Impact of iterative reconstruction on CT coronary calcium quantification

Kurata, Akira; Dharampal, Anoeshka S.; Dedic, Admir; Feyter, Pim J. de; Krestin, Gabriël P.; Dijkshoorn, Marcel L.; Nieman, Koen

doi:10.1007/s00330-013-3022-8

Cited by 67 publications

(52 citation statements)

References 30 publications

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“…This finding is in agreement with recent studies, which show smaller variability for mass scores [26,38,41,42]. Many recent studies have shown that increasing levels of iterative reconstruction causes a reduction in CCS [12,16,40,[43][44][45][46][47][48]. This result was also established in our study.…”

Section: Discussionsupporting

confidence: 83%

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Influence of iterative reconstruction on coronary calcium scores at multiple heart rates: a multivendor phantom study on state-of-the-art CT systems

Werf

Willemink

Willems

et al. 2017

Int J Cardiovasc Imaging

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The objective of this study was to evaluate the influence of iterative reconstruction on coronary calcium scores (CCS) at different heart rates for four state-of-the-art CT systems. Within an anthropomorphic chest phantom, artificial coronary arteries were translated in a water-filled compartment. The arteries contained three different calcifications with low (38 mg), medium (80 mg) and high (157 mg) mass. Linear velocities were applied, corresponding to heart rates of 0, < 60, 60-75 and > 75 bpm. Data were acquired on four state-of-the-art CT systems (CT1-CT4) with routinely used CCS protocols. Filtered back projection (FBP) and three increasing levels of iterative reconstruction (L1-L3) were used for reconstruction. CCS were quantified as Agatston score and mass score. An iterative reconstruction susceptibility (IRS) index was used to assess susceptibility of Agatston score (IRS AS ) and mass score (IRS MS ) to iterative reconstruction. IRS values were compared between CT systems and between calcification masses. For each heart rate, differences in CCS of iterative reconstructed images were evaluated with CCS of FBP images as reference, and indicated as small (< 5%), medium (5-10%) or large (> 10%). Statistical analysis was performed with repeated measures ANOVA tests. While subtle differences were found for Agatston scores of low mass calcification, medium and high mass calcifications showed increased CCS up to 77% with increasing heart rates. IRS AS of CT1-T4 were 17, 41, 130 and 22% higher than IRS MS . Not only were IRS significantly different between all CT systems, but also between calcification masses. Up to a fourfold increase in IRS was found for the low mass calcification in comparison with the high mass calcification. With increasing iterative reconstruction strength, maximum decreases of 21 and 13% for Agatston and mass score were found. In total, 21 large differences between Agatston scores from FBP and iterative reconstruction were found, while only five large differences were found between FBP and iterative reconstruction mass scores. Iterative reconstruction results in reduced CCS. The effect of iterative reconstruction on CCS is more prominent with low-density calcifications, high heart rates and increasing iterative reconstruction strength.

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Section: Discussionsupporting

confidence: 83%

“…The effect of iterative reconstruction on quantitative measurements in cardiovascular imaging has been subject of recent studies [11][12][13][14][15][16][17][18]. One of the most commonly used cardiovascular risk assessment tools in CT is coronary calcium scoring (CCS).…”

Section: Introductionmentioning

confidence: 99%

Influence of iterative reconstruction on coronary calcium scores at multiple heart rates: a multivendor phantom study on state-of-the-art CT systems

Werf

Willemink

Willems

et al. 2017

Int J Cardiovasc Imaging

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“…[8][9][10] An in vivo study by Kurata et al revealed that Agatston scores tend to decrease as sonogram affirmed iterative reconstruction (SAFIRE) levels increase. 18) Our observation that Agatston scores tend to decrease as IR levels increase further support these conclusions. The results of the present study, therefore, suggest that similar Agatston scores may be obtained when either standard-dose FBP or low-dose IR protocols are utilized.…”

Section: Discussionsupporting

confidence: 73%

The Impact of Iterative Reconstruction on Reducing the Radiation Dose for Coronary Calcium Scoring: An Investigation Using Pulsating Calcified Coronary Phantom

Kobayashi

Yukihisa

et al. 2016

J St. Marianna Univ

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Aim:The aim of the present study was to evaluate the effects of radiation dose reduction and iterative reconstruction protocols on coronary artery calcium (Agatston) scores using a pulsating cardiac phantom. Materials and Methods:We used a pulsating cardiac phantom containing three calcified cubes of different sizes (3-mm diameter: small, 4-mm diameter: medium, and 5-mm diameter: large) and four calcified hydroxyapatite cubes of varying density in order to model coronary artery calcification: 5% (44HU), 15% (233HU), 25% (586HU), and 35% (792HU). Images were acquired with a 320-slice MDCT (Aquilion ONE ViSION Edition, Toshiba, Nasu, Japan), using ECG gated volume scans with tube potential:120kV, 275 ms rotation time, 60, 70, 100, 150 and 240mA tube current. The Agatston scores at all dose variations in all five reconstruction methods (filtered back projection [FBP] and adaptive iterative dose reconstruction [AIDR3D]: Weak, Mild, Standard, and Strong) for all three phantom sizes were compared to the reference dose protocol reconstructed with FBP. Results: When the FBP and AIDR 3D: Weak protocol were used, Agatston scores significantly increased in all phantom sizes as doses of radiation decreased (p<0.001). When the AIDR3D: Mild, Standard, and Strong protocols were used, no significant differences in Agatston scores were observed for any phantom size among different radiation dose protocols. For all radiation dose protocols, Agatston scores significantly decreased as IR levels increased (p<0.003, respectively). When AIDR 3D: Mild was used, no significant differences in Agatston scores were observed between IR and FBP protocols for any phantom size. Conclusions: The AIDR3D: Mild protocol allowed for significant reductions in radiation dose relative to standard FBP protocols, without influencing Agatston scores. Therefore, evaluation of CAC score using a combination of low-dose radiation and IR may present a reliable alternative to conventional CAC scoring.

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“…Increasing levels of ASIR were associated with progressive decreases in Agatston and volume scores but not mass scores compared to FBP (60). Studies with IRIS and SAFIRE showed similar results: Agatston, volume, and mass scores were lower changing non-zero scores to zero in 4% of patients (61). Similarly, iDose 4 and IMR images each yielded 7% lower calcium score compared to FBP images with a risk reclassification rate of 2.4% (57).…”

Section: Coronary Stent Assessmentsupporting

confidence: 56%

The role of advanced reconstruction algorithms in cardiac CT

Halliburton

Tanabe

Partovi

et al. 2017

Cardiovasc. Diagn. Ther.

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Advanced non-linear iterative reconstruction (IR) algorithms have been introduced by all vendors as an alternative to traditional, linear filtered back projection (FBP) reconstruction ( Table 1). FBP is a simple reconstruction technique that requires relatively little computational processing, but is associated with higher noise and poor contrast resolution. Noise can be reduced in FBP only by increasing the radiation dose. IR algorithms operate by initially generating an expected dataset based on modeling, which is then compared to the actual, acquired dataset. Noise is detected and removed by using the difference between the anticipated and actual datasets using a process of iterative steps. All commercial IR algorithms employ statistics-model based de-noising in the image domain, raw (projection) data domain, or both. Statistics model-based algorithms operate by assigning a lower value to data with higher statistical uncertainty (noise). Some IR algorithms, described as partial model-based, additionally employ models of scanner geometry to estimate the acquired data. Full model-based IR algorithms, employ complete system models that include simulation of X-ray interaction with the imaged object. Statistics-model based algorithms can be utilized to either improve image quality at the same radiation dose or maintain image quality at a lower radiation dose compared to FBP. However, combining dose management with image quality improvements simultaneously is limited. Model-based IR can provide image quality improvements at lower doses. Model-based algorithms are also more likely to reduce other artifacts in addition to noise as well as improve spatial resolution.Although IR algorithms have been utilized in nuclear medicine for several decades, widespread use in CT is recent and facilitated by advances in computational processing. Cardiovascular CT imagers were early adopters of IR algorithms because most cardiovascular clinical targets are robust to changes in noise. Rigorous validation has come from both retrospective and prospective studies demonstrating non-inferiority of coronary CT data acquired at lower doses and reconstructed with IR techniques compared to standard dose data reconstructed with FBP. Other clinical studies have validated the diagnostic utility of low-dose coronary CT angiograms (CTA) reconstructed with IR algorithms using invasive coronary angiography (ICA) as a standard of reference (1-3).

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Impact of iterative reconstruction on CT coronary calcium quantification

Abstract: SAFIRE noise reduction techniques significantly affected the CAC, which potentially alters perceived cardiovascular risk.

Cited by 67 publications

References 30 publications

Influence of iterative reconstruction on coronary calcium scores at multiple heart rates: a multivendor phantom study on state-of-the-art CT systems

Influence of iterative reconstruction on coronary calcium scores at multiple heart rates: a multivendor phantom study on state-of-the-art CT systems

The Impact of Iterative Reconstruction on Reducing the Radiation Dose for Coronary Calcium Scoring: An Investigation Using Pulsating Calcified Coronary Phantom

The role of advanced reconstruction algorithms in cardiac CT

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