Elsevier

Atherosclerosis

Volume 190, Issue 1, January 2007, Pages 174-180
Atherosclerosis

Characterization of non-calcified coronary atherosclerotic plaque by multi-detector row CT: Comparison to IVUS

https://doi.org/10.1016/j.atherosclerosis.2006.01.013Get rights and content

Abstract

Multi-detector row Computed Tomography (MDCT) permits non-invasive visualization of the coronary arteries. The ability to visualize and, with limitations, to characterize non-calcified coronary atherosclerotic plaque has been described. We investigated the CT attenuation of non-calcified plaques as determined by 16-slice MDCT in comparison to intravascular ultrasound (IVUS).

Methods and results

Thirty-two patients were investigated by contrast-enhanced 16-slice CT. In addition, IVUS of one coronary artery (motorized pullback) was performed (LM+LAD: 22, LM+LCX: 4, RCA: 6). At 252 sites within the coronary system, in which non-calcified atherosclerotic plaque could be identified both in MDCT and IVUS, the CT attenuation within the plaque was measured using a centrally placed region of interest and correlated to the appearance of the plaque in IVUS at the corresponding location. The mean CT attenuation within plaque that corresponded to hyper-echogenic appearance in IVUS was 121 ± 34 HU (n = 76). The mean CT attenuation within plaque that corresponded to hypo-echogenic appearance was 58 ± 43 HU (n = 176, p < 0.001). However, there was substantial overlap of the density values measured by MDCT in the two groups.

Conclusions

A significant difference of the mean CT attenuation within atherosclerotic lesions of hypo-echogenic and hyper-echogenic appearance in IVUS could be observed. However, we observed substantial overlap of attenuation values between plaque types so that the differentiation of “vulnerable” and “stable” plaques based on their CT attenuation is doubtful.

Section snippets

Methods

Thirty-two patients (9 female, 23 male, mean age: 59 years) were studied (see Table 1). In all patients, MDCT had been performed as part of research protocols which enrolled consecutive subjects scheduled for invasive coronary angiography for clinical reasons. In all patients, significant coronary artery stenoses (diameter reduction >50%) were ruled out angiographically and an IVUS study of one coronary vessel was performed. Patients with arrhythmias, contraindications to iodinated contrast

Results

Two hundred and fifty-two sites within the coronary system that contained non-calcified atherosclerotic plaque could be identified in MDCT without artifacts caused by motion or extensive calcification and cross-correlated to IVUS. Table 2 lists the distribution of lesions throughout the coronary system. IVUS classified 176 cross-sections as predominantly hypo-echogenic and 76 lesions as predominantly hyper-echogenic. The mean CT density measured within lesions that had a hypo-echogenic

Discussion

We determined the CT attenuation within non-calcified coronary atherosclerotic plaques by contrast-enhanced 16-slice MDCT. By comparison to intrasvascular ultrasound, we could confirm earlier observations that plaque type has an influence on the CT density measured within the plaque: the mean CT density measured within 176 plaques that, by IVUS, were classified as “hypo-echogenic” and thus “soft” or “lipid-rich” was significantly lower than in 76 plaques that IVUS classified as

Conflict of interest disclosures

Stephan Achenbach has received research support from Siemens Medical Solutions.

Acknowledgments

Stephan Achenbach was supported in part by Deutsche Forschungsgemeinschaft. Dr. Maros Ferencik was supported in part by NIH grant 1 T32 HL076136-02.

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