Schindler, Thomas

RERO DOC Digital Library

EDITORIAL COMMENTAdapting the contrast material protocol to the body surfacearea for an optimized low-dose CT coronary angiographywith prospective ECG-triggering: a new evolving concept?Thomas Hellmut SchindlerReceived: 8 February 2010 / Accepted: 12 February 2010 / Published online: 25 February 2010 Springer Science+Business Media, B.V. 2010CT coronary angiography (CTA) with the applicationof 64-slice CT scanners has been increasingly usedfor the non-invasive identification of subclinicalCAD, exclusion of morphologically focal epicardiallesions (\50% diameter stenosis) in individuals witha low-to-intermediate probability of the presence ofCAD, and for 3D image fusion with SPECT or PET-determined myocardial perfusion imaging [1–5]. Thediagnostic value of CTA in patients with highprobability of the presence of CAD or clinicallymanifest CAD, however, is limited due to coronaryartery calcification (CAC)-induced blooming artifacts[5]. Another aspect is that the assessment of epicar-dial lesions still remains semiquantitative owing tolimitations in spatial resolution and motion artifacts.Apart from these technical limitations, the relativelyhigh radiation exposure for cardiovascular risk indi-viduals during CTA has raised concerns for a morewidespread clinical application [6, 7]. In this direc-tion, however, the increasing use of prospectiveECG-triggering or so called ‘‘snap-and-shoot mode’’,instead of conventional spiral image acquisitionduring CTA, has substantially reduced the radiationexposure of CTA from about 15–20 mSv to 1–3 mSv, while maintaining image quality and diag-nostic accuracy [7, 8]. Similarly, ECG-controlledtube current modulation during helical CTA acquisi-tion has also been shown to effectively reduceradiation exposure down to 5–7 mSv [9, 10].In the present issue of the International Journal ofCardiovascular Imaging, Pazhenkottil et al. [11],report of a body surface area (BSA)-adapted contrastmaterial (CM) protocol for CTA, which resulted in acomparable coronary contrast enhancement indepen-dent of the individual BSA. This appears to representan elegant approach to overcome, at least in part, aknown variability in contrast attenuation of thecoronary vessels [12] due to CM bolus dilutiondepending on the blood volume of the individualduring CTA. As an increase in BSA is paralleled byan increase in blood volume, the authors testedwhether a BSA-adapted CM protocol could compen-sate for the dilution of the CM depending on theblood volume of the individual person examined withCTA. An indeed, as it was observed in the presentstudy [11], the range and standard deviation of thecoronary attenuation were smaller in the BSA-adapted protocol than in the group with standardCM protocol. These observations may suggest a wellbalanced and consistent attenuation of the coronaryvessels throughout a large range of BSA. Whethersuch a BSA-adapted CM protocol results indeed inEditorial comment on the article of Pazhenkottil et al.(doi:10.1007/s10554-010-9594-3).T. H. Schindler (&)Department of Internal Medicine, Cardiovascular Center,6th Floor, Nuclear Cardiology, University Hospitals ofGeneva, Rue Gabrielle-Perret-Gentil 4, 1211 Geneva,Switzerlande-mail: thomas.schindler@hcuge.ch123Int J Cardiovasc Imaging (2010) 26:599–600DOI 10.1007/s10554-010-9604-5improved coronary vessel delineation as required forcoronary plaque imaging remains uncertain.Although CTA affords a reliable assessment ofcoronary artery plaque burden and arterial remodeling,an accurate qualitative and quantitative characteriza-tion of coronary plaque burden and its components hasremained a challenge. Plaque attenuation thresholdsmay vary significantly with intracoronary lumenattenuation [13] and choice of reconstruction kernels[12, 14]. The in the current study proposed BSA-adapted CM protocol could be another important stepin achieving a more consistent attenuation of theintracoronary lumen and, thereby, an improvement inthe delineation of the arterial wall in individuals withdifferent BSA or circulatory volume with CM dilution.On the other hand, it is equally possible that althoughthe proposed BSA-adapted protocol achieves a moreconsistent attenuation of the coronary lumen ascompared to a conventional rigid CM application, theintracoronary luminal contrast may not be sufficient toimprove the delineation of the arterial wall as neededfor imaging of coronary plaque burden. Thus, itremains a matter of ongoing research activities todefine the best BSA-adapted CM protocol with anappropriate amount of CM that enables not onlyconsistent intracoronary luminal attenuation but alsoan optimal delineation of the arterial wall for coronaryplaque imaging. Such optimized CM protocols forCTA, as suggested by Pazhenkottil et al. [11], may leadto a further improvement in the identification andquantitative assessment of coronary plaque burden andits components providing an important framework toevaluate but also to monitor potential beneficial effectsof primary or secondary preventive medical interven-tion on CAD process.References1. Haramati LB, Levsky JM, Jain VR et al (2009) CT angi-ography for evaluation of coronary artery disease in inner-city outpatients: an initial prospective comparison withstress myocardial perfusion imaging. Int J CardiovascImaging 25(3):303–3132. van der Wall EE, Schuijf JD, Schalij MJ, Jukema JW, BaxJJ (2009) CT angiography; useful in non-selected outpa-tients? Int J Cardiovasc Imaging 25(3):315–3183. von Kiedrowski H, Wiemer M, Franzke K et al (2009)Non-invasive coronary angiography: the clinical value ofmulti-slice computed tomography in the assessment ofpatients with prior coronary bypass surgery. Evaluatinggrafts and native vessels. Int J Cardiovasc Imaging25(2):161–1704. Bordeleau E, Lamonde A, Prenovault J et al (2007)Accuracy and rate of coronary artery segment visualizationwith CT angiography for the non-invasive detection ofcoronary artery stenoses. Int J Cardiovasc Imaging 23(6):771–7805. Raff GL, Gallagher MJ, O’Neill WW, Goldstein JA (2005)Diagnostic accuracy of noninvasive coronary angiographyusing 64-slice spiral computed tomography. J Am CollCardiol 46(3):552–5576. Hausleiter J, Meyer T, Hadamitzky M et al (2006) Radi-ation dose estimates from cardiac multislice computedtomography in daily practice: impact of different scanningprotocols on effective dose estimates. Circulation113(10):1305–13107. Husmann L, Valenta I, Gaemperli O et al (2008) Feasi-bility of low-dose coronary CT angiography: first experi-ence with prospective ECG-gating. Eur Heart J 29(2):191–1978. Husmann L, Herzog BA, Gaemperli O et al (2009) Diag-nostic accuracy of computed tomography coronary angi-ography and evaluation of stress-only single-photonemission computed tomography/computed tomographyhybrid imaging: comparison of prospective electro-cardiogram-triggering vs. retrospective gating. Eur Heart J30(5):600–6079. Hausleiter J, Meyer T (2008) Tips to minimize radiationexposure. J Cardiovasc Comput Tomogr 2(5):325–32710. Hausleiter J, Meyer T, Hermann F et al (2009) Estimatedradiation dose associated with cardiac CT angiography.JAMA 301(5):500–50711. Pazhenkottil A, Husmann L, Buechel R, et al. (2010)Validation of a new contrast material protocol adapted tobody surface area for optimized low-dose CT coronaryangiography with prospective ECG-triggering. Int J Car-diovasc Imaging (Epub ahead of print)12. Herzog BA, Husmann L, Valenta I et al (2009) Determi-nants of vessel contrast in BMI-adapted low dose CTcoronary angiography with prospective ECG-triggering.Int J Cardiovasc Imaging 25(6):625–63013. Cademartiri F, Mollet NR, Runza G et al (2005) Influenceof intracoronary attenuation on coronary plaque measure-ments using multislice computed tomography: observa-tions in an ex vivo model of coronary computedtomography angiography. Eur Radiol 15(7):1426–143114. Cademartiri F, La Grutta L, Runza G et al (2007) Influenceof convolution filtering on coronary plaque attenuationvalues: observations in an ex vivo model of multislicecomputed tomography coronary angiography. Eur Radiol17(7):1842–1849600 Int J Cardiovasc Imaging (2010) 26:599–600123

Adapting the contrast material protocol to the body surface area for an optimized low-dose CT coronary angiography with prospective ECG-triggering: a new evolving concept?

http://doc.rero.ch/record/314644/files/10554_2010_Article_9604.pdf

Adapting the contrast material protocol to the body surface area for an optimized low-dose CT coronary angiography with prospective ECG-triggering: a new evolving concept?

Abstract

Similar works

Full text

Available Versions

RERO DOC Digital Library