Coronary Plaque Imaging With 256-Slice Multidetector Computed Tomography: Interobserver Variability of Volumetric Lesion Parameters with Semiautomatic Plaque Analysis Software

Int J Cardiovasc Imaging. 2010; 27(4):418-427

Klass O, Kleinhans S, Walker MJ, Olszewski M, Feuerlein S, Juchems M, Hoffmann MH

OBJECTIVES: The purpose of this study was to evaluate the potential clinical value of coronary plaque imaging with a new generation CT scanner and the interobserver variability of coronary plaque assessment with a new semiautomatic plaque analysis application.

METHODS: Thirty-five isolated plaques of the left anterior descending coronary artery from 35 patients were evaluated with a new semiautomatic plaque analysis application. All patients were scanned with a 256-slice MDCT scanner (Brilliance iCT, Philips Healthcare, Cleveland OH, USA). Two independent observers evaluated lesion volume, maximum plaque burden, lesion CT number mean and standard deviation, and relative lesion composition.

RESULTS: We found 10 noncalcified, 16 mixed, and 9 calcified lesions in our study cohort. Relative interobserver bias and variability for lesion volume were -37%, -13%, -49%, -44% and 28%, 16%, 37%, and 90% for all, noncalcified, mixed, and calcified lesions, respectively. Absolute interobserver bias and variability for relative lesion composition were 1.2%, 0.5%, 1.5%, 1.3% and 3.3%, 4.5%, 7.0%, and 4.4% for all, noncalcified, mixed, and calcified lesions, respectively.

CONCLUSIONS: While mixed and calcified lesions demonstrated a high degree of lesion volume interobserver variability, noncalcified lesions had a lower degree of lesion volume interobserver variability. In addition, relative noncalcified lesion composition had a very low interobserver variability. Therefore, there may a role for MDCT in serial noncalcified plaque assessment with semiautomatic analysis software.

PMID: 20339922

4 Responses

  1. Ronen Rubinshtein, MD  on March 28th, 2010

    The manuscript described the advantages, but also the limitations of a semi-automatic plaque analysis software. Evaluation of plaque volume (or “burden”) by CT is still challenging.

  2. Jacobo Kirsch, MD  on March 29th, 2010

    The purpose of this study was to evaluate the potential clinical value of coronary plaque imaging with a new generation CT scanner and the interobserver variability of semiautomatic coronary plaque assessment with a new software application. The study was done in a population of 35 patients that resulted in 35 different lesions for analysis.

    In this small cohort, a large interobserver bias and variability for all lesions was found for lesion volume, maximum plaque burden, and lesion mean HU; however, much smaller differences existed for relative lesion composition. Specifically, for all lesion parameters, larger interobserver bias and variability existed for calcified and mixed lesions when compared to non-calcified lesions. This leads me to ponder if we still need to learn how to deal with calcium ‘blooming’ artifact, either manually or (definitely) automatically. Are new algorithms that recognize a gradual or algorithmic change of pixels surrounding calcified plaque necessary to recognize this artifact?

    Nice study on a small group of lesions that may serve as added data to the topic of plaque composition analysis. However, very few lesions using not only a new method, but also a new technology, and with no gold-standard to compare the findings seems very premature as self-standing results to rely on.

  3. Paul Schoenhagen, MD  on March 30th, 2010

    Read the following article by Chopard et al, which is quite critical about the current role of CT for plaque imaging:

    - How reliable are 40 MHz IVUS and 64-slice MDCT in characterizing coronary plaque composition? An ex vivo study with histopathological comparison.
    Chopard R, Boussel L, Motreff P, Rioufol G, Tabib A, Douek P, Meyronet D, Revel D, Finet G.
    Int J Cardiovasc Imaging. 2010 Jan 6.
    PMID: 20052618

    Also a more systematic review:

    - Comparison of multislice computed tomography with intravascular ultrasound for detection and characterization of coronary artery plaques: a systematic review.
    Springer I, Dewey M.
    Eur J Radiol. 2009 Aug;71(2):275-82. Review.
    PMID: 18586427

  4. Paul Schoenhagen, MD  on April 1st, 2010

    Also check the recent publication about this topic with dual source technology:

    Quantification of non-calcified coronary atherosclerotic plaques with dual-source computed tomography: comparison with intravascular ultrasound.
    Tiziano Schepis, Mohamed Marwan, Tobias Pflederer, Martin Seltmann, Dieter Ropers, Werner G Daniel, Stephan Achenbach.
    Heart 2010;96 610-615
    PMID: 19933294


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