Influence of Slice Thickness and Reconstruction Kernel on the Computed Tomographic Attenuation of Coronary Atherosclerotic Plaque

J Cardiovasc Comput Tomogr. 2010; 4(2):110-115

Achenbach S, Boehmer K, Pflederer T, Ropers D, Seltmann M, Lell M, Anders K, Kuettner A, Uder M, Daniel WG, Marwan M

OBJECTIVE: The computed tomographic (CT) attenuation of coronary atherosclerotic plaque has been proposed as a marker for tissue characterization and may thus potentially contribute to the assessment of plaque instability.We analyzed the influence of reconstruction parameters on CT attenuation measured within noncalcified coronary atherosclerotic lesions.

METHODS: Seventy-two patients were studied by contrast-enhanced dual-source CT coronary angiography (330 millisecond rotation time, 2 x 64 x 0.6 mm collimation, 120 kV, 400 mAs, 80 mL contrast agent intravenously at 6 mL/s), and a total of 100 distinct noncalcified coronary atherosclerotic plaques were identified. Image data sets were reconstructed with a soft (B20f), medium soft (B26f), and sharp (B46f) reconstruction kernel. With the medium soft kernel, image data sets were reconstructed with a slice thickness/increment of 0.6/0.3 mm, 0.75/0.4 mm, and 1.0/0.5mm. Within each plaque, CT attenuation was measured.

RESULTS: Mean CT attenuation using the medium soft kernel was 109 +/- 58 HU (range, -16 to 168 HU). Using the soft kernel, mean density was 113 +/- 57 HU (range, -13 to 169 HU), and using a sharp kernel, mean density was 97 +/- 49 HU (range, -23 to 131 HU). Similarly, reconstructed slice thickness had a significant influence on the measured CT attenuation (mean values for medium soft kernel: 102 +/- 52 HU versus 109 +/- 58 HU versus 113 +/- 57 HU for 0.6-mm, 0.75-mm, and 1.0-mm slice thickness). The differences between 0.75-mm and 0.6-mm slice thickness (P = 0.05) and between medium sharp and sharp kernels (P = 0.02) were statistically significant.

CONCLUSIONS: Image reconstruction significantly influences CT attenuation of noncalcified coronary atherosclerotic plaque. With decreasing spatial resolution (softer kernel or thicker slices), CT attenuation increases significantly. Using absolute CT attenuation values for plaque characterization may therefore be problematic.

PMID: 20430341

One Response

  1. Paul Schoenhagen  on June 29th, 2010

    See the post from January 12, 2010:

    How Reliable are 40 MHz IVUS and 64-Slice MDCT in Characterizing Coronary Plaque Composition? An Ex Vivo Study with Histopathological Comparison.
    Romain Chopard, Loic Boussel, Pascal Motreff, Gilles Rioufol, Alain Tabib, Philippe Douek, David Meyronet, Didier Revel, Gérard Finet.
    Int J Cardiovasc Imaging. 2010 Apr;26(4):373-83.
    PMID: 20052618


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