Calcium scoring using 64-slice MDCT, dual source CT and EBT: a comparative phantom study
Tóm tắt
Purpose Assessment of calcium scoring (Ca-scoring) on a 64-slice multi-detector computed tomography (MDCT) scanner, a dual-source computed tomography (DSCT) scanner and an electron beam tomography (EBT) scanner with a moving cardiac phantom as a function of heart rate, slice thickness and calcium density. Methods and materials Three artificial arteries with inserted calcifications of different sizes and densities were scanned at rest (0 beats per minute) and at 50–110 beats per minute (bpm) with an interval of 10 bpm using 64-slice MDCT, DSCT and EBT. Images were reconstructed with a slice thickness of 0.6 and 3.0 mm. Agatston score, volume score and equivalent mass score were determined for each artery. A cardiac motion susceptibility (CMS) index was introduced to assess the susceptibility of Ca-scoring to heart rate. In addition, a difference (Δ) index was introduced to assess the difference of absolute Ca-scoring on MDCT and DSCT with EBT. Results Ca-score is relatively constant up to 60 bpm and starts to decrease or increase above 70 bpm, depending on scoring method, calcification density and slice thickness. EBT showed the least susceptibility to cardiac motion with the smallest average CMS-index (2.5). The average CMS-index of 64-slice MDCT (9.0) is approximately 2.5 times the average CMS-index of DSCT (3.6). The use of a smaller slice thickness decreases the CMS-index for both CT-modalities. The Δ-index for DSCT at 0.6 mm (53.2) is approximately 30% lower than the Δ-index for 64-slice MDCT at 0.6 mm (72.0). The Δ-indexes at 3.0 mm are approximately equal for both modalities (96.9 and 102.0 for 64-slice MDCT and DSCT respectively). Conclusion Ca-scoring is influenced by heart rate, slice thickness and modality used. Ca-scoring on DSCT is approximately 50% less susceptible to cardiac motion as 64-slice MDCT. DSCT offers a better approximation of absolute calcium score on EBT than 64-slice MDCT when using a smaller slice thickness. A smaller slice thickness reduces the susceptibility to cardiac motion and reduces the difference between CT-data and EBT-data. The best approximation of EBT on CT is found for DSCT with a slice thickness of 0.6 mm.
Tài liệu tham khảo
Schmermund A, Mohlenkamp S, Erbel R (2003) Coronary artery calcium and its relationship to coronary artery disease. Cardiol Clin 21(4):521–534
Agatston AS, Janowitz WR, Hildner FJ et al (1990) Quantification of coronary artery calcium using ultrafast computed tomography. J Am Coll Cardiol 15(4):827–832
Callister TQ, Cooil B, Raya SP et al (1998) Coronary artery disease: improved reproducibility of calcium scoring with an electron-beam CT volumetric method. Radiology 208(3):807–814
Hoffmann U, Kwait DC, Handwerker J et al (2003) Vascular calcification in ex vivo carotid specimens: precision and accuracy of measurements with multi-detector row CT. Radiology 229(2):375–381
Hoffmann U, Siebert U, Bull-Stewart A et al (2006) Evidence for lower variability of coronary artery calcium mineral mass measurements by multi-detector computed tomography in a community-based cohort – consequences for progression studies. Eur J Radiol 57(3):396–402
Horiguchi J, Shen Y, Akiyama Y et al (2006) Electron beam CT versus 16-slice spiral CT: how accurately can we measure coronary artery calcium volume? Eur Radiol 16(2):374–380
Flohr T, McCollough C, Bruder H et al (2006) First performance evaluation of a dual-source CT (DSCT) system. Eur Radiol 16:256–268
Callister TQ, Raggi P, Cooil B et al (1998) Effect of HMG-CoA reductase inhibitors on coronary artery disease as assessed by electron-beam computed tomography. N Engl J Med 339:1972–1978
Budoff MJ, Lane KL, Bakhsheshi H et al (2000) Rates of progression of coronary calcium by electron beam tomography. Am J Cardiol 86:8–11
Schlosser T, Scheuermann T, Ulzheimer S et al (2007) In vitro evaluation of coronary stents and in-stent stenosis using a dynamic cardiac phantom and a 64-detector row CT scanner. Clin Res Cardiol 96:(online first)
Ulzheimer S, Kalender W (2003) Assessment of calcium scoring performance in cardiac computed tomography. Eur Radiol 13:484–497
Achenbach S, Ropers D, Holle J et al (2000) In-plane coronary arterial motion velocity: measurement with electron-beam CT. Radiology 216:457–463
Ohnesorge B, Flohr T, Fischbach R et al (2002) Reproducility of coronary calcium quantification in repeat examinations with retrospectively ECG-gated multisection spiral CT. Eur Radiol 12:1532–1540
Horiguchi J, Yamamoto H, Akiyama Y et al (2005) Variability of repeated coronary artery calcium measurements by 16-MDCT with retrospective reconstruction. AJR 184:1846–1917
Brown S, Hayball M, Coulden R (2000) Impact of motion artefact on the measurement of coronary calcium score. Br J Radiol 73:956–962
Stanford W, Thompson B, Burns T et al (2004) Coronary artery calcium quantification at multi-detector row helical CT versus electron-beam CT. Radiology 230:397–402
Horiguchi J, Shen Y, Akiyama Y et al (2005) Electron beam CT versus 16-MDCT on the variability of repeated coronary artery calcium measurements in a variable heart rate phantom. AJR 185:995–1000
Mühlenbruch G, Hohl C, Das M, Wildberger JE, Suess C, Klotz E, Flohr T, Koos R, Thomas C, Günther RW, Mahnken AH (2007) Evaluation of automated attenuation-based tube current adaptation for coronary calcium scoring in MDCT in a cohort of 262 patients. Eur Radiol 17(7):1850–1857
Horiguchi J, Yamamoto H, Hirai N et al (2006) Variability of repeated coronary artery calcium measurements on low-dose ECG-gated 16-MDCT. AJR 187:W1–W6
Moselewski F, Ferencik M, Achenbach S et al (2006) Threshold-dependent variability of coronary artery calcification measurements – implications for contrast-enhanced multi-detector row-computed tomography. Eur J Radiol 57:390–395
Thomas CK, Muhlenbruch G, Wildberger JE et al (2006) Coronary artery calcium scoring with multislice computed tomography: in vitro assessment of a low tube voltage protocol. Invest Radiol 41(9):668–673
Nelson JC, Kronmal RA, Carr JJ et al (2005) Measuring coronary calcium on CT images adjusted for density differences. Radiology 235(2):403–414