Hidenari Matsumoto1, Satoshi Watanabe2, Eisho Kyo2, Takafumi Tsuji2, Yosuke Ando2, Yuka Otaki3, Sebastien Cadet3, Piotr J Slomka3, Daniel S Berman4, Damini Dey5, Balaji K Tamarappoo4. 1. Department of Imaging, Cedars-Sinai Medical Center, Los Angeles, CA, USA. Electronic address: Hidenari.Matsumoto@cshs.org. 2. Department of Cardiology, Kusatsu Heart Center, Kusatsu, Shiga, Japan. 3. Department of Imaging, Cedars-Sinai Medical Center, Los Angeles, CA, USA. 4. Department of Imaging, Cedars-Sinai Medical Center, Los Angeles, CA, USA; The Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA. 5. Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA.
Abstract
BACKGROUND: It has been shown that CT attenuation of noncalcified plaques depends on luminal contrast attenuation (LCA). Although tube potential (kilovolt [kV]) has been shown to exert influence on plaque attenuation through LCA as well as its direct effects, in-vivo studies have not investigated plaque attenuation at lower tube potentials less than 120 kV. We sought to evaluate the effect of kV and LCA on thresholds for lipid-rich and fibrous plaques as defined by intravascular ultrasound (IVUS). METHODS: CT attenuation of IVUS-defined plaque components (lipid-rich, fibrous, and calcified plaques) were quantified in 52 consecutive patients with unstable angina, who had coronary CT angiography performed at 100 kV (n = 25) or 120 kV (n = 27) using kV-adjusted contrast protocol prior to IVUS. CT attenuation of plaque components was compared between the two groups. RESULTS: LCA was similar in the 100-kV and 120-kV groups (417.6 ± 83.7 Hounsfield Units [HU] vs 421.3 ± 54.9 HU, p = 0.77). LCA correlated with CT attenuation of lipid-rich (r = 0.49, p = 0.001) and fibrous plaques (r = 0.32, p < 0.05), but not with that of calcified plaques (r = 0.04, p = 0.81). When plaque attenuation was normalized to LCA, lipid-rich (0.087 ± 0.036, range -0.012-0.147) and fibrous plaque attenuation (0.234 ± 0.056, range 0.153-0.394) were distinct (p < 0.001) with no overlap for both kV groups. CT attenuation was not significantly different between 100-kV and 120-kV groups for lipid-rich (34.0 ± 21.5 vs 39.3 ± 12.9, p = 0.33) or fibrous plaques (95.4 ± 19.1 vs 97.6 ± 22.0, p = 0.75). CONCLUSION: Plaque attenuation thresholds for non-calcified plaque components should be adjusted based on LCA. Further adjustment may not be required for different tube potentials.
BACKGROUND: It has been shown that CT attenuation of noncalcified plaques depends on luminal contrast attenuation (LCA). Although tube potential (kilovolt [kV]) has been shown to exert influence on plaque attenuation through LCA as well as its direct effects, in-vivo studies have not investigated plaque attenuation at lower tube potentials less than 120 kV. We sought to evaluate the effect of kV and LCA on thresholds for lipid-rich and fibrous plaques as defined by intravascular ultrasound (IVUS). METHODS: CT attenuation of IVUS-defined plaque components (lipid-rich, fibrous, and calcified plaques) were quantified in 52 consecutive patients with unstable angina, who had coronary CT angiography performed at 100 kV (n = 25) or 120 kV (n = 27) using kV-adjusted contrast protocol prior to IVUS. CT attenuation of plaque components was compared between the two groups. RESULTS:LCA was similar in the 100-kV and 120-kV groups (417.6 ± 83.7 Hounsfield Units [HU] vs 421.3 ± 54.9 HU, p = 0.77). LCA correlated with CT attenuation of lipid-rich (r = 0.49, p = 0.001) and fibrous plaques (r = 0.32, p < 0.05), but not with that of calcified plaques (r = 0.04, p = 0.81). When plaque attenuation was normalized to LCA, lipid-rich (0.087 ± 0.036, range -0.012-0.147) and fibrous plaque attenuation (0.234 ± 0.056, range 0.153-0.394) were distinct (p < 0.001) with no overlap for both kV groups. CT attenuation was not significantly different between 100-kV and 120-kV groups for lipid-rich (34.0 ± 21.5 vs 39.3 ± 12.9, p = 0.33) or fibrous plaques (95.4 ± 19.1 vs 97.6 ± 22.0, p = 0.75). CONCLUSION: Plaque attenuation thresholds for non-calcified plaque components should be adjusted based on LCA. Further adjustment may not be required for different tube potentials.
Authors: Michelle C Williams; Jacek Kwiecinski; Mhairi Doris; Priscilla McElhinney; Michelle S D'Souza; Sebastien Cadet; Philip D Adamson; Alastair J Moss; Shirjel Alam; Amanda Hunter; Anoop S V Shah; Nicholas L Mills; Tania Pawade; Chengjia Wang; Jonathan R Weir-McCall; Michael Bonnici-Mallia; Christopher Murrills; Giles Roditi; Edwin J R van Beek; Leslee J Shaw; Edward D Nicol; Daniel S Berman; Piotr J Slomka; David E Newby; Marc R Dweck; Damini Dey Journal: JACC Cardiovasc Imaging Date: 2021-04-14