Causes of Interscan Variability of Coronary Artery Calcium Measurements at Electron-Beam CT

Lü, Bin; Budoff, Matthew J.; Zhuang, Nan; Child, Janis; Bakhsheshi, Hamid; Carson, Sivi; Mao, Songshou

doi:10.1016/s1076-6332(03)80310-0

Cited by 44 publications

(17 citation statements)

References 28 publications

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“…However, absolute differences of the mean values were the smallest of all scoring algorithms; when comparing the overall calcium mass of all six cylinders measured with the actual calcium mass of the six inserts (168.28 mg), the relative difference was +2.0% for 1-mm slices and −1.2% for 3-mm slices, both very accurate compared to, e.g., an interscan variability of 21.6% for the Agatston score and 17.8% for the calcium mass [31]. In accordance to this, Mao et al reported no significant difference between the true and measured values from 1.5-and 3-mm images for the volume score and calcium mass in EBCT [25].…”

Section: Discussionmentioning

confidence: 84%

The accuracy of 1- and 3-mm slices in coronary calcium scoring using multi-slice CT in vitro and in vivo

et al. 2006

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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.

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Section: Discussionmentioning

confidence: 84%

The accuracy of 1- and 3-mm slices in coronary calcium scoring using multi-slice CT in vitro and in vivo

et al. 2006

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“…It accumulates slice-wise the product of plaque area and a factor f that depends on the peak-intensity value within the plaque area. Although most existing patient data are based on Agatston scoring, this method has limitations, particularly regarding the considerable variability between examinations of up to 43% [6][7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

“…Recently, the volume score method was introduced [15], which is based on the product of the number of voxels containing calcium and the volume of one voxel. As compared to the Agatston method, the volume score has reduced the variability between examinations to some degree [6][7][8]10], however, it also has limitations. The volume score is vulnerable to overestimation of lesion size owing to partial volume effects.…”

Section: Introductionmentioning

confidence: 99%

ACCURATUM: improved calcium volume scoring using a mesh-based algorithm—a phantom study

et al. 2008

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To overcome the limitations of the classical volume scoring method for quantifying coronary calcifications, including accuracy, variability between examinations, and dependency on plaque density and acquisition parameters, a mesh-based volume measurement method has been developed. It was evaluated and compared with the classical volume scoring method for accuracy, i.e., the normalized volume (measured volume/ ground-truthed volume), and for variability between examinations (standard deviation of accuracy). A cardiac computed-tomography (CT) phantom containing various cylindrical calcifications was scanned using different tube voltages and reconstruction kernels, at various positions and orientations on the CT table and using different slice thicknesses. Mean accuracy for all plaques was significantly higher (p<0.0001) for the proposed method (1.220±0.507) than for the classical volume score (1.896± 1.095). In contrast to the classical volume score, plaque density (p=0.84), reconstruction kernel (p= 0.19), and tube voltage (p=0.27) had no impact on the accuracy of the developed method. In conclusion, the method presented herein is more accurate than classical calcium scoring and is less dependent on tube voltage, reconstruction kernel, and plaque density.

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“…The software packages allow for quantification of coronary calcification with poor to good inter-scan reproducibility [9] depending on the acquisition technique and scoring method. Quantitative volumetric scoring has been shown to have better interscan reproducibility than Agatston scoring [10][11][12]. Multi-detector CT has been reported to have better interscan reproducibility than EBT [9].…”

Section: Introductionmentioning

confidence: 99%

“…Multi-detector CT has been reported to have better interscan reproducibility than EBT [9]. Main factors for the variability between scans are partial volume errors, inconsistent breath-hold and inconsistent ECG triggering or gating (especially for arrhythmia) [12,13].…”

Section: Introductionmentioning

confidence: 99%

Influence of scoring parameter settings on Agatston and volume scores for coronary calcification

et al. 2004

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Current multi-detector CT and electron beam tomography (EBT) technology enables the evaluation of coronary calcification. Multiple software packages are available to quantify calcification using several scoring algorithms implementing user-definable scoring parameters. We investigated the effect of scoring parameters on the calcium score outcome. Three parameters (four-connected or eight-connected, lesion size threshold and interpolation) are evaluated. Their theoretical influence on the scoring outcome is shown using simplified examples. To evaluate the effect in real data, we performed calcium scoring on randomly chosen EBT scans from 50 participants in an epidemiological study. Both the Agatston and volume scores were calculated. Changing from eight-connected to four-connected connectivity decreased both Agatston and volume scores (mean variability Agatston 3.15% and volume score -3.52%). Decreasing the threshold from 4 to 2 pixels increased the calcium scores because smaller lesions were also selected as calcified plaques (mean variability Agatston 16.23% and volume score 18.66%). Finally, the use of interpolation had a large negative effect on the volume score (mean variability -29.67%) and almost no effect on the Agatston score. Parameter settings in software for quantification for coronary calcification affect the calcium score outcome. Therefore, parameter settings for calcium scoring should be standardized.

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Causes of Interscan Variability of Coronary Artery Calcium Measurements at Electron-Beam CT

Cited by 44 publications

References 28 publications

The accuracy of 1- and 3-mm slices in coronary calcium scoring using multi-slice CT in vitro and in vivo

The accuracy of 1- and 3-mm slices in coronary calcium scoring using multi-slice CT in vitro and in vivo

ACCURATUM: improved calcium volume scoring using a mesh-based algorithm—a phantom study

Influence of scoring parameter settings on Agatston and volume scores for coronary calcification

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