Zusammenfassung
Ziel: Beurteilung des Einflusses des Bodymass-Index (BMI) auf den Kontrast in den Koronararterien
bei der 64-Schicht-CT-Angiographie. Material und Methoden: Bei 62 Patienten wurde eineretrospektiv EKG-getriggerte 64-Schicht-CT-Koronarangiographie
(Röhrenspannung 120 kV, Strom-Zeit-Produkt 650 mAs) nach intravenöser Gabe von 80
ml jodhaltigem Kontrastmittel (320 mg/ml, 5 ml/s) durchgeführt. In der proximalen
rechten Koronararterie (RCA) und im linken koronaren Hauptstamm (LMA) wurden die Dichtewerte
(HU) gemessen und das Kontrast-zu-Rausch-Verhältnis (KRV) berechnet. Das KRV wurde
definiert als Differenz der mittleren Dichte im Gefäß von der mittleren Dichte im
angrenzenden Fettgewebe dividiert durch das Bildrauschen in der Aorta ascendens. Das
Körpergewicht und die -größe zum Zeitpunkt der CT-Untersuchung wurden vermerkt und
der BMI berechnet. Ergebnisse: Der mittlere BMI betrug 26,2 ± 3,2 kg/m2 (19,7 - 32,2 kg/m2 ). Die mittlere Dichte in der LMA betrug 330 ± 64 HU und 309 ± 68 HU in der RCA. Das
KRV in der LMA betrug 16,7 ± 3,8 und das KRV in der RCA betrug 15,9 ± 3,6. Das Bildrauschen
in der Aorta ascendens korrelierte signifikant mit dem BMI (r = 0,36, p < 0,01). Eine
niedrige negative Korrelation bestand zwischen dem BMI und der Dichte in der LMA (r
= - 0,28, p < 0,05), jedoch nicht zwischen dem BMI und der Dichte in der RCA (r =
- 0,21, p = 0,12). Eine signifikante negative Korrelation bestand zwischen dem BMI
und dem KRV in der RCA (r = - 0,41, p < 0,05) und dem KRV in der LMA (r = - 0,47,
p < 0,001). Schlussfolgerung: Bei konstantem Untersuchungs- und Kontrastmittelprotokoll sinkt mit zunehmendem BMI
das KRV in den Koronararterien. Dies legt eine zukünftige Umstellung bisheriger standardisierter
und fixer Untersuchungsprotokolle hin zu individuell adaptierten CT-Koronarangiographie-Protokollen
mit variablen Parametern nahe.
Abstract
Purpose: To evaluate the influence of the body mass index (BMI) on coronary artery opacification
in 64-slice CT. Material and Methods: Sixty-two patients retrospectively underwent ECG-gated 64-slice CT coronary angiography
(tube potential 120 kV, tube current time product 650 mAs) after intravenous injection
of 80 ml of iodinated contrast agent (320 mg/ml, 5 ml/s). Attenuation values (HU)
were measured and contrast-to-noise ratios (CNR) were calculated in the right coronary
artery (RCA) and left main artery (LMA). The CNR was defined as the difference between
the mean attenuation in the vessel and the mean attenuation in the perivascular fat
tissue divided by the image noise in the ascending aorta. The height and weight of
the patients at the time of the CT scan were recorded and the BMI was calculated.
Results: The mean BMI was 26.2 ± 3.2 kg/m2 (range 19.7 - 32.2 kg/m2 ), the mean attenuation in the LMA was 330 ± 64 HU, and the mean attenuation in the
RCA was 309 ± 68 HU. The CNR in the LMA was 16.7 ± 3.8, and the CNR in the RCA was
15.9 ± 3.6. The image noise in the ascending aorta significantly correlated with the
BMI (r = 0.36, p < 0.01). A weak negative correlation was found between the BMI and
LMA attenuation (r = - 0.28, p < 0.05), whereas no significant correlation was found
for the RCA (r = - 0.21, p = 0.12). A significant negative correlation was found
between the BMI and the CNR in the RCA (r = - 0.41, p < 0.05) and the LMA (r = -
0.47, p < 0.001). Conclusion: With constant scan parameters and a constant contrast medium amount, the CNR in both
coronary arteries decreases while the BMI increases. This implies a modification of
previously standardized and fixed examinations with respect to individually adapted
protocols with variable parameters for CT coronary angiography.
Key words
CT angiography - cardiac - body mass index
Literatur
1
Leschka S, Alkadhi H, Plass A. et al .
Accuracy of MSCT coronary angiography with 64-slice technology: first experience.
Eur Heart J.
2005;
26
1482-1487
2
Raff G L, Gallagher M J, O’Neill W W. et al .
Diagnostic accuracy of noninvasive coronary angiography using 64-slice spiral computed
tomography.
J Am Coll Cardiol.
2005;
46
552-557
3
Leber A W, Knez A, von Ziegler F. et al .
Quantification of obstructive and nonobstructive coronary lesions by 64-slice computed
tomography: a comparative study with quantitative coronary angiography and intravascular
ultrasound.
J Am Coll Cardiol.
2005;
46
147-154
4
Mollet N R, Cademartiri F, van Mieghem C A. et al .
High-resolution spiral computed tomography coronary angiography in patients referred
for diagnostic conventional coronary angiography.
Circulation.
2005;
112
2318-2323
5
Flohr T, Stierstorfer K, Raupach R. et al .
Performance evaluation of a 64-slice CT system with z-flying focal spot.
Fortschr Röntgenstr.
2004;
176
1803-1810
6
Stanford W, Burns T L, Thompson B H. et al .
Influence of body size and section level on calcium phantom measurements at coronary
artery calcium CT scanning.
Radiology.
2004;
230
198-205
7
Sevrukov A, Pratap A, Doss C. et al .
Electron beam tomography imaging of coronary calcium: the effect of body mass index
on radiologic noise.
J Comput Assist Tomogr.
2002;
26
592-597
8
Raggi P, Callister T Q, Cooil B.
Calcium scoring of the coronary artery by electron beam CT: how to apply an individual
attenuation threshold.
AJR Am J Roentgenol.
2002;
178
497-502
9
Becker C R, Hong C, Knez A. et al .
Optimal contrast application for cardiac 4-detector-row computed tomography.
Invest Radiol.
2003;
38
690-694
10
Bae K T, Heiken J P, Brink J A.
Aortic and hepatic contrast medium enhancement at CT. Part II. Effect of reduced cardiac
output in a porcine model.
Radiology.
1998;
207
657-662
11
Husmann L, Alkadhi H, Boehm T. et al .
Influence of cardiac hemodynamic parameters on coronary artery opacification with
64-slice computed tomography.
Eur Radiol.
2006;
16
1-6
12
Ann Intern Med.
1985;
103
977-1077
13
Poll L W, Cohnen M, Brachten S. et al .
Dose reduction in multi-slice CT of the heart by use of ECG-controlled tube current
modulation („ECG pulsing”): phantom measurements.
Fortschr Röntgenstr.
2002;
174
1500-1505
14
Flohr T, Ohnesorge B.
Heart rate adaptive optimization of spatial and temporal resolution for electrocardiogram-gated
multislice spiral CT of the heart.
J Comput Assist Tomogr.
2001;
25
907-923
15
Lembcke A, Wiese T H, Schnorr J. et al .
Image quality of noninvasive coronary angiography using multislice spiral computed
tomography and electron-beam computed tomography: intraindividual comparison in an
animal model.
Invest Radiol.
2004;
39
357-364
16
Achenbach S, Giesler T, Ropers D. et al .
Comparison of image quality in contrast-enhanced coronary-artery visualization by
electron beam tomography and retrospectively electrocardiogram-gated multislice spiral
computed tomography.
Invest Radiol.
2003;
38
119-128
17
Juergens K U, Grude M, Maintz D. et al .
Multi-detector row CT of left ventricular function with dedicated analysis software
versus MR imaging: initial experience.
Radiology.
2004;
230
403-410
18
Boehm T, Alkadhi H, Roffi M. et al .
Zeitbedarf, Untersucherabhängigkeit und Messgenauigkeit für die Bestimmung der linksventrikulären
Ejektionsfraktion mit der 4-Zeilen-Multidetektor-CT.
Fortschr Röntgenstr.
2004;
176
529-537
19
Juergens K U, Fischbach R.
Left ventricular function studied with MDCT.
Eur Radiol.
2005;
16
342-357
20
Mahnken A H, Gunther R W, Krombach G A.
Grundlagen der linksventrikulären Funktionsanalyse mittels MRT und MSCT.
Fortschr Röntgenstr.
2004;
176
1365-1379
21
Mulkens T H, Bellinck P, Baeyaert M. et al .
Use of an automatic exposure control mechanism for dose optimization in multi-detector
row CT examinations: clinical evaluation.
Radiology.
2005;
237
213-223
22
Vehmas T, Kivisaari L, Huuskonen M S. et al .
Scoring CT/HRCT findings among asbestos-exposed workers: effects of patient’s age,
body mass index and common laboratory test results.
Eur Radiol.
2005;
15
213-219
23
Huda W, Scalzetti E M, Levin G.
Technique factors and image quality as functions of patient weight at abdominal CT.
Radiology.
2000;
217
430-435
24
Kalender W A, Wolf H, Suess C. et al .
Dose reduction in CT by on-line tube current control: principles and validation on
phantoms and cadavers.
Eur Radiol.
1999;
9
323-328
25
Ende J F, Huda W, Ros P R. et al .
Image mottle in abdominal CT.
Invest Radiol.
1999;
34
282-286
26
Sigal-Cinqualbre A B, Hennequin R, Abada H T. et al .
Low-kilovoltage multi-detector row chest CT in adults: feasibility and effect on image
quality and iodine dose.
Radiology.
2004;
231
169-174
27
Cademartiri F, Mollet N R, van der Lugt A. et al .
Intravenous contrast material administration at helical 16-detector row CT coronary
angiography: effect of iodine concentration on vascular attenuation.
Radiology.
2005;
236
661-665
28
Cademartiri F, van der Lugt A, Luccichenti G. et al .
Parameters affecting bolus geometry in CTA: a review.
J Comput Assist Tomogr.
2002;
26
598-607
29
Cademartiri F, Nieman K, van der Lugt A. et al .
Intravenous contrast material administration at 16-detector row helical CT coronary
angiography: test bolus versus bolus-tracking technique.
Radiology.
2004;
233
817-823
30
Achenbach S, Giesler T, Ropers D. et al .
Detection of coronary artery stenoses by contrast-enhanced, retrospectively electrocardiographically-gated,
multislice spiral computed tomography.
Circulation.
2001;
103
2535-2538
31
Nieman K, Oudkerk M, Rensing B J. et al .
Coronary angiography with multi-slice computed tomography.
Lancet.
2001;
357
599-603
32
Mollet N R, Cademartiri F, Nieman K. et al .
Multislice spiral computed tomography coronary angiography in patients with stable
angina pectoris.
J Am Coll Cardiol.
2004;
43
2265-2270
33
Martuscelli E, Romagnoli A, D’Eliseo A. et al .
Accuracy of thin-slice computed tomography in the detection of coronary stenoses.
Eur Heart J.
2004;
25
1043-1048
34
Cademartiri F, Mollet N R, Runza G. et al .
Influence of intracoronary attenuation on coronary plaque measurements using multislice
computed tomography: observations in an ex vivo model of coronary computed tomography
angiography.
Eur Radiol.
2005;
15
1426-1431
Dr. Hatem Alkadhi
Departement für Medizinische Radiologie, Institut für Diagnostische Radiologie, Universitätsspital
Zürich
Rämistrasse 100
8091 Zürich
Phone: ++41/12 55/11 11
Fax: ++41/12 55/44 43
Email: hatem.alkadhi@usz.ch