1
|
de Jong DJ, van der Star S, Bleys RLAW, Schilham AMR, Kuijf HJ, de Jong PA, Kok M. Computed tomography-based calcium scoring in cadaver leg arteries: Influence of dose, reader, and reconstruction algorithm. Eur J Radiol 2021; 146:110080. [PMID: 34875474 DOI: 10.1016/j.ejrad.2021.110080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 11/25/2021] [Accepted: 11/27/2021] [Indexed: 11/25/2022]
Abstract
PURPOSE Computed tomography (CT) might be a good diagnostic test to accurately quantify calcium in vascular beds but there are multiple factors influencing the quantification. The aim of this study was to investigate the influence of different computed tomography protocol settings in the quantification of calcium in the lower extremities using modified Agatston and volume scores. METHODS Fresh-frozen human legs were scanned at different tube current protocols and reconstructed at different slice thickness. Two different iterative reconstruction protocols for conventional CT images were compared. Calcium was manually scored using modified Agatston and volume scores. Outcomes were statistically analyzed using Wilcoxon signed-rank tests and mean absolute and relative differences were plotted in Bland-Altman plots. RESULTS Of the 20 legs, 16 had CT detectable calcifications. Differences between thick and thin slice reconstruction protocols were 129 Agatston units and 125% for Agatston and 78.4 mm3 and 57.8% for volume (all p ≤ 0.001). No significant differences were found between low and high tube current protocols. Differences between iDose4 and IMR reconstruction protocols for modified Agatston were 34.2 Agatston units and 17.7% and the volume score 33.5 mm3 and 21.2% (all p ≤ 0.001). CONCLUSIONS Slice thickness reconstruction and reconstruction method protocols influenced the modified Agatston and volume scores in leg arteries, but tube current and different observers did not have an effect. This data emphasizes the need for standardized quantification of leg artery calcifications. Possible implications are in the development of a more universal quantification method, independent of the type of scan and vasculature.
Collapse
Affiliation(s)
- Daan J de Jong
- Department of Radiology, University Medical Center Utrecht, PO Box 85500, 3508 GA Utrecht, the Netherlands
| | - Simone van der Star
- Department of Radiology, University Medical Center Utrecht, PO Box 85500, 3508 GA Utrecht, the Netherlands
| | - Ronald L A W Bleys
- Department of Anatomy, University Medical Center Utrecht, PO Box 85500, 3508 GA Utrecht, the Netherlands
| | - Arnold M R Schilham
- Image Sciences Institute, University Medical Center Utrecht, PO Box 85500, 3508 GA Utrecht, the Netherlands
| | - Hugo J Kuijf
- Image Sciences Institute, University Medical Center Utrecht, PO Box 85500, 3508 GA Utrecht, the Netherlands
| | - Pim A de Jong
- Department of Radiology, University Medical Center Utrecht, PO Box 85500, 3508 GA Utrecht, the Netherlands
| | - Madeleine Kok
- Department of Radiology, University Medical Center Utrecht, PO Box 85500, 3508 GA Utrecht, the Netherlands.
| |
Collapse
|
2
|
Lebedev S, Fournié E, Maier J, Stierstorfer K, Kachelrieß M. Motion compensation for aortic valves using partial angle CT reconstructions motion compensation of cardiac valve CT. Med Phys 2021; 49:1495-1506. [PMID: 34822186 DOI: 10.1002/mp.15379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 09/28/2021] [Accepted: 11/02/2021] [Indexed: 11/07/2022] Open
Abstract
PURPOSE A motion compensation method that is aimed at correcting motion artifacts of cardiac valves is proposed. The primary focus is the aortic valve. METHODS The method is based around partial angle reconstructions and a cost function including the image entropy. A motion model is applied to approximate the cardiac motion in the temporal and spatial domain. Based on characteristic values for velocities and strain during cardiac motion, penalties for the velocity and spatial derivatives are introduced to maintain anatomically realistic motion vector fields and avoid distortions. The model addresses global elastic deformation, but not the finer and more complicated motion of the valve leaflets. RESULTS The method is verified based on clinical data. Image quality was improved for most artifact impaired reconstructions. An image quality study with Likert scoring of the motion artifact severity on a scale from 1 (highest image quality) to 5 (lowest image quality/extreme artifact presence) was performed. The biggest improvements after applying motion compensation were achieved for strongly artifact impaired initial images scoring 4 and 5, resulting in an average change of the scores by -0.59 ± 0.06 and -1.33 ± 0.03, respectively. In case of artifact free images, a chance to introduce blurring was observed and their average score was raised by 0.42 ± 0.03. CONCLUSION Motion artifacts were consistently removed and image quality improved.
Collapse
Affiliation(s)
- Sergej Lebedev
- X-Ray Imaging and Computed Tomography, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Siemens Healthineers, Forchheim, Germany
- Department of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany
| | | | - Joscha Maier
- X-Ray Imaging and Computed Tomography, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | | | - Marc Kachelrieß
- X-Ray Imaging and Computed Tomography, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Medical Faculty, University of Heidelberg, Heidelberg, Germany
| |
Collapse
|
3
|
Maier J, Lebedev S, Erath J, Eulig E, Sawall S, Fournié E, Stierstorfer K, Lell M, Kachelrieß M. Deep learning-based coronary artery motion estimation and compensation for short-scan cardiac CT. Med Phys 2021; 48:3559-3571. [PMID: 33959983 DOI: 10.1002/mp.14927] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 04/18/2021] [Accepted: 04/23/2021] [Indexed: 12/12/2022] Open
Abstract
PURPOSE During a typical cardiac short scan, the heart can move several millimeters. As a result, the corresponding CT reconstructions may be corrupted by motion artifacts. Especially the assessment of small structures, such as the coronary arteries, is potentially impaired by the presence of these artifacts. In order to estimate and compensate for coronary artery motion, this manuscript proposes the deep partial angle-based motion compensation (Deep PAMoCo). METHODS The basic principle of the Deep PAMoCo relies on the concept of partial angle reconstructions (PARs), that is, it divides the short scan data into several consecutive angular segments and reconstructs them separately. Subsequently, the PARs are deformed according to a motion vector field (MVF) such that they represent the same motion state and summed up to obtain the final motion-compensated reconstruction. However, in contrast to prior work that is based on the same principle, the Deep PAMoCo estimates and applies the MVF via a deep neural network to increase the computational performance as well as the quality of the motion compensated reconstructions. RESULTS Using simulated data, it could be demonstrated that the Deep PAMoCo is able to remove almost all motion artifacts independent of the contrast, the radius and the motion amplitude of the coronary artery. In any case, the average error of the CT values along the coronary artery is about 25 HU while errors of up to 300 HU can be observed if no correction is applied. Similar results were obtained for clinical cardiac CT scans where the Deep PAMoCo clearly outperforms state-of-the-art coronary artery motion compensation approaches in terms of processing time as well as accuracy. CONCLUSIONS The Deep PAMoCo provides an efficient approach to increase the diagnostic value of cardiac CT scans even if they are highly corrupted by motion.
Collapse
Affiliation(s)
- Joscha Maier
- German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Sergej Lebedev
- German Cancer Research Center (DKFZ), Heidelberg, Germany.,Ruprecht-Karls-University, Heidelberg, Germany.,Siemens Healthineers, Forchheim, Germany
| | - Julien Erath
- German Cancer Research Center (DKFZ), Heidelberg, Germany.,Ruprecht-Karls-University, Heidelberg, Germany.,Siemens Healthineers, Forchheim, Germany
| | - Elias Eulig
- German Cancer Research Center (DKFZ), Heidelberg, Germany.,Ruprecht-Karls-University, Heidelberg, Germany
| | - Stefan Sawall
- German Cancer Research Center (DKFZ), Heidelberg, Germany.,Ruprecht-Karls-University, Heidelberg, Germany
| | | | | | - Michael Lell
- Klinikum Nürnberg, Paracelsus Medical University, Nürnberg, Germany
| | - Marc Kachelrieß
- German Cancer Research Center (DKFZ), Heidelberg, Germany.,Ruprecht-Karls-University, Heidelberg, Germany
| |
Collapse
|
4
|
Abdullah KA, McEntee MF, Reed W, Kench PL. Evaluation of an integrated 3D-printed phantom for coronary CT angiography using iterative reconstruction algorithm. J Med Radiat Sci 2020; 67:170-176. [PMID: 32219989 PMCID: PMC7476188 DOI: 10.1002/jmrs.387] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 02/26/2020] [Accepted: 03/02/2020] [Indexed: 02/05/2023] Open
Abstract
INTRODUCTION 3D-printed imaging phantoms are now increasingly available and used for computed tomography (CT) dose optimisation study and image quality analysis. The aim of this study was to evaluate the integrated 3D-printed cardiac insert phantom when evaluating iterative reconstruction (IR) algorithm in coronary CT angiography (CCTA) protocols. METHODS The 3D-printed cardiac insert phantom was positioned into a chest phantom and scanned with a 16-slice CT scanner. Acquisitions were performed with CCTA protocols using 120 kVp at four different tube currents, 300, 200, 100 and 50 mA (protocols A, B, C and D, respectively). The image data sets were reconstructed with a filtered back projection (FBP) and three different IR algorithm strengths. The image quality metrics of image noise, signal-noise ratio (SNR) and contrast-noise ratio (CNR) were calculated for each protocol. RESULTS Decrease in dose levels has significantly increased the image noise, compared to FBP of protocol A (P < 0.001). As a result, the SNR and CNR were significantly decreased (P < 0.001). For FBP, the highest noise with poor SNR and CNR was protocol D with 19.0 ± 1.6 HU, 18.9 ± 2.5 and 25.1 ± 3.6, respectively. For IR algorithm, the highest strength (AIDR3Dstrong ) yielded the lowest noise with excellent SNR and CNR. CONCLUSIONS The use of IR algorithm and increasing its strengths have reduced noise significantly and thus increased the SNR and CNR when compared to FBP. Therefore, this integrated 3D-printed phantom approach could be used for dose optimisation study and image quality analysis in CCTA protocols.
Collapse
Affiliation(s)
| | - Mark F. McEntee
- Discipline of Medical Radiation SciencesFaculty of Health SciencesThe University of SydneyLidcombeNew South WalesAustralia
| | - Warren Reed
- Discipline of Medical Radiation SciencesFaculty of Health SciencesThe University of SydneyLidcombeNew South WalesAustralia
| | - Peter L. Kench
- Discipline of Medical Radiation SciencesFaculty of Health SciencesThe University of SydneyLidcombeNew South WalesAustralia
| |
Collapse
|
5
|
Abstract
Cardiac imaging has a pivotal role in the prevention, diagnosis and treatment of ischaemic heart disease. SPECT is most commonly used for clinical myocardial perfusion imaging, whereas PET is the clinical reference standard for the quantification of myocardial perfusion. MRI does not involve exposure to ionizing radiation, similar to echocardiography, which can be performed at the bedside. CT perfusion imaging is not frequently used but CT offers coronary angiography data, and invasive catheter-based methods can measure coronary flow and pressure. Technical improvements to the quantification of pathophysiological parameters of myocardial ischaemia can be achieved. Clinical consensus recommendations on the appropriateness of each technique were derived following a European quantitative cardiac imaging meeting and using a real-time Delphi process. SPECT using new detectors allows the quantification of myocardial blood flow and is now also suited to patients with a high BMI. PET is well suited to patients with multivessel disease to confirm or exclude balanced ischaemia. MRI allows the evaluation of patients with complex disease who would benefit from imaging of function and fibrosis in addition to perfusion. Echocardiography remains the preferred technique for assessing ischaemia in bedside situations, whereas CT has the greatest value for combined quantification of stenosis and characterization of atherosclerosis in relation to myocardial ischaemia. In patients with a high probability of needing invasive treatment, invasive coronary flow and pressure measurement is well suited to guide treatment decisions. In this Consensus Statement, we summarize the strengths and weaknesses as well as the future technological potential of each imaging modality.
Collapse
|
6
|
Hahn J, Bruder H, Rohkohl C, Allmendinger T, Stierstorfer K, Flohr T, Kachelrieß M. Motion compensation in the region of the coronary arteries based on partial angle reconstructions from short-scan CT data. Med Phys 2017; 44:5795-5813. [DOI: 10.1002/mp.12514] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 07/24/2017] [Accepted: 07/28/2017] [Indexed: 11/05/2022] Open
Affiliation(s)
- Juliane Hahn
- Siemens Healthcare GmbH; Forchheim Germany
- German Cancer Research Center; Heidelberg Germany
| | | | | | | | | | | | | |
Collapse
|
7
|
Optimization of the alpha image reconstruction – an iterative CT-image reconstruction with well-defined image quality metrics. Z Med Phys 2017; 27:180-192. [DOI: 10.1016/j.zemedi.2017.04.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 04/04/2017] [Accepted: 04/06/2017] [Indexed: 11/19/2022]
|
8
|
Andrew M, John H. The challenge of coronary calcium on coronary computed tomographic angiography (CCTA) scans: effect on interpretation and possible solutions. Int J Cardiovasc Imaging 2015; 31 Suppl 2:145-57. [DOI: 10.1007/s10554-015-0773-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 09/15/2015] [Indexed: 11/25/2022]
|
9
|
Improving head and neck CTA with hybrid and model-based iterative reconstruction techniques. Clin Radiol 2015; 70:1252-9. [PMID: 26227475 DOI: 10.1016/j.crad.2015.06.095] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 06/09/2015] [Accepted: 06/25/2015] [Indexed: 11/23/2022]
Abstract
AIM To compare image quality of head and neck computed tomography angiography (CTA) reconstructed with filtered back projection (FBP), hybrid iterative reconstruction (HIR) and model-based iterative reconstruction (MIR) algorithms. MATERIALS AND METHODS The raw data of 34 studies were simultaneously reconstructed with FBP, HIR (iDose(4), Philips Healthcare, Best, the Netherlands), and with a prototype version of a MIR algorithm (IMR, Philips Healthcare). Objective (contrast-to-noise ratio [CNR], vascular contrast, automatic vessel analysis [AVA], stenosis grade) and subjective image quality (ranking at level of the circle of Willis, carotid bifurcation, and shoulder) of the five reconstructions were compared using repeated-measures analysis of variance (ANOVA) and post-hoc analysis. RESULTS Vascular contrast was significantly higher in both the circle of Willis and carotid bifurcation with both levels of MIR compared to the other reconstruction methods (all p<0.0001). The CNR was highest for high MIR, followed by low MIR, high HIR, mid HIR and FBP (p<0.001 except low MIR versus high HIR; p>0.33). AVA showed most complete carotids in both MIR-levels, followed by high HIR (p>0.08), mid HIR (p<0.023) and FBP (p<0.010), vertebral arteries completeness was similar (p=0.40 and p=0.06). Stenosis grade showed no significant differences (p=0.16). High HIR showed the best subjective image quality at the circle of Willis and carotid bifurcation level, followed by mid HIR. At shoulder level, low MIR and high HIR were ranked best, followed by high MIR. CONCLUSION Objectively, MIR significantly improved the overall image quality, reduced image noise, and improved automated vessel analysis, whereas FBP showed the lowest objective image quality. Subjectively, the highest level of HIR was considered superior at the level of the circle of Willis and the carotid bifurcation, and along with the lowest level of MIR for the origins of the neck arteries at shoulder level.
Collapse
|
10
|
Hofmann C, Sawall S, Knaup M, Kachelrieß M. Alpha image reconstruction (AIR): A new iterative CT image reconstruction approach using voxel-wise alpha blending. Med Phys 2014; 41:061914. [DOI: 10.1118/1.4875975] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
11
|
Suchá D, Willemink MJ, de Jong PA, Schilham AMR, Leiner T, Symersky P, Budde RPJ. The impact of a new model-based iterative reconstruction algorithm on prosthetic heart valve related artifacts at reduced radiation dose MDCT. Int J Cardiovasc Imaging 2014; 30:785-93. [PMID: 24474347 DOI: 10.1007/s10554-014-0379-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Accepted: 01/20/2014] [Indexed: 11/28/2022]
Abstract
To assess the impact of hybrid iterative reconstruction (IR) and novel model-based iterative reconstruction (IMR) and dose reduction on prosthetic heart valve (PHV) related artifacts and objective image quality. One transcatheter and two mechanical PHVs were embedded in diluted contrast-gel, inserted in an anthropomorphic phantom and imaged stationary with retrospectively ECG-gated computed tomography. Eight acquisitions were obtained of each PHV at 120 kV, 600 mAs (routine), 300 and 150 mAs (reduced dose). Data were reconstructed with filtered back projection (FBP), IR and IMR. Hypodense and hyperdense artifact volumes were quantified using two threshold filters. Signal-to-noise (SNR) and contrast-to-noise (CNR) ratios were calculated. Artifact volumes differed significantly between reconstruction algorithms for all PHVs (P < 0.005). Compared to FBP, IR decreased overall hypodense and hyperdense artifact volumes; at 150 mAs by 53 and 20 % (IR) and 67 and 23 % (IMR), respectively and significantly increased SNR and CNR at all doses (P < 0.012). Even at reduced dose, IMR resulted in higher image quality than routine dose FBP and IR. Iterative reconstruction and particularly IMR significantly reduce PHV-related artifacts and improve objective image quality in non-pulsatile conditions, even in reduced-dose images. Also, this study suggests that IMR allows for more radiation dose reduction in comparison to hybrid IR while maintaining high image quality.
Collapse
Affiliation(s)
- Dominika Suchá
- Department of Radiology, University Medical Center Utrecht, Heidelberglaan 100, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands,
| | | | | | | | | | | | | |
Collapse
|
12
|
Hofmann C, Knaup M, Kachelrieß M. Effects of ray profile modeling on resolution recovery in clinical CT. Med Phys 2014; 41:021907. [DOI: 10.1118/1.4862510] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|
13
|
Recent developments of dual-energy CT in oncology. Eur Radiol 2014; 24:930-9. [DOI: 10.1007/s00330-013-3087-4] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 11/14/2013] [Accepted: 12/06/2013] [Indexed: 12/27/2022]
|