospital (RWTH) Aachen, Germany.
| | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Affiliation(s)
- Melvin E Clouse
- Beth Israel Deaconess Medical Center, Harvard Medical School, 1 Deaconess Rd, Room 302, Boston, MA 02215, USA.
| |
Collapse
|
28
|
Sandstede JJW, Stoffels J, Wendel F, Ritter C, Beer M, Hahn D. Different Reconstruction Intervals for Exclusion of Coronary Artery Calcifications by Retrospectively Gated MDCT. AJR Am J Roentgenol 2006; 186:193-7. [PMID: 16357401 DOI: 10.2214/ajr.04.0793] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE Exclusion of coronary artery calcifications has a high negative predictive value for the diagnosis of coronary artery disease. However, it is known that significant differences in calcium scoring can occur because of the ECG trigger interval. Thus, the aim of the study was to evaluate the influence of different reconstruction intervals on detection of any coronary calcium by using MDCT and retrospective cardiac gating. CONCLUSION For a true exclusion of coronary artery calcifications, different reconstruction intervals have to be evaluated.
Collapse
|
29
|
Mühlenbruch G, Thomas C, Wildberger JE, Koos R, Das M, Hohl C, Katoh M, Günther RW, Mahnken AH. Effect of Varying Slice Thickness on Coronary Calcium Scoring With Multislice Computed Tomography in Vitro and in Vivo. Invest Radiol 2005; 40:695-9. [PMID: 16230901 DOI: 10.1097/01.rli.0000179523.07907.a6] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
OBJECTIVES To compare coronary calcium scoring results (calcium volume, calcium mass, Agatston score, and number of lesions) of different slice thicknesses using a 16-slice CT (MSCT) scanner. MATERIALS AND METHODS A nonmoving anthropomorphic thorax phantom with calcium cylinders of different sizes and densities was scanned 30 times with repositioning applying a standardized retrospectively ECG-gated MSCT (SOMATOM Sensation 16; Siemens, Forchheim, Germany) scan protocol: collimation 12 x 0.75 mm, tube voltage 120 kV, effective tube current time-product 133 mAs(eff). Fifty patients (29 male; age 57.2 +/- 8.4 years) underwent a nonenhanced scan applying the same scan protocol. Two image sets (effective slice thicknesses 3 mm and 1 mm) were reconstructed at 60% of the RR interval. Image noise was measured in both studies. Calcium volume, calcium mass and Agatston score were calculated using a commercially available software tool. RESULTS Due to increased image noise in thinner slices, calcium scoring in all scans was performed applying a scoring threshold of 350 HU. In the phantom study, 1-mm slices showed significantly higher scoring results in respect to calcium volume (+8.2%), calcium mass (+12.5%), and Agatston score (+5.3%) (all P < 0.0001). In the patient study, 27 patients had coronary calcifications in 3-mm slices, and 31 patients had coronary calcifications in 1-mm slices. Thinner slices showed significantly higher scoring results in respect to volume (+47.1%), mass (+47.2%), and Agatston score (+29.7%) (all P < 0.0001). CONCLUSIONS When comparing 3-mm and 1-mm slices in coronary calcium scoring in MSCT, thinner slices lead to significantly increased scoring results.
Collapse
Affiliation(s)
- Georg Mühlenbruch
- Department of Diagnostic Radiology, University Hospital (RWTH), Aachen, Aachen, Germany.
| | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Horiguchi J, Shen Y, Akiyama Y, Hirai N, Sasaki K, Ishifuro M, Nakanishi T, Ito K. Electron Beam CT Versus 16-MDCT on the Variability of Repeated Coronary Artery Calcium Measurements in a Variable Heart Rate Phantom. AJR Am J Roentgenol 2005; 185:995-1000. [PMID: 16177422 DOI: 10.2214/ajr.04.1057] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE High reproducibility of coronary artery calcium (CAC) scoring is a key requirement for monitoring the progression of coronary atherosclerosis. The purposes of this study were to compare electron beam CT and 16-MDCT scanners in the variability of repeated CAC measurements and to assess the factors influencing this variability. MATERIALS AND METHODS CAC models of different sizes attached to a cardiac phantom with a programmable variable heart rate were scanned three times, and interscan variability of the CAC measurement was calculated each time. For helical CT, different slice-thickness images of either retrospective ECG-gated or prospective ECG-triggering reconstruction were obtained. The detection of small amounts of calcium, variability of the Agatston score, and CAC measurement algorithms (Agatston, volume, and mass scores) were compared between CT scanners and protocols. RESULTS All 1-mm-sized calcium models were detected on 0.625- and 1.25-mm helical CT, whereas some were missed on electron beam CT and 2.5-mm helical CT. Retrospective ECG-gated thin-slice helical CT showed the lowest variability. Reduction of variability by volume and mass scoring algorithms was less effective on 0.625- and 1.25-mm-thickness CT. CONCLUSION Retrospective ECG-gated thin-slice helical CT has the potential to be a useful tool for monitoring coronary atherosclerosis.
Collapse
Affiliation(s)
- Jun Horiguchi
- Department of Clinical Radiology, Hiroshima University Hospital, 1-2-3, Kasumi-cho, Minami-ku, Hiroshima 734-8551, Japan.
| | | | | | | | | | | | | | | |
Collapse
|
31
|
Sinha AM, Mahnken AH, Borghans A, Krüger S, Koos R, Dedden K, Wildberger JE, Hoffmann R. Multidetector-row computed tomography vs. angiography and intravascular ultrasound for the evaluation of the diameter of proximal coronary arteries. Int J Cardiol 2005; 110:40-5. [PMID: 16169611 DOI: 10.1016/j.ijcard.2005.07.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2005] [Revised: 07/05/2005] [Accepted: 07/24/2005] [Indexed: 02/08/2023]
Abstract
BACKGROUND Multidetector-row computed tomography has evolved as a promising method for noninvasive visualization of coronary arteries and detection of coronary artery calcification. We determined the accuracy of computed tomography for measurement of coronary artery lumen diameters in comparison to quantitative coronary angiography and intravascular ultrasound (IVUS). METHODS Eighteen patients (4 female, age 62+/-8 years) with known or suspected coronary artery disease were investigated by computer tomography (4x1 mm collimation, rotation time: 500 ms, table feed: 1.5 mm/rotation). Coronary angiography and IVUS were performed in the left anterior descending, left circumflex and right coronary artery according to common standards. Lumen diameters were measured at the origin of the coronary artery and 10, 30 and 50 mm distally. Results of all three techniques were compared. RESULTS Only measuring points evaluated by all measuring techniques were included. Thus, 50 diameters could be analyzed. The correlation R between computed tomography and angiography measures was 0.909 (p<0.05) at the origin of the artery, 0.907 (p<0.05) at 10, 0.841 (p<0.05) at 30 and 0.780 (p<0.05) at 50 mm distally. The correlation R between computed tomography and IVUS was 0.934 at the origin (p<0.05), 0.867 at 10 (p<0.05), 0.880 at 30 (p<0.05) and 0.727 at 50 mm (p<0.05). CONCLUSIONS Multidetector-row computed tomography is a promising tool to measure the proximal coronary artery diameters with a good correlation to angiographic and IVUS measurements. Multidetector-row computed tomography might become more feasible with improvement of technology, e.g. with 16 row scanners.
Collapse
Affiliation(s)
- Anil-Martin Sinha
- Department of Cardiology, University Hospital, RWTH Aachen, Germany.
| | | | | | | | | | | | | | | |
Collapse
|
32
|
Koos R, Mahnken AH, Mühlenbruch G, Brandenburg V, Pflueger B, Wildberger JE, Kühl HP. Relation of oral anticoagulation to cardiac valvular and coronary calcium assessed by multislice spiral computed tomography. Am J Cardiol 2005; 96:747-9. [PMID: 16169351 DOI: 10.1016/j.amjcard.2005.05.014] [Citation(s) in RCA: 138] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2005] [Revised: 05/05/2005] [Accepted: 05/05/2005] [Indexed: 02/07/2023]
Abstract
Vitamin K antagonists, known as oral anticoagulants, affect the synthesis and function of the matrix Gla protein, which is a potent inhibitor of tissue calcification. We performed multislice spiral computed tomography in 86 patients (53 men, mean age 71 +/- 8 years) with calcific aortic valve disease to quantitate the amount of calcification in the aortic valve and coronary arteries. Patients with long-term oral anticoagulation therapy (mean duration 88 +/- 113 months; n = 23) were compared with those without anticoagulation (n = 63). No differences were found in the demographic, clinical, or echocardiographic characteristics between the 2 study groups. Patients on oral anticoagulant therapy had increased coronary calcium (coronary Agatston score 1,561 +/- 1,141 vs 738 +/- 978, respectively; p = 0.024) and valvular calcium (valvular Agatston score 2,410 +/- 1,759 vs 1,070 +/- 1,085, respectively; p = 0.002) compared with patients without anticoagulation treatment. The results of our study have demonstrated that oral anticoagulation may be associated with increased valvular and coronary calcium in patients with aortic valve disease, presumably due to decreased activation of the matrix Gla protein.
Collapse
Affiliation(s)
- Ralf Koos
- Department of Cardiology, University Hospital Aachen, University of Technology Aachen, Aachen, Germany.
| | | | | | | | | | | | | |
Collapse
|
33
|
Mahnken AH, Mühlenbruch G, Koos R, Das M, Pohl S, Stanzel S, Günther RW, Wildberger JE. Influence of a small field-of-view size on the detection of coronary artery calcifications with MSCT: in vitro and in vivo study. Eur Radiol 2005; 16:358-64. [PMID: 16132923 DOI: 10.1007/s00330-005-2881-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2005] [Revised: 07/03/2005] [Accepted: 07/28/2005] [Indexed: 10/25/2022]
Abstract
The purpose of this study is to asses the impact of small field-of-view (FOV) sizes on the detection of coronary artery calcifications using multislice-spiral computed tomography (MSCT). First, a static chest phantom containing calcium inserts was scanned 10 times using a standardized scan protocol. Secondly, 50 patients (28 male, 63.6+/-10.6 years) underwent cardiac MSCT using the same protocol. Images were reconstructed with three different FOV sizes (180x180, 220x220, 380x380 mm(2)). Coronary calcium scoring and risk stratification were performed for each image series. In the phantom study, the Agatston score calculated with a FOV size of 180x180 mm(2) was 657.80+/-20.05. At a FOV of 220x220 mm(2) and 380x380 mm(2), the corresponding values were 657.04+/-21.36 and 655.04+/-20.74, respectively. The corresponding values in the patient study were 541.65+/-869.87, 541.91+/-872.57 and 536.61+/-867.81. No statistically significant differences in the calcium score were found comparing different FOV sizes. Significantly more lesions (p=0.00149) were detected in the patient study. Comparing the different FOV sizes of 180x180 mm(2) and 220x220 mm(2) (380x380 mm(2)), four (six) patients had to be assigned to different risk groups. The use of small FOV sizes resulted in an improved detection of coronary calcifications influencing the risk stratification for further cardiac events in MSCT coronary calcium scoring.
Collapse
Affiliation(s)
- Andreas H Mahnken
- Department of Diagnostic Radiology, Aachen University of Technology, Pauwelsstrasse 30, 52074, Aachen, Germany.
| | | | | | | | | | | | | | | |
Collapse
|
34
|
Koos R, Mahnken AH, Sinha AM, Wildberger JE, Hoffmann R, Kühl HP. Preliminary experience in the assessment of aortic valve calcification by ECG-gated multislice spiral computed tomography. Int J Cardiol 2005; 102:195-200. [PMID: 15982484 DOI: 10.1016/j.ijcard.2004.05.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2003] [Revised: 03/12/2004] [Accepted: 05/05/2004] [Indexed: 01/27/2023]
Abstract
BACKGROUND The aim was to correlate the degree of valvular calcification in patients with aortic stenosis determined by retrospectively electrocardiogram (ECG)-gated multislice spiral computed tomography with stenosis severity assessed by cardiac catheterization. METHODS Prospective study on 41 patients (18 men, mean age 71+/-8 years) with aortic stenosis, who underwent four detector row multislice spiral computed tomography and cardiac catheterization. Severity of aortic stenosis was classified by cardiac catheterization. Aortic valve area, peak to peak and mean transvalvular gradients were correlated with the degree of calcification determined by multislice spiral computed tomography. Aortic valve calcification was assessed using aortic Agatston score, aortic mass score and aortic volume score. RESULTS All measured aortic valve calcification scores were significantly higher in patients with severe aortic stenosis (n=29) than in patients with moderate (n=7) or mild aortic stenosis (n=5, p<0.001). Aortic valve calcification scores correlated significantly with aortic valve area (r=-0.49, p=0.001 for aortic mass score) and with peak to peak (r=0.68, p<0.001) and mean (r=0.60, p<0.001) transvalvular gradients. CONCLUSIONS Severity of aortic valve calcification assessed by cardiac multislice spiral computed tomography is inversely related to aortic valve area and positively correlated with transvalvular gradients. Based on this preliminary data larger studies should be performed with echocardiography as a reference standard in order to validate this new information and its utility in the clinical management of the patient.
Collapse
Affiliation(s)
- Ralf Koos
- Department of Cardiology, University Hospital Aachen, Pauwelsstr. 30, 52072 Aachen, Germany.
| | | | | | | | | | | |
Collapse
|
35
|
Horiguchi J, Yamamoto H, Akiyama Y, Hirai N, Marukawa K, Fukuda H, Ito K. Variability of Repeated Coronary Artery Calcium Measurements by 16-MDCT with Retrospective Reconstruction. AJR Am J Roentgenol 2005; 184:1917-23. [PMID: 15908554 DOI: 10.2214/ajr.184.6.01841917] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE High reproducibility on coronary calcium scoring is an important factor in monitoring the progression of coronary atherosclerosis. The purposes of this study were, using a 16-MDCT scanner with retrospective reconstruction, to compare the effects of thin-slice images and overlapping image reconstruction on the reproducibility of coronary calcium scoring and to compare 16-MDCT with electron beam CT (EBCT). MATERIALS AND METHODS Fifty patients underwent two sequential examinations using both EBCT and MDCT. For MDCT, images were reconstructed from the same raw data using the following thicknesses and increments (thickness/increment): 1.25 mm/1.25 mm, 2.5 mm/2.5 mm, and 2.5 mm/1.25 mm. The Agatston, volume, and mass scores were calculated on four pairs of image sets. Statistical analysis was performed to determine significant differences in interscan variability among image acquisition protocols and among measurement algorithms. RESULTS Overlapping reconstructed images (thickness/increment, 2.5 mm/1.25 mm) obtained on a 16-MDCT scanner showed the lowest variability (mean, 13%; median, 10%) when compared with the Agatston score. CONCLUSION The use of 16-MDCT with overlapping reconstruction by retrospective reconstruction, yielding low variability of coronary artery calcium measurement on two sequential scans, has an advantage over EBCT in monitoring the progression of atherosclerosis.
Collapse
Affiliation(s)
- Jun Horiguchi
- Department of Clinical Radiology, Hiroshima University Hospital, 1-2-3, Kasumi-cho, Minami-ku, Hiroshima 734-8551, Japan.
| | | | | | | | | | | | | |
Collapse
|
36
|
Mahnken AH, Wildberger JE, Koos R, Günther RW. Multislice Spiral Computed Tomography of the Heart: Technique, Current Applications, and Perspective. Cardiovasc Intervent Radiol 2005; 28:388-99. [PMID: 15959701 DOI: 10.1007/s00270-003-9218-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Multislice spiral computed tomography (MSCT) is a rapidly evolving, noninvasive technique for cardiac imaging. Knowledge of the principle of electrocardiogram-gated MSCT and its limitations in clinical routine are needed to optimize image quality. Therefore, the basic technical principle including essentials of image postprocessing is described. Cardiac MSCT imaging was initially focused on coronary calcium scoring, MSCT coronary angiography, and analysis of left ventricular function. Recent studies also evaluated the ability of cardiac MSCT to visualize myocardial infarction and assess valvular morphology. In combination with experimental approaches toward the assessment of aortic valve function and myocardial viability, cardiac MSCT holds the potential for a comprehensive examination of the heart using one single examination technique.
Collapse
Affiliation(s)
- Andreas H Mahnken
- Department of Diagnostic Radiology, Aachen University of Technology, Pauwelsstrasse 30, D-52074 Aachen, Germany.
| | | | | | | |
Collapse
|
37
|
Manzke R, Köhler T, Nielsen T, Hawkes D, Grass M. Automatic phase determination for retrospectively gated cardiac CT. Med Phys 2005; 31:3345-62. [PMID: 15651618 DOI: 10.1118/1.1791351] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The recent improvements in CT detector and gantry technology in combination with new heart rate adaptive cone beam reconstruction algorithms enable the visualization of the heart in three dimensions at high spatial resolution. However, the finite temporal resolution still impedes the artifact-free reconstruction of the heart at any arbitrary phase of the cardiac cycle. Cardiac phases must be found during which the heart is quasistationary to obtain outmost image quality. It is challenging to find these phases due to intercycle and patient-to-patient variability. Electrocardiogram (ECG) information does not always represent the heart motion with an adequate accuracy. In this publication, a simple and efficient image-based technique is introduced which is able to deliver stable cardiac phases in an automatic and patient-specific way. From low-resolution four-dimensional data sets, the most stable phases are derived by calculating the object similarity between subsequent phases in the cardiac cycle. Patient-specific information about the object motion can be determined and resolved spatially. This information is used to perform optimized high-resolution reconstructions at phases of little motion. Results based on a simulation study and three real patient data sets are presented. The projection data were generated using a 16-slice cone beam CT system in low-pitch helical mode with parallel ECG recording.
Collapse
Affiliation(s)
- R Manzke
- Philips Research Laboratories, Sector Technical Systems, Roentgenstrasse, 24-26, D-22335 Hamburg, Germany.
| | | | | | | | | |
Collapse
|
38
|
Marten K, Funke M, Rummeny EJ, Engelke C. Electrocardiographic assistance in multidetector CT of thoracic disorders. Clin Radiol 2005; 60:8-21. [PMID: 15642288 DOI: 10.1016/j.crad.2004.03.025] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2003] [Revised: 02/27/2004] [Accepted: 03/03/2004] [Indexed: 01/15/2023]
Abstract
ECG-synchronized multislice spiral CT (MSCT) allows a significant reduction of cardiac motion artefacts and as a result a virtually artefact-free display of intrathoracic structures. With their advantages in imaging geometry and continuous spiral image acquisition multislice CT scanners provide superior image quality and spatial resolution in these patients. Possible clinical applications for ECG assistance in MSCT include CT angiography of the coronary arteries, functional cardiac CT imaging and imaging of the cardiac valves, CT angiography of the aorta or pulmonary vascular tree as well as ECG-gated imaging of the lung parenchyma. Prospective ECG triggering and retrospectively ECG-gated image reconstruction comprise the technical corsage for reduction of pulsation artefacts in cardiac and other thoracic CT applications. In addition the development of time-optimised reconstruction algorithms for retrospective cardiac gating in 8- and 16 slice spiral CT scanners have enabled further improvements in temporal resolution. This overview describes the technique, its clinical indications and the merits of electrocardiographic assistance in MSCT of chest disorders.
Collapse
Affiliation(s)
- K Marten
- Department of Radiology, Klinikum rechts der Isar, Technical University, Munich, Germany.
| | | | | | | |
Collapse
|
39
|
Schlosser T, Hunold P, Schmermund A, Kühl H, Waltering KU, Debatin JF, Barkhausen J. Coronary Artery Calcium Score: Influence of Reconstruction Interval at 16–Detector Row CT with Retrospective Electrocardiographic Gating. Radiology 2004; 233:586-9. [PMID: 15459323 DOI: 10.1148/radiol.2332031470] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In 30 patients, Agatston and volumetric scores were assessed by using retrospectively gated multi-detector row computed tomography (CT). For each patient, 10 data sets were created at different times and were evenly spaced throughout the cardiac cycle. For each reconstruction, patients were assigned a percentile that described the level of cardiovascular risk. Nineteen (63%) of 30 patients could be assigned to more than one risk group depending on the reconstruction interval used. Agatston and volumetric scores both proved highly dependent on the reconstruction interval used (coefficient of variation, < or =63.1%) even with the most advanced CT scanners. Accurate and reproducible quantification of coronary calcium seems to require analysis of multiple reconstructions.
Collapse
Affiliation(s)
- Thomas Schlosser
- Departments of Diagnostic and Interventional Radiology and Cardiology, University Hospital, Hufelandstr 55, 45122 Essen, Germany
| | | | | | | | | | | | | |
Collapse
|
40
|
Lembcke A, Wiese TH, Schnorr J, Wagner S, Mews J, Kroencke TJ, Enzweiler CNH, Hamm B, Taupitz M. Image quality of noninvasive coronary angiography using multislice spiral computed tomography and electron-beam computed tomography: intraindividual comparison in an animal model. Invest Radiol 2004; 39:357-64. [PMID: 15167102 DOI: 10.1097/01.rli.0000123316.10765.6c] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Comparison of coronary artery visualization by multislice spiral CT (MSCT) and electron-beam CT (EBCT). MATERIALS AND METHODS Six minipigs underwent MSCT (collimation 4 x 1 mm, gantry rotation time 500 milliseconds, acquisition time per cardiac cycle 126 +/- 30 milliseconds) and EBCT (slice thickness 1.5 mm, acquisition time per scan 100 milliseconds). Visualized vessel length and contour sharpness was measured, contrast-to-noise ratios were calculated, and the frequency of motion artifacts were evaluated. RESULTS MSCT depicted significantly longer segments of the coronary tree than EBCT (length: 248.8 vs. 222.8 mm; P < 0.05), delineated the vessel contours more sharply (slope of density curves: 219.2 vs. 160.2 DeltaHU/mm; P < 0.05), and had a higher contrast-to-noise ratio (13.4 vs. 7.3; P < 0.05). The frequency of motion artifacts did not differ between both modalities (94.7% vs. 95.7% of visualized vessel length; P > 0.05). CONCLUSIONS Because its higher spatial resolution and lower image noise, MSCT seems to be superior to EBCT in the visualization of the coronary arteries. Despite different temporal resolutions motion artifacts seem to be similar with both modalities.
Collapse
Affiliation(s)
- Alexander Lembcke
- Department of Radiology, Charité Medical School, Humboldt-Universität zu Berlin, Schumannstrasse 20/21, 10098 Berlin, Germany.
| | | | | | | | | | | | | | | | | |
Collapse
|
41
|
Becker CR, Hong C, Knez A, Leber A, Bruening R, Schoepf UJ, Reiser MF. Optimal contrast application for cardiac 4-detector-row computed tomography. Invest Radiol 2004; 38:690-4. [PMID: 14566178 DOI: 10.1097/01.rli.0000084886.44676.e4] [Citation(s) in RCA: 144] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
RATIONALE AND OBJECTIVES This study was designed to determine the optimal contrast protocol for 4-detector-row computed tomography angiography of the heart. METHODS Sixty patients were randomly assigned to 1 of 4 groups with 300 and 400 mg/mL iodine concentrations and 2.5 and 3.5 mL/s flow rates. Contrast density was measured in the left ventricular cavity and coronary arteries. RESULTS Low iodine concentration injected at slow flow rate (0.75 g iodine/s) resulted in acceptable contrast enhancement in only 53.8% of the patients. There was no significant difference between low contrast concentration injected at high flow rate and high contrast concentration injected at slow flow rate ( approximately 1 g iodine/s). High contrast concentration administered with high flow rates (1.4 g iodine/s) may result in an enhancement above 350 Hounsfield units (HU) and interfere with coronary calcifications. CONCLUSIONS The injection of approximately 1 g iodine/s resulted in an optimal (250-300 HU) contrast enhancement for cardiac 4-detector-row computed tomography.
Collapse
Affiliation(s)
- Christoph R Becker
- Department of Clinical Radiology, University Hospital Munich, Grosshadern, Germany.
| | | | | | | | | | | | | |
Collapse
|
42
|
Nasir K, Budoff MJ, Post WS, Fishman EK, Mahesh M, Lima JA, Blumenthal RS. Electron beam CT versus helical CT scans for assessing coronary calcification: current utility and future directions. Am Heart J 2004; 146:969-77. [PMID: 14660987 DOI: 10.1016/s0002-8703(03)00450-2] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Traditional risk factors for coronary artery disease predict the development of atherosclerosis; however, their ability to identify individual patients at risk of events is limited. METHODS Coronary artery calcium (CAC) is a specific marker of atherosclerosis. It can be visualized and measured noninvasively by various imaging techniques, which may add incremental prognostic value to conventional coronary factors. RESULTS The field of atherosclerosis imaging has expanded rapidly in the last decade, and technologies such as electron-beam computed tomography (EBCT) have contributed to our understanding of the prevalence of occult coronary artery disease and its consequences. Other modalities have been previously limited by the decreased temporal and spatial resolution and slower acquisition. Recent advances in helical CT (HCT) imaging with the development of multiple row detectors CT (MDCT) and improvements in the temporal resolution have renewed clinicians' interests in using this modality to evaluate CAC, although the scores obtained with MDCT may differ somewhat from those obtained with the EBCT technology. This study critically analyzes the literature comparing the utility of EBCT and HCT in detecting coronary calcium to identify individuals at increased risk for future coronary events. CONCLUSIONS MDCT is a promising tool for coronary calcium scoring; however, more studies are needed comparing EBCT and MDCT, especially at lower CAC levels.
Collapse
Affiliation(s)
- Khurram Nasir
- Division of Cardiology, Johns Hopkins Hospital, Baltimore, Md 21287, USA
| | | | | | | | | | | | | |
Collapse
|
43
|
Knollmann FD, Helmig K, Kapell S, Hummel M, Bocksch W, Hetzer R, Felix R. Coronary Artery Calcium Scoring. Invest Radiol 2003; 38:761-8. [PMID: 14627893 DOI: 10.1097/01.rli.0000084257.43062.c2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To compare the diagnostic power of different software implementations for the quantification of coronary artery calcium. MATERIALS AND METHODS Electron beam computed tomography was performed in 109 heart transplant recipients at the same time as catheter coronary angiography and intracoronary ultrasound. Electron beam computed tomography images were analyzed by 3 software packages marketed for the quantification of coronary calcifications using the same software settings, and the resultant calcium scores correlated with the invasive reference methods by Bland-Altman plots and analysis of the receiver operating characteristics. RESULTS Although all scoring systems displayed close correlations upon regression analysis (r2=0.94-0.99), their ability to detect disease as per the invasive reference method varied significantly in some instances. The area under the ROC curve varied between Az=0.78 and 0.85 for the detection of coronary artery stenosis upon coronary angiography (P=0.05-0.13), and between Az=0.75 and 0.83 for the detection of accelerated intimal proliferation (P=0.03-0.18). CONCLUSIONS Different software implementations for the quantification of coronary artery calcium load may display diagnostically relevant differences in spite of close direct correlation.
Collapse
Affiliation(s)
- Friedrich D Knollmann
- Department of Radiology, Charité, Campus Virchow-Klinikum, Humboldt-University, Berlin, Germany.
| | | | | | | | | | | | | |
Collapse
|
44
|
Ferencik M, Ferullo A, Achenbach S, Abbara S, Chan RC, Booth SL, Brady TJ, Hoffmann U. Coronary calcium quantification using various calibration phantoms and scoring thresholds. Invest Radiol 2003; 38:559-66. [PMID: 12960525 DOI: 10.1097/01.rli.0000073449.90302.75] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
RATIONALE AND OBJECTIVES To compare scoring threshold and calibration method-dependent accuracy and variability of coronary calcium measurements by multidetector computed tomography (MDCT). METHODS Ninety-five subjects were scanned with MDCT. We calculated Agatston score and volume score. Mineral mass (MM) was calculated using patient-based and scanner-based calibration methods. Accuracy of calibration was validated using artificial calcium cylinders. RESULTS Patient-based and scanner-based calibration permitted accurate quantification of artificial calcium cylinders (bias: 0 mg and -2 mg). In the subjects, the mean relative difference of MM measurements performed at 90 and 130 Hounsfield units threshold (59%) was lower than for Agatston score (94%) and volume score (109%; P < 0.05). Patient-based and scanner-based calibration yielded systematically different MM measurements (bias: 22%). CONCLUSIONS MM lowers threshold-dependent variability of coronary calcium measurements. Patient-based and scanner-based calibration allows accurate calcium quantification ex vivo but reveal systematic differences in subjects. Patient-based calibration may better account for subject size and composition.
Collapse
Affiliation(s)
- Maros Ferencik
- Department of Radiology, Massachusetts General Hospital and Harvard Medical School, 100 Charles River Plaza, Suite 400, Boston, MA 02114, USA.
| | | | | | | | | | | | | | | |
Collapse
|
45
|
Mahnken AH, Wildberger JE, Simon J, Koos R, Flohr TG, Schaller S, Günther RW. Detection of coronary calcifications: feasibility of dose reduction with a body weight-adapted examination protocol. AJR Am J Roentgenol 2003; 181:533-8. [PMID: 12876041 DOI: 10.2214/ajr.181.2.1810533] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE The purpose of this study was to assess the applicability of individual body weight-adapted tube current time settings in multidetector CT for detection of coronary calcifications and to evaluate the effect of reducing the radiation dose on the coronary calcium score. SUBJECTS AND METHODS. One hundred patients underwent retrospectively ECG-gated MDCT for detection of coronary calcifications. First, fixed tube current time settings were used in 50 patients. Second, image noise corresponding to body weight-adapted tube current time settings was added to these images. Finally, body weight-adapted tube current time settings were applied to another 50 patients. For each patient group, the radiation dose was calculated. Coronary calcium scores were compared for the patient groups with the fixed tube current time settings with and without artificially added image noise. In all image series, image noise was assessed by a region-of-interest methodology. Image noise was analyzed using a regression analysis. RESULTS The effective radiation dose was reduced by 11.6% for men and 24.8% for women using the body weight-adapted tube current time settings. There were no statistically significant changes in the coronary calcium score after the addition of artificial image noise (p = 0.84). Adaptation of the tube current time settings did not lead to a relevant increase in image noise. The radiation doses for the plotted noise-to-body weight (slope, 0.081) and noise-to-body mass index (slope, 0.378) ratios for the standard protocol proved relatively high for patients of lower weight. An improved noise-to-body weight (slope, 0.054) and noise-to-body mass index (slope, 0.190) ratio was achieved by application of the body weight-adapted tube current time settings, resulting in nearly constant image noise related to body weight. CONCLUSION Individual body weight-adapted current time settings are applicable for coronary calcium scoring without a change of the coronary calcium score or relevant increase of the image noise.
Collapse
Affiliation(s)
- A H Mahnken
- Department of Diagnostic Radiology, University of Technology, Aachen, University Hospital, Pauwelsstr. 30, D-52074 Aachen, Germany
| | | | | | | | | | | | | |
Collapse
|
46
|
Mao S, Child J, Carson S, Liu SCK, Oudiz RJ, Budoff MJ. Sensitivity to detect small coronary artery calcium lesions with varying slice thickness using electron beam tomography. Invest Radiol 2003; 38:183-7. [PMID: 12595800 DOI: 10.1097/01.rli.0000055289.97726.b1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
RATIONALE AND OBJECTIVE To estimate the sensitivity to find small coronary artery calcium lesions with use of different slice widths with electron beam tomography. MATERIALS AND METHODS Two studies were performed. Study 1 utilized double scanning of a stationary cork phantom with three different slice thickness (1.5, 3, and 6 mm). Fifty different calcific lesions (all <20 mm2 in area) fitted in 10 cork coronary arteries were utilized. The calcium foci area, peak value and score were measured and compared. In group 2, 30 patients underwent coronary artery calcium (CAC) screen studies. Each patient was scanned with both 3-mm and 6-mm scan widths in a same study time. Lesions with < 20 mm2 of area of CAC were measured on both 3-mm and 6-mm images. The mean and peak Hounsfield unit measure, and Agatston score were compared between both images. RESULTS In the cork study, the sensitivity to detect small calcium foci were 96% (48/50), 82% (41/50), and 34% (17/50) in images with 1.5-, 3-, and 6-mm slice thickness, respectively. There is a smaller value in mass, and calcium volume in 6-mm images than 1.5-mm and 3-mm images ( P< 0.001). There was no significant difference between the true value and measured value from 1.5-mm and 3-mm images. In the human study, 18 (30%) of 60 CAC lesions with an area < 20 mm2 defined on 3 mm images were not visible on 6-mm images. Sensitivity of small lesions (P< 5 mm2) was 48% using 6-mm slices. There was a smaller value in CAC area, mean and peak Hounsfield units and score measured from 6-mm images, as compared with 3 mm slices ( P< 0.05). CONCLUSION Thinner slice imaging has a higher sensitivity to detect small calcium focus. There was no significant change in score between 3 mm and 1.5 mm on the cork phantom study. However, the use of 6-mm slices should be discouraged, as this protocol both underestimates calcific mass and misses a significant number of calcific lesions in both a phantom and human study.
Collapse
Affiliation(s)
- Songshou Mao
- Division of Cardiology, Harbor-UCLA Research and Education Institute, Torrance, California. dagger From the Department of Radiology, XiJing Hospital, Xi'an, China
| | | | | | | | | | | |
Collapse
|
47
|
Gerber TC, O'Brien PC, Pastor K, Kuzo RS, Blackshear JL, Morin RL. Evaluation of reconstruction windows for multislice computed tomography in quantification of coronary calcium. Invest Radiol 2003; 38:108-18. [PMID: 12544074 DOI: 10.1097/00004424-200302000-00006] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
RATIONALE AND OBJECTIVES To search for an optimum reconstruction window in retrospectively gated multislice computed tomography (MSCT) for quantification of coronary calcium. MATERIALS AND METHODS Coronary calcium quantified was examined as Agatston and volume scores by two experienced observers at 10 time points across the R-R interval of the electrocardiogram in 42 patients. A combination of statistical approaches was used to evaluate the distributions of minimum and maximum scores and of interobserver variability for both scoring methods across the cardiac cycle. RESULTS Based on the combination of evaluation approaches, 60% to 70% of the R-R interval appeared to be the optimum time point for obtaining maximum calcium scores with minimum interobserver variability. The optimum time point was more clearly defined for the Agatston score than for the volume score. CONCLUSION A reconstruction window beginning at 60% to 70% of the R-R interval seems to be most advantageous for retrospective gating of MSCT studies performed to quantify coronary calcium.
Collapse
Affiliation(s)
- Thomas C Gerber
- Department of Radiology, Mayo Clinic, Jacksonville, Florida 32224, USA.
| | | | | | | | | | | |
Collapse
|