Yu-Kun Pan1, Ming-Hua Sun2, Jia-Jia Wang1, Xing-Biao Chen3, Xiao-Jing Kan2, Ying-Hui Ge2, Zhi-Ping Guo4. 1. Department of Radiology, Central China Fuwai Hospital, People's Hospital of Zhengzhou University, Zhengzhou, China. 2. Department of Radiology, Henan Provincial People's Hospital, Department of Radiology of Central China Fuwai Hospital, Central China Fuwai Hospital of Zhengzhou University, Zhengzhou, China. 3. Clinical Science, Philips Healthcare, Shanghai, China. 4. Central China Fuwai Hospital, Zhengzhou, China.
Abstract
BACKGROUND: This study aimed to evaluate the effects of different iterative reconstruction (IR) algorithms on coronary artery calcium (CAC) score quantification using the reduced radiation dose (RRD) protocol in an anthropomorphic phantom and in patients. METHODS: A thorax phantom, containing 9 calcification inserts with varying hydroxyapatite (HA) densities, was scanned with the reference protocol [120 kv, 80 mAs, filtered back projection (FBP)] and RRD protocol (120 kV, 20-80 mAs, 5 mAs interval) using a 256-slice computed tomography (CT) scanner. Raw data were reconstructed with different reconstruction algorithms [iDose4 levels 1-7 and iterative model reconstruction (IMR) levels 1-3]. Signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and Agatston score (AS) were calculated for each image series. The correction factor was derived from linear regression analysis between the reference image series and other image series with different parameters. Additionally, 40 patients were scanned with the RRD protocol (50 mAs) and reconstructed with FBP, iDose4 level 4, and IMR level 2. AS was calculated for the 3-group image series, and was corrected by applying a correction factor for the IMR group. The agreement of risk stratification with different reconstruction algorithms was also analyzed. RESULTS: For the phantom study, the iDose4 and IMR groups had significantly higher SNR and CNR than the FBP group (all P<0.05). There were no significant differences in the total AS after comparing image series reconstructed with iDose4 (level 1-7) and FBP (all P>0.05), while AS from the IMR (level 1-3) image series were lower than the FBP group (all P<0.05). The tube current of 50 mAs was determined for the clinical study, and the correction factor was 1.14. For the clinical study, the median AS from the iDose4 and IMR groups were both significantly lower compared to the FBP image series [(112.89 (63.01, 314.09), 113.22 (64.78, 364.95) vs. 118.59 (65.05, 374.48), both P<0.05]. After applying the correction factor, the adjusted AS from the IMR group was not significantly different from that of the FBP group [126.48 (69.62, 355.85) vs. 118.59 (65.05, 374.48), P=0.145]. Moreover, the agreement in risk stratification between FBP and IMR improved from 0.81 to 0.85. CONCLUSIONS: The RRD CAC scoring scan using the IMR reconstruction algorithm is clinically feasible, and a correction factor can help reduce the AS underestimation effect. 2021 Quantitative Imaging in Medicine and Surgery. All rights reserved.
BACKGROUND: This study aimed to evaluate the effects of different iterative reconstruction (IR) algorithms on coronary artery calcium (CAC) score quantification using the reduced radiation dose (RRD) protocol in an anthropomorphic phantom and in patients. METHODS: A thorax phantom, containing 9 calcification inserts with varying hydroxyapatite (HA) densities, was scanned with the reference protocol [120 kv, 80 mAs, filtered back projection (FBP)] and RRD protocol (120 kV, 20-80 mAs, 5 mAs interval) using a 256-slice computed tomography (CT) scanner. Raw data were reconstructed with different reconstruction algorithms [iDose4 levels 1-7 and iterative model reconstruction (IMR) levels 1-3]. Signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and Agatston score (AS) were calculated for each image series. The correction factor was derived from linear regression analysis between the reference image series and other image series with different parameters. Additionally, 40 patients were scanned with the RRD protocol (50 mAs) and reconstructed with FBP, iDose4 level 4, and IMR level 2. AS was calculated for the 3-group image series, and was corrected by applying a correction factor for the IMR group. The agreement of risk stratification with different reconstruction algorithms was also analyzed. RESULTS: For the phantom study, the iDose4 and IMR groups had significantly higher SNR and CNR than the FBP group (all P<0.05). There were no significant differences in the total AS after comparing image series reconstructed with iDose4 (level 1-7) and FBP (all P>0.05), while AS from the IMR (level 1-3) image series were lower than the FBP group (all P<0.05). The tube current of 50 mAs was determined for the clinical study, and the correction factor was 1.14. For the clinical study, the median AS from the iDose4 and IMR groups were both significantly lower compared to the FBP image series [(112.89 (63.01, 314.09), 113.22 (64.78, 364.95) vs. 118.59 (65.05, 374.48), both P<0.05]. After applying the correction factor, the adjusted AS from the IMR group was not significantly different from that of the FBP group [126.48 (69.62, 355.85) vs. 118.59 (65.05, 374.48), P=0.145]. Moreover, the agreement in risk stratification between FBP and IMR improved from 0.81 to 0.85. CONCLUSIONS: The RRD CAC scoring scan using the IMR reconstruction algorithm is clinically feasible, and a correction factor can help reduce the AS underestimation effect. 2021 Quantitative Imaging in Medicine and Surgery. All rights reserved.
Authors: Bálint Szilveszter; Hesham Elzomor; Mihály Károlyi; Márton Kolossváry; Rolf Raaijmakers; Kálmán Benke; Csilla Celeng; Andrea Bartykowszki; Zsolt Bagyura; Árpád Lux; Béla Merkely; Pál Maurovich-Horvat Journal: Int J Cardiovasc Imaging Date: 2015-08-19 Impact factor: 2.357
Authors: Michael J Blaha; Martin Bødtker Mortensen; Sina Kianoush; Rajesh Tota-Maharaj; Miguel Cainzos-Achirica Journal: JACC Cardiovasc Imaging Date: 2017-08
Authors: Mihály Károlyi; Bálint Szilveszter; Márton Kolossváry; Richard A P Takx; Csilla Celeng; Andrea Bartykowszki; Ádám L Jermendy; Alexisz Panajotu; Júlia Karády; Rolf Raaijmakers; Walter Giepmans; Béla Merkely; Pál Maurovich-Horvat Journal: Eur J Radiol Date: 2016-12-14 Impact factor: 3.528
Authors: Marleen Vonder; Carlijn M van der Aalst; Rozemarijn Vliegenthart; Peter M A van Ooijen; Dirkjan Kuijpers; Jan Willem Gratama; Harry J de Koning; Matthijs Oudkerk Journal: Acad Radiol Date: 2017-08-23 Impact factor: 3.173
Authors: Matthew J Budoff; Thomas Mayrhofer; Maros Ferencik; Daniel Bittner; Kerry L Lee; Michael T Lu; Adrian Coles; James Jang; Mayil Krishnam; Pamela S Douglas; Udo Hoffmann Journal: Circulation Date: 2017-08-28 Impact factor: 29.690
Authors: Annemarie M den Harder; Martin J Willemink; Ronald L A W Bleys; Pim A de Jong; Ricardo P J Budde; Arnold M R Schilham; Tim Leiner Journal: Int J Cardiovasc Imaging Date: 2014-05-03 Impact factor: 2.357
Authors: Annemarie M den Harder; Jelmer M Wolterink; Martin J Willemink; Arnold M R Schilham; Pim A de Jong; Ricardo P J Budde; Hendrik M Nathoe; Ivana Išgum; Tim Leiner Journal: Eur J Radiol Date: 2016-09-30 Impact factor: 3.528
Authors: Cynthia H McCollough; Stefan Ulzheimer; Sandra S Halliburton; Kaiss Shanneik; Richard D White; Willi A Kalender Journal: Radiology Date: 2007-05 Impact factor: 11.105