Published online before print March 29, 2002, 10.1148/radiol.2232010919
(Radiology 2002;223:474-480.)
© RSNA, 2002
Coronary Artery Calcium: Absolute Quantification in Nonenhanced and Contrast-enhanced Multi–Detector Row CT Studies1
Cheng Hong, MD,
Christoph R. Becker, MD,
U. Joseph Schoepf, MD,
Bernd Ohnesorge, PhD,
Roland Bruening, MD and
Maximilian F. Reiser, MD
1 From the Department of Clinical Radiology, Klinikum Grosshadern, University of Munich, Marchioninistrasse 15, 81377 Munich, Germany (C.H., C.R.B., R.B., M.F.R.); Department of Radiology, Huazhong University of Science and Technology, Wuhan, People’s Republic of China (C.H.); and Siemens Medical Systems, Forchheim, Germany (B.O.). Received May 14, 2001; revision requested June 13; revision received August 27; accepted September 20. Address correspondence to C.R.B. (e-mail: christoph.becker@ikra.med.uni-muenchen.de).
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Figure 1. Transverse multi-detector row CT images of the phantom thorax and calibration insert obtained with (left) a 3-mm section width protocol and (right) a 1.25-mm section width protocol. At the same threshold of 130 HU, a fine spotty calcified cylinder (arrowhead) with the actual CaHA mass of 0.6 mg is visible but undetectable with the quantification software on the 3-mm section width image, whereas it is clearly revealed and measurable on the 1.25-mm section width image.
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Figure 3. Transverse CT scans at the level of the aortic root in a 57-year-old man with calcified coronary artery plaques. Spotty calcifications in the left main coronary artery (arrowheads, green area, left side of images) and long calcifications in the midsegment of the left anterior descending coronary artery (arrowheads, green area, right side of images) are clearly visible on both the 3-mm section width, nonenhanced, multi-detector row CT image (left) at a threshold of 130 HU and the 1.25-mm section width, multi-detector row CT angiography image (right) at a threshold of 350 HU.
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Figure 4. Regression plot shows the absolute CaHA mass in 50 patients determined at multi-detector row CT with a 3-mm section width protocol (x axis) and with a 1.25-mm section width protocol (y axis). Linear correlation was calculated with the following equation: calcium mass at CT angiography equals 0.2 plus 1.11 multiplied by calcium mass at traditional coronary screening (r = 0.977, P < .001). CS = coronary screening, CTA = CT angiography.
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Figure 5. Regression plot shows the linear correlation between scores and calcium mass values derived at the 3-mm section width imaging protocol. Linear correlation was calculated with the following equation: mass at traditional coronary screening equals 3.4 plus 0.19 multiplied by score at coronary screening (r = 0.942, P < .001). CS = coronary screening.
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Figure 6. Bland-Altman plot demonstrates a systematic error in the determination of absolute CaHA mass at the 1.25-mm section width CT angiography protocol compared with its determination at the traditional 3-mm section width imaging protocol (d = -6.7 mg). The agreement of the measurements of mass ranges from 45.0 mg to -58.5 mg. CS = coronary screening, CTA = CT angiography.
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Copyright © 2002 by the Radiological Society of North America.
, long-dashed line), 1.25-mm section width (
, solid line), and 0.6-mm section width (
, short-dashed line) imaging protocols. The attenuation threshold increases between 130 HU and 490 HU, especially in the 3-mm protocol. (Absolute mass = c/250 x area x section increment x mean attenuation value.)